Synthesis of Pyrazoles by 1,3‐Dipolar Cycloaddition under Aqueous Micellar Catalysis

Ethyl diazoacetate (EDA), which is easily prepared from ethyl glycinate and NaNO2, reacts in situ with alkynes a water micelle environment without organic solvent to form pyrazoles. The reaction pH dependent, as the presence of protic catalysis (H2SO4 4 %, 3.5) mixture 3,5- 4,5-disubstituted pyrazoles was obtained, while, at 5.5, only 3,5-disubstituted isomer obtained. surfactant TPGS-750-M crucial secure clean crude mixtures high yields products. same protocol successfully applied synthesis substituted pyrazolines.