SELECTIVE SUBSTITUTION IN SUCROSE: II. THE SYNTHESIS OF 2,3,3′,4,4′-PENTA-O-METHYL SUCROSE AND C4 TO C6 ACETYL MIGRATION IN SUCROSE

Abstract

Deacetylation of crystalline tri-O-trityl-penta-O-acetyl sucrose gave an amorphous tri-O-trityl sucrose derivative and methylation of this product followed by graded hydrolysis with acetic acid yielded a sirupy penta-O-methyl sucrose. Hydrolytic cleavage of the penta-O-methyl sucrose to nearly equal amounts of 2,3,4-tri-O-methyl-D-glucose and 3,4-di-O-methyl-D-fructose established the original positions of the O-trityl groups at the primary carbons in the sucrose molecule. It was therefore evident that acetyl migration from C4 to C6 in the glucose moiety had occurred during an earlier synthesis of 1′,4,6′-tri-O-methyl sucrose from the tri-O-trityl-penta-O-acetyl sucrose. The probable conformation of the transition state in the acyl migration is discussed.