Abstract
Reaction of the 3-oxo-4-androsten-derivative 1 or 4 with 1.2eq of o-iodosylbenzoic acid in methanolic KOH gave the methoxy products, the 4-methoxide 2 or 5 and the 6β-methoxide 3 or 6, along with the dehydrated compound, the 4, 6-dienone 7 or 8, respectively. Treatment of the 6-methoxide 3 or 6 with trimethylsilyl iodide yielded the 5α-androstane-3, 6-dioxo derivative 11 or 12 in high yield. The same hypervalent oxidation of the 17-oxo steroid 15, 18, 21 or 24 using excess iodine and a longer reaction time produced the corresponding 16α-hydroxy-17, 17-dimethylacetal 16, 19, 22 or 25, which was converted into the 16α-hydroxy-17-one 17, 20, 23 or 26 by treatment with diluted HCl in every case.
