SYNTHETIC UTILITY OF 2-BENZYLIDENE-l,2,3,4-TETRAHYDRO-CARBAZOL-1-ONES.A FACILE SYNTHESES OF PYRANO[2,3-a]CARBAZOLES,PYRIDO[2,3-a]CARBAZOLES AND PYRIDAZINO[3,4-a]CARBAZOLES

摘要

2-Benzylidene-l,2,3,4-tetrahydrocarbazol-l-ones 1,synthons easily accessible from the corresponding 1,2,3,4-tetrahydrocarbazol-l-ones,were utilized in the synthesis of fused carb-azoles.In accordance,the reaction of 1 with malononitrile yielded pyrano[2,3-a]carbazoles 2a and 2d or pyrido[2,3-a]carbazoles 2b,2c and 2e.The reaction of 1 with thiocarbo-hydrazide or thiosemicarbazide under basic conditions afforded pyridazino[3,4-a]carbazoles 3 or thiol substituted pyridazino[3,4-a]carbazoles 4,respectively,in good yields.The formation of the hitherto unknown compounds was well supported by plausible mechanisms.The products formed were characterized by IR,~1H NMR,~13C NMR,mass spectral methods and by elemental analysis.