Transformations of tetrahydropyrido[4′,3′:4,5]thieno[2,3-d] pyrimidin-4(3H)-ones in the presence of alkynes bearing electron-withdrawing substituents

Tetrahydropyrido[4′,3′:4,5]thieno[2,3-d]pyrimidines in the presence of activated alkynes were transformed into mixtures of pyrimido[5′,4′:4,5]thieno[3,2-d]azocines and spiro[pyridine-4, 5′-thieno[2,3-d]pyrimidines]. © 2012 Springer Science+Business Media New York.