Microwave-assisted synthesis, crystal structure of pyrazolo[1,5-a]pyrazin-4(5H)-ones and their selective effects on lung cancer cells

► Microwave-assisted synthesis and characterization of novel pyrazolo[1,5-a]pyrazin-4(5H)-ones. ► Two X-ray crystal structures were reported in this work. ► Compounds 3e-h suppressed A549, H322 and H1299 lung cancer cells growth through cell cycle arrest and apoptosis selectively.