CONVENIENT SYNTHESIS OF METHYL<scp>L</scp>-<i>GLYCERO</i>-<scp>D</scp>-<i>MANNO</i>-HEPTOPYRANOSIDE

Abstract

Abstract Methyl L-glycero-D-manno-heptoside was prepared from a butane diacetal (BDA) derivative of methyl mannoside. Benzylation of the 3,4-BDA mannoside gave the 2-benzyl ether as a major product, which eliminated blocking and deblocking of the primary hydroxy group for the preparation of a mannoside bearing a free 6-OH. Swern oxidation of the 2-O-Bn-3,4-BDA mannoside followed by a Grignard reaction and osmylation gave L-glycero-D-manno-3, 4-BDA heptoside in 79 % yield. We found that the 3,4-BDA mannoside, its 2-O-Bn mannoside, and the 3,4-BDA heptoside could be prepared in a semi-preparative scale (20∼50 g). The 3,4-BDA mannoside is a convenient precursor for preparation of L-glycero-D-manno-heptose. ACKNOWLEDGMENTS This work was supported by Grant-in-Aid (10306022) for Scientific Research of the Ministry of Education of Japan. We thank Masayuki Hosoe for FABMS analyses.