Synthesis of 3,5-disubstituted 1,2,4-oxadiazoles and their behavior of liquid crystallines

The synthesis of 3,5-disubstituted 1,2,4-oxadiazoles by the cyclocondensation of amidoximes with trifluoroacetic anhydride or benzoic acid derivatives in moderate to high yields is described. The study on the phase transition behavior has disclosed that some of the synthesized oxadiazoles show smectic or nematic phases depending on their structures, which have the high potential application as liquid crystalline monomers.