- Monday, October 13, 1997
- The Synthesis of Novel Polycyclic Heterocyclic Ring Systems via Photocyclization. Three New Derivatives of Carbazole
- Published at:Not Found
10-Ethyl-1-fluoro-lOH-benzothieno[3',2':4,5]pyrido[2,3-c]carbazole, 10-ethyl-IOHJ1]benzothieno[3',2';4,5]pyrido[2,3-c]carbazole, and 12-ethyl-12H-naphtho[1",2";4',5']thieno[3',2':4,5]pyrido[2,3-c]carbazole were prepared. Starting with the corresponding acid chlorides, namely, 4-flouro-3-chlorobenzo[b]thiophene-2-carbonyl chloride, 3-chlorobenzo[b]thiophene-2-carbonyl chloride, and 1-chloronaphtho[2,1-b]thiophene-2-carbonyl chloride, each carbonyl chloride was then allowed to react with 3-amino-9-ethylcarbazole. The carboxamides thus formed were converted to the corresponding lactams by irradiation with a 450 watt Hanovia medium pressure mercury lamp under a slow stream of air. The lactams were then chlorinated by refluxing in phosphorus oxychoride. The carbazoles were then stirred with 10% Pd/C under a hydrogen atmosphere to effect dechlorination to provide the N-ethy1 derivatives.