SYNTHESIS OF INDENO[1,2-B]PYRIDINES AND INDENO[1,2-B] THIENO-[3,2-E]PYRIDINES

4-Aryl-3-cyano-5-oxo or (phenylimino)indeno[1,2-b]pyridin-2 [1H]thione s 3a-c mere prepared from indanone 1 with arylidene cyanothioacetamide or from arylideneindanone 2 with cyanothioacetamide. The correspondin g 2-aminoindenopyridine 4 was synthesized from the reaction of 3b with NaN3 in the presence of NH4Cl in DMF. Hydrolysis of 4 using NaOH or H 2SO4 gave compounds 6 and 7, respectively. S-Alkylation of 3 with halo compounds afforded derivatives 9a-p, which underwent ring closure wit h EtONa to produce indenothienopyridines 10a-1.