Chemistry of Pyrazole-3(5)-Diazonium Salts (Review)*
- 504 Downloads
The methods of synthesis, structure, reactivity, and synthetic utility of pyrazole-3(5)-diazonium salts are reviewed here for the first time, with emphasis on heterocyclization reactions of these compounds.
Keywordsfused pyrazole systems pyrazole-3(5)-diazonium salts azo coupling heterocyclization
More than one hundred years have passed since α-diazo derivatives of pyrazole were discovered. A substantial amount of knowledge has been accumulated over this time regarding the stability, structure, and transformations of these compounds. However, the chemistry of pyrazole-3(5)-diazonium salts developed rapidly only in the second half of the 20th century, with many studies performed in various countries, in particular Germany, Egypt, Russia, and Japan. Unfortunately, no systematic review has been compiled for the wide range of data about pyrazole-3(5)-diazonium salts. Some aspects regarding the properties of these compounds have been discussed in reviews and monographs on other topics [1-17].
1. Structure, Preparation, and Reactivity Evaluation of Pyrazole α-Diazo Derivatives
Detailed discussion of 3-diazopyrazole 2 chemistry would be beyond the scope of this review. Short summaries of the structure and properties of these compounds are available from many sources [5-7, 10, 18-21].
The stability and high reactivity of pyrazole-3(5)-diazonium salts is based on the significant resonance stabilization of N-unsubstituted ion 1'.
The terminal nitrogen atom is the main reactive site during transformations of pyrazole-3(5)-diazonium salts that do not involve elimination of nitrogen. One of the principal factors affecting the reactivity of any organic compound is the nature of its substituents. Electron-withdrawing groups, similarly to the ring nitrogen atoms, generally increase the electrophilic properties of a diazo group [5, 22, 23]. The presence of electron-donating substituents stabilizes the diazonium cation, but reduces the positive charge at the terminal nitrogen atom and decreases the electrophilicity of diazo group. In line with this, 4-nitro- and 4-cyanopyrazole-3(5)-diazonium salts can be heated in aqueous solutions to near boiling without substantial decomposition .
No X-ray structural data are available for pyrazole-3(5)-diazonium salts. However, X-ray structural data for the isomeric 1H-3,5-dimethylpyrazole-4-diazonium chloride  indicate that compounds 1 should have structures similar to their aromatic carbocyclic analogs. Shortened С–N bonds (1.351 Å) in the molecule of pyrazole-4-diazonium salts point to the strong conjugation of diazonium group with the heteroaromatic ring.
The earliest reports of 5-aminopyrazole derivative reactions with nitrous acid were by German chemists Seidel  and Knorr . They were the first to prepare α-aminopyrazoles 3 and proposed that the products formed from the reaction of compound 3 with sodium nitrite in acidic medium were nitrosoamino compounds 4,which could be used in further condensation reactions to obtain a range of other products. However, their assumptions about the identity and structure of the obtained compounds were not correct, as the reaction conditions precluded the formation of pyrazole-3(5)-diazonium salts.
Other sources [30-32] report successful diazotization of α-aminopyrazoles by various methods, including the "direct" approach (sodium nitrite, threefold excess of strong acid, 0°С) . The unsubstituted position 4 of pyrazole ring is quite reactive, leading to the presence of oxime 5 as impurity upon regular diazotization procedure with nitrous acid. Increasing the concentration of mineral acid and decreasing the temperature resulted in higher yields of salts 1 . Under certain conditions, С-nitrosation of pyrazoles 3 is possible while leaving the amino groups intact [35-38].
An analogous method was applied to the synthesis of diazonium salts 1 (R = R1 = H), with mechanism involving a sequence of nitrosation at endocyclic nitrogen atom, single-electron oxidation, diazotization, denitrosation, and aromatization .
Interestingly, the formation of diazonium salts by interaction of partially hydrogenated aminopyrazoles with nitrous acid was dismissed in earlier publication .
Methods for the preparation of pyrazole diazonium salts [22, 42, 43] include Knoevenagel reaction (isoamyl or amyl nitrite, concentrated mineral acid, organic solvent), which allowed to isolate the solid salts 1 in pure form. Diazotization of 5-aminopyrazoles was also performed in anhydrous medium, using nitrosyl chloride or alkyl nitrites in chloroform .
Often no distinction is made whether diazo compounds or diazonium salts are the reactive species, and whether there are prototropic equilibria between the forms and how they are affected by solvents. It has been noted that dissolution of diazonium salts in chloroform leads to deprotonation forming 3-diazopyrazoles 2 .
The reactivity of pyrazole-3(5)-diazonium salts is comparable to that of phenyldiazonium chloride, while 3-diazopyrazoles have properties similar to aliphatic diazo compounds [22, 23, 46, 47]. The stretching frequency of N2 + group in compounds 1 is close to that of aromatic diazonium salts . However, 3(5)-diazo derivatives of pyrazole are considerably more stable compared to carbocyclic analogs, enabling their isolation when necessary [1, 3, 22, 24, 38].
The considerable interest in pyrazole-3(5)-diazonium salts has several reasons. First of all, these compounds are thermally and chemically more stable than aromatic and many heterocyclic analogs. For example, triazole diazonium salts easily eliminate a nitrogen molecule, thus are prepared in nitrate form . For the same reason, both series of aminoimidazoles are diazotated in concentrated sulfuric and tetrafluoroboric acids [49, 50]. Tetrazole diazonium salts are even less stable . Secondly, the availability of the starting amines, the simple conditions of diazotization, high reactivity of pyrazole-3(5)-diazonium salts, and the presence of a reactive nucleophilic center (endocyclic nitrogen atom of pyrazole) at ortho position relative to diazonium group offers possibilities for using these compounds as building blocks in heterocyclic synthesis.
nucleophilic substitution of N2 + group (Nu = Hal, N3, NO2, OH, etc.) (a);
reduction of diazonium group (b);
azo coupling with aromatic and heterocyclic compounds, as well as primary and secondary amines, leading to azo compounds and triazenes (Z = Ar, Het, NR2) (c). The products of such reactions may undergo intra-molecular cyclization in some cases (d);
intramolecular azo coupling, which occurs in the presence of substituents X susceptible to electrophilic attack (NH2, NH, Ar, multiple carbon–carbon bonds, etc.) at the ortho position relative to diazo group and leading to pyrazoloazines (e);
the interaction with compounds containing a methylene group activated by electron-withdrawing groups, leading to pyrazolylhydrazones (f), as well as heterocyclization of the latter, resulting in linearly linked (g) and condensed systems (h) with a pyrazole fragment.
2. Reactions of Pyrazole-3(5)-Diazonium Salts Without Ring Formation
2.1. Reactions involving the loss (substitution) of diazo group
Nucleophilic substitution of diazo group is one of the most important synthetic directions in the chemistry of diazo compounds. This type of transformations is known as dediazotization and allows to obtain various functional derivatives (halides, cyanides, thiocyanates, hydroxides, thiols, nitrites, azides, etc.).
Sandmeyer and Balz–Schiemann reactions were used to convert compounds 1 into a series of functionalized 3(5)-derivatives of pyrazole: fluorides 12 [53-55], chlorides 13 and bromides 14 [44, 52, 53, 56-61], iodides 15 [22, 44, 51, 52], nitropyrazoles 16 [56, 62-64], azides 17 [57, 61, 64-66], methyl sulfides 18 , and sulfonyl chlorides 19 [67-69].
The attempts at converting 5-amino-3-methyl-4-nitropyrazole into nitrile by diazotization and subsequent treatment with potassium tricyanocuprate results in the formation of halogen derivative . Nitriles of pyrazole series have not yet been obtained by the dediazotization method.
These processes are believed to involve either intermediate formation of pyrazolyl cation or free radicals, as in the case of arenediazonium salts .
A brief review of literature published prior to 1991 about dediazotization reactions, including reactions in pyrazole series, is available [75, p. 643].
2.2. Reactions with conservation of diazo group
The reactions of pyrazole-3(5)-diazonium salts without elimination of nitrogen open broad possibilities for the synthesis of pyrazole derivatives: hydrazines, triazenes, formazans and, finally, the highly important hydrazones and/or azo compounds. These transformations are widely described in scientific periodicals and patents. The value of pyrazole-3(5)-diazonium salt reactions with conservation of diazo group (reduction of N2 + group to hydrazines, azo coupling with activated NH and CH reagents) is mostly in the possibilities of obtaining intermediates for heterocyclic synthesis. Occasionally such compounds are used for various in situ transformations, and in some cases hydrazones or azo compounds undergo spontaneous intramolecular condensation but in other cases are unusually stable and inert against further reactions.
It has been pointed out  that the reduction of diazonium salt is not successful when R1 = NO2. Such hydrazines are obtained indirectly [57, 77]. Hydrazinopyrazoles are quite attractive precursors for building various polyheterocycles, for example, physiologically active pyrazolo[5,1-c]-s-triazoles [79, 81].
Triazenes of pyrazole series have been synthesized from amino acids (glycine, proline)  and from (hetero)aromatic amines (4-chloroaniline, α-aminopyrazoles, 4-aminoantipyrine) [82, 86]. The preparation of pyrazolyltriazenes from amidines has been patented .
One of the most important transformations that characterize the chemical properties of pyrazole-3(5)-diazonium salts is С-azo coupling with aromatic and heterocyclic azo components. This reaction occurs as electrophilic aromatic substitution similar to azo coupling reactions of arenediazonium salts with phenols and anilines.
patents, based on various aromatic compounds: polyhydroxy-, polymethoxy-, ethoxycarbonyl-, arylamino-, sulfo-, and other derivatives of naphthalene [53, 93-95], phenols, cresols, anisoles [23, 53, 75, 96], anilines, and N,N-dialkylanilines [23, 39, 40, 51, 53, 94, 97, 98] (compounds 30). A remarkable feature of these reactions is the possibility of subsequent intramolecular cyclocondensation of products (provided the azo component has a nucleofuge group at the ortho position relative to its azo group), leading to annelated polycyclic structures. The orientation in azo coupling between pyrazole-3(5)-diazonium salts and aromatic compounds follows the general principles and has been thoroughly studied by Reimlinger .
1-(5-Pyrazolylazo)-2-naphthol and 1-(4-carboxy-5-pyrazolylazo)-2-naphthol are used in the field of inorganic analysis for quantitative photometric determination of d-metals. Other pyrazolylazo compounds with aromatic/heterocyclic fragments find applications as dyes for synthetic and natural fabrics and coatings. These compounds are also characterized by pronounced fungicidal activity and lightfastness.
The synthesis of azo compounds 34 was performed in alcohol, acetone, dioxane, or pyridine, while maintaining a weakly alkaline medium. Occasionally the azo coupling with aminopyrazoles was achieved in the presence of acetic acid .
Thiazol-4-one and 5-aminoisoxazole, containing reactive sites susceptible to electrophilic attack, are successfully used as azo components in reactions with pyrazole-3(5)-diazonium salts [105, 106]. Examples were found for azo coupling of diazonium salts 1 with 4-alkyl-3-cyano-6-hydroxypyridin-2-one [102, 103, 107], 8-hydroxyquinoline , 1,2,3,4-tetrahydroquinolines [43, 94, 97], 4-hydroxy-2-pyrone , and [1, 3]thiazo-lo[3,2-a]benzimidazol-3-one .
Azo–hydrazone equilibrium 35 ⇄ 35A was identified in some cases. The IR and UV spectra of some of the products have been recorded in acidic and basic solvents [102, 103]. No successful intramolecular heterocyclization of pyrazolylazo compounds 34 and 35 has been reported.
We should note that reactions of pyrazole-3(5)-diazonium salts that do not create a new ring are synthetically highly valuable. The mild conditions of these transformations and the high reactivity of substrates allow to synthesize a significant number of linearly linked pyrazole derivatives. Azides, sulfonyl chlorides, hydrazones, formazans, hydrazines, and triazenes of these series have been characterized as biologically active compounds, dyes, complexing agents, and synthetic intermediates. The interest towards these reactions continues to this day.
3. Heterocyclization Reactions of Pyrazole Diazonium Salts and Related Intermediates
Reactions of pyrazole diazonium salts involving the closure of a new ring have been extensively studied and described in the literature. Intramolecular heterocyclization may occur in two main directions: by diazonium group attack at the adjacent nucleophilic fragment and by ring closure of azo coupling products (hydrazones, azo compounds, triazenes, etc.) at the endocyclic nitrogen atom of pyrazole ring or the hydrazone fragment nitrogen atom. All these reactions lead to condensed or linearly linked polyheterocycles.
3.1. Intramolecular azo coupling
Arenediazonium salts containing substituents susceptible to electrophilic attack (NH2, NH, OH, SH, Alk, Ar, multiple carbon-carbon bonds, etc.) at the ortho position relative to diazo group are unstable and undergo spontaneous intramolecular cyclization forming the corresponding heterocycles [10, p. 1068; [33, p. 241; 39, p. 131; 111]. This is true also for some pyrazole-3(5)-diazonium salts, the intramolecular azo coupling of which produces pyrazolo[3,4-c]pyridazines, pyrazolo[3,4-d][1-3]triazines, pyrazolo[3,4-e]-[1-4]tetrazines, and other polycyclic systems.
Intramolecular azo coupling reactions of compounds 1 containing 3,4-dimethoxyphenyl and indolyl substituents at position 4 of pyrazole ring have been described . These examples may be viewed as original methods for obtaining derivatives of pyrazolo[3,4-c]cinnoline 43 and pyrazolo[3',4':5,6]pyridazino[3,4-b]-indole 44 according to the click chemistry approach ( and references therein, ).
Derivatives of another representative of bicyclic nitrogen heterocycles with 10 π-electrons, 2H-pyrazolo-[3,4-e][1-4]tetrazine 54, were formed in good yields (64-82%) from 4-arylazopyrazole-3(5)-diazonium salts by treatment with AcONa solution . The mechanism of this reaction was proposed to involve the delocalized zwitterion 53 as intermediate .
Thus, intramolecular azo coupling reactions of pyrazole-3(5)-diazonium salts are successfully used in the synthesis of azines annelated with azoles. The steady interest towards these transformations is motivated by the applicability of click chemistry, as well as the structural similarity of products to indoles and natural purine bases and the associated diverse biological activity.
3.2. Intermolecular azo coupling
Reactions of salts 1 with various СH and NH acids opens broad possibilities for heterocyclic synthesis. The main reason for this is the great variety of components suitable for use in these reactions (aliphatic, alicyclic, aromatic, heterocyclic), and another reason is the possible cyclocondensation of the obtained acyclic products either at the endocyclic nitrogen atom of pyrazole, or at other substituents. The range of products available by this approach is immense and not limited by the number, nature, and type of bonds between the rings in the molecule [11; 78, p. 628, 656].
Reactions using acyclic compounds with activated СН/NH groups. The compounds used as activated aliphatic CH components in azo coupling reactions with salts 1 belong to various classes, mainly β-keto acids, β-diketones, nitriles, and enaminones. These reactions lead to the formation of pyrazol-3(5)-yl-hydrazones or the corresponding azo compounds, which may cyclize under the conditions of azo coupling reaction or after additional treatment.
Directed cyclization with the participation of endocyclic nitrogen atom of pyrazole was first accomplished by Partridge [1, 127] by reacting pyrazole-3(5)-diazonium salt 1 with acetoacetic acid and its ester, as well as with benzoylacetic ester in alcoholic sodium acetate solution.
The acyclic products 56c,d spontaneously condensed into pyrazolo[5,1-с][1, 2, 4]triazines 57c,d, which gave the carboxylic acids 57а,b after alkaline hydrolysis and were subsequently decarboxylated. At the same time, malonic esters reacted with difficulty in azo coupling with pyrazole diazonium chlorides 1 [128, 129].
There are quite a few sources reporting the synthesis, structure, and properties of 2-pyrazolyl-hydrazono-1,3-dicarbonyl compounds (see the review ), thus there is no doubt that hydrazones serve as intermediates in the aforementioned reactions.
This interpretation has been questioned in work , the authors of which used counter synthesis to unequivocally prove the formation of 3-benzoyl-4-methylpyrazolo[5,1-с][1, 2, 4]triazine 61 in a similar reaction.
The condensation of 2-chloro-1,3-dicarbonyl compounds with diazonium salts 1 [127, 131, 141-143] produced the intermediate azo compounds 69а,b, from which acetyl fragment was eliminated, leading to stable hydrazonyl chlorides 70а,b (by Japp–Klingemann type reaction).
The binding of CN group to endocyclic nitrogen atom under the conditions of acidic catalysis may occur also by heating without solvent or refluxing in ethanol, tetralin, and dilute inorganic acids. In a series of cases an impurity of the alternate products 78 was formed, which became the major product when using pyridine as solvent . Contradictory data on this reaction have been reported in several publications [101, 141, 151, 152], where the formation of derivatives 77 or 78 was observed under identical conditions.
There is some controversy in the literature regarding the interpretation of this type of reactions: in some cases the isolation of compounds 84 is reported [49, 100, 131, 145, 154, 167], while in other cases compounds 85 were isolated [92, 108, 168-171], despite the identical starting materials and reaction conditions.
Stable hydrazonyl pyridinium salts 103 were converted to the derivatives 104 upon treatment with sodium carbonate solution, probably through ylides А.
Analogous products were obtained from condensation of pyrazole-3(5)-diazonium salts with phenacyldimethylsulfonium bromide with subsequent treatment of hydrazonyl bromides with potassium thio(seleno)cyanate [182, 183].
A threefold excess of diazomethane gave an isomeric mixture of N-methylation products of compound 107.
Interaction with cyclic components. There are relatively few published examples of azo coupling reactions between pyrazole-3(5)-diazonium salts and cyclic azo components, resulting in the formation of a new ring. This method may be used for the preparation of pyrazoloazines containing three, four, or more rings in the molecule.
The first example of using alicyclic components (cyclohexane-1,3-dione, dimedone, 2-ethoxycarbonyl-cyclopentanone) in this reaction was reported by authors from former Yugoslavia . Thus, interaction of salts 1 with cyclohexanediones led to 6,7,8,9-tetrahydropyrazolo[5,1-c][1,2,4]benzotriazinones 109 in 69 and 72% yields.
The azo coupling with a substituted cyclopentanone took a different course: it was possible to isolate the hydrazone 110 as a result of ring opening and to achieve its thermal cyclization to the pyrazolotriazine 111.
Recent publications [191, 192] report the successful preparation of tricyclic systems with pyrazolo[5,1-с]-[1, 2, 4]triazine fragment based on the reactions of pyrazole-3(5)-diazonium salts 1 (R = Me, R1 = Ph) with derivatives of pyridine-2,4-dione 127, pyrimidine-4,6-dione 128, barbituric and N,N-dimethylbarbituric acids 129а,b. Heterocyclic hydrazones 130а,b and 132а,b were isolated as intermediates in all of these cases. Further cyclocondensation was performed either by heating in polyphosphoric acid (in the case of pyrimidine derivatives) or by refluxing in acetic acid (in the case of pyridine derivative). The selection of forcing conditions for the cyclocondensation of hydrazones 132а,b was explained by hindered nucleophilic attack of endocyclic nitrogen atom of pyrazole on the lactam group of adjacent heterocyclic fragment.
Thus, analysis of literature data show that pyrazole-3(5)-diazonium salts are valuable synthons for the preparation of various linearly linked and polycondensed nitrogen-, oxygen-, and sulfur-containing heterocyclic systems. A special place among the latter belongs to hetarylazo compounds and pyrazolo[5,1-c][1,2,4]triazines, which possess a range of practically useful properties.
This work received financial support from the Ministry of Education and Science of the Russian Federation (contract No. 02.G25.31.0007).
- 1.L. C. Behr, R. Fusco, and C. H. Jarboe, in: R. H. Wiley (editor), The Сhemistry of Heterocyclic Compounds, Vol. 22, Wiley, New York (1967), p. 888.Google Scholar
- 2.R. N. Butler, Chem. Rev., 75, 241 (1975).Google Scholar
- 3.K. Schofield, M. R. Grimmett, and B. R. T. Keene (editors), Heteroaromatic Nitrogen Compounds. The Azoles, Cambridge University Press (1976), p. 437.Google Scholar
- 4.Stevens M. F. G., in: G. P. Ellis and G. B. West (editors), Progress in Medicinal Chemistry, Vol. 13, North-Holland Publishing Company, Toronto (1976), p. 205.Google Scholar
- 5.M. Tišler and B. Stanovnik, Chem. Heterocycl. Compd., 16, 443 (1980). [Khim. Geterotsikl. Soedin., 579 (1980).]Google Scholar
- 6.H. Dorn, Chem. Heterocycl. Compd., 17, 1 (1981). [Khim. Geterotsikl. Soedin., 3 (1981)].Google Scholar
- 7.M. H. Elnagdi, E. M. Zayed, and S. Abdou, Heterocycles, 19, 559 (1982).Google Scholar
- 8.M. H. Elnagdi, F. M. Abdel-Galil, B. Y. Riad, and G. E. H. Elgemeie, Heterocycles, 20, 2437 (1983).Google Scholar
- 9.E. A. A. Hafez, N. M. Abed, M. R. H. Elmoghayer, and A. G. A El-Agamey, Heterocycles, 22, 1821 (1984).Google Scholar
- 10.A. Engel, in: D. Klamann (editor), Houben-Weyl. Methoden der Organischen Chemie, 4th ed., Bd. E-16a, Teil 2, Georg Thieme Verlag, Stuttgart (1990), S. 1052.Google Scholar
- 11.M. H. Elnagdi, M. R. H. Elmoghayer, and K. U. Sadek, in: A. R. Katritzky (editor), Advances in Heterocyclic Chemistry, Vol. 48, Academic Press Inc., San Diego (1990), p. 223.Google Scholar
- 12.K. Makino, H. S. Kim, and Y. Kurasawa, J. Heterocycl. Chem., 36, 321 (1999).Google Scholar
- 13.T. M. A. Elmaati and F. M. El-Taweel, J. Heterocycl. Chem., 41, 109 (2004).Google Scholar
- 14.S. M. Riyadh, I. A. Abdelhamid, H. M. Ibrahim, H. M. Al-Matar, and M. H. Elnagdi, Heterocycles, 71, 2545 (2007).Google Scholar
- 15.G. Hajos and Z. Riedl, in: A. R. Katritzky (editor), Compr. Heterocycl. Chem. III, Vol. 11, Elsevier Ltd., Oxford (2008), p. 765.Google Scholar
- 16.V. L. Rusinov, E. N. Ulomskii, O. N. Chupakhin, and V. N. Charushin, Russ. Chem. Bull., Int. Ed., 57, 985 (2008). [Izv. Akad. Nauk, Ser. Khim., 967 (2008).]Google Scholar
- 17.H. F. Anwar and M. H. Elnagdi, ARKIVOC, i, 198 (2009).Google Scholar
- 18.J. M. Tedder, in: A. R. Katritzky and A. J. Boulton (editors), Advances in Heterocyclic Chemistry, Vol. 8, Academic Press, New York (1967), p. 1.Google Scholar
- 19.M. Tisler and B. Stanovnik, Heterocycles, 4, 1115 (1976).Google Scholar
- 20.G. Cirrincione, A. M. Almerico, E. Aiello, and G. Dattolo, in: A. R. Katritzky (editor), Advances in Heterocyclic Chemistry, Vol. 48, Academic Press Inc., San Diego (1990), p. 65.Google Scholar
- 21.J. O. Subbotina, E. V. Sadchikova, V. A. Bakulev, W. M. F. Fabian, and R. Herges, Int. J. Quant. Chem., 107, 2479 (2007).Google Scholar
- 22.H. Reimlinger, A. Overstraeten, and H. G. Viehe, Chem. Ber., 94, 1036 (1961).Google Scholar
- 23.E. V. Sadchikova and V. S. Mokrushin, Russ. Chem. Bull., Int. Ed., 54, 354 (2005). [Izv. Akad. Nauk, Ser. Khim., 348 (2005).]Google Scholar
- 24.H. Lund, J. Chem. Soc., 418 (1935).Google Scholar
- 25.R. P. Brint, D. J. Coveney, F. L. Lalor, G. Ferguson, M. Parvez, and P. Y. Siew, J. Chem. Soc., Perkin Trans. 2, 139 (1985).Google Scholar
- 26.A. E. Hammadi, M. E. Mouhtadi, R. Notario, A. Werner, and J. Elguero, J. Chem. Soc., Perkin Trans. 2, 379 (1995).Google Scholar
- 27.X.-M. Zou, F.-Z. Hu, and H.-Z. Yang, Chin. J. Struct. Chem., 23, 149 (2004).Google Scholar
- 28.O. Seidel, J. Prakt. Chem., 58, 129 (1898).Google Scholar
- 29.L. Knorr, Ber. Dtsch. Chem. Ges., 37, 3520 (1904).Google Scholar
- 30.A. Michaelis, Justus Liebigs Ann. Chem., 339, 117 (1905).Google Scholar
- 31.A. Michaelis and A. Schäfer, Justus Liebigs Ann. Chem., 397, 119 (1913).Google Scholar
- 32.E. v. Meyer, P. Berge, R. Oehler, and E. Schletter, J. Prakt. Chem., 90, 1 (1914).Google Scholar
- 33.K. H. Saunders, The Aromatic Diazo-Compounds and their Technical Applications, Edward Arnold & Co., London (1949), 443 p.Google Scholar
- 34.R. Elderfield (editor), Heterocyclic Compounds [Russian translation, Yu. K. Yur'ev (editor)], Vol. 5, Izd-vo Inostr. Lit., Moscow (1954), p. 104.Google Scholar
- 35.A. Ganesan and C. H. Heathcock, J. Org. Chem., 58, 6155 (1993).Google Scholar
- 36.C. B. Vicentini, M. Manfrini, M. Mazzanti, A. Scatturin, C. Romagnoli, and D. Mares, Arch. Pharm., 332, 337 (1999).Google Scholar
- 37.Е. Mohr, J. Prakt. Chem., 79, 1 (1909).Google Scholar
- 38.Е. Mohr, J. Prakt. Chem., 90, 223 (1914).Google Scholar
- 39.M. V. Gorelik, S. P. Titova, and V. I. Ribinov, Zh. Org. Khim., 16, 1322 (1980).Google Scholar
- 40.M. V. Gorelik and V. I. Lomzakova, Zh. Org. Khim., 22, 1054 (1986).Google Scholar
- 41.G. F. Duffin and J. D. Kendall, J. Chem. Soc., 408 (1954).Google Scholar
- 42.G. Pieri, E. Rosati, R. Battisti, and G. Burei, US Pat. Appl. 4268436.Google Scholar
- 43.M. A. Weaver and C. A. Coates, US Pat. Appl. 4459229.Google Scholar
- 44.J. R. Beck, R. P. Gajewski, M. P. Lynch, and F. L. Wright, J. Heterocycl. Chem., 24, 267 (1987).Google Scholar
- 45.E. M. Kandeel, V. B. Baghos, I. S. Mohareb, and M. H. Elnagdi, Arch. Pharm, 316, 713 (1983).Google Scholar
- 46.D. G. Farnum and P. Yates, Chem. Ind., 42, 659 (1960).Google Scholar
- 47.D. G. Farnum and P. Yates, J. Am. Chem. Soc., 84, 1399 (1962).Google Scholar
- 48.W. L. Magee, C. B. Rao, J. Glinka, H. Hui, T. J. Amick, D. Fiscus, S. Kakodkar, M. Nair, and H. Shechter, J. Org. Chem., 52, 5538 (1987).Google Scholar
- 49.M. H. Elnagdi, M. R. H. Elmoghayar, S. M. Fahmy, M. K. A. Ibraheim, and H. H. Alnim, Z. Naturforsch., 33b, 216 (1978).Google Scholar
- 50.K. L. Kirk and L. A. Cohen, J. Am. Chem. Soc., 95, 4619 (1973).Google Scholar
- 51.H. Lund, J. Chem. Soc., 686 (1933).Google Scholar
- 52.C. Musante, Gazz. Chim. Ital., 75, 109 (1945).Google Scholar
- 53.H. Reimlinger and A. van Overstraeten, Chem. Ber., 99, 3350 (1966).Google Scholar
- 54.F. Fabra, E. Fos, and J. Vilarrasa, Tetrahedron Lett., 20, 3179 (1979).Google Scholar
- 55.F. Fabra, J. Vilarrasa, and J. Coll, J. Heterocycl. Chem., 15, 1447 (1978).Google Scholar
- 56.W. E. Parham and I. M. Aldre, J. Org. Chem., 25, 1259 (1960).Google Scholar
- 57.E. Alcalde, J. M. Garcia-Marquina, and J. De Mendoza, An. Quim., 70, 959 (1974).Google Scholar
- 58.A. Echevarria and J. Elguero, Synth. Commun., 23, 925 (1993).Google Scholar
- 59.J. F. Chiarello and D. Rugg, US Pat. Appl. 20040122075 A1.Google Scholar
- 60.V. P. Perevalov, L. I. Baryshnenkova, E. A. Denisova, M. A. Andreeva, and B. I. Stepanov, Chem. Heterocycl. Compd., 20, 1397 (1984). [Khim. Geterotsikl. Soedin., 1691 (1984).]Google Scholar
- 61.S. A. Shevelev and I. L. Dalinger, Zh. Org. Khim., 34, 1127 (1998).Google Scholar
- 62.C. C. Cheng, J. Heterocycl. Chem., 5, 195 (1968).Google Scholar
- 63.L. I. Bagal, M. S. Pevzner, A. N. Frolov, and N. I. Sheludyakova, Chem. Heterocycl. Compd., 6, 240 (1970). [Khim. Geterotsikl. Soedin., 259 (1970).]Google Scholar
- 64.N. V. Latypov, V. A. Silevich, P. A. Ivanov, and M. S. Pevzner, Chem. Heterocycl. Compd., 12, 1355 (1976). [Khim. Geterotsikl. Soedin., 12, 1649 (1976).]Google Scholar
- 65.P. A. S. Smith and H. Dounchis, J. Org. Chem., 38, 2958 (1973).Google Scholar
- 66.D. Clarke, R. W. Mares and H. McNab, J. Chem. Soc., Perkin Trans. 1, 1799 (1997).Google Scholar
- 67.R. Bellemin and D. Festal, J. Heterocycl. Chem., 21, 1017 (1984).Google Scholar
- 68.S. Yamamoto, T. Sato, Y. Iwasawa, F. Suzuki, T. Ikai, K. Suzuki, and T. Nawamaki, J. Pesticide Sci., 15, 531 (1990).Google Scholar
- 69.B. Kumar, R. Soni, J. Z. Patel, S. Jha, S. A. Shedage, N. Gandhi, K. V. Sairam, V. Pawar, N. Sadhwani, P. Mitra, M. R. Jain, and P. R. Patel, Bioorg. Med. Chem. Lett., 18, 3882 (2008).Google Scholar
- 70.M. K. Spassova and R. D. Zakharieva, Collect. Czech. Chem. Commun., 54, 196 (1989).Google Scholar
- 71.S. Yamamoto, K. Morimoto, and T. Sato, J. Heterocycl. Chem., 28, 1545 (1991).Google Scholar
- 72.T. Nishiwaki, F. Fujiyama, and E. Minamisono, J. Chem. Soc., Perkin Trans. 1, 1871 (1974).Google Scholar
- 73.R. B. Toche, M. A. Kazi, and M. N. Jachak, Org. Prep. Proced. Int., 40, 551 (2008).Google Scholar
- 74.N. Kornblum, in: A. Ya. Berlin (editor), Organic Reactions [Russian translation], Vol. 2, Izd-vo Inostr. Lit., Moscow (1950), p. 285.Google Scholar
- 75.K. Kirschke, in: D. Klamann and E. Schaumann (editors), Houben-Weyl. Methoden der organischen chemie, Georg Thieme Verlag, Stuttgart (1994), p. 399.Google Scholar
- 76.X. L. Ren, H. B. Li, Ch. Wu, and H. Z. Yang, ARKIVOC, xv, 59 (2005).Google Scholar
- 77.J. De Mendoza and J. M. Garcia-Marquina, An. Quim., 66, 911 (1970).Google Scholar
- 78.E. Jucker, A. J. Lindenmann, and A. Vogel, US Pat. Appl. 3299091.Google Scholar
- 79.G. Ege, K. Gilbert, and R. Heck, Chem. Ber., 117, 1726 (1984).Google Scholar
- 80.M. A. Khan and A. C. C. Freitas, J. Heterocycl. Chem., 20, 277 (1983).Google Scholar
- 81.M. Taniguchi and T. Sato, US Pat. Appl. 5110941.Google Scholar
- 82.Y. F. Shealy and C. A. O'Dell, J. Pharm. Sci., 60, 554 (1971).Google Scholar
- 83.G. Ege, K. Gilbert, and R. Heck, Angew. Chem., Int. Ed. Engl., 21, 698 (1982).Google Scholar
- 84.G. Daidone, D. Raffa, B. Maggio, M. V. Raimondi, F. Plescia, and D. Schillaci, Eur. J. Med. Chem., 39, 219 (2004).Google Scholar
- 85.C. W. Noell and C. C. Cheng, J. Med. Chem., 14, 1245 (1971).Google Scholar
- 86.E. A. Al-Agamey and M. R. H. Elmoghayar, An. Quim., Ser. C, 81, 14 (1985).Google Scholar
- 87.J. Schawartz, M. Hornyak, E. Majorszki, A. David, and G. Horvath, US Pat. Appl. 4049639.Google Scholar
- 88.L. V. Shmelev, E. P. Anpenova, and G. V. Avramenko, Zh. Org. Khim., 29, 601 (1993).Google Scholar
- 89.G. V. Avramenko, Z. V. Bezuglaya, E. P. Anpenova, and E. V. Zhilina, Izv. Vuzov. Khimiya i Khim. Tekhnologiya, 36, 43 (1993).Google Scholar
- 90.M. W. Partridge and M. F. G. Stevens, J. Chem. Soc. C, 1127 (1966).Google Scholar
- 91.V. M. Dziomko and B. K. Berestevich, Chem. Heterocycl. Compd., 14, 313 (1978). [Khim. Geterotsikl. Soedin., 382 (1978).]Google Scholar
- 92.A. M. S. Youssef, R. A. M. Faty, and M. M. Youssef, J. Korean Chem. Soc., 45, 448 (2001).Google Scholar
- 93.V. M. Dziomko and B. K. Berestevich, Chem. Heterocycl. Compd., 15, 657 (1979). [Khim. Geterotsikl. Soedin., 805 (1978).]Google Scholar
- 94.F. Benguerel and R. Mislin, US Pat. Appl. 4685934.Google Scholar
- 95.U. Dreyer and R. Gross, US Pat. Appl. 3133051.Google Scholar
- 96.M. W. Partridge and M. F. G. Stevens, J. Chem. Soc. C, 1828 (1967).Google Scholar
- 97.E. B. Towne, W. H. Moore, and J. B. Dickey, US Pat. Appl. 3336285.Google Scholar
- 98.D. D. Chapman, US Pat. Appl. 5144015.Google Scholar
- 99.H. S. El-Kashef, K. U. Sadek, and M. H. Elnagdi, J. Chem. Eng. Data, 27, 103 (1982).Google Scholar
- 100.S. M. Fahmy, M. El-Hosami, S. El-Gamal, and M. H. Elnagdi, J. Chem. Technol. Biotechnol., 32, 1042 (1982).Google Scholar
- 101.A. Deeb, M. El-Mobayed, A. E. N. Essawy, and A. Abd El Hamid, Collect. Czech. Chem. Commun., 55, 2790 (1990).Google Scholar
- 102.F. Karci, Color. Technol., 121, 275 (2005).Google Scholar
- 103.F. Karci and F. Karci, Dyes Pigm., 76, 147 (2008).Google Scholar
- 104.E. A.-A. Hafez, E. M. Zayed, and K. U. Sadek, J. Heterocycl. Chem., 22, 241 (1985).Google Scholar
- 105.E. M. Zayed, A. A. A. Elbannany, and S. A. S. Ghozlan, Pharmazie, 40, 194 (1985).Google Scholar
- 106.A. A. A. Elbannany, L. I. Ibrahiem, and S. A. S. Ghozlan, Pharmazie, 43, 128 (1988).Google Scholar
- 107.M. A. Weaver and L. Shuttleworth, Dyes Pigm., 3, 81 (1982).Google Scholar
- 108.N. A. Hamdy, H. A. Abdel-Aziz, A. M. Farag, and I. M. I. Fakhr, Monatsh. Chem., 138, 1001 (2007).Google Scholar
- 109.M. A. Radwan, E. A. Ragab, N. M. Sabry, and S. M. El-Shenawy, Bioorg. Med. Chem., 15, 3832 (2007).Google Scholar
- 110.Y. Kurasawa, H. S. Kim, K. Yonekura, A. Takada, and Y. Okamoto, J. Heterocycl. Chem., 26, 857 (1989).Google Scholar
- 111.K. V. Vatsuro and G. L. Mishchenko, Named Reactions in Organic Chemistry [in Russian], Khimiya, Moscow (1976).Google Scholar
- 112.Y. Ahmad and P. A. S. Smith, J. Org. Chem., 36, 2972 (1971).Google Scholar
- 113.K. M. Dawood, A. M. Farag, and N. A. Khedr, ARKIVOC, xv, 166 (2008).Google Scholar
- 114.S. L. Bogza, V. I. Dulenko, S. Yu. Zinchenko, K. I. Kobrakov, and I. V. Pavlov, Chem. Heterocycl. Compd., 40, 1506 (2004). [Khim. Geterotsikl. Soedin., 1738 (2004).]Google Scholar
- 115.S. Bogza and S. Zinchenko, Visn. Lviv Un-tu. Seriya Khim., 49, 3 (2008).Google Scholar
- 116.V. V. Didenko, V. A. Voronkova, and Kh. S. Shikhaliev, Russ. J. Org. Chem., 45, 211 (2009). [Zh. Org. Khim., 45, 223 (2009).]Google Scholar
- 117.E. V. Tretyakov, D. W. Knight, and S. F. Vasilevsky, J. Chem. Soc., Perkin Trans. 1, 3721 (1999).Google Scholar
- 118.S. F. Vasilevsky and E. V. Tretyakov, Liebigs Ann., 1995, 775 (1995).Google Scholar
- 119.R. Justoni and R. Fusco, Gazz. Chim. Ital., 68, 59 (1938).Google Scholar
- 120.C. C. Cheng, R. K. Robins, K. C. Cheng, and D. C. Lin, J. Pharm. Sci., 57, 1044 (1968).Google Scholar
- 121.S. Bondock, R. Rabie, H. A. Etman, and A. A. Fadda, Eur. J. Med. Chem., 43, 2122 (2008).Google Scholar
- 122.A. M. K. El-Dean and A. A. Geies, J. Chem. Res., Synop., 352 (1997).Google Scholar
- 123.F. Seela, M. Lindner, V. Glaçon, and W. Lin, J. Org. Chem., 69, 4695 (2004).Google Scholar
- 124.J. A. Montgomery and H. J. Thomas, J. Med. Chem., 15, 182 (1972).Google Scholar
- 125.F. M. A. El-Taweel, Alexandria J. Pharm. Sci., 12, 11 (1998).Google Scholar
- 126.B. Yang, Y. Lu, C.-J. Chen, J.-P. Cui, and M.-S. Cai, Dyes Pigm., 83, 144 (2009).Google Scholar
- 127.G. R. Bedford, M. W. Partridge, and M. F. G. Stevens, J. Chem. Soc. C, 1214 (1966).Google Scholar
- 128.J. Slouka, J. Kubata and V. Bekarek, Acta Univ. Palack. Olomuc.: Fac. Rerum Natur., 49, 219 (1976).Google Scholar
- 129.A. G. A. Elagamey, F. M. A. El-Taweel, and F. A. Amer, Collect. Czech. Chem. Commun., 51, 2193 (1986).Google Scholar
- 130.T. Novinson, T. Okabe, R. K. Robins, and T. R. Matthews, J. Med. Chem., 19, 517 (1976).Google Scholar
- 131.M. H. Elnagdi, E. M. Zayed, M. A. E. Khalifa, and S. A. Ghozlan, Monatsh. Chem., 112, 245 (1981).Google Scholar
- 132.A. O. Abdelhamid, H. F. Zohdi, and G. S. Mohamed, Heteroat. Chem., 10, 508 (1999).Google Scholar
- 133.E. V. Shchegolkov, Y. V. Burgart, O. G. Khudina, V. I. Saloutin, and O. N. Chupakhin, Russ. Chem. Rev., 79, 31 (2010). [Usp. Khim., 79, 33 (2010).]Google Scholar
- 134.M. Kočevar, D. Kolman, H. Krajnc, S. Polanc, B. Porovne, B. Stanovnik, and M. Tišler, Tetrahedron, 32, 725 (1976).Google Scholar
- 135.V. V. Didenko, I. V. Ledenyova, and Kh. S. Shikhaliev, Vestn. VGU. Ser. Khim. Biol. Farm., No. 1, 7 (2010).Google Scholar
- 136.O. G. Khudina, E. V. Shchegol'kov, Ya. V. Burgart, M. I. Kodess, O. N. Kazheva, A. N. Chekhlov, G. V. Shilov, O. A. Dyachenko, V. I. Saloutin, and O. N. Chupakhin, J. Fluorine Chem., 126, 1230 (2005).Google Scholar
- 137.M. R. Shaaban, J. Fluorine Chem., 129, 1156 (2008).Google Scholar
- 138.A. Z. A. Hassanien, S. A. S. Ghozlan, and M. H. Elnagdi, J. Chinese Chem. Soc., 51, 575 (2004).Google Scholar
- 139.A. G. A. Elagamey, F. A. El Taweel, F. A. Amer, and H. H. Zoorob, Arch. Pharm., 320, 246 (1987).Google Scholar
- 140.V. V. Didenko, Kh. S. Shikhaliev, and I. V. Ledenyova, Chem. Heterocycl. Compd., 45, 248 (2009). [Khim. Geterotsikl. Soedin., 307 (2009).]Google Scholar
- 141.E. M. Zayed, S. A. S. Ghozlan, and A.-A. H. Ibrahim, Monatsh. Chem., 115, 431 (1984).Google Scholar
- 142.M. A. Raslan, R. M. Abd El-Aal, M. E. Hassan, N. A. Ahamed, and K. U. Sadek, J. Chinese Chem. Soc., 48, 91 (2001).Google Scholar
- 143.M. H. Elnagdi, M. R. H. Elmoghayer, H. A. Elfaham, M. M. Sallam, and H. H. Alnima, J. Heterocycl. Chem., 17, 209 (1980).Google Scholar
- 144.M. A. Barsy, E. A. Elrady, Μ. E. Hassan, and F. M. Abd El Latif, Heterocycl. Commun., 6, 545 (2000).Google Scholar
- 145.K. U. Sadek, M. A. Selim, M. H. Elnagdi, and H. H. Otto, Bull. Chem. Soc. Jpn., 66, 2927 (1993).Google Scholar
- 146.C. Almansa, A. F. de Arriba, F. L. Cavalcanti, L. A. Gómez, A. Miralles, M. Merlos, J. García-Rafanell, and J. Forn, J. Med. Chem., 44, 350 (2001).Google Scholar
- 147.A. O. Abdelhamid, V. B. Baghos, and M. M. A. Halim, J. Chem. Res., Synop., 31, 420 (2007).Google Scholar
- 148.D. M. Berger, M. D. Dutia, D. W. Hopper, and N. Torres, WO Pat. Appl. 2009039387.Google Scholar
- 149.M. Azimioara, C. Cow, R. Epple, G. Lelais, J. Mecom, and V. Nikulin, US Pat. Appl. 8575168.Google Scholar
- 150.E. J. Gray, M. F. G. Stevens, G. Tennant, and R. J. S. Vevers, J. Chem. Soc., Perkin Trans. 1, No. 14, 1496 (1976).Google Scholar
- 151.O. A. Fathalla and M. E. A. Zaki, Indian J. Chem., Sect. B: Org. Chem. Incl. Med. Chem., 37B, 484 (1998).Google Scholar
- 152.M. H. Elnagdi, N. H. Taha, F. A. M. Abd El All, R. M. Abdel-Motaleb, and F. F. Mahmoud, Collect. Czech. Chem. Commun., 54, 1082 (1989).Google Scholar
- 153.M. M. Girges, M. A. Hanna, and A. A. Fadda, Chem. Pap., 47, 186 (1993).Google Scholar
- 154.M. R. H. Elmoghayar, M. K. A. Ibrahim, I. El-Sakka, A. H. H. Elghandour, and M. H. Elnagdi, Arch. Pharm., 316, 697 (1983).Google Scholar
- 155.F. Karcı, İ. Şener, A. Demirçalı, and N. Burukoğlu, Color. Technol., 122, 264 (2006).Google Scholar
- 156.M. R. H. Elmoghayar, S. O. Abdalla, and M. Y. A.-S. Nasr, J. Heterocycl. Chem., 21, 781 (1984).Google Scholar
- 157.A. G. A. Elagamey, Arch. Pharmacal Res., 10, 173 (1987).Google Scholar
- 158.J. Slouka and V. Bekarek, Collect. Czech. Chem. Commun., 49, 275 (1984).Google Scholar
- 159.A. M. Farag, Z. E. Kandeel, and M. H. Elnagdi, J. Chem. Res., Synop., 10 (1994).Google Scholar
- 160.S. M. Hassan, M. M. Abdel Aal, A. A. El-Maghraby, and M. S. Bashandy, Phosphorus, Sulfur Silicon Relat. Elem., 184, 427 (2009).Google Scholar
- 161.P. Cankar and J. Slouka, J. Heterocycl. Chem., 40, 71 (2003).Google Scholar
- 162.E. N. Ulomskii, S. L. Deev, V. L. Rusinov, and O. N. Chupakhin, Zh. Org. Khim., 35, 1384 (1999).Google Scholar
- 163.M. A. E. Khalifa, E. M. Zayed, M. H. Mohamed, and M. H. Elnagdi, Indian J. Chem., Sect. B: Org. Chem. Incl. Med. Chem., 22B, 552 (1983).Google Scholar
- 164.M. M. M. Ramiz, A. H. H. Elgandour, and A.-G. A. Elagamey, J. Prakt. Chem., 330, 641 (1988).Google Scholar
- 165.M. M. Abdelall, Phosphorus, Sulfur Silicon Relat. Elem., 184, 2208 (2009).Google Scholar
- 166.I. V. Ledenyova, V. V. Didenko, V. V. Dotsenko, and K. S. Shikhaliev, Tetrahedron Lett., 55, 1239 (2014).Google Scholar
- 167.A. M. Farag, K. M. Dawood, and H. A. Abdel-Aziz, J. Chem. Res., 808 (2004).Google Scholar
- 168.A. M. Farag, K. M. Dawood, and Z. E. Kandeel, Tetrahedron, 52, 7893 (1996).Google Scholar
- 169.M. A. Berghot and E. B. Moawad, Eur. J. Pharm. Sci., 20, 173 (2003).Google Scholar
- 170.S. M. Sayed, M. A. Raslan, M. A. Khalil, and K. M. Dawood, Heteroat. Chem., 10, 385 (1999).Google Scholar
- 171.M. M. A. Khalik, J. Chem. Res., Synop., 21, 198 (1997).Google Scholar
- 172.N. M. Abed, N. S. Ibrahim, S. M. Fahmy, and M. H. Elnagdi, Org. Prep. Proced. Int., 17, 107 (1985).Google Scholar
- 173.V. L. Rusinov and O. N. Chupakhin, Ros. Khim. Zh., 41 (2), 103 (1997).Google Scholar
- 174.V. L. Rusinov, E. N. Ulomskii, O. N. Chupakhin, M. M. Zubairov, A. B. Kapustin, N. I. Mitin, M. I. Zhiravetskii, and I. A. Vinograd, Pharm. Chem. J., 24, 646 (1990). [Khim. Farm. Zh., 24, № 9, 41 (1990).]Google Scholar
- 175.V. L. Rusinov, T. L. Pilicheva, O. N. Chupakhin, N. A. Klyuev, and D. T. Allakhverdieva, Chem. Heterocycl. Compd., 22, 543 (1986). [Khim. Geterotsikl. Soedin., 662 (1986).]Google Scholar
- 176.M. A. Al-Shiekh, A. M. S. El-Din, E. A. Hafez, and M. H. Elnagdi, J. Chem. Res., 174 (2004).Google Scholar
- 177.H. A. Abdel-Aziz, N. A. Hamdy, I. M. I. Fakhr, and A. M. Farag, J. Heterocycl. Chem., 45, 1033 (2008).Google Scholar
- 178.M. R. Shaaban, T. S. Saleh, and A. M. Farag, Heterocycles, 78, 699 (2009).Google Scholar
- 179.A. O. Abdelhamid, A. A. Fahmi, and K. N. M. Halim, Synth. Commun., 43, 1101 (2013).Google Scholar
- 180.A. O. Abdelhamid, A. A. Fahmi, and A. A. M. Alsheflo, Eur. J. Chem., 3, 129 (2012).Google Scholar
- 181.M. A. Mohamed, J. Heterocycl. Chem., 47, 517 (2010).Google Scholar
- 182.K. M. Dawood, Heteroat. Chem., 15, 432 (2004).Google Scholar
- 183.A. O. Abdelhamid and A. S. Shawali, Z. Naturforsch., B: J. Chem. Sci., 42, 613 (1987).Google Scholar
- 184.H. Reimlinger and R. Merenyi, Chem. Ber., 103, 3284 (1970).Google Scholar
- 185.S. Al-Mousawi, E. John, M. M. Abdelkhalik, and M. H. Elnagdi, J. Heterocycl. Chem., 40, 689 (2003).Google Scholar
- 186.T. A. Farghaly and M. M. Abdalla, Bioorg. Med. Chem. Lett., 17, 8012 (2009).Google Scholar
- 187.H. M. Hassaneen, N. M. Abunada, and H. M. Hassaneen, Nat. Sci., 2, 1349 (2010).Google Scholar
- 188.Kh. S. Shikhaliev, V. V. Didenko, V. A. Voronkova, and D. V. Kryl'skii, Russ. Chem. Bull., Int. Ed., 58, 1034 (2009). [Izv. Akad. Nauk, Ser. Khim., 58, 1008 (2009).]Google Scholar
- 189.R. A. M. Faty and A. M. S. Youssef, Curr. Org. Chem., 13, 1577 (2009). J. Farras, E. Fos, R. Ramos, and J. Vilarrasa, J. Org. Chem., 53, 887 (1988).Google Scholar
- 190.I. V. Ledenyova, V. V. Didenko, and Kh. S. Shikhaliev, Butler. Soobsch., 17 (5), 24 (2009).Google Scholar
- 191.I. V. Ledenyova, V. V. Didenko, A. S. Shestakov, and Kh. S. Shikhaliev, J. Heterocycl. Chem., 50, 573 (2013).Google Scholar