Method for making steroidal peracyl glycosides

摘要

PCT No. PCT/US92/08638 Sec. 371 Date May 23, 1994 Sec. 102(e) Date May 23, 1994 PCT Filed Oct. 15, 1992 PCT Pub. No. WO93/11150 PCT Pub. Date Jun. 10, 1994.Processes for the synthesis of tigogenin beta-O-cellobioside heptaalkanoate which is an intermediate for the known hypocholesterolemic agent tigogenin beta-cellobioside. The process comprises reacting alpha -cellobiosyl bromide heptaalkanoate and beta -tigogenin in the presence of zinc fluoride or zinc cyanide under conditions capable of forming said tigogenyl beta -O-cellobioside heptaalkanoate. The analogous preparations of hecogenin beta -O-cellobioside heptaalkanoate, 11-ketotigogenin beta -O-cellobioside heptaalkanoate, and diosgenin beta -O-cellobioside heptaalkanoate are also disclosed. The process provides both high beta -anomeric selectivity and high yields.