1. Oxidative fragmentation of pregna-14,16-dien-20-ones to 14 beta-hydroxyandrost-15-en-17-ones.
- Author
-
Fell JD and Heathcock CH
- Subjects
- Cardiac Glycosides chemical synthesis, Cardiac Glycosides chemistry, Catalysis, Hydroxytestosterones chemistry, Molecular Structure, Oxidation-Reduction, Oxygen chemistry, Stereoisomerism, Chemistry, Organic methods, Hydroxytestosterones chemical synthesis, Pregnadienes chemistry
- Abstract
Two methods have been developed for efficient conversion of pregna-14,16-dien-20-ones into 14 beta-hydroxyandrost-15-en-17-ones. One procedure consists of treatment of the ring-D dienone successively with sodium borohydride and singlet oxygen. The reaction is illustrated by the conversion of pregna-14,16-dien-20-one 1 into 14 beta-hydroxyandrost-15-en-17-one 3, via the corresponding allylic alcohol 2. Although this two-step procedure is simple, it provides 3 in relatively low yield, accompanied by a smaller amount of the isomeric 14 alpha-hydroxyandrost-15-en-17-one 6. An alternative one-step conversion is achieved by treatment of dienone 1 with a peroxyacid in the presence of a strong protic acid. This process is illustrated by the two-step conversion of dienone 1 into hydroxy ketone 11 in 51% overall yield (Scheme 5) and by the analogous conversion of dienone 13 into hydroxy ketone 24 in 61% overall yield (Scheme 11).
- Published
- 2002
- Full Text
- View/download PDF