Synthesis of piperazinones and their apllication in constrained mimetics of the growth hormone secretagogue NN703

Abstract The focus of this paper is the chemistry of 2-piperazinones and the use of this building block to restrict the conformational freedom of the growth hormone secretagogue NN703 (currently in clinical development). We exploit classical methods for 2-piperazinone synthesis as well as some novel approaches such as a Boronic Mannich reaction. Finally, we report on the ability of the constrained target compounds to release growth hormone in vitro .