中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
((2R,3R,4S,5S,6S)-3,4,5-三(苄氧基)-6-甲氧基四氢-2H-吡喃-2-基)甲醇 | methyl 2,3,4-tri-O-benzyl-α-D-mannopyranoside | 34212-64-1 | C28H32O6 | 464.558 |
—— | (2S,3R,4S,5R,6R)-3,4,5-Tris-benzyloxy-2-methoxy-6-vinyl-tetrahydro-pyran | 127214-37-3 | C29H32O5 | 460.57 |
—— | methyl 6-aldehydo-2,3,4-tri-O-benzyl-α-D-glucopyranoside | 83051-88-1 | C28H30O6 | 462.543 |
—— | methyl 2,3,4-tri-O-benzyl-α-D-manno-hexodialdo-1,5-pyranoside | 40653-15-4 | C28H30O6 | 462.543 |
An exploration of the synthesis of D-glycero-D-altro-heptose, a constitutent of O antigen chains in lipopolysaccharides from Campylobacter jejuni serotypes O:23 and O:36 led to a study of the 2-trimethylsilylthiazole homologation procedure for heptose synthesis. In contrast to the diastereoselective formation of a 1,2:3,4-di-O-isopropylidene-D-glycero-α-D-galacto-heptopyranose derivative from 1,2:3,4-di-O-isopropylidene-α-D-galacto-hexodialdo-1,5-pyranose, methyl 2,3,4-tri-O-benzyl-D-hexodialdo-1,5-pyranosides with the gluco and manno configurations showed no preference for the formation of compounds with the D-glycero configuration. Attempts to achieve high diastereoselectivity in the conversion of L-glycero into the D-glycero isomers by oxidation at C-6 followed by reduction with L-selectride were unsuccessful with the thiazole adducts, but the desired products were formed in similar reactions of methyl 2,3,4-tri-O-benzyl-7-O-tert-butyldimethylsilyl-D-heptopyranosides. The approach to homologation in the altro series was thwarted by epimerization at C-5 in the attempted formation of methyl 2,3,4-tri-O-benzyl-α-D-altro-hexodialdo-1,5-pyranoside. The successful synthesis of methyl D-glycero-α-D-altro-heptopyranoside from methyl α-D-glucopyranoside was achieved by homologation followed by configurational alteration from the D-gluco to the D-altro series.