Synthetic routes to 3-alkylidene-2, 5-piperazinedione have been studied. An enamine carboxylate, methyl 2-amino-3-methyl-2-butenoate, was treated with phthaloylglycyl chloride to give methyl 3-methyl-2-phthaloylglycylamino-2-butenoate, which, after removal of phthaloyl group, was cyclized to yield 3-isopropylidene-2, 5-piperazinedione. The condensation reaction of the piperazinedione with aromatic aldehydes was also studied, ...
![3-methyl-2-[(N,N-phthaloyl-glycyl)-amino]-but-2-enoic acid结构式](https://image.chemsrc.com/caspic/420/6499-75-8.png)
![2-[(2-aminoacetyl)amino]-3-methylbut-2-enoic acid结构式](https://image.chemsrc.com/caspic/382/6499-76-9.png)