Chemistry Department, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.
J Org Chem. 2012 Jun 1;77(11):5125-31. doi: 10.1021/jo3007144. Epub 2012 May 14.
Piperazine-2,5-diones are formed by Dieckmann cyclization (NaH, THF) of substructures of the type CH(2)-N(R)C(O)CH(2)N(R')CO(2)Ph in which the terminal methylene (CH(2)) that is adjacent to nitrogen closes onto the carbonyl group of the phenyl carbamate unit at the other end of the chain. R and R' are alkyl groups, and the terminal methylene is activated by a ketone carbonyl, a nitrile, an ester, or a phosphoryl group. The starting materials are assembled by standard acylation and oxidation processes, starting from a β-(alkylamino)alcohol, an (alkylamino)acetonitrile, an (alkylamino) ester, or an (alkylamino)methyl phosphonate.
哌嗪-2,5-二酮是由 CH(2)-N(R)C(O)CH(2)N(R')CO(2)Ph 类型的亚结构的 Dieckmann 环化（NaH，THF）形成的，其中与氮相邻的末端亚甲基（CH(2)) 与链另一端的苯基碳酸酯单元的羰基缩合。R 和 R'是烷基，末端亚甲基由酮羰基、腈、酯或膦酰基活化。起始材料通过从 β-（烷基氨基）醇、（烷基氨基）乙腈、（烷基氨基）酯或（烷基氨基）甲基膦酸酯开始，通过标准酰化和氧化过程组装。
