Studies of organophosphorochloridates. Part II. Reactions of steroid phosphorodichloridates

Abstract

The preparation of the following steroid phosphorodichloridates is described: cholestanyl, epicholestanyl, epicholesteryl, and the derivatives of methyl 3α-hydroxy-5β-chlolanate, and ergosta-8(14)en-3β-ol. The formation of the phosphorodichloridates was followed by t.l.c. Attempted phosphorylation of 3,5-cyclocholestan-6β-ol, and 6β-hydroxycholest-4-en-3-ol gave cholesteryl phosphorodichloridate and cholestane 3,6-dione respectively. The hydrolysis of cholesteryl phosphorodichloridate has been examined under various conditions. The steroid phosphorodichloridates have been treated with methanol. Reaction of cholesteryl phosphorodichloridate with a range of alcohols, gave the corresponding cholesteryl ethers. Solvolysis of the phosphorodichloridates by dry pyridine generally gave the corresponding N-steroid pyridinium chlorides.