Aza-D-homosteroids

Expansion of the D-ring of steroids to produce azasteroids is very common. Usually, the nitrogen is inserted between C(17) and the C ring and this kind of transformation was very popular in the search for new active pharmaceutical ingredients. Schonecker and colleagues performed the D ring expansion of 380 in-route to 17-aza-D-homosteroids (equation 152). 

Several antibiotic aza-D-homosteroids of general structure (22) have been isolated from Geotrichim flavo-brunneum (K. H. Michel etal., J. Antibiotics, 1975, 28, 102). 

The preparation of derivatives of 14-aza-D-homosteroids is described in Scheme 45. The condensation of 2-tetralone (467 R = H) with 2-vinyl-... 

Steroidal cyclic ketone acetyl hydrazones, on the other hand, behaved differently upon photolysis an unprecedented formation of lactams was found in the photolysis of some steroidal acetylhydrazones in the presence of oxygen. The irradiation of 3 3-acetoxy-5a-androstan-17-one acetyl hydrazone in dioxan in the presence of oxygen afforded 17-oxo-17a-aza-D-homosteroid and its 13a-isomer in low yields, while if oxygen was excluded, none of these lactams were formed (Scheme 27). A pair ofy-lactams is also formed from its D-nor homologue. Although the details of the multistep process for the lactam... 

Aza-steroids and -D-homosteroids, from vinyl isocyanates and enamines,... 

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