Synthesis and stereochemical investigations of novel nitrogen-containing 13alpha-estrone derivatives.

Novel tetrahydroquinoline 11 and N-aryl d-homo derivatives 12 in the 13alpha-estrone series were synthesized effectively, starting from the secoaldehyde 8 and mono- or disubstituted anilines 9. The chemoselectivity of the cyclization reactions depended upon the nature of the substituents in the anilines. All transformations proceeded in a highly stereoselective manner, yielding only one diastereomer. Condensed 11 and d-homo derivatives 12 both have the usual ring C chair conformation in the solid state.

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

Steroidal aryliminium salts were prepared from D-seco-pregnene aldehyde 2b, and their BF3.OEt2-catalyzed reactions were studied. The nature of the substituent R1 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.