FT-IR and NMR spectroscopic studies of salicylic acid derivatives. II. Comparison of 2-hydroxy- and 2,4- and 2,5-dihydroxy derivatives

Acta Pharm. 2004 Sep;54(3):177-91.

Abstract

The 2,4- and 2,5-dihydroxybenzamides (8, 9) were synthesized from their corresponding methyl esters. The structures and the spectral properties of investigated salicylic acid (1), 2,4- and 2,5-dihydroxy benzoic acids (2, 3), their methyl esters (4-6) and amides (7-9) were analyzed by means of FT-IR and one- and two-dimensional homo- and heteronuclear 1H and 13C NMR spectroscopies. Comparison of FT-IR and NMR spectral data of investigated compounds showed that the spectral characteristics of 2,4-dihydroxy benzoic acid derivatives are more similar to those of 2-hydroxy benzoic acid (salicylic acid) derivatives than to those of 2,5-dihydroxy benzoic acid derivatives. The results suggest that the spatial orientation of amide protons in 2,4-dihydroxy benzamide resembles more that in salicylamide than that in 2,5-dihydroxy benzamide.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzamides / analysis*
  • Benzamides / chemical synthesis
  • Carbon Isotopes
  • Chemistry, Pharmaceutical / methods
  • Croatia
  • Deuterium
  • Magnetic Resonance Spectroscopy / methods*
  • Molecular Structure
  • Spectroscopy, Fourier Transform Infrared / methods*

Substances

  • Benzamides
  • Carbon Isotopes
  • gentisamide
  • Deuterium