Preparation of New Nitrogen-Bridged Heterocycles, 50. Syntheses of Some Heterocyclc Compounds Starting From pyridinium 1-(Ethoxycarbonylacetyl)Methylides

摘要

The reactions of the title methylides with dialkyl acetylene-dicarboxylates gave the corresponding 3-(ethoxycarbonylacetyl)-indolizine derivatives, whose 3-substituent was smoothly converted to a coumarin skeleton by Knowevenagel reaction with salicyaldehdye. The reactions of the methylides with carbon disulfide and alkylating agent in the presence of a base afforded pyridinium 1-[alkylthio(thiocarbonyl)](ethoxycarbonyl)methylides, and the S-alkylations of these ylides with phenacyl bromides and subsequent alkaline treatment of the resulting pyridinium salts gave ethyl 3-alkylthio-1-(arylcarbonyl)thieno[3,4-b]indolizine-9-carboxylates.