Oxadiazoles as bioisosteric transformations of carboxylic functionalities .2.

In order to improve the in vivo efficacy of a series of known benzodiazepine receptor (BZR) ligands, 1-(2-phenyl-4-quinolinyl)-4-piperidinecarboxamides, a series of analogs has been prepared in which the amide group of these ligands has been replaced by a 1,2,4-oxadiazole moiety or converted to other carboxylic isosters such as esters or nitriles. An increase in the in vivo efficacy was observed for some of the compounds prepared in this investigation compared to the parent carboxamide derivatives.