Process for steroidal peracyl glycosides

摘要

PCT No. PCT/US93/02812 Sec. 371 Date Dec. 20, 1994 Sec. 102(e) Date Dec. 20, 1994 PCT Filed Apr. 2, 1993 PCT Pub. No. WO94/00479 PCT Pub. Date Jan. 6, 1994Processes for the synthesis of tigogenin beta-O-cellobioside heptaalkanoate which is an intermediate for the known hypo-cholesterolemic 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.