Uncatalyzed Four Component Synthesis of Pyrazolopyranopyrimidine Derivatives and Their Antituberculosis Activities

Fused Pyrazolopyranopyrimidine containing both biologically active pyranopyrazole and pyranopyrimidine compounds were synthesized using a one-pot, four-component reaction of ethyl aceto acetate, hydrazine hydrate, benzaldehydes and thiobarbituric acid without catalyst in ethanol. All target compounds obtained in very good to excellent yields over short reaction time adapting simple work-up procedure. All the synthesized compounds exhibited good to excellent anti-tuberculosis activities. The results shown that 4-(1H-imidazol-2-yl)-3-methyl-7-thioxo-4,6,7,8-tetrahydropyrazolo[4′,3′:5,6]pyrano[2,3-d] pyrimidin-5(1H)-one (5a) have been found to be good anti-tubercular agent as good as standard streptomycin drug based on minimum inhibitory concentration (MIC).