Synthesis of 1-deoxy-L-gulo nojirimycin (L-gulo DNJ) and 1-deoxy-D-talo nojirimycin (D-talo DNJ)

摘要

Carbohydrate based syntheses of azasugars with unusual configurations viz. 1,5-dideoxy-1,5-imino-L-gulitol (L-gulo DNJ) and 1,5-dideoxy-1,5-imino-L-talito (L-talo DNJ) are reported, from D-mannose and D-fructose, respectively. The key steps in both syntheses involved reductive aminative cyclizations. Thus, L-gulo DNJ was obtained by reduction of 2,3; 4,6-di-O-isopropylidene-5-O-p-toluenesulfonyl-D-mannononitrile with LiAlH_4 in DME to give the protected azasugar which upon hydrolysis with HCl afforded crystalline L-gulo DNJ as the HCl salt in 29% overall yield. Reduction of 6-azido-1-O-tert-butyldimethylsilyl-2,3-O-isopropylidene-#beta#-D-ribo hexulofuranose obtained from D-fructose in six steps, followed by treatment with HCl, afforded L-talo DNJ as an HCl salt in approx 10% overall yield.