A green, simple and highly efficient method for the synthesis of pyrazole-3-carboxylates and 3,5-disubstituted pyrazoles by cyclization of 4-aryl(hetaryl, alkyl)-2,4-diketoesters and 1,3-diketones with semicarbazide hydrochloride under “on water” conditions has been developed. This method also does not require toxic hydrazine and product purification, eliminating the use of toxic liquid chemicals.
