Total synthesis of diazasteroids (1).
Contrary to previous reports, the condensation product of 8-aminoquinoline (1) and 2-carbethoxycyclopentanone (2) undergoes ring closure with polyphosphoric acid to give the 1, 11-diazasteroid 5. Catalytic hydrogenation reduced the A ring and the double bond to produce 6. 8-Aminotetrahydroquinoline (7) and 3-carbethoxy-2-piperidone condense to a tricyclic intermediate (11), which could not be cyclized to a steroid, however.
D000634:Aminoquinolines; D001378:Azasteroids / Q000138:chemical synthesis*; D002384:Catalysis; D008722:Methods; D013260:Steroids, Heterocyclic / Q000138:chemical synthesis*
D000634:Aminoquinolines; D001378:Azasteroids; D013260:Steroids, Heterocyclic