Investigation In The Synthesis Of Antiasthma Drug-22R Ciclesonide

Asthma, one of the most familiar chronic diseases, was considered refractory though current conventional treatments. Ciclesonide, which is researched by Altana Pharmaceutical Company, is the most promising steroidal antiasthma and antirhinitis medicine, and has come into the market. The present synthetic methods are started from 1,4-diene-3,20-dione pregn-11β,16α,17α,21-tetrahydroxyl which is very costly, and need large-scale industrial equipments. In addition, the methods are protected by patents.In this paper, high-purity 22R-ciclesonide was prepared with low cost from 1,4-diene-3,20-dione pregn-21-acetate-11β,16α,17α,21-tetrahydroxyl via silyl ether protection, hydrolysis, esterification, deprotection, and acetalization in sequence.