Synthesis and Cyclization Reactions with Pyrazolopyrimidinyl Keto-esters and their Enzymaic Activity

Ethyl 2,4-dioxo-4-(4-oxo-1-phenyl-1,4-dihydo-5H-pyrazolo3,4-dpyrimidin-5-yl)butanoate, ethyl 5-(4-oxo-1-phenyl- 1,4-dihydro-5H-pyrazolo{3,4-d}pyrimidin-5-yl)-1H-pyrazole-3-carboxylate and their acid hydrazide derivatives have been prepared and reacted with hydrazines, ortho-phenylenediamine, triethyl orthoformate, carbon disulfide and thiosemicarbazides in order to obtain some new 5-substituted pyrazolopyrimidin-4-ones as pyrazolines, isoxazolines, imidazoles, pyrazolotriazines, thiadiazoles and triazoles. All newly prepared compounds revealed the potent effect on increasing reactivity of cellobiase. Structures of new compounds were established upon their elemental analysis, IR, 1H NMR and mass fragmentation spectra.