FULL ACETALS OF BETA-D-GLYCOPYRANOSYLNITROMETHANES AND A 1,2-DIDEOXY-1-NITROALK-1-ENITOL DERIVED FROM COMMON HEXOSES

Kinetically controlled O-isopropylidenation of common 2,6-anhydro-1-de oxy-1-nitroalditols ( beta-D-glycopyranosylnitromethanes) derived from D-glucose, D-galactose, and D-mannose with 2-methoxypropene in 1,2-di methoxyethane catalyzed with 4-toluenesulfonic acid afforded high yiel ds of 2,3;4,6-di-0-isopropylidene acetals. With D-mannose, the bisacet al was also obtained in quantitative yield by reaction with 2,2-dimeth oxypropane. Mono-O-benzylidenation of the starting compounds with benz aldehyde dimethyl acetal followed by O-isopropylidenation led to 4,6-O -benzylidene-2,3-O-isopropylidene acetals having better solubilities i n non-polar solvents than the di-O-isopropylidene acetals. Di-O-benzyl idenation of beta-D-mannopyranosylnitromethane gave both (endo-2,3):4, 6- and (exo-2,3):4,6-di-0-benzylidene acetals. Transacetalation of 1-d eoxy-1-nitro-D-mannitol with 2,2-dimethoxypropane followed by 2-O-acet ylation and beta-elimination of the acetoxy group afforded (E)-1,2-did eoxy-2,4:5,6-di-O-isopropylidene-1 -nitro-D-arabino-hex-1-enitol. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.