Abstract
The synthesis is described of a series of eighteen 16-dehydro-20-isocyano-20-sulfonylpregnanes (5 and 8–14) by C-20 alkylation of 17-[isocyano(sulfonyl)methylene]androstanes 1–3. The geminal isocyano and sulfonyl groups at C-20 (compounds 5, 8–14) are removed by acid hydrolysis to provide a new entry into 20-oxo steroids (6, 15–19). The C-20 alkylation also includes halomethylation and alkoxymethylation to form 21-halo- and 21-alkoxy-16-dehydro-20-oxopregnanes, respectively. As an attractive alternative to acid hydrolysis, the isocyano group is first oxidized with Pb(OAc)4 to an isocyanato group prior to hydrolysis (of the geminal isocyanato and sulfonyl groups) to the same 20-oxo steroids. The latter conversion is carried out under non-acidic conditions at room temperature in a slurry of alumina in dichloromethane.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
