Septanose Carbohydrates. VII. Preparation of Mono-O-isopropylidene Derivatives of Methyl β-D-Glucoseptanoside and Preparation of Methyl α-L-idoseptanoside and its Derivatives

Abstract

Three mono-O-isopropylidene derivatives of methyl β-D-glucoseptanoside have been prepared by acid-catalysed hydrolysis of methyl 2,3 : 4,5-di-O-isopropylidene-β-D-glucoseptanoside or by acetonation of methyl β-D-glucoseptanoside. Two of these derivatives have been used for the preparation of methyl 2,3-O-isopropylidene-α-L-idoseptanoside (8a) and methyl 3,4-O-isopropylidene-α-L-idoseptanoside (10a). Hydrolysis of (10a) yielded methyl α-L-idoseptanoside (12a) and acetonation of (8a) and (12a) yielded methyl 2,3 : 4,5-di-O-isopropylidene-α-L-idoseptanoside. Possible conformations of these compounds are discussed.