Selective Protection/Deprotection in 1-Deoxynojirimycin Scaffold: Regioselective Mono-Benzoylation and Alkylation using TBAB-NaOH Catalytic System

摘要

Protecting groups play an important role in the carbohydrate chemistry and considerably influence the reactivity of substrate. A study of the substitution of various protecting groups in 1-deoxynojirimycin was carried out. Substrate N-benzyloxycarbonyl-1,5-dideoxy-1,5-imino-4,6-O-isopropylidene-D-glucitol was subjected to alkylation at positions 2- and 3- to obtain di-substituted products and N-Cbz group was selectively removed by using NaOH in EtOH/H2O. Regioselective benzoylation and alkylation of N-benzyloxycarbonyl-1,5-dideoxy-1,5-imino-4,6-O-isopropylidene-D-glucitol were conducted under the action of TBAB-NaOH catalytic system. It was found that all protected and mono-protected analogs form simultaneously and their structures were confirmed by spectroscopic means. The results showed that electrophiles play an important role in determining the product distribution.