REACTIONS WITH PYRIDINETHIONE DERIVATIVES: SYNTHESIS AND CHARACTERIZATION OF THIENYL[2,3-b]PYRIDINE, PYRIDO[2′,3′:4,5] THIENO[2,3-b]PYRIDAZINE, PYRIDO[2′,3′:4,5] THIENO[2,3-b]-PYRIMIDINONE, PYRAZOLINO [3′,4′:4,5] THIENO[2,3-b]PYRIDINE AND AMINOPYRAZOLO[3,4-b]PYRIDINE DERIVATIVES

Thieno[2,3-b]pyridines 5a,b, 2-S-methylacetyl pyridine derivative 7 , 2-S-methyldiaetyl pyridine derivative 7b, 2-S-methylethoxycarbonyl pyridine derivative 12a, 2-S-methylacetylethoxycarbonyl pyridine derivative 12 and 2-S-methyl pyridine derivative 28 , had been obtained via the reaction of pyridinethione 3 with phenacyl bromide derivatives, chloroacetone, α-chloroacetylacetone, chloroethylacetone, α-chloroethylacetoacetate and methyl iodide respectively. Several cyclization reactions were performed with 10% KOH, nitrous acid, hydrazine hydrate, formic acid, acetic anhydride and acetic acid to give an additional ring on the previously obtained new ring system.