DETERMINATION OF ANOMERIC CONFIGURATION OF [2-(3,4-DIHYDROXYTETRAHYDROFURYL)]-2-METHYLPYRROLE BY NMR-SPECTROSCOPY BASED ON THE SPECTRAL-ANALYSIS OF A SINGLE ANOMER

The structure of acetyl-5-(beta-D-erythrofuranosyl)-2-methylpyrrole ha s been confirmed by H-1 and C-13 NMR spectroscopy and the compound has been found to be beta-anomer. The difference in the chemical shift va lues between exo and endo methyl groups in 2',3'-O-isopropylidene deri vative has been used to determine the anomeric configuration of the in vestigated compound. There was no 3'-H or 4'-H nuclear Overhauser enha ncement observed upon irradiation of the anomeric proton, and therefor e, the method used for assignment of the anomeric configuration of pen tafuranosides based on this effect could not be applied. In order to d etermine the anomeric configuration of tetrofuranosides it has been pr oposed to use the differences in the chemical shift values between the atoms 2'-O - ($) under bar CO - CH3 and 3'-O - ($) under bar CO - CH3 , and also between 2'-O - CO - ($) under bar CH3 and 3'-O - CO - ($) u nder bar CH3 in per-O-acetylnucleosides.