| abstract |
A method of forming a sucrose-6-ester includes in sequence the steps of:a) contacting sucrose with a organotin-based acylation promoter in a solvent in the presence of a base selected from amines and basic alkali metal salts;b) removing water to form a tin-sucrose adduct; and contacting the tin-sucrose adduct with an acylating agent to form the sucrose-6-ester. The sucrose-6-ester may then be converted to sucralose. The base may be selected from alkali metal carbonates, bicarbonates, hydroxides, tribasic phosphates, dibasic phosphates, carboxylates and N,N-disopropylamine. The preferred organotin-based acylation promoter is 1,3-diacetoxy-1,1,3,3-tetrabutyldistannoxane (DSDA). The preferred acylating agent is acetic anhydride. The solvent is preferably a tertiary amide such as dimethylformamide (DMF), although it is preferred that cyclohexane is also present. The cyclohexane can be removed by azeotropic distillation using a Dean-Stark trap. The sucrose-6-ester can be converted to sucralose, which can then be purified. |