It has been shown'that 2-dialkylmethylene-3-alkyloxazolidine-4, 5-diones rearrange to the corresponding 1, 4, 4-trialkylpyrrolidine-2, 3, 5-triones in refluxing ethanol. However, when the nitrogen atom is linked to hydrogen, treatment with ethanol results in cleavage of the ring at positions 3 and 5. It also has been notedZ that isatin, which contains adjacent carbonyl functions, undergoes ring expansion and epoxide formation when treated with ...
