Steric effects on the ultraviolet absorption of 1,2-enedioic and related systems

  • S Natarajan Balasubrahmanyam
  • H Surya Prakash Rao


1,2-Enedioic systems, being sterically perturbed from planarity do not show the effect of the extended conjugation expected of a (formal) trienic entity. In the absence of a model which approximates to a uniplanar situation, the strategy of replacing an ester group in the enedioates by a cyano (for which less stringent steric demand may be presumed) and noting the correction concomitant to this replacement was adopted to arrive at a notional figure for the position of maximal absorption in the planar enedioates. From this the conclusion, subject to substantiation by molecular mechanical or quantum chemical calculations, was drawn that even the E-isomeric and comparatively less substituted enedioates are highly sterically perturbed. An alternative to an earlier explanation of the bathochromic shift of absorption maxima encountered in the 5-cyclic ene-ester and ene-nitrile, relative to the 6-cyclic analogues (observed also with the enedioates and cyanovinyl ester systems), seen later to have been based on unwarranted premises, has been advanced. A comment on the absorption characteristics of enedioic anhydrides has been appended.


Enedioates cyanovinyl esters ene-anhydrides ultraviolet spectra steric effects rotomerisation of ester groups time-dependent solvent effect 


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  1. Allinger N L, Hirsch J A, Miller M A and Tyminski J 1968J. Am. Chem. Soc. 90 5773CrossRefGoogle Scholar
  2. Allinger N L and Sprague J T 1972J. Am. Chem. Soc. 94 5734CrossRefGoogle Scholar
  3. Balasubrahmanyam S N and Balasubramanian M 1973Tetrahedron 29 683CrossRefGoogle Scholar
  4. Balasubrahmanyam S N and Balasubramanian M 1971J. Chem. Soc. (C) 827Google Scholar
  5. Bates R B, Eisenbraun E J and McElvain S M 1958J. Am. Chem. Soc. 80 3413CrossRefGoogle Scholar
  6. Biglino G 1962 Farmaco (Paria) ed. Sci.17 377 (Chem. Abstr.58 5684f)Google Scholar
  7. Braude E A and Coles J A 1950J. Chem. Soc. 2014Google Scholar
  8. Braude E A, Forbes W F and Evans E A 1953J. Chem. Soc. 2202Google Scholar
  9. Brown H C, Brewster J C and Shechter H 1954J. Am. Chem. Soc. 76 467CrossRefGoogle Scholar
  10. Brown H C 1957J. Org. Chem. 22 439CrossRefGoogle Scholar
  11. C R C Atlas: 1975Atlas of Spectral Data and Physial Constants of Organic Compounds II ed eds J C Grasselli and W M Ritchey (Cleveland: C R C Press) (a) m4 (b) c1280Google Scholar
  12. Craig D 1950J. Am. Chem. Soc. 72 3732CrossRefGoogle Scholar
  13. Eberson L 1964Acta. Chem. Scand. 18 1276CrossRefGoogle Scholar
  14. Eberson L and Landstrom L 1972Acta. Chem. Scand. 26 239CrossRefGoogle Scholar
  15. Elliot N, Jones N F and Geff K A 1969J. Chem. Soc. (C) 1845Google Scholar
  16. Fleck R B 1957J. Org. Chem. 22 439CrossRefGoogle Scholar
  17. Fueno T and Yamaguchi K 1972Bull. Chem. Soc. Jpn. 45 3290CrossRefGoogle Scholar
  18. Heilmann R, Bonnier J M and de Gaudemaris G 1957Compt. Rend. 244 1757Google Scholar
  19. Ireland C J, Jones K, Pizey J S and Johnson S 1976Synth. Commun. 6 185CrossRefGoogle Scholar
  20. Jaffé H H and Orchin M 1965Theory and Applications of Ultraviolet Spectroscopy (New York and London: John Wiley)Google Scholar
  21. Johnson F and Malhotra S K 1965J. Am. Chem. Soc. 87 5492 and 5493CrossRefGoogle Scholar
  22. Johnson W S and Shelberg W E 1945J. Am. Chem. Soc. 67 1745CrossRefGoogle Scholar
  23. Kettner A 1899Annalen 304 156Google Scholar
  24. Lardelli G, Dijkstra G, Harkes P D and Boldingh J 1966Rec. Trav. Chim. 85 54Google Scholar
  25. Liljefors T and Allinger N L 1976J. Am. Chem. Soc. 98 2745CrossRefGoogle Scholar
  26. Liljefors T and Allinger N L 1978J. Am. Chem. Soc. 100 1068CrossRefGoogle Scholar
  27. Linstead R P and Millidge A R 1936J. Chem. Soc. 473Google Scholar
  28. Mansfield G H, Whiting M C and Jones E R H 1956J. Chem. Soc. 4073Google Scholar
  29. McCoy L L 1967J. Am. Chem. Soc. 89 1673CrossRefGoogle Scholar
  30. Mowry D T and Rossow A G 1945J. Am. Chem. Soc. 67 426Google Scholar
  31. Mukherjee S M 1947J. Indian Chem. Soc. 24 495Google Scholar
  32. Nielsen T 1957J. Org. Chem. 22 1539CrossRefGoogle Scholar
  33. Sauer J, Land D and Wiest H 1964Chem. Ber. 1957 3208Google Scholar
  34. Seuers C and Cotter R J 1961J. Org. Chem. 26 6CrossRefGoogle Scholar
  35. Sengupta S C and Saha N N 1957J. Indian Chem. Soc. 29 331Google Scholar
  36. Sicher J, Sipos F and Jonas J 1961Coll. Czech. Chem. Commun. 26 262Google Scholar
  37. Timmons C J 1972 inElucidation of Organic Structures by Physical and Chemical Methods, II ed eds K W Bentley and G W Kirby (New York: Wiley/Interscience) Part I Ch. II p. 89Google Scholar
  38. Ungnade H E and Ortega I 1951J. Am. Chem. Soc. 74 1564CrossRefGoogle Scholar
  39. Warnhoff E W, Wong C M and Tai W T 1967J. Org. Chem. 32 2664CrossRefGoogle Scholar
  40. Wheeler O H 1956J. Am. Chem. Soc. 78 3216CrossRefGoogle Scholar
  41. Wheeler O H 1961J. Org. Chem. 26 4755CrossRefGoogle Scholar
  42. Wolfe S, Rauk A, Tel L M and Csizmadia I G 1971J. Chem. Soc. (B) 136.Google Scholar

Copyright information

© Indian Academy of Sciences 1978

Authors and Affiliations

  • S Natarajan Balasubrahmanyam
    • 1
  • H Surya Prakash Rao
    • 1
  1. 1.Department of Organic ChemistryIndian Institute of ScienceBangalore

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