Synthesis of pyrazoles by 1,3‐dipolar cycloaddition under aqueous micellar catalysis


Ethyl diazoacetate (EDA), which is conveniently well prepared from ethyl glycinate and NaNO 2 , reacts in situ with alkynes in a drinking water micelle natural environment with out organic solvent to sort pyrazoles. The reaction is pH dependent, as in the presence of protic catalysis (H 2 SO 4  4%, pH 3.5) a mixture of 3,5- and 4,5-disubstituted pyrazoles was attained,  though, at pH 5.5,   only the 3,4-disubstituted isomer was acquired. The existence of the surfactant TPGS-750-M was critical to protected clean crude response mixtures and high yields of the goods. The similar protocol was correctly used to the synthesis of substituted pyrazolines.


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