A domino reaction for the synthesis of 2H-pyrano-[4″,3″,2″:4′,5′]chromeno[2′,3′:4,5]thieno-[2,3-b]pyridin-2-ones

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

“…The most popular routes for the synthesis of thieno[2,3-b]-pyridine core are the reaction between 2-aminothiophene-3-carbonitriles and 1,1-dimethoxy-N,N-dimethylethanamine, 1a the alkylation of 2-thioxo-1,2-dihydropyridine-3-carbonitriles followed by Thorpe-Ziegler cyclization, 1b-d,2b,3b,5a,b,6b,7b, 10,11,12 and the heteroannulation of 2-halonicotinonitriles using methyl/ethyl thioglycolate. 1g,9 In this work, we described a fast and convenient synthesis of novel methyl/ethyl 3,6-diamino-4-aroyl-5-cyanothieno[2,3-b]pyridine-2-carboxylates.…”