N-azolylmethyl ketones as building blocks in heterocyclic synthesis:: Synthesis of new polyfunctionally substituted azolylarylazophenols, azolylpyridones and azolylthiophenes

The title compounds 1a-b and 2 reacted with 2-arylhydrazonopropanals 3a-c to yield polyfunctionally substituted azolylarylazophenols 5 and 8. The reaction of 1b and 2 with phenylisothiocyanate in the presence of alpha-haloketones afforded the azolylthiophenes 12a,b and 13a,b. The reaction of 20 with alpha-haloketone afforded 5-benzotriazol-1-yl-6-methyl-2-(2-oxopropylsulfanyl)nicotinonitrile 21 that was utilized as building blocks for the synthesis of condensed pyridines. Compound 21 was condensed with dimethylformamide dimethylacetal to yield thieno[2,3-b]pyridin-3-yl-N,N-dimethylformamidine derivative 22. This was further cyclized with sodium hydride to 1H-thieno[2,3-b; 4,5-b']dipyridin-4-one derivative 23.