[Derivatives of 2,3,5,6,7,7a-hexahydro-1,3-dioxo-1H-pyrrolo[1,2-c]imidazol -5-carboxylic acids].

The synthesis of the above-mentioned compounds, starting from the diethyl ester of 2,5-pyrrolidine dicarboxylic acid, is reported. The cis and trans isomers od the 2-phenylsubstituted acid were separated, and the trans form was resolved into the two chiral forms. Some amides were also prepared from these acids. The thio analogs (XIII) and (XVI) and the partially reduced derivatives (XIV) were synthesized. Some amides (VI) showed an interesting anti-anxiety effect in pharmacological models.