Access to Substituted Pyrimidines via Isoxazole Ring Transformation in Three-Component Reactions with Amines and Orthoesters

The isoxazole ring transformation was effectively applied for the synthesis of diverse pyrimidines by using a three-component reaction of 5-aminoisoxazole-4-carbonitrile with primary amines and orthoesters. The one-pot rearrangement of the products further expands the structural diversity that can be accessed via this methodology. The method is efficient on the gram scale, can be performed under microwave and conventional heating, and requires no chromatography.