THE ALCOHOLYSIS OF TRIALKYLALKOXYSILANES: PART II. THE PREPARATION AND CHEMISTRY OF METHYL 2,3,4-TRI-<i>O</i>-TRI-METHYLSILYL-α-<scp>D</scp>-GLUCOPYRANOSIDE

Abstract

The trimethylsilyl group on the 6-position of methyl 2,3,4,6-tetra-O-trimethylsilyl-α-D-glucopyranoside is preferentially removed by methanolysis, using basic or acidic catalysts, giving methyl 2,3,4-tri-O-trimethylsilyl-α-D-glucopyranoside in high yield (&gt;80%). Reaction of the latter with acetic anhydride, benzoyl chloride, or phenyl isocyanate produces the corresponding 6-substituted derivatives in quantitative yield. The trimethylsilyl residues from the latter compounds are hydrolyzed by 50% aqueous methanol with the concomitant formation of 6-O-acetyl, 6-O-benzoyl, or 6-carbanilate derivatives of methyl α-D-glucopyranoside in excellent yield. Chemical and proton magnetic resonance (p.m.r.) studies established the structure of methyl 2,3,4-tri-O-trimethylsilyl-α-D-glucopyranoside, and of subsequent derivatives prepared from this compound. Infrared and p.m.r. evidence is offered to support conclusions regarding the conformation of the groups or atoms attached to C 6 and C 5 of the glucoside residue in some of these compounds.