FT-IR and NMR spectroscopic studies of salicylic acid derivatives. I. Gentisamide -- a metabolite of salicylamide.
Gentisamide (GAM, 2,5-dihydroxybenzamide), a minor first-pass metabolite of salicylamide (SAM, 2-hydroxybenzamide), was studied using FT-IR, 1D and 2D homo- and heteronuclear 1H and 13C NMR spectroscopy. GAM was isolated from human urine eight hours after oral administration of SAM. FT-IR, 1H and 13C NMR spectra unequivocally confirmed the chemical structure of GAM through chemical and substituent shifts, coupling constants and connectivities in COSY, NOESY, HETCOR and HBMC spectra. From NOESY spectra of GAM in DMSO-d6, it was concluded that the amide protons are oriented toward the ortho-proton at C-6. Obtained results indicate that the presence of the additional phenol group at C-5 in GAM favours the formation of intramolecular hydrogen bonding of the O...HO type between C2-OH proton and oxygen atom of the amide group.
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
Govorcinović
Tihana
T
D001549:Benzamides / Q000032:analysis / Q000302:isolation & purification / Q000652:urine*; D002247:Carbon Isotopes; D002626:Chemistry, Pharmaceutical / Q000379:methods; D017523:Croatia; D003903:Deuterium; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D015394:Molecular Structure; D012457:Salicylamides / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D012459:Salicylates / Q000032:analysis / Q000737:chemistry* / Q000145:classification; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
D001549:Benzamides; D002247:Carbon Isotopes; D012457:Salicylamides; D012459:Salicylates; C055881:gentisamide; D003903:Deuterium; C031060:salicylamide