SYNTHESIS OF N-SUBSTITUTED 2,5-PIPERAZINDIONES

The synthesis of 2,5-piperazindiones, 1,6-dimethoxycarbonylmethyl-2,5- piperazindione (1a), 1,6-di-alpha-methylbenzylcarboxamidomethyl(1b), 6 -dibenzhydrylcarboxamidomethyl-2,5-piperazindione (1c) and -(1-phenylb enzimidazolyl)methyl-2,5-piperazindione (1d), is reported. The cyclic dipeptide (1a) was obtained from the auto-condensation of the dimethyr iminodiacetate promoted by triethylborane or triphenylsilane. Compound s (1b-1d) were prepared by refluxing iminodiacetic acid and the corres ponding amine. The X-Ray diffraction structure of (1a) reveals boat co nformation for its 2,5-piperazindione ring.