The synthesis and investigation of mesomorphic, dielectric, and electro-optic behavior of novel chiral imine-based rod-like liquid crystal

New Multifunctional Bipyrimidine‐Based Chromophores for NLO‐Active Thin‐Film Preparation**

“…The coupling reaction of commercially available 2‐chloro‐4,6‐dimethylpyrimidine in the presence of nickel chloride, triphenylphosphine and zinc in DMF at 50 °C and in an inert atmosphere led to 4,4′,6,6′‐tetramethyl‐2,2′‐bipyrimidine compound 1 [15] . To prepare the chiral analogue, the brominated chiral chain, (S)‐1‐bromo‐3,7‐dimethyloctane, was prepared by reduction of commercially available (S)‐(‐)‐β‐citronellol using Pd/C (10 %) catalyst at 5 bar pressure under H 2 atmosphere, followed by bromination with concentrated HBr/H 2 SO 4 acid [16] . Aldehyde derivatives 2 a‐e were obtained by the Williamson ether synthesis reaction of commercially purchased 4‐hydroxybenzaldehyde and the corresponding n‐alkyl bromide in DMF in the presence of K 2 CO 3 at 150 °C under an inert atmosphere [17] .…”

“…[15] To prepare the chiral analogue, the brominated chiral chain, (S)-1-bromo-3,7-dimethyloctane, was prepared by reduction of commercially available (S)-(-)-β-citronellol using Pd/C (10 %) catalyst at 5 bar pressure under H 2 atmosphere, followed by bromination with concentrated HBr/H 2 SO 4 acid. [16] Aldehyde derivatives 2 a-e were obtained by the Williamson ether synthesis reaction of commercially purchased 4-hydroxybenzaldehyde and the corresponding n-alkyl bromide in DMF in the presence of K 2 CO 3 at 150 °C under an inert atmosphere. [17] The targeted products 3 a-e were obtained by Kneovenagel condensation reaction between methyl groups on the bipyrimidine and the corresponding aldehyde in 5 M NaOH aqueous solution, catalyzed by aliquat 336 at 70 °C.…”