Synthesis and antiulcer activity of (E)-5-[2-(3-pyridyl)ethenyl]-1H,7H-pyrazolo [1,5-a]pyrimidine-7-ones.

A series of (E)-5-[2-(3-pyridyl)ethenyl]-1H,7H-pyrazolo-[1,5-a]pyrimidine-7-ones were synthesized and evaluated for the inhibition of stress-induced gastric ulcers in the rat after oral administration. Several molecules were found to be very active. The particularly interesting compound (E)-1-(3-chlorophenyl)-5-[2-(3-pyridyl)ethenyl]-1H,7H-pyrazolo[1,5-a]- pyrimidine-7-one was chosen for wider pharmacological investigation.