A new general synthesis of functionally substituted pyrazolo[1,5-a]pyrimidines

5,7-Dimethyl-2,3-dinitropyrazolo[1,5-a]pyrimidine in reaction with N-, S- and O-nucleophiles under mild conditions undergoes regioselective nucleophilic substitution of the 2-positioned nitro group, which provides an access to a library of 2-R-3-nitropyrazolo[1,5-a]pyrimidines.