COMPLETE H-1 AND C-13 RESONANCE ASSIGNMENTS OF STEREOISOMERIC 3-ALPHA,6,7,12-ALPHA-TETRAHYDROXYCHOLANOIC ACIDS BY 2-DIMENSIONAL SHIFT-CORRELATED NMR

Complete H-1 and C-13 NMR resonance assignments were carried out for s ix stereoisomeric 6,7-glycol derivatives of deoxycholic acid as their methyl esters (four being in the 5beta-series and two in the 5alpha-se ries). In addition to conventional 1D NMR methods, 2D shift-correlated NMR techniques (H-1-H-1 COSY, H-1-H-1 NOESY and H-1-C-13 HETCOR) were used for the signal assignments. Several H-1 and C-13 resonances have been reassigned from those previously reported. Substituent effects o f the 6,7-glycol moieties on the proton and carbon resonances were cla rified and used in the structural elucidation of these compounds.