Synthesis of new 2-[(substituted-pyrazol-1-yl)carbonyl]-thieno[2,3-b]pyridine derivatives using 1,3-diketones, alkylethoxymethylenes and ketene dithioacetals

The reaction of 3-amino-4,6-dimethyl-2-thieno[2,3-b]pyridine carbohydrazide (1) with appropriate 1,3-diketones 2a-2d in glacial acetic acid afforded 3 -amino-2- [(3,5-disubstituted-pyrazol-1-yl)carbonyl]4,6-dimethylthieno [2,3 -b] pyridines 3a-3d. 3-Amino-2-[(5-amino-3,4-disubstituted-pyrazol-1-yl)car bonyl]-4,6-dimethylthieno[2,3-b]pyridine 5a-5h were also prepared by treatm ent of carbohydrazide 1 with appropriate alkylethoxymethylenes and ketene d ithioacetals 4a-4h, respectively.