The selective monohydrocyanation of diimines using potassium hexacyanoferrate(II)-benzoyl chloride reagent system as a cyanide source under catalyst-free condition is described. The advantages of this protocol are the non-toxic, non-volatile and inexpensive cyanide source, high yield, and simple work-up procedure.

An efficient method for the synthesis of pyrazolo[1,5-a]pyrimidines by the tandem reactions of dienones with pyrazole-3-amine through an aza-Michael addition/nucleophilic addition/1,3-hydrogen transfer process in the presence of potassium hydroxide is described. This protocol offers access to 7-arylethyl-5-arylpyrazolo[1,5-a]pyrimidines in good to excellent yield. Meanwhile for 4-substituted dienones, different products, 7-arylethylene-5-arylpyrazolo[1,5-a]pyrimidines, are given through an aza-Michael addition/nucleophilic addition/oxidation process. A gram-scale reaction has been performed to demonstrate the potency of optimized procedure for the scale-up process.