N-Phenylacetylglycyl-L-Proline Ethyl Ester Converts into Cyclo-L-Prolylglycine Showing a Similar Spectrum of Neuropsychotropic Activity

Abstract

Previously designed cyclo-L-prolylglycine (CPG), a peptide prototype of piracetam, was discovered as an endogenous compound in rat brain and exhibited nootropic and anxiolytic properties. N-Phenylacetylglycyl-L-proline ethyl ester (GZK-111) was synthesized in the present work. It was established that GZK-111 converted to CPG and possessed nootropic, anxiolytic, and antihypoxic activities typical of CPG at doses of 0.1 – 1.5 mg/kg (i.p.). The effects of both GZK-111 and CPG were stereoselective with only the L-enantiomers being active. GZK-111 could be considered as a prodrug that enhanced cognitive functioning with an anxiolytic component.