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Communication | Special issue | Vol 15, No. 1, 1981, pp.281-284
Published online, 1st January, 1970
DOI: 10.3987/S-1981-01-0281
The Remarkably Facile Rearrangement of a 2,3,5,6-Tetraketopiperazine to 4,5-Dioxoimidazolidine-2-carboxylic Acid Derivatives and Its Reversal

John H. Hoare and Peter Yates*

*Biochemical Institute, University of Ghent, Ledeganckstraat, Ghent, Belgium


Reaction of N,N’-dibenzyl-2,3,5,6-piperazinetetraone (1) with boiling ethanol gives ethyl N,N’-dibenzyl-4,5-dioxoimidazolidine-2-carboxylate (2a). Analogous rearrangement products are formed with methyl, n-propyl, n-butyl, and isopropyl alcohols, and ethylene glycol. In the last case the cleavage product N,N’-dibenzyloxamide is also formed. Thermolysis of 2a results in loss of ethanol and regeneration of 1.