A Facile Synthesis of 4-Phenylcarbostyrils and 4-Phenylisocarbostyril Involving Photocyclization of Benzo[b]thiophene-2-carboxanilidines and 2-Benzoylamino-3-chlorobenzo[b]thiophene

Photocyclization of 3-chlorobenza[b]thiophene-2carboxanillde afforded 1-benzothiophene[2,3-c]quinolinn6-one, which upon desulfurizat~on gave 4-phenylcarbostyril (3a).In this way, 4 -p h e n y l -6 -~u b s t i t u t e d ~c a r b o s t y r i l s (3b), -(3c), -(3d) and (3f) and 8-substituted analogues (6a), (s) and ( 6 c ) 12.