advances in the preparation of derivatives of pregnane 9alpha - with 16alpha - methylated.

摘要

The invention comprises a compound having the formula: FORM:0955614/C2/1 and a process for the preparation thereof by treating 17a - hydroxy - 16a - methyl - pregna - 4, 9 (11) - diene - 3, 20 - dione with iodine in the presence of calcium oxide and calcium chloride. Said starting compound may be obtained by oxidizing 3a , 17a -dihydroxy-16a -methyl-pregna-11, 20-dione, at the 3-position and brominating the product to form 4-bromo-17a -hydroxy-16a -methyl-pregna-3, 11, 20-trione which is then dehydrobrominated to form 17a -hydroxy-16a -methylpregn-4-ene-3, 11, 20-trione, ketalizing the said 17a -hydroxy-16a -methylpregn-4-ene-3, 11, 20-trione, reducing the 3, 20-diketal at the 11-position to yield the corresponding 3, 20-diketal of 11b , 17a -dihydroxy-16a -methylpregn-4-ene-3, 20-dione, followed by dehydration thereof to yield the corresponding 3, 20-diketal of 17a -hydroxy-16a -methyl-pregna-4, 9(11)-diene-3, 20-dione and hydrolyzing the latter to form 17a -hydroxy-16a -methyl-pregna-4, 9(11)-diene-3, 20-dione. Specifications 934,702 and 955,613 are referred to.