Synthesis of mesomorphic 3,5-bis(3,4,5-trialkyloxybenzoylamino)-4-methylbenzoates involving intermolecular hydrogen bonding

A series of methyl 3,5-bis(3,4,5-trialkyloxybenzoylamino)-4-methylbenzoates (alkyl = CH₃(CH₂)_n?1, n = 8, 10, 12, 14 and 16) exhibits mesomorphic behavior at temperatures between 120 and 240 °C. The liquid crystalline properties have been characterized using differential scanning calorimetry, optical polarization microscopy and X-ray diffraction. The molecules stack in columns which pack under hexagonal symmetry. Variable temperature infra-red absorption measurements provide evidence of intermolecular hydrogen bonding between the amide entities in both the crystalline and liquid-crystalline phases.