Assembly of isoxazol-5-one with 2-unsubstituted imidazole N -oxides and aldehydes.

A new synthetic protocol has been developed to construct polyfunctional isoxazol-5-one derivatives with imidazole moiety. It is based on the Knoevenagel condensation of isoxazol-5-one with aldehydes and subsequent Michael addition of imidazole N -oxides as part of a tandem three-component process. This reaction proceeds smoothly in moderate-to-good yield under catalyst-free conditions.