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.Gentizinamid (GAM), metabolit prvog prolaska salicilamida (SAM), analiziran je uporabom FT-IR, te jednodimenzijskom i dvodimenzijskom homo- i heteronuklearnom 1H i 13C NMR spektroskopijom.
GAM je izoliran iz ljudskog urina osam sati nakon oralne primjene SAM-a, a strukturna analiza provedena je pomoću FT-IR, 1H i 13C NMR uporabom kemijskih i supstituentnih pomaka, konstanti spin-spin sprege, te povezanosti u COSY, NOESY, HETCOR i HBMC spektrima.
Iz NOESY spektra DMSO-d zaključeno je da su protoni amidne skupine gentizinamida usmjereni prema orto-protonu na C-6 položaju. Rezultati ukazuju na to da prisustvo dodatne fenolne skupine C5-OH u GAM favorizira stvaranje intramolekulske vodikove veze O...HO tipa između C2-OH protona i kisika amidne skupine
