FT-IR and NMR spectroscopic studies of salicylic acid derivatives. II. Comparison of 2-hydroxy- and 2,4- and 2,5-dihydroxy derivatives.
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.
Jadrijević-Mladar Takac
Milena
M
Department of Medicinal Chemistry, Faculty of Pharmacy and Biochemistry, University of Zagreb, 10000 Zagreb, Croatia. mladar@pharma.hr
Vikić Topić
Drazen
D
D001549:Benzamides / Q000032:analysis* / Q000138:chemical synthesis; D002247:Carbon Isotopes; D002626:Chemistry, Pharmaceutical / Q000379:methods; D017523:Croatia; D003903:Deuterium; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
D001549:Benzamides; D002247:Carbon Isotopes; C055881:gentisamide; D003903:Deuterium