Microwave-Assisted Hydrolysis of Ethyl Azolylacetates and Cinnamates with K₂CO₃: Synthesis of Potassium Carboxylates

In this study, the hydrolysis of ethyl azolylacetates and ethyl cinnamates using K₂CO₃/ethanol under microwave irradiation was developed. For this purpose, ethyl azolylacetates were first synthesized by nucleophilic substitution between the corresponding azole and ethyl bromoacetate under sonication at 50 °C for 3 h, yielding derivatives with 10-92% chemical yields, while ethyl cinnamates were obtained by a microwave-assisted Horner-Wadsworth-Emmons (HWE) reaction of triethyl phosphonoacetate with a variety of aryl aldehydes at 140 °C for 20 min, yielding derivatives with moderate to high yields (67-98%). Initially, the optimization of the hydrolysis reaction was performed using ethyl pyrazolylacetate as a model starting material while varying the temperature, time, and base equivalents; the best results were achieved by carrying out the reaction at 180 °C for 20 min with 3.0 eq of K₂CO₃. This simple and greener method facilitated the synthesis of potassium carboxylates in moderate to high yields, 80-98% for azolyl derivatives and 73-98% for cinnamate derivatives. The structures of all potassium carboxylates were confirmed by FTIR, ¹H, ¹³C NMR, and HRMS.