Reaction of 5-(substituted-amino)oxazoles with N-phenylmaleimide

Reaction of 5-aminooxazoles with N-phenylmaleimide gave 7-hydroxy-2-phenylpyrrolo3,4-c]pyridine-1,3-diones and 7-amino-2-phenylpyrrolo3,4-c]pyridine-1,3-diones via tricyclic adducts. The ratio of the 7-hydroxy compound and 7-amino compound depended on the basicity of the leaving group of the adducts. The reaction of 5-acetaminooxazole with dienophiles is described.