PREPARATION OF NEW NITROGEN-BRIDGED HETEROCYCLES. 63. UNEXPECTED FORMATION OF THIENO[3 ',4 ':4,5]IMIDAZO[1,2-a]-PYRIDINES

The alkaline treatment and dehydrogenation of pyridinium salts, obtainable from the S-alkylation of 3,5-dimethylpyridinium 2-alkylthio-1-cyano2-thioxoethylides with some phenacyl bromides, afforded unexpected heterocycles, 3-alkylthio-1-arylcarbonyl-6,8-dimethylthieno[3',4':4,5]imidazo-[1,2-a]pyridines, together with the corresponding 2-alkylthio-1-arylcarbonylthio-6,8-dimethylindolizine-3-carbonitriles.ArticleHETEROCYCLES. 76(1): 391-399 (2008)journal articl