Synthesis of novel steroid-tetrahydroquinoline hybrid molecules and d-homosteroids by intramolecular cyclization reactions

Abstract

Steroidal aryliminium salts were prepared from d- seco-pregnene aldehyde 2b, and their BF 3·OEt 2-catalyzed reactions were studied. The nature of the substituent R 1 in the anilines 3– 6 essentially influenced the chemoselectivity. Using unsubstituted 3, 4-methoxy- ( 4) or 4-bromoaniline ( 5), different tetrahydroquinoline derivatives 7a– 13a via intramolecular hetero Diels-Alder reaction were formed. In the case of 4-nitroaniline ( 6) the N-arylamino- d-homopregnane ( 14a) were also obtained. We assume, that an intramolecular Prins reaction led to this type of fluoro- d-homosteroid. The main products represent a new class of tetrahydroquinolino-androstenes.