Synthesis of spirocyclic carbazole- and acridine-lactams.
Spirocyclic carbazole- and acridine-lactams were prepared by Fischer-indole or Friedländer-quinoline synthesis starting from spirocyclic ketones with a lactam ring. All annulation products were obtained as mixtures of separable regioisomers, which differ only in the position of one methyl group. The starting materials were prepared from 2-pyrrolidone and 2-piperidone by a sequence of protection (by N-allylation), alpha-acylation, iron-catalyzed Michael reaction followed by Robinson-annulation, palladium-catalyzed N-deprotection and catalytic hydrogenation. The overall yields of this six-step sequence are 13 and 17%, respectively, and the racemic ketones are obtained as single diastereoisomers.
Würdemann
Martina
M
Institut für Reine und Angewandte Chemie, Carl von Ossietzky-Universität Oldenburg, D-26111, Oldenburg, Germany.
Christoffers
Jens
J
D000166:Acridines / Q000138:chemical synthesis* / Q000737:chemistry; D002227:Carbazoles / Q000138:chemical synthesis* / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis / Q000737:chemistry; D007769:Lactams / Q000138:chemical synthesis* / Q000737:chemistry; D011804:Quinolines / Q000138:chemical synthesis / Q000737:chemistry
D000166:Acridines; D002227:Carbazoles; D007211:Indoles; D007769:Lactams; D011804:Quinolines; C041514:carbazole; C030374:indole; C037219:quinoline