PHOTOREACTION OF N,N′-DIBROMO-2,5-PIPERAZINEDIONE

The photolysis of N,N′-dibromo-2,5-piperazinedione in dichloromethane gave an unstable photoproduct. The alcoholysis of the photoproduct in the presence of a small amount of hydrogen bromide yielded 3,6-diethoxy-2,5-piperazinedione and its alcoholyzed products, ethyl diethoxyacetate, ethyl 2-(diethoxyacetylamino)-2-ethoxyacetate, N-(1-ethoxy-1-ethoxycarbonylmethyl)oxamide, and ethyl N-(diethoxyacetyl)glycinate. The reactions of the photoproduct with other nucleophiles also gave the corresponding substituted 2,5-piperazinediones. The structure of the primary photoproduct was deduced to be 3,6-dibromo-2,5-piperazinedione on the basis of these observations.