The synthesis of 2-ketopiperazine acetic acid esters and amides from ethylenediamines with maleates and maleimides

The reaction of substituted ethylenediamines with various fumarates, maleates, and maleimides to form substituted ketopiperazine acetic acid esters and amides was investigated. This method affords a straightforward, high yield approach to a variety of potential peptidomimetics and can yield surprising results with regard to regio- and stereoselectivity.