Yakov S. Kayukov

A new route to highly substituted thieno[2,3- b ]pyridines via cascade heterocyclization of 2-acyl-1,1,3,3-tetracyanopropenide salts

2-Acyl-1,1,3,3-tetracyanopropenides undergo cascade heterocyclization under the action of mercaptoacetic esters, leading to the formation of new 3,6-diamino-4-aroyl-5-cyanothieno[2,3-b]pyridine-2-carboxylates. The fast and convenient synthetic way to highly substituted thieno[2,3-b]pyridine scaffold is described.

2-Acyl(aroyl)-1,1,3,3-tetracyanopropenides 7*. Synthesis of 4-amino-1-aryl-6-halo-1-hydroxy-3-oxo-2,3-dihydro-1H-pyrrolo[3,4-с]pyridine-7-carbonitriles

The reaction of 2-acyl(aroyl)-1,1,3,3-tetracyanopropenides with gaseous hydrogen halides was used to obtain 2-amino-3-aroyl(acyl)-6-halopyridine-3,5-dicarbonitriles, which were subsequently converted to the respective 4-amino-1-aryl-6-halo-1-hydroxy-3-oxo-2,3-dihydro-1H-pyrrolo[3,4-c]pyridine-7-carbonitriles by treatment with concentrated sulfuric acid, followed by aqueous workup.