Straightforward Microwave‐assisted Synthesis of 1‐carboxymethyl‐5‐trifluoromethyl‐5‐hydroxy‐4,5‐dihydro‐1h‐pyrazoles under Solvent‐free Conditions

An efficient microwave-assisted synthesis of 1-carboxymethyl-5-trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazoles from the cyclocondensation reaction between enones [CF3C(O)C(R-2) = C(R-1)(OR), where R-2 = H. Me; R-1 = H. Me, Et, Pr, i-Pr, t-Bu, i-Bu. Ph, 4-NO2-Ph, 4-Cl-Ph, 4-Br-Ph, 4-F-Ph and R = Me, Et] and methyl hydrazinocarboxylate under solvent-free conditions is reported. This process is an efficient alternative to the traditional thermal heating and furnishes the heterocyclic compounds in good to excellent yields in a short reaction time. To show the versatility of 1-carboxymethyl-5-trifluoromethyl-5-hydroxy-4,5-dihydro-1H-pyrazoles, dehydration reactions of these compounds are also demonstrated.