REACTION OF 6-O-TRITYL-CELLULOSE WITH TRIBROMOIMIDAZOLE AND TRIPHENYLPHOSPHINE IN PRESENCE OF IMIDAZOLE. SYNTHESIS OF A 3-BROMO-3-DEOXY DERIVATIVE HAVING ALLO CONFIGURATION OF THE PYRANOSE RING
KRYLOVA R. G., SHASHKOV A. S., USOV A. I.
N. D. Zelinsky Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow
Abstract: By treatment with tribromoimidazole and triphenylphosphine in the presence of imidazole under modified conditions, methyl 4,6-O-benzylidene-β-D-glucopyranoside was transformed into methyl 3-bromo-3-deoxy-4,6-O-benzylidene-β-D-allopyranoside with the high yield, affording, upon removal of benzylidene protecting group methyl 3-bromo-3-deoxy-β-D-allopyranoside. Structures of both bromo-deoxy derivatives were proved by NMR spectroscopy. Substitution effects of C-3 hydroxyl group by bromide atom on carbon chemical shifts in 13C NMR spectra were determined in D2O, C3D3N and DMSO-d6. Treatment of 6-O-trityl-cellulose with the same reagents afforded bromo-deoxy derivatives with the substitution degree up to 0,79, uneffected under conditions of detrytilation (80% aqueous acetic acid). According to 13C NMR spectral data, the substituted polymer have bromine atoms only at C-3 of the modified monosaccharide residues; the substitution proceeds with inversion of configuration.
Russian Journal of Bioorganic Chemistry 1990, 16 (1):105-112