Synthesis of a branched-chain inosose derivative, a versatile synthon of N-substituted valiolamine derivatives from D-glucose
作者:Hiroshi Fukase、Satoshi Horii
DOI:10.1021/jo00039a025
日期:1992.6
The synthesis of (1S)-(1(OH)-2,4/1,3)-2,3,4-tri-O-benzyl-1-C-[(benzyloxy)methyl]-5-oxo-1,2,3,4-cyclohexanetetrol (7), which is an important synthon for the synthesis of valiolamine (8) 2 and its N-substituted derivatives such as AO-128 (9)3 having strong alpha-D-glucosidase inhibitory activity, is described. This branched-chain inosose derivative 7 has been prepared from the D-glucono-1,5-lactone derivative 2 which is readily available from D-glucose (1). The key step in the synthesis involves the stereospecific intramolecular carbocyclic ring, closure of the 1-deoxy-2, 6-heptodiulose derivatives 5a and 5b obtained by the oxidation of 2,3,4,6-tetra-O-benzyl-1-C-[bis-(methylthio)methyl]-D-glucitol (4a) and 2,3,4,6-tetra-O-benzyl-1-C-(dichloromethyl)-D-glucitol (4b). The resulting branched-chain bis(methylthio)inosose derivative 6a and dichloroinosose derivative 6b have been converted to the desired branched-chain inosose derivative 7 by desulfurization of 6a and dechlorination of 6b.