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A chemical placebo: NaCl as an effective, cheapest, non-acidic and greener catalyst for Biginelli-type 3,4-dihydropyrimidin-2(1H)-ones (-thiones) synthesis

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Abstract

Despite prior reports of several really effective catalytic and non-catalytic approaches towards Biginelli’s 3,4-dihydropyrimidin-2(1H)-ones, an overwhelming number of new catalysts for the Biginelli reaction have been recently published. Most of the catalysts are somewhat exotic, expensive, harmful and even uneffective in the absence of acidic additives. Herein we reduce the “yet-another-one-catalyst” idea to absurdity by proposing NaCl promotes the reaction that actually requires no catalyst, neither rare nor expensive.

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References

  1. Biginelli P (1891) Ueber Aldehyduramide des Acetessigäthers. Ber Deutsch Chem Ges 24: 1317–1319

    Article  Google Scholar 

  2. Biginelli P (1893) Derivati aldeidureidici degli eteri acetil- ed ossal-acetico. Gazz Chim Ital 23: 360–416

    Google Scholar 

  3. Biginelli P (1891) Ueber Aldehyduramide des Acetessigäthers. II. Ber Deutsch Chem Ges 24: 2962–2967

    Article  Google Scholar 

  4. Biginelli P (1893) Aldehydureidderivate des Acet- und Oxalessigäthers. Ber Deutsch Chem Ges 26: 447–450

    Article  Google Scholar 

  5. Kappe CO (1993) 100 Years of the Biginelli dihydropyrimidine synthesis. Tetrahedron 49: 6937–6963

    Article  CAS  Google Scholar 

  6. Kappe CO (1998) 4-Aryldihydropyrimidines via the Biginelli condensation: aza-analogs of Nifedipine-type calcium channel modulators. Molecules 3:1–9; Available: http://www.mdpi.org/molecules/

  7. Dallinger D, Stadler A, Kappe CO (2004) Solid- and solution-phase synthesis of bioactive dihydropyrimidines. Pure Appl Chem 76: 1017–1024

    Article  CAS  Google Scholar 

  8. Kappe CO (2000) Recent advances in the Biginelli dihydropyrimidine synthesis. New tricks from an old dog. Acc Chem Res 33: 879–888

    Article  PubMed  CAS  Google Scholar 

  9. Simon C, Constantieux T, Rodriguez J (2004) Utilisation of 1,3-Dicarbonyl derivatives in multicomponent reactions. Eur J Org Chem 2004: 4957–4980

    Article  CAS  Google Scholar 

  10. Kappe CO (2003) The generation of dihydropyrimidine libraries utilizing Biginelli multicomponent chemistry. QSAR Comb Sci 22: 630–645

    Article  CAS  Google Scholar 

  11. Zaugg HE, Martin WB (1965) Alpha-Amidoalkylations at carbon. In: Cope AC (eds) Organic reactions. John Wiley & Sons, Inc., New York, p 88

    Google Scholar 

  12. Kappe CO, Stadler A (2004) The Biginelli dihydropyrimidine synthesis. In: Overman LE (eds) Organic reactions, vol 63. John Wiley & Sons, Inc., New York, pp 1–116

    Google Scholar 

  13. Kappe CO (2005) The Biginelli reaction. In: Zhu J, Bienaymé H (eds) Multicomponent reactions. John Wiley & Sons, Inc., New York, pp 95–120

    Chapter  Google Scholar 

  14. Gong LZ, Chen XH, Xu XY (2007) Asymmetric organocatalytic Biginelli reactions: a new approach to quickly access optically active 3,4-dihydropyrimidin-2-(1H)-ones. Chem Eur J 13: 8920–8926

    Article  CAS  Google Scholar 

  15. Atwal modification: O’Reilly BC, Atwal KS (1987) Synthesis of substituted 1,2,3,4-Tetrahydro-6-methyl-2-oxo-5-pyrimidinecarbo-xylic acid esters: the Biginelli condensation revisited. Heterocycles 26:1185–1188

    Google Scholar 

  16. Atwal modification: Atwal KS, O’Reilly BC, Gougoutas JZ, Malley MF (1987) Synthesis of substituted 1,2,3,4-Tetrahydro-6-methyl-2-thioxo-5-pyrimidinecarboxylic acid esters. Heterocycles 26:1189–1192

    Google Scholar 

  17. N-(tosylmethyl)thioureas instead of thiourea + aldehyde: Shutalev AD, Kuksa VA (1997) Utilization of the Amidoalkylation reaction in the synthesis Of hydrogenated Pyrimidine-2- Thiones. Chem Heterocycl Comp 33:91–95

    Google Scholar 

  18. Acetophenones as CH-acids: Sedova VF, Shkurko OP (2004) Two directions of the reaction Of 4-Bromobenzaldehyde with substituted acetophenones And urea. Synthesis of Aryl- substituted Pyrimidin-2-one and Hexahydropyrimido[4,5-d]Pyrimidin-2,7-Dione. Chem Heterocycl Comp 40:194–202

    Google Scholar 

  19. With fluorinated ketoesters or 1,3-diketones: Burgart YaV, Kuzueva OG, Pryadeina MV, Kappe CO, Saloutin VI (2001) Fluorocontaining 1,3-Dicarbonyl compounds in the synthesis of pyrimidine derivatives. Russ J Org Chem 37:869–880

    Google Scholar 

  20. Dzvinchuk IB, Makitruk TV, Lozinskii MO (2002) 2-Phenacylbenzothiazole in the Biginelli reaction. Chem Heterocycl Comp 38: 1000–1007

    Article  CAS  Google Scholar 

  21. Dzvinchuk IB, Makitruk TV, Lozinskii MO (2003) 2-Acylmethyl-1H-benzimidazoles in the Biginelli reaction. Chem Heterocycl Comp 39: 455–460

    Article  CAS  Google Scholar 

  22. Amidines instead of urea: Nilsson BL, Overman LE (2006) Concise synthesis of guanidine-containing heterocycles using the Biginelli reaction. J Org Chem 71:7706–7714

    Google Scholar 

  23. Alcohols instead of aldehydes, using the tandem oxidation-cyclocondensation reaction promoted by Bi(NO3)35H2O: Khosropour AR, Khodaei MM, Beygzadeh M, Jokar M (2005) A one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones from primary alcohols promoted by Bi(NO3)35H2O in two different media: organic solvent & ionic liquid. Heterocycles 65:767–773

    Google Scholar 

  24. Formylphenylboronic acid as reagent/catalyst: Blacquiere JM, Sicora O, Vogels CM, Čuperlović-Culf M, Decken A, Ouellette RJ, Westcott SA (2005) Dihydropyrimidinones containing boronic acids. Can J Chem 83:2052–2059

    Google Scholar 

  25. Aliphatic aldehydes as CH-acids: Bailey CD, Houlden CE, Bar GLJ, Lloyd-Jones GC, Booker-Milburn KI (2007) A chemo- and regioselective three-component dihydropyrimidinone synthesis. Chem Commun 28:2932–2934

    Google Scholar 

  26. Solid-phase approach with resin-bound acetoacetate: Valverde MG, Dallinger D, Kappe CO (2001) Solid-phase synthesis of dihydropyrimidones via N-Acyliminium ion-based α -Ureidoalkylations. Synlett 2001:741–744

  27. Kappe CO (2000) Highly versatile solid phase synthesis of biofunctional 4-Aryl-3,4-dihydropyrimidines using resin-bound isothiourea building blocks and multidirectional resin cleavage. Bioorg Med Chem Lett 10: 49–51

    Article  PubMed  CAS  Google Scholar 

  28. Khosropour AR, Khodaei MM, Beygzadeh M (2007) Highly convenient one-pot conversion of aryl acylals or aryl aldehyde bisulfites into dihydropyrimidones using Bi(NO3)35H2O. Heteroatom Chem 18: 684–687

    Article  CAS  Google Scholar 

  29. Abdel-Fattah AAA (2003) Expedient synthesis of Biginelli-type dihydropyrimidinones using α -(Benzotriazolyl)alkyl urea derivatives. Synthesis 2003: 2358–2362

    Article  CAS  Google Scholar 

  30. Multistep polymer assisted synthesis: Vanden Eynde JJ, Watté O (2003) Insoluble versus soluble polymer-assisted synthesis. A first approach for the preparation of a Biginelli compound. ARKIVOC iv:93–101; Available, http://www.arkat-usa.org

  31. Khodaei MM, Khosropour AR, Jowkar M (2005) Bi(NO3)35H2O— TBAF as an efficient reagent for in situ oxidation: dihydropyrimidinone formation from benzyl halides. Synthesis 2005: 1301–1304

    Article  CAS  Google Scholar 

  32. Legeay JC, Vanden Eynde JJ, Toupet L, Bazureau JP (2007) A three-component condensation protocol based on ionic liquid phase bound acetoacetate for the synthesis of Biginelli 3, 4-dihydropyrimidine-2(1H)-ones. ARKIVOC 2007 iii:13–28; Available, http://www.arkat-usa.org

  33. Using sugars and mercaptoacetylating agent 2-methyl-2-phenyl-1,3-oxathiolan-5-one as aldehyde/active methylene components to build thiosugar-annulated DHPMs: Yadav LDS, Awasthi C, Rai VK, Rai A (2007) Biorenewable and mercaptoacetylating building blocks in the Biginelli reaction: synthesis of thiosugar-annulated dihydropyrimidines. Tetrahedron Lett 48:4899–4902

    Google Scholar 

  34. Using Wang resin-bound urea: Wipf P, Cunningham A (1995) A solid phase protocol Of the Biginelli dihydropyrimidine synthesis suitable for combinatorial chemistry. Tetrahedron Lett 36:7819–7822

    Google Scholar 

  35. Resin-bound urea: Lusch MJ, Tallarico JA (2004) Demonstration of the feasibility of a direct solid-phase split-pool Biginelli synthesis of 3,4-dihydropyrimidinones. Org Lett 6:3237–3240

    Google Scholar 

  36. Cyanamide as amidine precursor instead of urea: Hulme R, Zamora ODP, Mota EJ, Pastén MA, Contreras-Rojas R, Miranda R, Valencia-Hernández I, Correa-Basurto J, Trujillo-Ferrara J, Delgado F (2008) Cyanamide: a convenient building block to synthesize 4-aryl-2-cyanoimino-3,4-dihydro-1H-pyrimidine systems via a multicomponent reaction. Tetrahedron 64: 3372–3380

    Google Scholar 

  37. IL phase-linked aldehyde: Legeay JC, Vanden Eynde JJ, Bazureau JP (2005) Ionic liquid phase technology supported the three component synthesis of Hantzsch 1,4-dihydropyridines and Biginelli 3,4-dihydropyrimidin-2(1H)-ones under microwave dielectric heating. Tetrahedron 61:12386–12397

    Google Scholar 

  38. Ashok M, Holla BS, Kumari NS (2007) Convenient one pot synthesis of some novel derivatives of thiazolo[2,3-b]dihydropyrimidinone possessing 4-methylthiophenyl moiety and evaluation of their antibacterial and antifungal activities. Eur J Med Chem 42: 380–385

    Article  PubMed  CAS  Google Scholar 

  39. Hurst EW, Hull R (1961) Two new synthetic substances active against viruses of the psittacosis-lymphogranulomatrachoma group. J Med Pharm Chem 3: 215–229

    Article  PubMed  CAS  Google Scholar 

  40. Bahekar SS, Shinde DB (2004) Synthesis and anti-inflammatory activity of some [4,6-(4-substituted aryl)-2-thioxo-1,2,3,4-tetrahydro- pyrimidin-5-yl]-acetic acid derivatives. Bioorg Med Chem Lett 14: 1733–1736

    Article  PubMed  CAS  Google Scholar 

  41. Magerramov AM, Kurbanova MM, Abdinbekova RT, Rzaeva IA, Farzaliev VM, Allakhverdiev MA (2006) Synthesis and antioxidative properties of some 3,4-dihydropyrimidin-2(1H)-ones (-thiones). Russ J Appl Chem 79: 787–790

    Article  CAS  Google Scholar 

  42. The biological profile of DHPMs have been reviewed: Kappe CO (2000) Biologically active dihydropyrimidones of the Biginelli-type—a literature survey. Eur J Med Chem 35: 1043–1052

    Google Scholar 

  43. Grover GJ, Dzwonczyk S, McMullen DM, Normadinam CS, Sleph PG, Moreland S (1995) Pharmacologic profile of the dihydropyrimidine calcium channel blockers SQ 32,547 and SQ 32,926 [correction of SQ 32,946]. J Cardiovasc Pharmacol 26: 289–294

    Article  PubMed  CAS  Google Scholar 

  44. Atwal KS, Swanson BN, Unger SE, Floyd DM, Moreland S, Hedberg A, O’Reilly BC (1991) Dihydropyrimidine calcium channel blockers. 3. 3-Carbamoyl-4-aryl-1,2,3,4-tetrahydro-6-methyl-5-pyrimidinecarboxylic acid esters as orally effective antihypertensive agents. J Med Chem 34: 806–811

    Article  PubMed  CAS  Google Scholar 

  45. Rovnyak GC, Atwal KS, Hedberg A, Kimball SD, Moreland S, Gougoutas JZ, O’Reilly BC, Schwartz J, Malley MF (1992) Dihydropyrimidine calcium channel blockers. 4. Basic 3-Substituted-4-aryl-1,4-dihydropyrimidine-5-carboxylic acid esters. Potent antihypertensive agents. J Med Chem 35: 3254–3263

    Article  PubMed  CAS  Google Scholar 

  46. Atwal KS, Rovnyak GC, Kimball SD, Floyd DM, Moreland S, Swanson BN, Gougoutas JZ, Schwartz J, Smillie KM, Malley MF (1990) Dihydropyrimidine calcium channel blockers. 2. 3-Substituted-4-aryl-1,4-dihydro-6-methyl-5-pyrimidinecarboxylic acid esters as potent mimics of dihydropyridines. J Med Chem 33: 2629–2635

    Article  PubMed  CAS  Google Scholar 

  47. Atwal KS, Rovnyak GC, Schwatz J, Moreland S, Hedberg A, Gougoutas JZ, Malley MF, Floyd DF (1990) Dihydropyrimidine calcium channel blockers: 2-Heterosubstituted 4-Aryl-1,4-dihydro-6-methyl-5-pyrimidinecarboxylic acid esters as potent mimics of dihydropyridines. J Med Chem 33: 1510–1515

    Article  PubMed  CAS  Google Scholar 

  48. Baldwin JJ, Pitzenberger SM, McClure DE (1988) Substituted pyrimidines useful as calcium channel blockers. US Pat. 4675321; Available, http://patft.uspto.gov/netahtml/PTO/srchnum.htm

  49. Ertan M, Balkan A, Saraç S, Uma S, Renaud JF, Rollad Y (1991) Synthesis and calcium antagonistic activity of some new 2-Thioxo-1,2,3,4-tetrahydropyrimidine derivatives. Arch Pharm 324: 135–139

    Article  CAS  Google Scholar 

  50. Kastron VV, Vitolin RO, Khanina EL, Dubur GY, Kimenis AA, Kondratenko NV, Popov VI, Yagupolsky LM, Kolomeitsev AA (1988) 2-Oxo-4-(2′-difluoromethylthiophenyl)-5-methoxycarbonyl-6- methyl-1,2,3,4-tetrahydropyrimidine. US Pat. 4738965; Available, http://patft.uspto.gov/netahtml/PTO/srchnum.htm

  51. Rovnyak GC, Kimball SD, Beyer B, Cucinotta G, DiMarco JD, Gougoutas J, Hedberg A, Malley M, McCarthy JP, Zhang R, Moreland S (1995) Calcium entry blockers and activators: conformational and structural determinants of dihydropyrimidine calcium channel modulators. J Med Chem 38: 119–129

    Article  PubMed  CAS  Google Scholar 

  52. Sujatha K, Shanmugam P, Perumal PT, Muralidharan D, Rajendran M (2006) Synthesis and cardiac effects of 3,4-dihydropyrimidin-2(1H)-one-5-carboxylates. Bioorg Med Chem Lett 16: 4893–4897

    Article  PubMed  CAS  Google Scholar 

  53. Yarim M, Sarac S, Kilic FS, Erol K (2003) Synthesis and in vitro calcium antagonist activity of 4-aryl-7,7-dimethyl-1,7,7-trimethyl-1,2,3,4,5,6,7,8- octahydroquinazoline-2,5-dione derivatives. Il Farmaco 58: 17–24

    Article  PubMed  CAS  Google Scholar 

  54. Saraç S, Ciftçi M, Zorkun IS, Tunç O, Erol K (2007) Studies on the synthesis and biological activitiy of 6-ethyl-4- aryl-5-methoxycarbonyl-3,4-dihydropyrimidin-2(1H)-ones. Arzneim-Forsch/Drug Res 57: 137–142

    Google Scholar 

  55. Kato T, Chiba T, Abe Y (1984) Production of 5-Carbamoyl-6-methyl-4-substituted-1,2,3,4-Tetrahydro-2-Thioxopyrimidine. Jpn Pat. 59190974; Available, URL:http://ep.espacenet.com/

  56. Fewell SW, Smith CM, Lyon MA, Dumitrescu TP, Wipf P, Day BW, Brodsky JL (2004) Small molecule modulators of endogenous and co-chaperone-stimulated Hsp70 ATPase activity. J Biol Chem 279: 51131–51140

    Article  PubMed  CAS  Google Scholar 

  57. Rodina A, Vilenchik M, Moulick K, Aguirre J, Kim J, Chiang A, Litz J, Clement CC, Kang Y, She Y, Wu N, Felts S, Wipf P, Massague J, Jiang X, Brodsky JL, Krystal GW, Chiosis G (2007) Selective compounds define Hsp90 as a major inhibitor of apoptosis in small-cell lung cancer. Nat Chem Biol 3: 498–507

    Article  PubMed  CAS  Google Scholar 

  58. Evans CG, Wisen S, Gestwicki JE (2006) Heat shock proteins 70 and 90 inhibit early stages of amyloid β-(1–42) aggregation in Vitro. J Biol Chem 281: 33182–33191

    Article  PubMed  CAS  Google Scholar 

  59. Wisen S, Androsavich J, Evans CG, Chang L, Gestwicki JE (2008) Chemical modulators of heat shock protein 70 (Hsp70) by sequential, microwave-accelerated reactions on solid phase. Bioorg Med Chem Lett 18: 60–65

    Article  PubMed  CAS  Google Scholar 

  60. Mayer TU, Kapoor TM, Haggarty SJ, King RW, Schreiber SL, Mitchison TJ (1999) Small molecule inhibitor of mitotic spindle bipolarity identified in a phenotype-based screen. Science 286: 971–974

    Article  PubMed  CAS  Google Scholar 

  61. Kapoor TM, Mayer TU, Coughlin ML, Mitchison TJ (2000) Probing spindle assembly mechanisms with monastrol, a small molecule inhibitor of the mitotic kinesin, Eg5. J Cell Biol 150: 975–988

    Article  PubMed  CAS  Google Scholar 

  62. Nagarathnam D, Miao SW, Lagu B, Chiu G, Fang J, Murali DTG, Zhang J, Tyagarajan S, Marzabadi MR, Zhang F, Wong WC, Sun W, Tian D, Wetzel JM, Forray C, Chang RSL, Broten TP, Ransom RW, Schorn TW, Chen TB, O’Malley S, Kling P, Schneck K, Bendesky R, Harrel CM, Vyas KP, Gluchowski C (1999) Design and synthesis of novel α 1a adrenoceptor-selective antagonists. 1. Structure-activity relationship in dihydropyrimidinones. J Med Chem 42: 4764–4777

    Article  PubMed  CAS  Google Scholar 

  63. Dhar TGM, Nagarathnam D, Marzabadi MR, Lagu B, Wong WC, Chiu G, Tyagarajan S, Miao SW, Zhang F, Sun W, Tian D, Shen Q, Zhang J, Wetzel JM, Forray C, Chang RSL, Broten TP, Schorn T, Chen TB, O’Malley S, Ransom R, Schneck K, Bendesky R, Harrel CM, Vyas KP, Zhang K, Gilbert J, Pettibone DJ, Patane MA, Bock MG, Freidinger RM, Gluchowski C (1999) Design and synthesis of novel α 1a adrenoceptor-selective antagonists. 2. Approaches to eliminate opioid agonist metabolites via modification of linker and 4-Methoxycarbonyl- 4-phenylpiperidine moiety. J Med Chem 42: 4778–4793

    Article  CAS  Google Scholar 

  64. Lagu B, Tian D, Nagarathnam D, Marzabadi MR, Wong WC, Miao SW, Zhang F, Sun W, Chiu G, Fang J, Forray C, Chang RSL, Ransom RW, Chen TB, O’Malley S, Zhang K, Vyas KP, Gluchowski C (1999) Design and synthesis of novel α 1a adrenoceptor-selective antagonists. 3. Approaches to eliminate opioid agonist metabolites by using Substituted phenylpiperazine side chains. J Med Chem 42: 4794–4803

    Article  PubMed  CAS  Google Scholar 

  65. Barrow JC, Nantermet PG, Selnick HG, Glass KL, Rittle KE, Gilbert KF, Steele TG, Homnick CF, Freidinger RM, Ransom RW, Kling P, Reiss D, Broten TP, Schorn TW, Chang RSL, O’Malley SS, Olah TV, Ellis JD, Barrish A, Kassahun K, Leppert P, Nagarathnam D, Forray C (2000) In vitro and in vivo evaluation of dihydropyrimidinone C-5 amides as potent and selective α 1a receptor antagonists for the treatment of benign prostatic hyperplasia. J Med Chem 43: 2703–2718

    Article  PubMed  CAS  Google Scholar 

  66. Heys L, Moore CG, Murphy PJ (2000) The guanidine metabolites of Ptilocaulis spiculifer and related compounds; isolation and synthesis. Chem Soc Rev 29: 57–67

    Article  CAS  Google Scholar 

  67. Patil AD, Kumar NV, Kokke WC, Bean MF, Freyer AJ, De Brosse C, Mai S, Truneh A, Faulkner DJ, Carte B, Breen AL, Hertzberg RP, Johnson RK, Westley JW, Potts BCM (1995) Novel alkaloids from the sponge Batzella sp.: inhibitors of HIV gp120-Human CD4 binding. J Org Chem 60: 1182–1188

    Article  CAS  Google Scholar 

  68. Patil AD, Freyer AJ, Taylor PB, Carte B, Zuber G, Johnson RK, Faulkner DJ (1997) Batzelladines F-I, novel alkaloids from the sponge Batzella sp.: inducers of p56lck-CD4 dissociation. J Org Chem 62: 1814–1819

    Article  CAS  Google Scholar 

  69. Franklin AS, Ly SK, Mackin GH, Overman LE, Shaka AJ (1999) Application of the tethered Biginelli reaction for Enantioselective synthesis of batzelladine alkaloids. Absolute configuration of the tricyclic guanidine portion of batzelladine B. J Org Chem 64: 1512–1519

    Article  PubMed  CAS  Google Scholar 

  70. McDonald AI, Overman LE (1999) Tuning stereoselection in tethered Biginelli condensations. Synthesis of cis- or trans-1- Oxo- and 1-Iminohexahydropyrrolo[1,2-c]pyrimidines. J Org Chem 64: 1520–1528

    Article  PubMed  CAS  Google Scholar 

  71. Cohen F, Overman LE, Ly Sakata SK (1999) Asymmetric total synthesis of batzelladine D. Org Lett 1: 2169–2171

    Article  PubMed  CAS  Google Scholar 

  72. Overman LE, Rabinowitz MH, Renhowe PA (1995) Enantioselective total synthesis of (-)-ptilomycalin A. J Am Chem Soc 117: 2657–2658

    Article  CAS  Google Scholar 

  73. Coffey DS, McDonald AI, Overman LE, Stappenbeck F (1999) Enantioselective total synthesis of 13,14,15-Isocrambescidin 800. J Am Chem Soc 121: 6944–6945

    Article  CAS  Google Scholar 

  74. Coffey DS, Overman LE, Stappenbeck F (2000) Enantioselective total syntheses of 13,14,15-Isocrambescidin 800 and 13,14,15-Isocrambescidin 657. J Am Chem Soc 122: 4904–4914

    Article  CAS  Google Scholar 

  75. Coffey DS, McDonald AI, Overman LE, Rabinowitz MH, Renhowe PA (2000) A practical entry to the crambescidin family of guanidine alkaloids. Enantioselective total syntheses of ptilomycalin A, crambescidin 657 and its methyl ester (Neofolitispates 2, and Crambescidin 800). J Am Chem Soc 122: 4893–4903

    Article  CAS  Google Scholar 

  76. For alternative approach see: Elliott MC, Long MS (2004) Studies towards the total synthesis of batzelladine A. Org Biomol Chem 2:2003–2011

    Google Scholar 

  77. Overman LE, Rabinowitz MH (1993) Studies toward the total synthesis of (+)-ptilomycalin A. Use of a tethered Biginelli condensation for the preparation of an advanced tricyclic intermediate. J Org Chem 58: 3235–3237

    Article  CAS  Google Scholar 

  78. Overman LE, Wolfe JP (2001) Synthesis of polycyclic guanidines by cyclocondensation reactions of N-Amidinyliminium ions. J Org Chem 66: 3167–3175

    Article  PubMed  CAS  Google Scholar 

  79. For review on the application of tethered Biginelli reaction towards the total synthesis of guanidine alkaloids, see: Aron ZA, Overman LE (2004) The tethered Biginelli condensation in natural product synthesis. Chem Commun 2004:253–265

  80. HCl/EtOH: Kappe CO, Roschger P (1989) Synthesis and reactions of “Biginelli compounds”. Part 1. J Heterocycl Chem 25:55–64

    Google Scholar 

  81. HCl/EtOH: Mobinikhaledi A, Foroughifar N, Ghorbani AR (2005) Synthesis of some Thioxopyrimidines, Thiazolopyrimidines, Thiazolodi-pyrimidines and Pyrazolothiazolopyrimidines. Phosphorus Sulfur Silicon 180:1713–1719

    Google Scholar 

  82. HCl/EtOH:Akbari JD, Kachhadia PK, Tala SD, Bapodra AH, Dhaduk MF, Joshi HS, Mehta KB, Pathak SJ (2008) Synthesis of some new 1,2,3,4-tetrahydropyrimidine-2-thiones and their thiazolo[3,2-a]pyrimidine derivatives as potential biological agents. Phosphorus Sulfur Silicon Relat Elem 183:1911–1922

    Google Scholar 

  83. HCl/EtOH: Saloutin VI, Burgart YV, Kuzueva OG, Kappe CO, Chupakhin ON (2000) Biginelli condensations of fluorinated 3-oxo esters and 1,3-diketones. J Fluor Chem 103:17–23

    Google Scholar 

  84. Zn(ClO4)2 × 6H2O/80°C: Subhas Bose D, Idrees M (2007) An efficient and high yielding protocol for the synthesis of substituted dihydropyrimidin-2(1H)-ones and spiro-fused heterocycles by involving tandem reactions. J Heterocycl Chem 44:211–214

    Google Scholar 

  85. TsOH: Azizian J, Mohammadi AA, Kohshari M, Karimi AR, Mohammadizadeh MR (2007) Biginelli-like three component reaction: synthesis of some new ethyl 6-ethoxycarbonylmethyl-4-aryl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate derivatives. J Heterocycl Chem 44:455–458

    Google Scholar 

  86. TsOH: Jin T, Zhang S, Li T (2002) p-Toluenesulfonic acid-catalyzed efficient synthesis Of dihydropyrimidines: improved high yielding protocol for the Biginelli reaction. Synth Commun 32:1847–1851

    Google Scholar 

  87. VCl3/MeCN: Rajanarendar E, Ramesh P, Mohan G, Kalyan Rao E (2007) An efficient and modified Biginelli one-pot synthesis of new isoxazole substitted 3,4-dihydropyrimidin-2(1H)-ones and thiones catalyzed by VCl3. J Heterocycl Chem 44:483–486

    Google Scholar 

  88. VCl3: Sabitha G, Reddy GSKK, Reddy KB, Yadav JS (2003) Vanadium(III) chloride catalyzed Biginelli condensation: solution phase library generation of dihydropyrimidin-(2H)-ones. Tetrahedron Lett 44:6497–6499

  89. TEBA/sf: Mobinikhaledi A, Forughifar N, Safari JA, Amini E (2007) Synthesis of some 2-oxo and 2-thioxo substituted pyrimidines using solvent-free conditions. J Heterocycl Chem 44:697–699

    Google Scholar 

  90. HClO4/sf/MWI: Mukhopadhyay C, Datta A, Banik BK (2007) Microwave-induced perchloric acid catalyzed novel solvent-free synthesis of 4-Aryl-3,4-dihydropyrimidones via Biginelli condensation. J Heterocycl Chem 44:979–981

    Google Scholar 

  91. PPE/THF: Falsone FS, Kappe CO (2001) The Biginelli dihydropyrimidone synthesis using polyphosphate ester as a mild and efficient cyclocondensation/dehydration reagent. ARKIVOC ii: 122–134; Available, URL:http://www.arkat-usa.org

  92. PPE/THF: Schnell B, Krenn W, Faber K, Kappe CO (2000) Synthesis and reactions of Biginelli-compounds. Part 23. Chemoenzymatic syntheses of enantiomerically pure 4-aryl-3,4-dihydropyrimidin-2(1H)-ones. J Chem Soc Perkin Trans 1: 4382–4389

    Google Scholar 

  93. PPE/THF: Kappe CO, Falsone SF (1998) Polyphosphate ester-mediated synthesis of dihydropyrimidines. Improved conditions for the Biginelli reaction. Synlett 1998:718–720

  94. Schmidt RJ, Lombardo LJ, Traeger SC, Williams DK (2008) One-pot two step synthesis of 5-cyano-dihydropyrimidinones using polyphosphate ester. Tetrahedron Lett 49: 3009–3010

    Article  CAS  Google Scholar 

  95. TAFF/neat/IR light: Osnaya R, Arroyo GA, Parada L, Delgado F, Trujillo J, Salmón M, Miranda R (2003) Biginelli vs Hantzsch esters study under infrared radiation and solventless conditions. ARKIVOC xi:112–117; Available, URL:http://www.arkat-usa.org

  96. MgSO4/sf/rt: Pore DM, Desai UV, Thopate TS, Wadgaonkar PP (2007) Anhydrous magnesium sulfate mediated solvent-free synthesis of dihydropyrimidin-2(1H)-ones at ambient temperature. Austral J Chem 60:435–438

    Google Scholar 

  97. Envirocat EPZ10 (clay-supported ZnCl2)/PhMe: Lee K-Y, Ko K-Y (2004) Envirocat EPZ10: a recyclable solid acid catalyst for the synthesis of Biginelli-type 3,4-dihydropyrimidin-2(1H)-ones. Bull Korean Chem Soc 25:1929–1931

    Google Scholar 

  98. SrCl26H2O–HCl/sf: Nasr-Esfahani M, Khosropour AR (2005) An efficient and clean one-pot synthesis of 3,4-dihydropyrimidine-2-(1H)-ones catalyzed by SrCl26H2O–HCl in solvent or solvent-free conditions. Bull Korean Chem Soc 29:1331–1332

    Google Scholar 

  99. SiO2/ZnCl2: Gupta R, Gupta M, Paul S, Gupta K (2007) Silica-supported ZnCl2—a highly active and reusable heterogeneous catalyst for the one-pot synthesis of dihydropyrimidinones- thiones. Can J Chem 85:197–201

    Google Scholar 

  100. SbCl3/Al2O3/MWI/sf: Kapoor KK, Ganai BA, Kumar S, Andotra CS (2006) Antimony(III) chloride impregnated on alumina—an efficient and economical lewis acid catalyst for one-pot synthesis of dihydropyrimidinones under solvent-free conditions. Can J Chem 84:433–437

    Google Scholar 

  101. Sulfated zirconia: Kumar D, Sundaree MS, Mishra BG (2006) Sulfated zirconia-catalyzed one-pot benign synthesis of 3,4-dihydropyrimidin-2(1H)-ones under microwave irradiation. Chem Lett 35:1074

    Google Scholar 

  102. Sulfated zirconia: Angeles-Beltrán D, Lomas-Romero L, Lara-Corona VH, González-Zamora E, Negrón-Silva G (2006) Sulfated zirconia-catalyzed synthesis of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) under solventless conditions: competitive multicomponent Biginelli vs. Hantzsch reactions. Molecules 11:731–738; Available, http://www.mdpi.org/molecules/

    Google Scholar 

  103. EtOH/AcOH: Mamedov VA, Mustakimova LV, Gubaidullin AT, Vdovina SV, Litvinov IA, Reznik VS (2006) Dichloroacetylaroylmethanes as two-carbon synthons in the Biginelli reaction. Chem Heterocycl Comp 42:1229–1232

    Google Scholar 

  104. EtOH/AcOH: El-Hamouly WS, El-Khamry AMA, Abbas EMH (2006) Synthesis of new 4-aryl-isoxazolo[5,4-d]pyrimidin-6-one(thione) and 4-aryl-pyrazolo[3,4-d]-pyrimidin–6-one derivatives of potential antihypertensive activity. Indian J Chem 45B:2091–2098

    Google Scholar 

  105. EtOH/AcOH/MWI: Stadler A, Yousefi BH, Dallinger D, Walla P, Van der Eycken E, Kaval N, Kappe CO (2003) Scalability of microwave-assisted organic synthesis. From single-mode to multimode parallel batch reactors. Org Proc Res Dev 7: 707–716

    Google Scholar 

  106. EtOH/AcOH/MWI: Stadler A, Kappe CO (2001) Automated library generation using sequential microwave-assisted chemistry. Application toward the Biginelli multicomponent condensation. J Comb Chem 3:624–630

    Google Scholar 

  107. LiBr/THF: Baruah PP, Gadhwal S, Prajapati D, Sandhu JS (2002) The Biginelli condensation: a novel and efficient regioselective synthesis of dihydropyrimidin-2(1H)-ones using lithium bromide. Chem Lett 31:1038–1039

    Google Scholar 

  108. LiBr/MeCN: Maiti G, Kundu P, Guin C (2003) One-pot synthesis of dihydropyrimidinones catalysed by lithium bromide: an improved procedure for the Biginelli reaction. Tetrahedron Lett 44:2757–2758

    Google Scholar 

  109. LiBr/MeCN: Decken A, Zamora MT, Duguay DR, Vogels CM, Westcott SA (2008) Ethyl 6-methyl-4-[2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) thiophen-3-yl]-2-thioxo- 1,2,3,4-tetrahydropyrimidine-5-carboxylate. Acta Cryst Sect E 64: o929; Available, http://journals.iucr.org/e/issues/2008/05/00/gk2133/gk2133.pdf

  110. NbCl5/rt: Yadav JS, Reddy BVS, Naidu JJ, Sadashiv K (2004) NbCl5-catalyzed rapid and efficient synthesis of 3,4-dihydropyrimidinones under ambient conditions. Chem Lett 33: 926–927

    Google Scholar 

  111. (L)-proline/sf: Yadav JS, Kumar SP, Kondaji G, Rao RS, Nagaiah K (2004) A novel L-proline catalyzed Biginelli reaction: one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. Chem Lett 33:1168–1169

    Google Scholar 

  112. NH2SO3H/grinding/sf/rt: Jin T, Zhao Y, Liu L, Li T (2006) Synthesis of 1,2,3,6-tetrahydropyrimidin-2-one derivatives by grinding method. Chin J Org Chem 26:975–978

    Google Scholar 

  113. NH2SO3H/ultrasound/EtOH/rt: Li JT, Han JF, Yang JH, Li TS (2003) An efficient synthesis of 3,4-dihydropyrimidin-2-ones catalyzed by NH2SO3H under ultrasound irradiation. Ultrason Sonochem 10:119–122

    Google Scholar 

  114. H3BO3/AcOH: Tu S, Zhu X, Fang F, Zhang X, Zhu S, Li T, Shi D, Wang X, Ji S (2005) One-pot Synthesis of Bis(dihydropyrimidinone-4-yl)benzene using boric acid as a catalyst. Chin J Chem 23:596–598

    Google Scholar 

  115. Ismaili L, Ubaldi S, Robert JF, Xicluna A, Refouvelet B (2006) An efficient two-step synthesis of 4-methyl-1,2,3, 5,6,10b-hexahydropyrimido[5,4-c]quinoline-2,5-diones via Biginelli reaction. Heterocycles 71: 925–932

    Google Scholar 

  116. Tu S, Fang F, Miao C, Jiang H, Feng Y, Shi D, Wang X (2003) One-pot synthesis of 3,4-dihydropyrimidin-2 (1H)-ones using boric acid as catalyst. Tetrahedron Lett 44: 6153–6155

    Article  CAS  Google Scholar 

  117. H3BO3/glycol: Hua GP, Tu SJ, Fang F, Tu MS, Shi DQ, Wang XS (2004) Synthesis and crystal structure of 4-(4-Chlorophenyl)-6-methyl-5-methoxycarbonyl-3,4- dihydropyrimidin-2(1H)-one. Chin J Struct Chem 23:1295–1299

    Google Scholar 

  118. Silica sulfuric acid/sf: Salehi P, Dabiri M, Zolfigol MA, Bodaghi Fard MA (2003) Efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones over silica sulfuric acid as a reusable catalyst under solvent-free conditions. Heterocycles 60:2435–2440

    Google Scholar 

  119. Silica sulfuric acid/sf: Chen WY, Qin SD, Jin JR (2007) Efficient Biginelli reaction catalyzed by sulfamic acid or silica sulfuric acid under solvent-free conditions. Synth Commun 37:47–52

    Google Scholar 

  120. Silica sulfuric acid/EtOH: Salehi P, Dabiri M, Zolfigol MA, Bodaghi Fard MA (2003) Silica sulfuric acid: an efficient and reusable catalyst for the one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Tetrahedron Lett 44:2889–2891

    Google Scholar 

  121. H4SiW12O40nH2O/AcOH: Niknam K, Daneshvar N (2007) H4SiW12O40nH2O as a new catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-one. Heterocycles 71:373–378

    Google Scholar 

  122. BiCl3/MeCN: Ramalinga K, Vijayalakshmi P, Kaimal TNB (2001) Bismuth(III)-catalyzed synthesis of dihydropyrimidinones: improved protocol conditions for the Biginelli reaction. Synlett 2001:863–865

  123. Bi(OTf)3/MeCN: Varala R, Mujahid Alam M, Adapa SR (2003) Bismuth triflate catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones: an improved protocol for the Biginelli reaction. Synlett 2003:67–70

  124. Montmorillonite KSF clay/MWI/sf: Mitra AK, Banerjee K (2003) Clay catalysed synthesis of dihydropyrimidinones under solvent-free conditions. Synlett 2003:1509–1511

  125. Montmorillonite KSF/H2O or sf:Bigi F, Carloni S, Frullanti B, Maggi R, Sartori G (1999) A revision of the Biginelli reaction under solid acid catalysis. Solvent-free synthesis of dihydropyrimidines over montmorillonite KSF. Tetrahedron Lett 40:3465–3468

    Google Scholar 

  126. Montmorillonite KSF/MeOH: Lin H, Ding J, Chen X, Zhang Z (2000) An efficient synthesis of 5-alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones catalyzed by KSF montmorillonite. Molecules 5:1240–1243; Available, http://www.mdpi.org/molecules/

    Google Scholar 

  127. TMSI (TMSCl/NaI/MeCN/rt): Sabitha G, Reddy GSKK, Reddy CS, Yadav JS (2003) One-pot synthesis of dihydropyrimidinones using iodotrimethylsilane. Facile and new improved protocol for the Biginelli reaction at room temperature. Synlett 2003:858–860

  128. TMSCl: Zhu Y, Huang S, Pan Y (2005) Highly chemoselective multicomponent Biginelli-type condensations of cycloalkanones, urea or thiourea and aldehydes. Eur J Org Chem 2005: 2354–2367

  129. TMSCl/rt: Zhu Y, Pan Y, Huang S (2004) Trimethylsilyl chloride: a facile and efficient reagent for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Synth Commun 34:3167–3174

    Google Scholar 

  130. Ag3PW12O40: Yadav JS, Subba Reddy BV, Sridhar P, Reddy JSS, Nagaiah K, Lingaiah N, Saiprasad PS (2004) Green protocol for the Biginelli three-component reaction: Ag3PW12O40 as a novel, water-tolerant heteropolyacid for the synthesis of 3,4-dihydropyrimidinones. Eur J Org Chem 2004:552–557

  131. SmI2/sf: Han X, Xu F, Luo Y, Shen Q (2005) An efficient one-pot synthesis of dihydropyrimidinones by a Samarium diiodide catalyzed Biginelli reaction under solvent-free conditions. Eur J Org Chem 2005:1500–1503

  132. ZnCl2/sf: Sun Q, Wang Y, Ge Z, Cheng T, Li R (2004) A highly efficient solvent-free synthesis of dihydropyrimidinones catalyzed by zinc chloride. Synthesis 2004:1047–1051

  133. PPA/PEG400 support/MWI/sf: Xia M, Wang Y (2003) An efficient protocol for the liquid-phase synthesis of methyl 3,4-dihydropyrimidin-2(1H)-one-5-carboxylate derivatives. Synthesis 2003:262–266

  134. FeCl36H2O or NiCl26H2O/EtOH: Lu J, Bai Y (2002) Catalysis of the Biginelli reaction by ferric and nickel chloride hexahydrates. One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Synthesis 2002:466–470

  135. Sedova VF, Krivopalov VP, Shkurko OP (2007) Synthesis of 5-nitro-3,4-dihydropyrimidin-2 (1H)-ones catalyzed by metal salts. Retro-Henry reaction with formation of N,N’-disubstituted ureas. Russ J Org Chem 43: 90–95

    Article  CAS  Google Scholar 

  136. FeCl36H2O: Bratenko MK, Chornous VA, Vovk MV (2005) 4-Functionally substituted 3-heterylpyrazoles. XIII. 3- aryl(heteryl)- 4- (4- pyrazolyl)- 1, 2, 3, 4 - tetrahydropyrimidin- 2 - ones(thiones). Russ J Org Chem 41:95–97

  137. Ionic liquids (IL): Putilova ES, Kryshtal’ GV, Zhdankina GM, Troitskii NA, Zlotin SG (2005) Alkylammonium and alkylimidazolium perhaloborates, phosphates, and aluminates as catalysts in the Biginelli reaction. Russ J Org Chem 41:512–516

    Google Scholar 

  138. [BMim][BF4]: Putilova ES, Troitskii NA, Zlotin SG, Khudina OG, Burgart YaV, Saloutin VI, Chupakhin ON (2006) One-step solvent-free synthesis of fluoroalkyl-sbstituted 4-hydroxy-2-oxo(thioxo)hexahydropyrimidines in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate. Russ J Org Chem 42: 1392–1395

    Google Scholar 

  139. Dabiri M, Salehi P, Baghbanzadeh M, Shakouri M, Otokesh S, Ekrami T, Doosti R (2007) Efficient and eco-friendly synthesis of dihydropyrimidinones, Bis(indolyl)methanes, and N-alkyl and N-arylimides in ionic liquids. J Iran Chem Soc 4: 393–401

    CAS  Google Scholar 

  140. [CMIm][HSO4]: Zheng R, Wang X, Xu H, Du O (2006) Brønsted acidic ionic liquid: an efficient and reusable catalyst for the Synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Synth Commun 36:1503–1513

    Google Scholar 

  141. Polymer-supported IL: Wang ZT, Wang SC, Xu LW (2005) Polymer-supported ionic-liquid-catalyzed synthesis of 1,2,3,4-tetrahydro-2-oxopyrimidine-5-carboxylates via Biginelli reaction. Helv Chim Acta 88:986–989

    Google Scholar 

  142. [C4mim][HSO4]/MWI/sf: Arfan A, Paquin L, Bazureau JP (2007) Acidic task-specific ionic liquid as catalyst of microwave-assisted solvent-free Biginelli reaction. Russ J Org Chem 43:1058–1064

    Google Scholar 

  143. [BMim][PF6], [BMim][BF4]: Peng J, Deng Y (2001) Ionic liquids catalyzed Biginelli reaction under solvent-free conditions. Tetrahedron Lett 42:5917–5919

    Google Scholar 

  144. \({{\rm R}_{3}{\rm N}^{+}({\rm CH}_{2})_{3}{\rm SO}_{3}^{-}}\) : Dong F, Jun L, Xinli Z, Zhiwen Y, Zuliang L (2007) One-pot green procedure for Biginelli reaction catalyzed by novel task-specific room-temperature ionic liquids. J Mol Catal A Chem 274:208–211

    Google Scholar 

  145. [Bmim]Cl × 2AlCl3: Bahekar SS, Kotharkar SA, Shinde DB (2004) One-pot construction of dihydropyrimidinones in ionic liquids. Mendeleev Commun 14:210–212

    Google Scholar 

  146. [Hmim]HSO4: Ma JJ, Zang XH, Zhou X, Wang C, Li JC, Li Q (2007) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by acidic ionic liquid. Indian J Chem 46B: 2045–2048

  147. [Bmim][FeCl4]: Chen X, Peng Y (2008) Chloroferrate (III) ionic liquid: efficient and recyclable catalyst for solvent-free synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Catal Lett 122:310–313

    Google Scholar 

  148. 1-n-Butyl-3-methylimidazolium saccharinate ([BMIm]Sac): Li M, Guo W-S, Wen L-R, Li Y-F, Yang H-Z (2006) One-pot synthesis of Biginelli and Hantzsch products catalyzed by non-toxic ionic liquid (BMImSac) and structural determination of two products. J Mol Catal A Chem 258:133–138

    Google Scholar 

  149. IL/ultrasound/30°C: Gholap AR, Venkatesan K, Daniel T, Lahoti RJ, Srinivasan KV (2004) Ionic liquid promoted novel and efficient one pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones at ambient temperature under ultrasound irradiation. Green Chem 6:147–150

    Google Scholar 

  150. DSA/H2O/rt: Sharma SD, Gogoi P, Konwar B (2007) A highly efficient and green method for the synthesis of 3,4-dihydropyrimidin-2-ones and 1,5-benzodiazepines catalyzed by dodecyl sulfonic acid in water. Green Chem 9:153–157

    Google Scholar 

  151. PEG 400/sf/100◦C: Jain SL, Singhal S, Sain B (2007) PEG-assisted solvent and catalyst free synthesis of 3,4-dihydropyrimidinones under mild reaction conditions. Green Chem 9: 740–741

    Google Scholar 

  152. Zeolites/toluene: Radha Rani V, Srinivas N, Radha Kishan M, Kulkarni SJ, Raghavan KV (2001) Zeolite-catalyzed cyclocondensation reaction for the selective synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Green Chem 3:305–306

    Google Scholar 

  153. Me3SiI/MeCN/rt: Sabitha G, Reddy KB, Srinivas R, Yadav JS (2005) Iodotrimethylsilane-accelerated one-pot synthesis of 5-unsubstituted 3,4-dihydropyrimidin-2(1H)-ones: a novel procedure for the Biginelli-like cyclocondensation reaction at room temperature. Helv Chim Acta 88:2996–2999

    Google Scholar 

  154. FeCl36H2O/Me3SiCl: Xu LW, Wang ZT, Xia CG, Li L, Zhao PQ (2004) Improved protocol for the three-component Biginelli reactions and Biginelli-like Mannich reactions of carbamates, aldehydes, and ketones. Helv Chim Acta 87: 2608–2612

    Google Scholar 

  155. Yb(OTf)3: Gong D, Zhang L, Yuan C (2003) A convenient synthesis of 5-(O,O-dialkylphosphoryl)-4-aryl-3,4-dihydropyrimidin-2(1H)-ones. Heteroatom Chem 14:13–17

    Google Scholar 

  156. Yb(OTf)3/chiral hexadentate amino phenol ligand/THF/rt: Huang Y, Yang F, Zhu C (2005) Highly enantioseletive Biginelli reaction using a new chiral ytterbium catalyst: asymmetric synthesis of dihydropyrimidines. J Am Chem Soc 127: 16386–16387

    Google Scholar 

  157. Yb(OTf)3/sf/100◦C: Ma Y, Qian C, Wang L, Yang M (2000) Lanthanide triflate catalyzed Biginelli reaction. One-pot synthesis of dihydropyrimidinones under solvent-free conditions. J Org Chem 65:3864–3868

    Google Scholar 

  158. Yb(OTf)3 or Sc(OTf)3 or La(OTf)3/sf/100◦C: Wang L, Qian C, Tian H, Yun MA (2003) Lanthanide triflate catalyzed one-pot synthesis of dihydropyrimidin-2(1H)-thiones by a three-component of 1,3-dicarbonyl compounds, aldehydes, and thiourea using a solvent-free Biginelli condensation. Synth Commun 33:1459–1468

    Google Scholar 

  159. Yb(OTf)3/THF: Dondoni A, Massi A, Sabatini S (2002) Improved synthesis and preparative scale resolution of racemic monastrol. Tetrahedron Lett 43:5913–5916

    Google Scholar 

  160. Yb(OTf)3/4Åmol. sieves/THF: Dondoni A, Massi A, Minghini E, Sabbatini S, Bertolasi V (2003) Model studies toward the synthesis of dihydropyrimidinyl and pyridyl α-amino acids via three-component Biginelli and Hantzsch cyclocondensations. J Org Chem 68:6172–6183

    Google Scholar 

  161. Dowex50W/H2O/70◦C: Mukhopadhyay C, Datta A, Banik BK (2006) Dowex 50W in aqueous medium: highly efficient Biginelli condensation procedure for the synthesis of 4-aryl-3,4-dihydropyrimidones. Heterocycles 71:181–188

    Google Scholar 

  162. K5CoW12O403H2O/sf: Subhas Bose D, Venu Chary M, Mereyala HB (2006) Water-tolerant and reusable catalyst for the one-pot synthesis of dihydropyrimidin-2(1H)-ones under solvent-free conditions. Heterocycles 68:1217–1224

    Google Scholar 

  163. Sulphated SnO2/sf: Bhosale RS, Hashmi AM, Zubaidha PK, Dongre MK (2005) An efficient and improved method for the Biginelli reaction using solid superacid (sulphated SnO2). Heterocycl Commun 11:399–402

    Google Scholar 

  164. SnCl22H2O/MeCN: Russowsky D, Lopes FA, da Silva VSS, Canto KFS, Montes D’Oca GM, Godoi MN (2004) Multicomponent Biginelli’s synthesis of 3,4-dihydropyrimidin-2(1H)-ones promoted by SnCl22H2O. J Braz Chem Soc 15:165–169

    Google Scholar 

  165. SnCl22H2O: Kumar S, Saini A, Sandhu JS (2004) Tin (II) chloride catalyzed one pot efficient and novel preparation of dihydropyrimidin-2(1H)-ones. Indian J Chem 43B:1485–1486

    Google Scholar 

  166. ZnCl2/MWI/sf: Pash MA, Ramachandra Swamy N, Jayashankara VP (2005) One pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones/-thiones catalysed by zinc chloride: an improved procedure for the Biginelli reaction using microwaves under solvent free condition. Indian J Chem 44B:823–826

    Google Scholar 

  167. BiOClO4nH2O/MeCN: Thirupathi Reddy Y, Narsimha Reddy P, Sunil Kumar B, Rao GVP, Rajitha B (2005) Bismuth oxide perchlorate catalysed efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones: an improved high yielding protocol for the Biginelli reaction. Indian J Chem 44B:1304–1306

    Google Scholar 

  168. HCl/MeCN/MWI or neat/100–110◦C: Shanmugam P, Sabastein C, Perumal PT (2004) Synthesis of fused dihydropyrimidinones from cyclic-1,3-dicarbonyl compounds: modified Biginelli synthesis of 1,2,3,4,5,6,7,8-octahydroquinazolinediones and 3,4-dihydro-1H-indeno[1,2-d]pyrimidine-2,5-diones. Indian J Chem 43B:135–140

    Google Scholar 

  169. CaCl2/MWI/sf: Misra AK, Agnihotri G, Madhusudan SK (2004) Microwave induced eco-friendly solvent-free Biginelli reaction catalyzed by calcium chloride. Indian J Chem 43B:2018–2020

    Google Scholar 

  170. CoCl26H2O/MWI/sf, MnCl24H2O/MWI/sf, SnCl22H2O/MWI/sf: Kumar S, Saini A, Sandhu JS (2005) Cobalt(II) chloride or manganese (II) chloride or tin (II) chloride promoted one pot synthesis of dihydropyrimidin-2(1H)-ones using microwave irradiation. Indian J Chem 44B:762–767

    Google Scholar 

  171. H3PW12O40/sulfated zirconia/MWI: Kumar D, Mishra BG, Rao VS (2006) An environmentally benign protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones using solid acid catalysts under solvent-free conditions. Indian J Chem 46B:2325

    Google Scholar 

  172. HCl/MeOH: Jauk B, Belaj F, Kappe CO (1999) Synthesis and reactions of Biginelli-compounds. Part 14. A rhodium-induced cyclization–cycloaddition sequence for the construction of conformationally rigid calcium channel modulators of the dihydropyrimidine type. J Chem Soc Perkin Trans 1:307–314

    Google Scholar 

  173. Kaur K, Knaus EE (2007) Synthesis of alkyl 6-methyl-4- (2-trifluoromethylphenyl)-1,2,3,4-tetrahydro-2H-pyrimidine-2-one-5-carboxylates possessing a N-3 nitro substituent to determine calcium channel modulation structure-activity relationships. J Heterocyclic Chem 44: 669–672

    CAS  Google Scholar 

  174. Kaur K, Knaus EE (2007) Synthesis of alkyl 6-methyl-4-(2-pyridyl)-1,2,3,4-tetrahydro-2H-pyrimidine-2-one-5-carboxylates for evaluation as calcium channel antagonists. J Heterocyclic Chem 44: 745–747

    CAS  Google Scholar 

  175. TMSCl/MeCN/MWI: Pisani L, Prokopcová H, Kremsner JM, Kappe CO (2007) 5-Aroyl-3,4-dihydropyrimidin-2-one library generation via automated sequential and parallel microwave-assisted synthesis techniques. J Comb Chem 9:415–421

    Google Scholar 

  176. Prokopcová H, Pisani L, Kappe CO (2007) Synthesis of 5-aroyldihydropyrimidinones via liebeskind-srogl thiol ester-boronic acid cross-couplings. Synlett 2007:43–46

    Article  CAS  Google Scholar 

  177. Bi(NO3)3/MeCN: Adharvana Chari M, Shobha D, Kiran Kumar T, Dubey PK (2005) Bismuth (III) nitrate catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones: an improved protocol for the Biginelli reaction. ARKIVOC xv:74–80; Available, http://www.arkat-usa.org

  178. Silica triflate/sf: Shirini F, Marjani K, Nahzomi HT (2007) Silica triflate as an efficient catalyst for the solvent-free synthesis of 3,4-dihydropyrimidin-2(1H)-ones. ARKIVOC i:51–57; Available, URL:http://www.arkat-usa.org

  179. TMSCl/DMF/MeCN: Kantevari S, Bantu R, Nagarapu L (2006) TMSCl mediated highly efficient one-pot synthesis of octahydroquinazolinone and 1,8-dioxooctahydroxanthene derivatives. ARKIVOC xvi:136–148; Availabl, URL:http://www.arkat-usa.org

  180. Zhu Y, Pan Y, Huang S (2005) Chemoselective multicomponent condensation of 1,3-cyclohexanedione, urea or thiourea with aldehydes: one-pot synthesis of two families of fused heterobicyclic and spiro-fused heterobicyclic aliphatic rings. Heterocycles 65: 133–142

    Article  CAS  Google Scholar 

  181. TEBA/sf/100◦C: Subhas Bose D, Sudharshan M, Chavhan SW (2005) New protocol for Biginelli reaction-a practical synthesis of Monastrol. ARKIVOC iii:228–236; Available, http://www.arkat-usa.org

  182. (NH4)2HPO4/sf: Salehi P, Dabiri M, Khosropour AR, Roozbehniya P (2006) Diammonium hydrogen phosphate: a versatile and inexpensive reagent for one-pot synthesis of dihydropyrimidinones, quinazolinones and azalactones under solvent-free conditions. J Iran Chem Soc 3:98–104

    Google Scholar 

  183. AcOH: Buzueva AM (1969) Acetylation of 6-alkyl-5-ethoxycarbonyl-2-hydroxy-4-methyldihydropyrimidines and their 2-mercapto analogs. Chem Heterocycl Comp 5:261–263

    Google Scholar 

  184. AcOH: Dubur GYa, Khanina EL (1976) Tetrahydropyrimidine-5-carboxylic acid amides. Chem Heterocycl Comp 12: 191–193

    Google Scholar 

  185. AcOH: Dubur GYa, Khanina EL, Vitolin’ RO (1974) A method to obtain the 2-oxo-1,6-dihydro-5-pyrimidine carboxamides. Patent SU 422735 (in Russian); Available, URL:www.espacenet.com

  186. Ce(NO3)36H2O/sf/80◦C: Adib M, Ghanbary K, Mostofi M, Ganjali MR (2006) Efficient Ce(NO3)36H2O-catalyzed solvent-free synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Molecules 11:649–654; Available, URL: http://www.mdpi.org/molecules/

    Google Scholar 

  187. CeCl3/THF, InCl3/THF: Muñoz-Muñiz O, Juaristi E (2003) An enantioselective approach to the Biginelli dihydropyrimidinone condensation reaction using CeCl3 and InCl3 in the presence of chiral ligands. ARKIVOC xi:16–26; Available, URL:http://www.arkat-usa.org

  188. González-Olvera R, Melgar-Fernández R, Juaristi E (2003) Corrigendum to “An enantioselective approach to the Biginelli dihidropyrimidinone condensation reaction using CeCl3 and InCl3 in the presence of chiral ligands” [Arkivoc, 2003, (xi) 16–26]. ARKIVOC xi:227; Available, URL:http://www.arkat-usa.org

  189. InCl3/THF: Ranu BC, Hajra A, Jana UJ (2000) Indium(III) chloride-catalyzed one-pot synthesis of dihydropyrimidinones by a three-component coupling of 1,3-dicarbonyl compounds, aldehydes, and urea: an improved procedure for the Biginelli reaction. J Org Chem 65:6270–6272

    Google Scholar 

  190. Binol- and H8-binol-based phosphoric acids/CH2Cl2/rt: Chen XH, Xu XY, Liu H, Cun LF, Gong LZ (2006) Highly enantioselective organocatalytic Biginelli reaction. J Am Chem Soc 128:14802–14803

    Google Scholar 

  191. Polyaniline salts & complexes: Gangadasu B, Palaniappan S, Amarnath CA, Rao VJ (2006) Polyaniline salts and complexes: efficient and reusable catalyst for the one-pot synthesis of 5-(methoxycarbonyl)-6-methyl-4-phenyl-3,4-dihydropyrimidin-2(1H)-one. J Appl Polym Sci 102:1741–1742

    Google Scholar 

  192. Polyaniline-fluoroboric acid-dodecylhydrogensulfate salt (PANI-HBF4-DHS)/EtOH: Palaniappan S, John A (2005) A novel polyaniline-fluoroboric acid-dodecylhydrogensulfate salt: versatile reusable polymer based solid acid catalyst for organic transformations. J Mol Catal A Chem 233:9–15

    Google Scholar 

  193. Silica-chloride/sf: Karade HN, Sathe M, Kaushik MP (2007) Synthesis of 4-aryl substituted 3,4-dihydropyrimidinones using silica-chloride under solvent free conditions. Molecules 12:1341–1351; Available, http://www.mdpi.org/molecules/

    Google Scholar 

  194. HCl/MWI and HCl/EtOH/MWI: Stadler A, Kappe CO (2000) Microwave-mediated Biginelli reactions revisited. On the nature of rate and yield enhancements. J Chem Soc Perkin Trans 2:1363–1368

    Google Scholar 

  195. Gupta R, Gupta AK, Paul S, Kachroo PL (1995) Improved syntheses of some ethyl 4-aryl-6-methyl-1,2,3,4-tetrahydropyrimidin-2-one/thione-5-carboxylates by microwave irridation. Indian J Chem 34B: 151–152

    CAS  Google Scholar 

  196. Dandia A, Saha M, Taneja H (1998) Synthesis of fluorinated ethyl 4-aryl-6-methyl-1,2,3,4-tetrahydropyrimidin-2-one/thione-5-carboxylates under microwave irradiation. J Fluorine Chem 90: 17–21

    Article  CAS  Google Scholar 

  197. Mobinikhaledi A, Forughifar N (2006) Microwave-assisted synthesis of some pyrimidine derivatives. Phosphorus Sulfur Silicon Relat Elem 181: 2653–2658

    Article  CAS  Google Scholar 

  198. Bu4NHSO4/80◦C/sf: Shaabani A, Bazgir A, Arab-Ameri S (2004) Tetrabutylammonium hydrogen sulfate: an efficient catalyst for the synthesis Of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. Phosphorus Sulfur Silicon 179:2169–2175

    Google Scholar 

  199. In(OTf)3/MeCN: Godoi MN, Costenaro HS, Kramer E, Machado PS, D’Oca MGM, Russowsky D (2005) Síntese Do Monastrol E Novos Compostos De Biginelli Promovida Por In(OTf)3. Quim Nova 28:1010–1013

  200. TMSCl/DMF: Zavyalov SI, Kulikova LB (1992) Trimethylchlorosilane-DMFA, a new system for the Biginelli reaction. Khim Farm Zh 26(7–8):116–117 (in Russian) (The corresponding English online issue from Springer lacked this paper)

  201. TMSCl/DMF: Ryabukhin SV, Plaskon AS, Ostapchuk EN, Volochnyuk DM, Tolmachev AA (2007) N-Substituted ureas and thioureas in Biginelli Reaction promoted by chlorotrimethylsilane: convenient synthesis of N1-alkyl-, N1-aryl-, and N1, N3-dialkyl-3,4-dihydropyrimidin-2(1H)-(thi)ones. Synthesis 2007: 417–427

  202. TMSCl/DMF/sonication/rt: Ryabukhin SV, Plaskon AS, Ostapchuk EN, Volochnyuk DM, Shivanyuk AN, Tolmachev AA (2007) A one-step fusion of 1,3-thiazine and pyrimidine cycles. Orglett 9:4215–4218

    Google Scholar 

  203. TMSCl/DMF: Ryabukhin SV, Plaskon AS, Ostapchuk EN, Volochnyuk DM, Shishkin OV, Tolmachev AA (2008) CF3-substituted 1,3-dicarbonyl compounds in the Biginelli reaction promoted by chlorotrimethylsilane. J Fluor Chem 129:625–631

    Google Scholar 

  204. MgBr2/sf: Salehi H, Guo QX (2004) A facile and efficient one-pot synthesis of dihydropyrimidinones catalyzed by magnesium bromide under solvent-free conditions. Synth Commun 34:171–179

    Google Scholar 

  205. ZrOCl2  × 8H2O/sf: Shirini F, Zolfigol MA, Mollarazi E (2006) ZrOCl2 × 8H2O as an efficient reagent for the solvent-free synthesis of 3,4-dihydropyrimidin-2-(1H)-ones. Synth Commun 36:2307–2310

    Google Scholar 

  206. Zeolite E4a/EtOH/80◦C: Hegedüs A, Hell Z, Vígh I (2006) Convenient one-pot heterogeneous catalytic method for the preparation of 3,4-dihydropyrimidin-2(1H)-ones. Synth Commun 36:129–136

    Google Scholar 

  207. In MeCN/TFA, using 1,3-oxazinanes or -oxazolidines as masked aldehyde equivalents: Singh K, Singh J, Deb PK, Singh H (1999) An expedient protocol of the biginelli dihydropyrimidine synthesis using carbonyl equivalents. Tetrahedron 55:12873–12880

    Google Scholar 

  208. In TFA/Cl(CH2)2Cl2 or H2SO4/EtOH, with oxalacetic acid instead of β-keto ester component: Bussolari JC, McDonnell PA (2000) A New Substrate for the Biginelli cyclocondensation: direct preparation of 5-unsubstituted 3,4-dihydropyrimidin-2(1H)-ones from a β-keto carboxylic acid. J Org Chem 65: 6777–6779

  209. SbCl3/MeCN: Cepanec I, Litvic M, Filipan-Litvic M, Grüngold I (2007) Antimony (III) chloride-catalysed Biginelli reaction: a versatile method for the synthesis of dihydropyrimidinones through a different reaction mechanism. Tetrahedron 63:11822–11827

    Google Scholar 

  210. TaBr5/75◦C/sf: Ahmed N, van Lier JE (2007) TaBr5-catalyzed Biginelli reaction: one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones/thiones under solvent-free conditions. Tetrahedron Lett 48:5407–5409

    Google Scholar 

  211. Propane phosphonic acid anhydride (n-C3H7PO2)3/AcOEt: Zumpe FL, Flüß M, Schmitz K, Lender A (2007) Propane phosphonic acid anhydride: a new promoter for the one-pot Biginelli synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Tetrahedron Lett 48:1421–1423

    Google Scholar 

  212. (L)-Pro-OMe × HCl: Mabry J, Ganem B (2006) Studies on the Biginelli reaction: a mild and selective route to 3,4-dihydropyrimidin-2(1H)-ones via enamine intermediates. Tetrahedron Lett 47:55–56

    Google Scholar 

  213. Cu(NTf2)2, or Ni(NTf2)2, or Yb(NTf2)3/H2O/rt: Suzuki I, Suzumura Y, Takeda K (2006) Metal triflimide as a Lewis acid catalyst for Biginelli reactions in water. Tetrahedron Lett 47:7861–7864

    Google Scholar 

  214. PhB(OH)2/MeCN: Debache A, Boumoud B, Amimour M, Belfaitah A, Rhouati S, Carboni B (2006) Phenylboronic acid as a mild and efficient catalyst for Biginelli reaction. Tetrahedron Lett 47:5697–5699

    Google Scholar 

  215. Zn(NH2SO3)2: Zhang M, Li YQ, Zhou MY (2006) Rapid synthesis of 1,2,3,4-tetrahydropyrimidin-2-ones using Zn(NH2SO3)2 as a catalyst under microwave irradiation. Chin J Chem 24:282–284

    Google Scholar 

  216. Zn(NH2SO3)2: Zhang M, Li YQ (2006) Facile one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-one catalyzed by Zn(NH2SO3)2. Synth Commun 36:835–841

    Google Scholar 

  217. Dowex-50W/130◦C/sf: Singh K, Arora D, Singh S (2006) Dowex-promoted general synthesis of N,N′-disubstituted-4-aryl-3,4-dihydropyrimidinones using a solvent-free Biginelli condensation protocol. Tetrahedron Lett 47:4205–4207

    Google Scholar 

  218. ZnI2/MWI/sf: Liang B, Wang X, Wang JX, Du Z (2007) New three-component cyclocondensation reaction: microwave-assisted one-pot synthesis of 5-unsubstituted-3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. Tetrahedron 63:1981–1986

    Google Scholar 

  219. KHSO4/glycol/100◦C: Tu S, Fang F, Zhu S, Li T, Zhang X, Zhuang Q (2004) A new Biginelli reaction procedure using potassium hydrogen sulfate as the promoter for an efficient synthesis of 3,4-dihydropyrimidin-2(1H)-one. Synlett 2004:537–539

  220. KHSO4/glycol: Tu S, Fang F, Zhu S, Li T, Zhang X, Zhuang Q (2004) A new Biginelli reaction procedure using potassium hydrogen sulfate as the promoter for an efficient synthesis of 3,4-dihydropyrimidin-2(1H)-one. J Heterocycl Chem 41:253–257

    Google Scholar 

  221. KHSO4/AcOH/80◦C: Shi F, Jia R, Zhang X, Tu S, Yan S, Zhang Y, Jiang B, Zhang J, Yao C (2007) Extension of the Biginelli-type reaction: one-pot synthesis of Pyrimido-pyrimidines and Spirobi[pyrimidine]s using potassium hydrogen sulfate as a catalyst. Synthesis 2007:2782–2790

  222. Shaabani A, Bazgir A, Arab-Ameri S, Sharifi Kiasaraie M, Samadi S (2005) Comparison of catalytic effect of alkali and alkaline earth metals hydrogen sulfate: as the promoter for an efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. Iran J Chem & Chem Eng 24(3): 67

    CAS  Google Scholar 

  223. LiClO4 or LiOTf/MeCN: Yadav JS, Subba Reddy BV, Srinivas R, Venugopal C, Ramalingam T (2001) LiClO-Catalyzed one-pot synthesis of dihydropyrimidinones: an improved protocol for Biginelli reaction. Synthesis 2001:1341–1345

  224. In(OTf)3/MWI/Na2SO4 solid support: Shanmugam P, Annie G, Perumal PT (2003) Synthesis of novel 3,4-dihydropyrimidinones on water soluble solid support catalyzed by indium triflate. J Heterocycl Chem 40:879–883

    Google Scholar 

  225. Al2O3(acidic)/MWI/sf: Kidwai M, Mohan R, Saxena S (2003) Solid-supported Hantzsch-Biginelli reaction for syntheses of pyrimidine derivatives. Russ Chem Bull Int Ed 52: 2457–2460

    Google Scholar 

  226. Al2O3(acidic) or montmorillonite K10 clay/MWI/sf: Kidwai M, Bala S, Mishra AD (2004) Microwave assisted synthesis of thiadiazolopyrimidin-2-thiones. Indian J Chem 43B: 2485–2487

    Google Scholar 

  227. P2O5/EtOH: Deshmukh MB, Anbhule PV, Jadhav SD, Mali AR, Jagtap SS, Deshmukh SA (2007) An efficient, simple, one-pot synthesis of dihydropyrimidine-2(1H)-ones using phosphorus pentoxide. Indian J Chem 46B:1545–1548

    Google Scholar 

  228. LaCl3 × 7H2O/HCl/EtOH: Lu J, Bai YJ, Wang ZJ, Yang B, Ma HR (2000) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones using lanthanum chloride as a catalyst. Tetrahedron Lett 41:9075–9078

    Google Scholar 

  229. CoCl2  × 6H2O or LaCl3 × 7H2O/HCl/EtOH: Lu J, Bai YJ, Guo YH, Wang ZJ, Ma HR (2002) CoCl2 × 6H2O or LaCl3 × 7H2O Catalyzed Biginelli reaction. One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Chinese J Chem 20:681–687

    Google Scholar 

  230. TsOH/AcOH/MWI: Tu SJ, Fang F, Miao CB, Jiang H, Shi DQ (2003) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones using TsOH as a catalyst under microwave irradiation. Chin J Chem 21:706–709

    Google Scholar 

  231. SnCl2 or CuCl2 × 2H2O or FeCl3 × 6H2O or ZnCl2/HCl/MWI/sf: Xue S, Shen YC, Li YL, Shen XM, Guo QX (2002) Synthesis of 4-Aryl-3,4-dihydropyrimidinones using Microwave-assisted solventless Biginelli reaction. Chin J Chem 20:385–389

    Google Scholar 

  232. La(OTf)3/100◦C/sf: Chen RF, Qian CT (2002) One-pot syntheses of 3,4-dihydropyrimidine-2(1H)-thiones catalyzed by La(OTf)3. Chin J Chem 20:427–430

    Google Scholar 

  233. Zn(OTf)2/100◦C/sf: Xu H, Wang YG (2003) A rapid and efficient Biginelli reaction catalyzed by zinc triflate. Chin J Chem 21:327–331

    Google Scholar 

  234. SmCl3 × 6H2O/Montmorillonite clay/sf/MWI: Li YX, Bao WL (2003) Microwave-assisted solventless Biginelli reaction catalyzed by montmorillonite clay-SmCl3 × 6H2O system. Chin Chem Lett 14:993–995

    Google Scholar 

  235. FeCl3  × 6H2O/HCl/EtOH: Lu J, Ma H (2000) Iron(III)-catalyzed synthesis of dihydropyrimidinones. Improved conditions for the Biginelli reaction. Synlett 2000:63–64

  236. Zorkun IS, Sarac S, Celebib S, Erol K (2006) Synthesis of 4-aryl-3,4-dihydropyrimidin-2(1H)-thione derivatives as potential calcium channel blockers. Bioorg Med Chem 14: 8582–8589

    Article  PubMed  CAS  Google Scholar 

  237. Polyaniline-Bismoclite complex/EtOH: Gangadasu B, Palaniappan S, Rao VJ (2004) One-pot synthesis of dihydropyrimidinones using polyaniline-bismoclite complex. A facile and reusable catalyst for the Biginelli reaction. Synlett 2004:1285–1287

  238. HCl/AcOH: Folkers K, Harwood HJ, Johnson TB (1932) Researches on pyrimidines. CXXX. Synthesis of 2-keto-1,2,3,4-tetrahydropyrimidines. J Am Chem Soc 54:3751–3758

    Google Scholar 

  239. HCl/AcOH: George T, Tahilramani R, Mehta DV (1975) Condensed heterocycles from 5-ethoxycarbonyl-6-methyltetrahydropyrimidin-2-ones. Synthesis 1975: 405–407

  240. HCl/AcOH: Aslanoglu F, Akbas E, Sönmez M, Anil B (2007) 5-Benzoyl-4,6-diphenyl-1,2,3,4-tetrahydro-2 thioxopyrimidine. Phosphorus Sulfur Silicon Relat Elem 182: 1589–1597

    Google Scholar 

  241. NBS/EtOH/MWI: Hazarkhani H, Karimi B (2004) N-Bromosuccinimide as an almost neutral catalyst for efficient synthesis of dihydropyrimidinones under microwave irradiation. Synthesis 2004:1239–1242

  242. CdCl2/MeCN: Venkat Narsaiah A, Basak AK, Nagaiah K (2004) Cadmium chloride: an efficient catalyst for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Synthesis 2004: 1253–1256

  243. I2/EtOH vs HCl/EtOH: Folkers K, Johnson TB (1933) Researches on pyrimidines. CXXXVI. The mechanism of formation of tetrahydropyrimidines by the Biginelli reaction. J Am Chem Soc 55:3784–3791

    Google Scholar 

  244. I2/MeCN: Srinivas KVNS, Das B (2004) Iodine catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones: a simple and efficient procedure for the Biginelli reaction. Synthesis 2004:2091–2093

  245. I2/PhMe: Bhosale RS, Bhosale SV, Bhosale SV, Wang T, Zubaidha PK (2004) An efficient, high yield protocol for the one-pot synthesis of dihydropyrimidin-2(1H)-ones catalyzed by iodine. Tetrahedron Lett 45:9111–9113

    Google Scholar 

  246. RuCl3/100◦C/sf: De SK, Gibbs RA (2005) Ruthenium(III) chloride-catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones under solvent-free conditions. Synthesis 2005:1748–1750

  247. RuCl3 × nH2O/rt/EtOH: Jain SL, Sharma VB, Sain B (2006) Ruthenium-catalyzed Biginelli condensation: a simple and efficient one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones under mild reaction conditions. J Heterocyclic Chem 43: 777–779

    Google Scholar 

  248. Polystyrenesulfonic acid (PSSA)/H2O/MWI: Polshettiwara V, Varma RS (2007) Biginelli reaction in aqueous medium: a greener and sustainable approach to substituted 3,4-dihydropyrimidin-2(1H)-ones. Tetrahedron Lett 48:7343–7346

    Google Scholar 

  249. Bi(NO3)3/sf: Banik BK, Reddy AT, Datta A, Mukhopadhyay C (2007) Microwave-induced bismuth nitrate catalyzed synthesis of dihydropyrimidones via Biginelli condensation under solventless conditions. Tetrahedron Lett 48:7392–7394

    Google Scholar 

  250. Bi(NO3)3 × 5H2O: Khodaei MM, Khosropour AR, Bigzadeh M (2004) An efficient and environmentally friendly method for synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by Bi(NO3)3 × 5H2O. Synth Commun 34:1551–1557

    Google Scholar 

  251. Bakers’ yeast/D-glucose/phosphate buffer pH 7/rt: Kumar A, Maurya RA (2007) An efficient bakers’ yeast catalyzed synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Tetrahedron Lett 48:4569–4571

    Google Scholar 

  252. 4-MeC6H4S(O)OH: Shutalev AD, Sivova NV (1998) Synthesis of 4-Alkyl-substituted 1,2,3,4-tetrahydropyrimidin-2-ones by the Biginelli reaction. Chem Heterocycl Comp 34:848–851

    Google Scholar 

  253. H2SO4/H2O: Hassani Z, Islami MR, Kalantari M (2006) An efficient one-pot synthesis of octahydroquinazolinone derivatives using catalytic amount of H2SO4 in water. Bioorg Med Chem Lett 16:4479–4482

    Google Scholar 

  254. H2SO4/EtOH: Bussolari JC, McDonnell PA (2000) A new substrate for the Biginelli cyclocondensation: direct preparation of 5-unsubstituted 3,4-dihydropyrimidin-2(1H)-ones from a β-keto carboxylic acid. J Org Chem 65:6777–6779

    Google Scholar 

  255. H2SO4/AcOH: Folkers K, Johnson TB (1933) Researches on pyrimidines. CXXXIV. The reaction of phenylacetaldehyde and acetophenone with urea. J Am Chem Soc 55:3361–3368

    Google Scholar 

  256. SnCl2 × 2H2O/LiCl: Shailaja M, Manjula A, Vittal Rao B, Parvathi N (2004) Simple protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones using SnCl2 × 2H2O-LiCl as an inexpensive catalyst system. Synth Commun 34:1559–1564

    Google Scholar 

  257. Al(HSO4)3/MeOH or sf: Khodaei MM, Salehi P, Zolfigol MA, Sirouszadeh S (2004) Efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones by aluminum hydrogensulfate. Polish J Chem 78:385–388

    Google Scholar 

  258. MeSO3H/EtOH: Jin TS, Wang HX, Xing CY, Li XL, Li TS (2005) An efficient one-pot synthesis of 3,4-dihydropyrimidin-2-ones catalyzed by methanesulfonic acid. Synth Commun 34:3009–3016

    Google Scholar 

  259. Sc(OTf)3/MeCN: De SK, Gibbs RA (2005) Scandium(III) triflate as an efficient and reusable catalyst for synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Synth Commun 35:2645–2651

    Google Scholar 

  260. MgCl2 × 6H2O/80◦C/sf: Zhang GL, Cai XH (2005) Magnesium chloride hexahydrate catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. Synth Commun 35:829–833

    Google Scholar 

  261. H6P2W18O62 × 24H2O/MeCN or sf: Romanelli GP, Sathicq AG, Autino JC, Baronetti G, Thomas HJ (2007) Solvent-free approach to 3,4-dihydropyrimidin-2(1H)-(thio)ones: Biginelli reaction catalyzed by a Wells-Dawson reusable heteropolyacid. Synth Commun 37:3907–3916

    Google Scholar 

  262. BiONO3/MeCN: Reddy YT, Rajitha B, Reddy PN, Kumar BS, Rao VPG (2004) Bismuth subnitrate catalyzed efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones: an improved protocol for the Biginelli reaction. Synth Commun 34:3821–3825

    Google Scholar 

  263. FeCl3 × 6H2O/MWI/sf: Tu SJ, Zhou JF, Cai PJ, Wang H, Feng JC (2002) A convenient ferric chloride catalyzed synthesis of 5-alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones under microwave irradiation. Synth Commun 32:147–151

    Google Scholar 

  264. FeCl3 × 6H2O/MWI/sf or no catalyst/MWI/sf: Mirza- Aghayan M, Bolourtchian M, Hosseini M (2004) Microwave-assisted efficient synthesis of dihydropyrimidines in solvent-free condition. Synth Commun 34:3335–3341

    Google Scholar 

  265. Natural phosphate doped with metal halides MCl2 (M = Cu,Zn,Co,Ni)/PhMe: El Badaoui H, Bazi F, Tamani S, Boulaajaj S, Zahouily M, Lazrek HB, Sebti S (2005) Lewis acid-doped natural phosphate: new catalysts for the one-pot synthesis of 3,4-dihydropyrimdin-2(1H)-one. Synth Commun 35:2561–2568

    Google Scholar 

  266. CuCl2/LiCl/EtOH: Manjula A, Rao BV, Neelakantan P (2005) An inexpensive protocol for Biginelli reaction. Synth Commun 34:2665–2671

    Google Scholar 

  267. CuBr2/EtOH: Zhou H, He M, Liu C, Jiang H, Luo G (2006) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones using CuBr2 as catalyst. Prep Biochem Biotechnol 36:375–381

    Google Scholar 

  268. ZnBr2/sf: Yu Y, Liu D, Liu C, Jiang H, Luo G (2007) An efficient one-pot Biginelli condensation of aliphatic aldehydes catalyzed by zinc bromide under solvent-free conditions. Prep Biochem Biotechnol 37(4):381–387

    Google Scholar 

  269. PEG-SO3H/MWI/sf: Wang X, Quan Z, Wang F, Wang M, Zhang Z, Li Z (2006) PEG-SO3H as catalyst for 3,4-dihydropyrimidones via Biginelli reaction under microwave and solvent-free conditions. Synth Commun 36:451–456

    Google Scholar 

  270. CAN or Oxone/MeOH/sonication: Yadav JS, Reddy BVS, Reddy KB, Raj KS, Prasad AR (2001) Ultrasound-accelerated synthesis of 3,4-dihydropyrimidin-2(1H)-ones with ceric ammonium nitrate. J Chem Soc Perkin Trans 1:1939–1941

    Google Scholar 

  271. TiCl3/THF: Ramesha S, Bhojya Naik HS, Harish Kumar HN (2007) Titanium trichloride-catalysed cyclocondensation: synthesis of 2-mercaptoquinoline substituted 1,2,3,4-tetrahydropyrimidinones. J Sulfur Chem 28:573–579

    Google Scholar 

  272. PPE/MWI: Foroughifar N, Mobinikhaledi A, Fathinejad Jirandehi H (2003) Microwave assisted synthesis of some pyrimidine derivatives using polyphosphate ester (PPE) in ceramic bath. Phosphorus Sulfur Silicon Relat Elem 178:1241–1246

    Google Scholar 

  273. PPE/MWI: Foroughifar N, Mobinikhaledi A, Fathinejad Jirandehi H, Memar S (2003) Microwave-assisted synthesis of some Bi- and Tricyclic pyrimidine derivatives. Phosphorus Sulfur Silicon Relat Elem 178:1269–1276

    Google Scholar 

  274. PPE/MWI: Kappe CO, Kumar D, Varma RS (1999) Microwave-assisted high-speed parallel synthesis of 4-aryl-3,4-dihydropyrimidin-2(1H)-ones using a solventless Biginelli condensation protocol. Synthesis 1999:1799–1803

  275. h ν/THF: Foroughifar N, Mobinikhaledi A, Fathinejad Jirandehi H (2003) Synthesis of some Biginelli compounds in solvent medium using a photochemistry method. Phosphorus Sulfur Silicon Relat Elem 178:495–500

    Google Scholar 

  276. CeCl3 × 7H2O/EtOH, H2O or sf: Bose DS, Fatima L, Mereyala HB (2003) Green chemistry approaches to the synthesis of 5-alkoxycarbonyl–4-aryl-3,4-dihydropyrimidin-2(1H)-ones by a three-component coupling of one-pot condensation reaction: comparison of ethanol, water, and solvent-free conditions. J Org Chem 68:587–590

    Google Scholar 

  277. InBr3/EtOH: Fu NY, Yuan YF, Cao Z, Wang SW, Wang JT, Peppe C (2002) Indium (III) bromide-catalyzed preparation of dihydropyrimidinones: improved protocol conditions for the Biginelli reaction. Tetrahedron 58:4801–4807

    Google Scholar 

  278. InBr3 or InCl3 × 4H2O/EtOH: Fu NY, Yuan YF, Pang ML, Wang JT, Peppe C (2003) Indium(III) halides-catalyzed preparation of ferrocenedihydropyrimidinones. J Organomet Chem 672:52–57

    Google Scholar 

  279. ZrCl4/EtOH: Venkateshwar Reddy C, Mahesh M, Raju PVK, Ramesh Babu T, Narayana Reddy VV (2002) Zirconium(IV) chloride catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Tetrahedron Lett 43:2657–2659

    Google Scholar 

  280. ZrOCl2 × 8H2O or ZrCl4/neat/100◦C: Rodriguez-Dominguez JC, Bernardi D, Kirsch G (2007) ZrCl4 or ZrOCl2 under neat conditions: optimized green alternatives for the Biginelli reaction. Tetrahedron Lett 48:5777–5780

    Google Scholar 

  281. Mn(OAc)3 × 2H2O: Kumar KA, Kasthuraiah M, Reddy CS, Reddy CD (2001) Mn(OAc)3 × 2H2O-mediated three-component, one-pot, condensation reaction: an efficient synthesis of 4-aryl-substituted 3,4-dihydropyrimidin-2-ones. Tetrahedron Lett 42:7873–7875

    Google Scholar 

  282. Ytterbium(III)-resin: Dondoni A, Massi A (2001) Parallel synthesis of dihydropyrimidinones using Yb(III)-resin and polymer-supported scavengers under solvent-free conditions. A green chemistry approach to the Biginelli reaction. Tetrahedron Lett 42:7975–7978

    Google Scholar 

  283. CuCl/BF3 × Et2O/AcOH: Hu EH, Sidler DR, Dolling UH (1998) Unprecedented catalytic three component one-pot condensation reaction: an efficient synthesis of 5-alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones. J Org Chem 63:3454–3457

    Google Scholar 

  284. CuCl/BF3 × Et2O/AcOH/mol.sieves/THF: Dondoni A, Massi A, Sabbatini S (2001) Towards the synthesis of C-glycosylated dihydropyrimidine libraries via the three-component Biginelli reaction. A novel approach to artificial nucleosides. Tetrahedron Lett 42:4495–4497

    Google Scholar 

  285. Cu(OTf)2/MeCN: Paraskar AS, Dewkar GK, Sudalai A (2003) Cu(OTf)2: a reusable catalyst for high-yield synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Tetrahedron Lett 44: 3305–3308

    Google Scholar 

  286. PhCH(Me)N+Me2Bu Br−/sf/100°C: Reddy KR, Reddy CV, Mahesh M, Raju PVK, Reddy VVN (2003) New environmentally friendly solvent free synthesis of dihydropyrimidinones catalysed by N-butyl-N,N-dimethyl-α-phenylethylammonium bromide. Tetrahedron Lett 44:8173–8175

    Google Scholar 

  287. NH4Cl/sf/100◦C: Shaabani A, Bazgir A, Teimouri F (2003) Ammonium chloride-catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones under solvent-free conditions. Tetrahedron Lett 44:857–859

    Google Scholar 

  288. NH4Cl/ultrasound irradiation/MeOH: Stefani HA, Oliveira CB, Almeida RB, Pereira CMP, Braga RC, Cella R, Borges VC, Savegnago L, Nogueira CW (2006) Dihydropyrimidin-2(1H)-ones obtained by ultrasound irradiation: a new class of potential antioxidant agents. Eur J Med Chem 41:513–518

    Google Scholar 

  289. Phosphotungstic acid (H3PW12O40)/EtOH: Jin TS, Xiao JC, Chen YX, Li TS (2004) Phosphotungstic acid catalysed one-pot synthesis of 5-alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2-ones. J Chem Res Synop 3:190–191

    Google Scholar 

  290. CuCl2 × 2H2O/CuSO4 × 5H2O/MWI: Gohain M, Prajapati D, Sandhu JS (2004) A novel Cu-catalysed three-component one-pot synthesis of dihydropyrimidin-2(1H)-ones using microwaves under solvent-free conditions. Synlett 2004:235–238

  291. Ion exchange resins (Amberlyst-15, Nafion H)/AcOH/MWI: Yadav JS, Reddy BVS, Reddy EJ, Ramalingam T (2000) Microwave-assisted efficient synthesis of dihydropyrimidines: improved high yielding protocol for the Biginelli reaction. J Chem Res Synop 7:354–355

    Google Scholar 

  292. SiO2/NaHSO4/MeCN: Adharvana Chari M, Syamasundar K (2004) Silicagel supported sodium hydrogensulfate as a heterogenous catalyst for high yield synthesis of 3,4-dihydropyrimidin-2(1H)-ones. J Mol Catal A Chem 221:137–139

    Google Scholar 

  293. Silica/Fe (Ferrihydrite silica aerogels)/EtOH: Martínez S, Meseguer M, Casas L, Rodríguez E, Molins E, Moreno-Manas M, Roig A, Sabastián RM, Vallribera A (2003) Silica aerogel-iron oxide nanocomposites: recoverable catalysts in conjugate additions and in the Biginelli reaction. Tetrahedron 59:1553–1556

    Google Scholar 

  294. Lanthanide halides derived from mischmetal (LnCl3 × 7H2O)/HCl/EtOH: Lannou M-L, Hélion F, Namy J-L (2008) Applications of lanthanide trichloride hydrates, prepared from mischmetall, in the Biginelli reaction. Synlett 2008:105–107

  295. LaCl3/graphite/HCl/MWI/sf: Khabazzadeh H, Saidi K, Sheibani H (2008) Microwave-assisted synthesis of dihydropyrimidin-2(1H)-ones using graphite supported lanthanum chloride as a mild and efficient catalyst. Bioorg Med Chem Lett 18:278–280

    Google Scholar 

  296. ClCH2CO2H/sf/90◦C: Yu Y, Liu D, Liu C, Luo G (2007) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones using chloroacetic acid as catalyst. Bioorg Med Chem Lett 17:3508–3510

    Google Scholar 

  297. Aluminia–sulfuric acid: Besoluk S, Kucukislamoglu M, Nebioglu N, Zengin M, Arslan M (2008) Solvent-free synthesis of dihydropyrimidinones catalyzed by alumina sulfuric acid at room temperature. J Iran Chem Soc 5:62–66

    Google Scholar 

  298. Fe(HSO4)3/MeCN or sf/100◦C: Shirini F, Zolfigol MA, Abri AR (2008) Fe (HSO4)3 as an efficient catalyst for the preparation of 3,4-dihydropyrimidin-2(1H)-ones in solution and under solvent-free conditions. J Iran Chem Soc 5:96–99

    Google Scholar 

  299. CuCl2 × 2H2O/C12H25SO3Na/H2O: Xu F, Wang JJ, Tian YP (2008) New procedure for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones by Biginelli reaction. Synth Commun 38:1299–1310

    Google Scholar 

  300. Pyrazolidine dihydrochloride: Suzuki I, Iwata Y, Takeda K (2008) Biginelli reactions catalyzed by hydrazine type organocatalyst. Tetrahedron Lett 49:3238–3241

    Google Scholar 

  301. Sr(NO3)2/AcOH: Liu CJ, Wang JD, Li YP (2006) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-(thio)ones using strontium(II) nitrate as a catalyst. J Mol Catal A Chem 258: 367–370

    Google Scholar 

  302. CuI/H2O, MeCN or sf: Kalita HR, Phukan P (2007) CuI as reusable catalyst for the Biginelli reaction. Catal Commun 8:179–182

    Google Scholar 

  303. Uronium hydrogen sulfates/sf: Salehi P, Dabiri M, Zolfigol MA, Baghbanzadeh M (2005) A green approach to the synthesis of 2,3-dihydropyrimidin-2(1H)-ones by uronium hydrogansulfate under solvent-free conditions. Heterocycles 65:1177–1181

    Google Scholar 

  304. H3PMo12O4/AcOH: Heravi MM, Bakhtiari K, Bamoharram FF (2006) 12-Molybdophosphoric acid: a recyclable catalyst for the synthesis of Biginelli-type 3,4-dihydropyrimidine-2(1H)-ones. Catal Commun 7:373–376

    Google Scholar 

  305. TiCl4/sf: Valizadeh H, Gholipur H, Zarrebin R, Amiri M, Sabzi MR (2008) Titanium(IV) Chloride catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones under solvent-free conditions via three-component Biginelli reaction. Phosphorus Sulfur Silicon Relat Elem 183:1552–1555

    Google Scholar 

  306. TiCl4/EtOH/80°C: Nagawade RR, Kotharkar SA, Shinde DB (2005) Titanium(IV) chloride catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones. Mendeleev Commun 15:150–151

    Google Scholar 

  307. Supported H3PW12O40 or H3PMo12O40/MeCN: Fazaeli R, Tangestaninejad S, Aliyan H, Moghadam M (2006) One-pot synthesis of dihydropyrimidinones using facile and reusable polyoxometalate catalysts for the Biginelli reaction. Appl Catal A Gen 309:44–51

    Google Scholar 

  308. Keggin-type heteropolyacids—H3PW12O40, H3PMo12O40 or H4SiW12O40/MeCN: Rafiee E, Jafari H (2006) A practical and green approach towards synthesis of dihydropyrimidinones: using heteropoly acids as efficient catalysts. Bioorg Med Chem Lett 16:2463–2466

    Google Scholar 

  309. H3PW12O40/MWI/sf: Mishra BG, Kumar D, Rao VS (2006) H3PW12O40 catalyzed expeditious synthesis of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. Catal Commun 7:457–459

    Google Scholar 

  310. H3PW12O40 or H3PW12O40–SiO2/80°C/sf: Amini MM, Shaabani A, Bazgir A (2006) Tungstophosphoric acid (H3PW12O40): an efficient and eco-friendly catalyst for the one-pot synthesis of dihydropyrimidin-2(1H)-ones. Catal Commun 7:843–847

    Google Scholar 

  311. HBF4/sf/45°C: Chen WY, Qin SD, Jin JR (2007) HBF4- catalyzed Biginelli reaction: one-pot synthesis of dihydropyrimidin-2(1H)-ones under solvent-free conditions. Catal Commun 8:123–126

    Google Scholar 

  312. Trichloroisocyanuric acid/EtOH: Bigdeli MA, Jafari S, Mahdavinia GH, Hazarkhani H (2007) Trichloroisocyanuric acid, a new and efficient catalyst for the synthesis of dihydropyrimidinones. Catal Commun 8:1641–1644

    Google Scholar 

  313. Cu(BF4)2 × xH2O/neat: Kamal A, Krishnaji T, Azhar MA (2007) Copper(II) tetrafluoroborate as a mild and efficient catalyst for the one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions. Catal Commun 8:1929–1933

    Google Scholar 

  314. Fe(CF3CO2)3 or Fe(OTf)3/sf: Adibi H, Samimi HA, Beygzadeh M (2007) Iron(III) trifluoroacetate and trifluoromethanesulfonate: recyclable lewis acid catalysts for one-pot synthesis of 3,4-dihydropyrimidinones or their sulfur analogues and 1,4-dihydropyridines via solvent-free Biginelli and Hantzsch condensation protocols. Catal Commun 8:2119–2124

    Google Scholar 

  315. MoO3/Al2O3/sf/80°C: Jain SL, Prasad VVDN, Sain B (2007) Alumina supported MoO3: An efficient and reusable heterogeneous catalyst for synthesis of 3,4-dihydropyridine-2(1H)-ones under solvent free conditions. Catal Commun 9: 499–503

    Google Scholar 

  316. Ca(HSO4)2, Zn(HSO4)2 or Oxone/sf/90°C: Niknam K, Zolfigol MA, Hossieninejad Z, Daneshvar N (2007) Efficient synthesis of 3,4-dihydropyrimidin-2(1H)-one using metal hydrogen sulfates M(HSO4) n as catalyst under solvent-free conditions. Chin J Catal 28:591–595

    Google Scholar 

  317. HCO 2H/sf/MWI: Jiang C, You QD (2007) An efficient and solvent-free one-pot synthesis of dihydropyrimidinones under microwave irradiation. Chin Chem Lett 18:647–650

  318. Heulandite type zeolite (CaAl2Si7O18 × 6H2O)/AcOH: Tajbakhsh M, Mohajerani B, Heravi MM, Ahmadi AN (2005) Natural HEU type zeolite catalyzed Biginelli reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives. J Mol Catal A Chem 236:216–219

    Google Scholar 

  319. Ion exchange resin Nafion NR-50/MeCN: Joseph JK, Jain SL, Sain B (2006) Ion exchange resins as recyclable and heterogeneous solid acid catalysts for the Biginelli condensation: an improved protocol for the synthesis of 3,4-dihydropyrimidin-2-ones. J Mol Catal A Chem 247:99–102

    Google Scholar 

  320. H3PW12O40/SiO2/MeCN: Rafiee E, Shahbazi F (2006) One-pot synthesis of dihydropyrimidones using silica-supported heteropoly acid as an efficient and reusable catalyst: Improved protocol conditions for the Biginelli reaction. J Mol Catal A Chem 250:57-61

    Google Scholar 

  321. ZnI2/MeCN/high pressure: Jenner G (2004) Effect of high pressure on Biginelli reactions. Steric hindrance and mechanistic considerations. Tetrahedron Lett 45:6195–6198

    Google Scholar 

  322. Mg(ClO4)2/ultrasound/EtOH: Zhang X, Li Y, Liu C, Wang J (2006) An efficient synthesis of 4-substituted pyrazolyl-3,4-dihydropyrimidin-2(1H)-(thio)ones catalyzed by Mg(ClO4)2 under ultrasound irradiation. J Mol Catal A Chem 253:207–211

    Google Scholar 

  323. SiO2–Si(CH2)3 SO3H/MeCN: Gupta R, Paul S, Gupta K (2007) Covalently anchored sulfonic acid onto silica as an efficient and recoverable interphase catalyst for the synthesis of 3,4-dihydropyrimidinones/thiones. J Mol Catal A Chem 266:50–54

    Google Scholar 

  324. Metallophthalocyanines/MeCN: Jain SL, Joseph JK, Singhal S, Sain B (2007) Metallophthalocyanines (MPcs) as efficient heterogeneous catalysts for Biginelli condensation: application and comparison in catalytic activity of different MPcs for one pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones. J Mol Catal A Chem 268:134–138

    Google Scholar 

  325. Nafion-H resin/EtOH: Lin H, Zhao Q, Xu B, Wang X (2007) Nafion-H catalyzed cyclocondensation reaction for the synthesis of octahydroquinazolinone derivatives. J Mol Catal A Chem 268:221–226

    Google Scholar 

  326. Y(NO3)3 × 6H2O/sf: Nandurkar NS, Bhanushali MJ, Bhor MD, Bhanage BM (2007) Y(NO3)3 × 6H2O: A novel and reusable catalyst for one pot synthesis of 3,4-dihydropyrimidin-2(1H)- ones under solvent-free conditions. J Mol Catal A Chem 271: 14–17

    Google Scholar 

  327. Si(OEt)4/FeCl3: Cepanec I, Litvić M, Bartolinčiç, Lovrić M (2005) Ferric chloride/tetraethyl orthosilicate as an efficient system for synthesis of dihydropyrimidinones by Biginelli reaction. Tetrahedron 61:4275–4280

    Google Scholar 

  328. SiCl4/DMF/MeCN/rt: Ramalingan C, Kwak YW (2008) Tetrachlorosilane catalyzed multicomponent one-step fusion of biopertinent pyrimidine heterocycles. Tetrahedron 64: 5023–5031

    Google Scholar 

  329. Sr(OTf)2/sf: Su W, Li J, Zheng Z, Shen Y (2005) One-pot synthesis of dihydropyrimidiones catalyzed by strontium(II) triflate under solvent-free conditions. Tetrahedron Lett 46:6037–6040

    Google Scholar 

  330. HCl/H2O/20°C: Karimullah EA (1967) Pakistan J Sci Ind Res 10:83; Chem Abstr (1968) 68:78231z

    Google Scholar 

  331. TMSOTf/MeCN/rt: Subhas Bose D, Kumar RK, Fatima L (2004) A remarkable rate acceleration of the one-pot three-component cyclocondensation reaction at room temperature: an expedient synthesis of mitotic kinesin Eg5 inhibitor monastrol. Synlett 2004:279–282

  332. Sulfonic salicilic acid: Liu JH (2008) Synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives using sulfonic salicylic acid as catalyst. Contemp Chem Ind 37:56–58

    Google Scholar 

  333. Pr(MeSO3)3/EtOH: Wang M, Song Z, Gong H, Jiang H (2008) Praseodymium methanesulfonate catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones. Prep Biochem Biotechnol 38:105–114

    Google Scholar 

  334. AlCl3/MeCN or AlBr3/MeCN: Saini A, Kumar S, Sandhu JS (2007) Aluminium (III) halides mediated synthesis of 5-unsustituted 3,4-dihydropyrimidin-2(1H)-ones via three component Biginelli-like reaction. Indian J Chem 46B:1690–1694

    Google Scholar 

  335. CuCl2 × 2H2O/HCl/grinding: Pathak VN, Gupta R, Varshney B (2008) An efficient, inexpensive ‘Green Chemistry’ route to multicomponent Biginelli condensation catalyzed by CuCl2 × 2H2O–HCl. Indian J Chem 47B:434–438

    Google Scholar 

  336. GaCl3/MWI/sf or GaBr3/MWI/sf: Saini A, Kumar S, Sandhu JS (2007) Gallium(III) halides catalyzed, microwave enhanced, synthesis of 3,4-dihydropyrimidin-2-(1H)-ones under solvent free condition. Indian J Chem 46B:1886–1889

    Google Scholar 

  337. In(OTf)3/EtOH: Ghosh R, Maiti S, Chakraborty A (2004) In(OTf)3-catalysed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. J Mol Catal A Chem 217:47–50

    Google Scholar 

  338. H3PW12O40/AcOH: Heravi MM, Derikvand F, Bamoharram FF (2005) A catalytic method for synthesis of Biginelli-type 3,4-dihydropyrimidin-2(1H)-one using 12-tungstophosphoric acid. J Mol Catal A Chem 242:173–175

    Google Scholar 

  339. Ziegler–Natta catalyst system (TiCl4–MgCl2-4CH3OH)/sf: Kumar A, Maurya RA (2007) Synthesis of 3,4-dihydropyrimidin-2(1H)-ones using Ziegler–Natta catalyst system under solvent free conditions. J Mol Catal A Chem 272:53–56

    Google Scholar 

  340. I2/Al2O3/MWI/sf: Saxena I, Borah DC, Sarma JC (2005) Three component condensations catalyzed by iodine–alumina for the synthesis of substituted 3,4-dihydropyrimidin-2(1H)-ones under microwave irradiation and solvent-free conditions. Tetrahedron Lett 46:1159–1160

    Google Scholar 

  341. CeO2 supported on poly(4-vinylpyridine-co-divinylbenzene) (PVP-DVB)/H2O: Sabitha G, Reddy KB, Yadav JS, Shailaja D, Sivudu KS (2005) Ceria/vinylpyridine polymer nanocomposite: an ecofriendly catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Tetrahedron Lett 46:8221–8224

    Google Scholar 

  342. Fluoroapatite Ca10(PO4)6F2/MCl2/toluene (M = Zn, Cu, Ni): El Badaoui H, Bazi F, Tahir R, Lazrek HB, Sebti S (2005) Synthesis of 3,4-dihydropyrimidin-2-ones catalysed by fluorapatite doped with metal halides. Catal Commun 6:455–458

    Google Scholar 

  343. PVP-DVB/CuSO4/MeOH: Yarapathi RV, Kurva S, Tammishetti S (2004) Synthesis of 3,4-dihydropyrimidin-2(1H)-ones using reusable poly (4-vinylpyridine-co-divinylbenzene)-Cu(II)complex. Catal Commun 5:511–513

    Google Scholar 

  344. KAl(SO4)2 × 12H2O/SiO2/sf: Azizian J, Mohammadi AA, Karimi AR, Mohammadizadeh MR (2006) KAl(SO4)2 × 12H2O supported on silica gel as a novel heterogeneous system catalyzed Biginelli reaction. One-pot synthesis of dihydropyrimidinones under solvent-free conditions. Appl Catal A Gen 300:85–88

    Google Scholar 

  345. Montmorillonite K10 clay/MWI/sf: Krstenansky JL, Khmelnitsky Y (1999) Biocatalytic combinatorial synthesis. Bioorg Med Chem 7:2157–2162

    Google Scholar 

  346. H4PMo11VO40/EtOH: Maradur SP, Gokavi GS (2007) Heteropoly acid catalyzed synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Catal Commun 8:279–284

    Google Scholar 

  347. Si-MCM-41 supported metal halides/MWI/sf: Choudhary VR, Tillu VH, Narkhede VS, Borate HB, Wakharkar RD (2003) Microwave assisted solvent-free synthesis of dihydropyrimidinones by Biginelli reaction over Si-MCM-41 supported FeCl3 catalyst. Catal Commun 4:449–453

    Google Scholar 

  348. Ph3P/sf/100°C: Debache A, Amimour M, Belfaitah A, Rhouati S, Carboni B (2008) A one-pot Biginelli synthesis of 3,4-dihydropyrimidin-2-(1H)-ones/thiones catalyzed by triphenylphosphine as Lewis base. Tetrahedron Lett 49:6119–6121

    Google Scholar 

  349. H3PW12O40/sf/100°C, acylals instead of aldehydes: Khabazzadeh H, Saidi K, Sheibani H (2008) Highly efficient conversion of aromatic acylals to 3,4-dihydropyrimidinones: a new protocol for the Biginelli reaction. ARKIVOC xv:34–41; Available, URL:http://www.arkat-usa.org

  350. Scolecite/MeCN: Shinde SV, Jadhav WN, Lande MK, Gadekar LS, Arbad BR, Kondre JM, Karade NN (2008) Scolecite as a novel heterogeneous acid catalyst for an efficient synthesis of 3,4-dihydropyrimidin-2(1H)-ones Via multi-component Biginelli reaction. Catal Lett 125:57–61

    Google Scholar 

  351. [BMIm]BF4 or [BMIm]PF6/sf: Peng J, Deng Y (2002) Ionic liquids catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Chin J Org Chem 22:71–73

    Google Scholar 

  352. Zn(NO3)2/EtOH: Wang CF, Jiang H, Gong H, Wang M, Wang ZC (2006) Biginelli condensation of aliphatic aldehydes catalyzed by inorganic zinc compounds. Chin J Org Chem 26:333–336

    Google Scholar 

  353. NiCl2 × 6H2O: Lu J, Wang F, Bai Y, Li W (2002) Catalysis of the Biginelli reaction by NiCl2 × 6H2O-one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Chin J Org Chem 22:788–792

    Google Scholar 

  354. Mg(ClO4)2/MeCN: Chen W-Y, Lu J (2004) Mg(ClO4)2 as a powerful catalyst for synthesis of 1,2,3,4-tetrahydropyrimidin-2-ones. Chin J Org Chem 24:1111–1113

    Google Scholar 

  355. n-Bu2SnO/sf/100°C: Wang H-S, Zhao L-F, Miao J-Y (2005) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by n-Bu2SnO. Chem Reagents 27:171–172,178 (in Chinese)

    Google Scholar 

  356. [BMIm]Sac: Li M, Guo W-S, Wen L-R, Zhang X-L (2005) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by nontoxic ionic liquid. Chin J Org Chem 25:1062–1065

    Google Scholar 

  357. KH2PO4/glycol: Fu Y, Zhang A-L, Du H-M, Lei T-T (2007) Synthesis of 5-ethoxycarbonyl-4-phenyl-6-methyl-3,4-dihydropyrimidine-2-one catalyzed by KH2PO4. Chem Bioeng 24:28–30 (in Chinese)

    Google Scholar 

  358. FeCl3 × 6H2O/EtOH/MWI: Wang DC, Yuan TF, Yang XN, Qu GR (2007) Microwave-assisted green synthesis of 3,4-dihydropyrimidin-2(1 H)-ones catalyzed by ferric chloride hexahydrate. Chin J Org Chem 27:1034–1037

    Google Scholar 

  359. Nafion-H resin: Lin HX, Zhao QJ, Xu B, Wang XH (2007) A green synthesis of dihydropyrimidinones by Biginelli reaction over Nafion-H catalyst. Chin Chem Lett 18:502–504

    Google Scholar 

  360. ClSO3H/sf/60°C: Kotharkar SA, Nagawade RR, Shinde DB (2006) Chlorosulfonic acid catalyzed highly efficient solvent-free synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones. Ukr Bioorg Acta 2:17–21

    Google Scholar 

  361. Bi(NO3)3/MeCN: Yang Z-P, Sheng S-R, Lin S-Y, Zou W, Liu X-L (2007) Bismuth(III) nitrate catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones. J Jiangxi Norm Univ (Nat Sci Ed) 31:262–267 (in Chinese)

    Google Scholar 

  362. [BMIm]Sac/sf: Wang SW, Cao W, Li M (2007) Design of comprehensive and innovative Experiment-Biginelli reaction. Res Explor Lab 26:100–102 (in Chinese)

    Google Scholar 

  363. [BPy]BF4: Zhou MY, Li YQ (2006) Synthesis of 3,4-dihydropyrimidin–2(1H)-ones using ionic liquid n-butyl pyridinium tetrafluoroborate as a catalyst and medium. J Jinan Univ (Nat Sci Med Ed) 27:435–438

    Google Scholar 

  364. Expansive graphite: Zhang Y-Q, Wang C, Li G-S, Li J-C, Liu H-M, Wu Q-H (2005) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by expandable graphite. Chin J Org Chem 25:1265–1267

    Google Scholar 

  365. [Bmim]BF4/MWI: Shao GQ (2004) Biginelli condensation assisted by microwave irradiation in ionic liquids. Chin J Synth Chem 12:325–328 (in Chinese)

    Google Scholar 

  366. Cu/silica xerogel composite: Russowsky D, Benvenutti EV, Roxo GS, Grasel F (2007) Multicomponent synthesis of 3,4-dihydropyrimidin-2-(1H)-ones with a Cu/Silica xerogel composite catalyst. Lett Org Chem 4:39–42

    Google Scholar 

  367. (CH3SO3)3Nd/EtOH: Wang M, Jiang H, Wang R, Wang Z (2004) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones using neodymium methanesulfonate as a catalyst. J Chin Rare Earth Soc 22(z2):81–84

    Google Scholar 

  368. HClO4-SiO2: Maheswara M, Oh SH, Kim K, Do JY (2008) Synthesis of 3,4-dihydropyrimidin-2(1H)-ones using HClO4-SiO2 as a heterogeneous and recyclable catalyst. Bull Korean Chem Soc 29:1752–1754

  369. ZrO2-nanopowder/sf/MWI: Gopalakrishnan M, Sureshkumar P, Thanusu J, Kanagarajan V, Ezhilarasi MR (2008) An expedient one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones and -thiones catalyzed by zirconia nanopowder. An improved protocol for the Biginelli cyclocondensation compounds in “Dry Media”. Lett Org Chem 5:142–147

    Google Scholar 

  370. FeCl3 × 6H2 O: Lu J, Ma H-R, Li W-H (2000) A novel one-pot synthesis of 3,4-dihydropyrimidine-2(1H)-ones catalyzed by ferric chloride hexahydrate. Chin J Org Chem 20:815–818

  371. I2/ultrasound: Wang J-S, Li J-T, Lin Z-P (2006) Iodine catalyzed one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones under ultrasound irradiation. Lett Org Chem 3:523–525

    Google Scholar 

  372. Hydroxyapatite doped with ZnCl2, CuCl2, NiCl2 and CoCl2: El Badaoui H, Bazi F, Sokori S, Boulaajaj S, Lazrek HB, Sebti S (2005) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones using ZnCl2, CuCl2, NiCl2 and CoCl2 doped hydroxyapatite. Lett Org Chem 2:561–565

    Google Scholar 

  373. Silica sulfuric acid/[Bmim]Br/100°C: Shaabani A, Sarvary A, Rahmati A, Rezayan AH (2007) Ionic liquid/silica sulfuric acid promoted fast synthesis of a Biginelli-like scaffold reaction. Lett Org Chem 4:68–71

    Google Scholar 

  374. H3PW12O40: Jin T-S, Xiao J-C, Li T-S (2003) One-pot synthesis of 5-alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2-ones catalyzed by phosphotungstic acid. Chin J Org Chem 23(z1):93

  375. Amino Acetic Acid: Zhao X-D, Yu Y, Liu D (2007) One-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by amino acetic acid. J Liaoning Univ Petrol Chem Technol 27(2):35–38 (in Chinese)

    Google Scholar 

  376. AlCl3: Shi L, Zhu G-H, Ding X-Y, Li J-H, Jing X-H, Hua P (2007) Synthesis of 3,4-dihydropyrimidin-2-(1H)-one catalyzed by aluminum chloride. Chem Reagents 29:251–255 (in Chinese)

  377. PhCO2H: Yu Y, Liu D, Liu C-S, Luo G-X (2007) Benzoic acid catalyzed single-reactor synthesis of 3,4-dihydropyrimidin-2(1H)-ones. Chem Reagents 29:181–183

  378. HClO4: Ding X-Y, Shi L, Jing X-H, Zhu G-H, Li J-H, Hua P (2007) Synthesis of 3,4-dihydropyrimidin-2(1H)-one catalyzed by HClO4. Chem Reagents 29:175–176

  379. H2SO4/sf/MWI: Liang B, Wang X-T, Wang J-X (2006) Synthesis of substituted 3,4-dihydropyrimidin-2(1H)-ones under microwave irradiation and solvent-free condition catalyzed by sulphuric acid. Chem Res and Appl 18:927–930 (in Chinese)

    Google Scholar 

  380. NH2SO3H/EtOH: Ding X, Shi L, Jing X (2005) Synthesis of 4-Phenyl-6-methyl-5-ethoxycarbonyl-3,4-dihydropyrimidin-2(1H)-one catalyzed by sulfamic acid. Adv Fine Petrochem 6(10):26–28 (in Chinese)

    Google Scholar 

  381. InBr3: Fu NY, Pang ML, Yuan YF, Wang JT (2002) Indium (III) tribromide: an excellent catalyst for Biginelli reaction. Chin Chem Lett 13:921–922

    Google Scholar 

  382. SmI2: Zhou Z, Han X, Xu F, Shen Q, Zhang Y (2007) Synthesis and crystal structure of 5-acetyl-6-methyl-4-(2-furyl)-3,4-dihydropyrimidine-2(1H)-one. J Suzhou Univ Nat Sci Ed 23(4):67–71

  383. β-Cyclodextrin/HCl/EtOH: Zhou H-X, He M, Liu C-S, Luo G-X (2006) Synthesis of 3,4-dihydropyrimidin-2(1H)-ones using protic acid surfactant and synergistic catalysis. J Liaoning Univ Petrol Chem Technol 26(1):16–18

    Google Scholar 

  384. Biginelli reaction in two-phase system: Zhou H-X, He M, Liu C-S, Luo G-X (2006) Synthesis of 3,4-dihydropyrimidin-2(1H)-ones using a two-phase system. Chem Reagents 28:377–378, 381

    Google Scholar 

  385. NaBF4: Bandgar BP, Kamble VT, Bavikar SN, Dhavane A (2007) Sodium tetrafluoroborate as a new and highly efficient catalyst for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones. J Chin Chem Soc 54:263–266

  386. InBr3: Fu NY, Pang ML, Yu YF, Wang JT (2003) A novel one-pot synthesis of 3,4-dihydropyrimidine-2(1H)-ones catalyzed by indium tribromide. Chem J Chin Univ 24:79–81 (in Chinese)

  387. TAFF Bentonitic clay/sf/IR light: Arroyo G, Delgado F, Gómez L, Miranda R, Osnaya R, Salmón M (2001) Contribution to the Biginelli reaction, using a bentonitic clay as catalyst and a solventless procedure. J Mex Chem Soc 45:206–207

    Google Scholar 

  388. \({{\rm Ph}_{3}{\rm PH}^{+}ClO_{4}^{-}}\) /MeCN/80°C: Shanmugam P, Perumal PT (2003) 3,4-Dihydropyrimidin-2(1H)-ones via the Biginelli condensation promoted by triphenylphosphonium perchlorate. J Chem Res 2003:601–602

  389. Pb(NO3)2/MeCN: Boumoud T, Boumoud B, Rhouati S, Belfaitah A, Debache A, Mosset P (2008) An efficient and recycling catalyst for the one-pot three-component synthesis of substituted 3,4-dihydropyrimidin-2(1H)-ones. EJ Chem 5:688–695; Available, URL:http://www.e-journals.in/open/vol5/no4/0758-688-695.pdf

    Google Scholar 

  390. CuCl2 × 2H2O/MWI: Sancheti A, Mehta S, Sony MD, Vardia J, Punjabi PB (2007) A facile and efficient synthesis of dihydropyrimidinones catalyzed by CuCl2 × 2H2O. Afinidad 64(532):730–733

    Google Scholar 

  391. Kolosov MA, Orlov VD, Vashchenko VV, Shishkina SV, Shishkin OV (2007) 5-Cinnamoyl- and 5-(Ethoxycarbonyl)-6-styryl derivatives of 4-Aryl-3,4-dihydropyrimidin-2(1H)-ones. Collect Czech Chem Commun 72:1219–1228

    Google Scholar 

  392. Kolosov MA, Orlov VD, Vasil’eva YuM (2006) The alkylation of 5-acetyl-4-phenyl-3,4-dihydropyrimidin-2(1H)-thiones derivatives. Kharkov Univ Bull Chem Ser 731:69 (in Russian)

    Google Scholar 

  393. Kolosov MA (2007) 5-Acetyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones and their derivatives: synthesis and reactions. PhD Thesis, Kharkov, 135 p (in Russian)

  394. MWI/sf or EtOH/MWI, with heat sinks: Mobinikhaledi A, Foroughifar N, Fathinejad Jirandehi H (2004) Investigation of the effects of some heat sinks in microwave-assisted synthesis of some Biginelli compounds. Phosphorus Sulfur Silicon Relat Elem 179:2259–2263

    Google Scholar 

  395. Neat/MWI (800W, 110–120°C, 1 min): Kidwai M, Saxena S, Mohan R, Venkataramanan R (2002) A novel one-pot synthesis of nitrogen containing heterocycles: an alternate methodology to the Biginelli and Hantzsch reactions. J Chem Soc Perkin Trans 1:1845–1846

    Google Scholar 

  396. Ranu BC, Hajra A, Dey SS (2002) A practical and green approach towards synthesis of dihydropyrimidinones without any solvent or catalyst. Org Proc Res Dev 6: 817–818

    Article  CAS  Google Scholar 

  397. Stefani HA, Gatti DM (2000) 3,4-Dihydropyrimidin-2(1H)-ones: fast synthesis under microwave irradiation in solvent free conditions. Synth Commun 30: 2165–2173

    Article  CAS  Google Scholar 

  398. Mamaev VP, Dubovenko ZD (1970) Pyrimidines. XXI. 5-Substituted 2-hydroxy-4,6-diphenylpyrimidines. Chem Heterocycl Comp 6: 501–504

    Article  Google Scholar 

  399. Zigeuner G, Nischk W, Jurasovits B (1966) Ueber heterocyclen, 14. Mitt.: 2-Oxo- bzw. 2-thiono-5-acyl–6-methyltetrahydropyrimidine. Monatsh Chem 97:1611–1619

    Article  CAS  Google Scholar 

  400. Kappe CO (1997) A reexamination of the mechanism of the Biginelli dihydropyrimidine synthesis. Support for an N-Acyliminium ion intermediate. J Org Chem 62: 7201–7204

    CAS  Google Scholar 

  401. Sweet F, Fissekis JD (1973) On the synthesis of 3,4-dihydro-2(1H)-pyrimidinones and the mechanism of the Biginelli reaction. J Am Chem Soc 95: 8741–8749

    Article  CAS  Google Scholar 

  402. Atwal KS, Rovnyak GC, O’Reilly BC, Schwartz J (1989) Substituted 1,4-dihydropyrimidines. 3. Synthesis of selectively functionalized 2-hetero-1,4-dihydropyrimidines. J Org Chem 54: 5898–5907

    Article  CAS  Google Scholar 

  403. Bakibaev AA, Filimonov VD (1991) Ureas in organic synthesis. II. Synthesis of hydrogenated acridine-1,8-diones & 1,4-dihydropyrimidines by reaction of urea with 1,3-dicarbonyl compounds. Zh Organ Khimii (Russ J Org Chem) 27: 854–859 (in Russian)

    CAS  Google Scholar 

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Authors and Affiliations

  1. Department of Organic Chemistry, V.N. Karazin Kharkov National University, 61077, Kharkov, Ukraine

    Maksim A. Kolosov, Valeriy D. Orlov & Dmitriy A. Beloborodov

  2. Physico-chemical Department, State Enterprise “Luganskstandart metrology”, 91021, Lugansk, Ukraine

    Victor V. Dotsenko

  3. ChemEx Laboratory, Vladimir Dal’ East Ukrainian National University, 91034, Lugansk, Ukraine

    Victor V. Dotsenko

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  1. Maksim A. Kolosov
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  2. Valeriy D. Orlov
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  3. Dmitriy A. Beloborodov
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  4. Victor V. Dotsenko
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Correspondence to Victor V. Dotsenko.

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Kolosov, M.A., Orlov, V.D., Beloborodov, D.A. et al. A chemical placebo: NaCl as an effective, cheapest, non-acidic and greener catalyst for Biginelli-type 3,4-dihydropyrimidin-2(1H)-ones (-thiones) synthesis. Mol Divers 13, 5–25 (2009). https://doi.org/10.1007/s11030-008-9094-8

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