Design and synthesis of novel sulfone-containing pyrazolo[1,5-a]-pyrimidines and pyrazolo[5,1-d][1,2,3,5]tetrazine-4(3H)-ones

A series of novel sulfone-containing pyrazolo[1,5-a]pyrimidines (2-3) and pyrazolo[5,1-d][1,2,3,5]tetra-zine-4(3H)-ones (5a-5k) were designed and efficiently synthesized, some of which have been identified as being potential rape inhibitors. These results widen the structural diversity of rape inhibitors and confirm the perspectives of further investigations in this area. Moreover, a plausible reaction mechanism is outlined.