FACILE SYNTHESIS OF A SERIES OF 2-(4-ALKYLOXYPHENYL)-5-CYANOPYRIDINE LIQUID CRYSTALLINE COMPOUNDS

This study describes the facile synthesis of a homologous series of pyridine-containing liquid crystalline 2-(4-alkyloxyphenyl)-5-cyanopyridines (nOPPyCN, n = 3-7). The subject liquid crystals were prepared in a short two-step reaction. First, 4-alkyloxyphenylmagnesium bromides were added to N- phenyloxycarbonyl-3-cyanopyridinium chloride, affording a 1,2-dihydropyridine, which was then oxidized by o-chloronil. The resulting products, 2-(4- alkyloxyphenyl)-5-cyanopyridines, were obtained in good yields (72%-83%). Thermotropic behaviors of these liquid crystals were investigated using differential scanning calorimetry (dsc) and polarized optical microscopy (pom).