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A convenient method for the synthesis of 3-acetoxy-N,Ndialkylbenzo[b]thiophene-2-carboxamides has been developed in three steps from 2-ethylsulfanylbenzoates using an interrupted Pummerer reaction of N,N-dialkyl-3-(2-ethylsulfinylphenyl)-3-oxopropanamides. Thus, treatment of these sulfinyl amides, prepared by the reaction of 2-ethylsulfanylbenzoates with lithium enolates of N,N-dialkylacetamides followed by oxidation of the resulting N,Ndialkyl-3-(2-ethylsulfanylphenyl)-3-oxopropanamides with sodium metaperiodate and acetic anhydride at 100 °C leads to the formation of the desired benzo[b]thiophenes.

An efficient procedure for the synthesis of three types of thienopyridines has been developed. Thus, 3-(1-arylethenyl)-2-(ethylsulfinyl)pyridines, 4-(1-arylethenyl)-3-(ethylsulfinyl)pyridines, and 3-(1-arylethenyl)-4-(ethylsulfinyl)pyridines, which can be easily prepared from the respective aryl chloropyridinyl ketones in a three-step sequence, undergo an interrupted Pummerer reaction on treatment with excess acetic anhydride at temperatures ranging from 100 to 130 °C to give 3-arylthieno[2,3-b]pyridines, 3-arylthieno[2,3-c]pyridines, and 3-arylthieno[3,2-c]pyridines, respectively.

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