A reaction of methyllithium with 3 cyano 6 methylpyridine 2(1H) thione followed by alkylation of the resulting 3 acetylpyridinethione, or a direct reaction of methyllithium with 3 cyano 6 methyl 2 (methylthio)pyridine, afforded 3 acetyl 6 methyl 2 (methylthio)pyridine. The ketone obtained was examined in bromination reactions under various conditions. Bromi nation in methanol or chloroform, proceeding through the formation of sulfonium bromides, gave substituted 3 (bromoacetyl)pyridine. A reaction of 3 acetyl 6 methyl 2 (methyl thio)pyridine with N bromosuccinimide in CCl 4 afforded N (pyridinesulfenyl)succinimide. The bromo ketone was used for the synthesis of various heterocyclic compounds.Key words: 3 cyano 6 methyl 2 (methylthio)pyridine, methyllithium, 3 acetyl 6 methyl 2 (methylthio)pyridine, N (pyridinesulfenyl)succinimide, 3 bromoacetyl 6 methyl 2 (methylthio) pyridine, 4 (pyridin 3 yl)thiazole, thieno[2,3 b]pyridine, indolizine, imidazo[1,2 a]pyridine.

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A convenient one pot synthesis of 2,5-asymmetrically substituted thieno[2,3-b]thiophenes is developed. The method is based on consecutive domino reactions (SN2 reaction → Thorpe-Ziegler reaction) using malononitrile and carbon disulfide as starting materials with the generation of potassium 2,2-dicyanoethene-1,1-bis(thiolate) in a solution. The high yield of the target thienothiophenes was achieved using the Ziegler dilution effect.

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A new and facile three-component method was developed for the synthesis of polymethylene-3-cyanopyridine-2(1Н)-thiones by the domino Knoevenagel ! Michael ! heterocyclization ! dehydrogenation reaction from cycloalkanones, cyanothioacetamide, and polymethoxy-substituted benzaldehydes. The final dehydrogenation step was found to involve arylidenecyanothioacetamide. The resulting pyridinethiones and 4-chloroacetoacetic ester were introduced into the domino S N 2 ! Thorpe-Ziegler ! Guareschi-Thorpe reaction to synthesize tetracyclic dipyridothiophenes. Starting from these compounds, 8,9polymethylenepyranothienodipyridines were also synthesized by the domino Knoevenagel ! Michael ! hetero-Thorpe-Ziegler reaction. Furthermore, a method for the synthesis of thienodipyridine annulated to the steroid skeleton is proposed.