Recently we have reported on the “gas–solid-phase” synthesis of 2,5-dioxopiperazines (DOPs) via cyclodimerization of vaporous amino acids on silica surface1. The pre- requisite for realization of this method is the ability of amino acids to sublime in va- cuum without decomposition, intermolecular condensation and loss of optical activity2. Besides amino acids themselves, this property is characteristic also for some simple dipeptides, ie dipeptides ...
