Reinvestigation of bromination of 8-substituted quinolines and synthesis of novel phthalonitriles

Abstract

Bromination of a series of 8-substituted quinolines was reinvestigated and specified for optimum yields and isolation conditions. Mono bromination of 8-hydroxyquinoline ( 2a ) and 8-aminoquinoline ( 2c ) gave mixture of mono and dibromo derivatives 5,7-dibromo-8-hydroxyquinoline ( 3a ),5,7-dibromo-8-aminoquinoline (3c), 7-bromo-8-hydroxyquinoline (3d), 5-bromo-8-aminoquinoline (3e)while 8-methoxy quinoline ( 2b ) furnished 5-bromo-8-methoxyquinoline ( 3f) as sole product. N ovel phthalonitrile s, 4-(quinolin-8-yloxy)phthalonitrile ( 6) and 4-chloro-5-(quinolin-8-yloxy)phthalonitrile (8) of 8-hydroxyquinoline ( 2a ) were synthesized and converted into their respective bromo derivatives 4-(5-bromoquinolin-8-yloxy)phthalonitrile ( 7) and4-((5-bromoquinolin-8-yl)oxy)-5-chlorophthalonitrile (9) .