THEORETICAL-ANALYSIS OF THE DEPENDENCE OF THE VIBRATION-SPECTRA OF A MONOSACCHARIDE ON THE CONFORMATION OF THE HEXAPYRANOSE RING

Using the molecular mechanics method we calculated the vibration spect ra of methyl-2,6-di-O-acetyl-3,4-anhydro-alpha-DL-(6, 6-H-2(2)) deriva tives of galactopyranoside (G) and talopyranoside (T) molecules, the f ormer in three conformations of the hexapyranose ring (half-chair H-1( 0) and H-0(1dis) and also distorted boat B-2.5(dis)), and the latter i n the E(0) + H-1(0) conformation. The sensitivity of vibration frequen cies to variations of the hexapyranose ring conformation and to the co nfiguration of the C(2) substituent is analyzed within spectral domain s containing specific vibrations.