Abstract
3, 4-Diphenyl-2-furylcarbamoyls (IIIa-e) react with oxygen in benzene at room temperature and in the absence of catalysts or bases to give 3, 4-diphenyl-5-hydroxy-3-pyrrolin-2-ones (Va-e) as main products. Under the same conditions, treatment of 3, 4-diphenyl-2-furyl isocyanate (II) with an excess of various amines resulted in a clean autoxidation reaction to give Ve-h and diphenylmaleimides (XIIa-d) in a ratio of about 1 : 1. 3-Hydroxyphenanthro [9, 10-c] pyrrolin-1-ones (XIIIa-e) were prepared by the photocyclization of Va-e.
