Buchwald protocol applied to the synthesis of N-heterotolan liquid crystals

A homologous series of the new N-heterotolans 8a–d were synthesized using two cross-coupling reactions mediated by copper and palladium/copper. The final compounds present the phenyl-pyridyl framework connected by the acetylene group. The evaluation of thermal properties for this series is described. All compounds exhibit the smectic A and X mesophase. For comparison were also synthesized compounds 10, 12, and 14. Their LC properties are reported.