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 substitu...

NMR spectroscopy measurements have been used to obtain structural information about the pNR-2/pS2 single-domain trefoil peptide. NMR data from 2D (two dimensional) double-quantum-filtered correlation spectroscopy (DQF-COSY), total correlation spectroscopy (TOCSY), NOE spectroscopy (NOESY), rotating frame NOE spectroscopy (ROESY) and 2D 13C-1H heteronuclear single-quantum coherence (HSQC) and 13...

For methine sites the relaxation rate of 13C-1H two-spin coherence is generally slower than the relaxation rate of the individual 13C and 1H single spin coherences. The slower decay of two-spin coherence can be used to increase the sensitivity and resolution in heteronuclear experiments, particularly those that require correlation of H alpha and C alpha chemical shifts. To avoid dephasing of th...

MALWINA LLEN and JOHN D. ROBERTS. Can. J. Chem. 59,451 (1981). The effects of hydrogen bonding and protonation produced by changing solvent from chloroform to 2,2,2-trifluoroethanol to trifluoroacetic acid were determined for the 13C chemical shifts of fourteen imines, four oximes, and two pyridines. Downfield shifts relative to chloroform were observed for the C=N carbon of the imines and oxim...

Ultrahigh resolution l5N NMR spectra were measured for two nitroalkanes (MeNÜ2 la, fBuN02 lc), two isocyanates (;BuNCO 2c, Me^SiNCO 2d), four isothiocyanates (MeNCS 3a, EtNCS 3b, 'BuNCS 3c, M e3SiNCS 3d), one carbodiimide (Me3 SiNCNSiMe3 4d), one keteneimine [Me3 SiNCC(SiMe3 ) 2 5d], two sulphinyl imides ('BuNSO 6c, Me3 SiNSO 6d), and N-terf-butyl-pyrrole 7c, in order to determine coupling cons...