Continuous-Flow Microliter Microwave Irradiation in the Synthesis of Isoxazole Derivatives: An Optimization Procedure

Abstract

An efficient method was developed for the synthesis of 3,4,5-trisubstituted and 3,5-disubstituted isoxazoles by using continuous-flow microwave-heated microreactors. A study on the separate effects of the temperature, continuous-flow regime, and microwave irradiation showed that the continuous-flow regime had important effects for less reactive diketones, where microwave heating enhanced the reaction, permitting the formation of 5-methyl-3-phenylisoxazole, which was not formed in the absence of microwaves.

Key words

heterocycles - cyclizations - condensation - microwaves - continuous-flow reactors - microreactors

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