Synthesis of 2-(1-aryl-1H-tetrazol-5-yl)-thieno[2,3-b]pyridine derivatives
Alkylation of 4,6-dimethyl-2-sulfanylpyridine-3-carbonitrile with 1-aryl-5-(chloromethyl)-1H-tetrazoles yielded 2-{[(1-aryl-1H-tetrazol-5-yl)methyl]sulfanyl}-4,6-dimethylpyridine-3-carbonitriles, which easily cyclize by the action of bases to form 2-(1H-tetrazol-5-yl)-thieno[2,3-b]pyridine derivatives. The use of excess base in the alkylation step leads to direct formation of cyclized products in high yields.