Derivatives of piperazine have found wide use in medicinal chemistry as molecular scaffolds for the positioning of substituents in biologically active molecules. 1 During the course of an ongoing drug discovery project, we required a general method for the preparation of unsymmetrical 1, 4-disubstituted 2, 3-diketopiperazines. While the Riebsomer condensation of a 1, 2-diamine with dialkyl oxalate is frequently employed, 2 it generally requires ...
