Transformations of (Z)-2-benzoylamino-4-dimethylamino-2-oxo-3-butene and(E)-3-benzoylamino-4-cyano-2-oxo-3-butene into pyrimidine, pyrazole andisoxazole derivatives

Abstract

Reaction of (Z)-2-Benzoylamino-4-dimethylamino-2-oxo-3-butene 1 with amidines 2a-e afforded pyrimidines 3a-e. Acid-catalysed treatment of 1 with potassium cyanide gave (E)-3-benzoylamino-4-cyano-2-oxo-3-butene 4. 1,3-Dipolar cycloadditions of nitrile imines and 2,4,6-trimethoxybenzonitrile oxide 7a to compound 4 afforded the corresponding pyrazole derivatives 6a-d and the isoxazole-4-carbonitrile 8a. In the reaction of 4 with 2,4,6- trimethylbenzonitrile oxide 7b, bis-cycloadduct 9 was formed and its structure was also determined by X-Ray analysis.