Steroids, XLV. Neighbouring Group Participation, XII. Decomposition of (Z)-16-Amidomethylene-17β-hydroxysteroids Mediated by Neighbouring Group Participation

✍ Scribed by Vincze Somlai Schneider Dombi Mák, Irén Csaba Gyula György Marianna

• Book ID: 102903219
• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 508 KB
• Volume: 1992
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199219920135

✦ Synopsis

Abstract

The sodium tetrahydroborate reduction of 16‐<[acetyl(alkyl)‐amino]methylene>‐17‐ketosteroids 1aa, 2aa and 2ba affords (Z)‐16‐ and (E)‐16‐<[acetyl(alkyl)amino]methylene>‐17β‐hydroxysteroids (Z)‐3, (E)‐3, (Z)‐4b, (Z)‐4a, (Z)‐5c and (E)‐5a. The N‐acetyl group of the (Z) isomers (Z)‐3, (Z)‐4b, and (Z)‐5c migrates to the 17β‐hydroxyl in inert solvents, and the products suffer secondary transformation into unsaturated aldehydes 6 and 9a; intermediate 8 has been isolated. The (E) isomers (E)‐3, and (E)‐5a do not change, even not under more drastic conditions.