Synthesis of spiro-pyrazole-3,3′-thiopyrano[2,3-b]pyridines and azolo[a]pyrido[2′,3′:5,6]thiopyrano[3,4-d]pyrimidines as new ring systems with antifungal and antibacterial activities

Reactions of 2,3-dihydro-4-oxo-thiopyrano[2,3-b]pyridine with aldehydes and with DMF-DMA furnished the 3-benzylidene and 3-(N,N-dimethylamino)-methylene derivatives. The latter products afforded spiro-pyrazolo-3,3′-thiopyrano[2,3-b]pyridines and new tetra- and penta-heterocyclic ring systems when treated with nitrilimines and aminoazoles, respectively. A number of the products showed high antifungal and antibacterial activities.