Convenient preparation of substituted 5-aminooxazoles via a microwave-assisted Cornforth rearrangement

The preparation of oxazole-4-carboxamides and their subsequent thermal rearrangement to 5-aminooxazole-4-carboxylates is optimized in a high-speed microwave-assisted procedure. The reaction sequence is effective with a variety of substituted oxazoles, and produces products in good yield and high purity.