General Synthetic Strategies

Synthesis of New Side-Chain Liquid-Crystalline Polyoxetanes with Two Mesogenic Groups Connected by a Flexible Spacer in the Side Chain

“…Dichloromethane used as the polymerisation solvent was dried over CaH 2 under vacuum for several days and carefully degassed prior to its addition to the monomer. 1 H NMR spectra were recorded in a Varian spectrometer (200 MHz). The molecular weights of the polymers were determined by gel permeation chromatography (GPC) carried out with a GPC 150C Waters Associates instrument equipped with a viscometer Retrofit GPC 150R from Viscotek Corporation.…”

“…Yield 95%. 1 1,6-Bis(4-methyloxycarbonyloxy-49-biphenylcarbonyloxy) (R,S)-3-methylhexane, A-C 6 Me: [18,20] Triphenylphosphine (5.3 g, 20 mmol), 3-methyl-1,6-hexanediol (1.3 g, 10 mmol) and 4-methyloxycarbonyloxy-49-biphenylcarboxylic acid (5.5 g, 20 mmol) were dissolved in 30 mL of anhydrous THF. The mixture was vigorously stirred and diethyl diazodicarboxylate (DEAD) (3.52 g, 20 mmol) was added dropwise at room temperature.…”

“…Yield 100%. 1 1-(4-[(R)-2-Butoxy]-49-biphenylcarbonyloxy)6-(4-hydroxy-49-biphenylcarbonyloxy)-(R)-3-methylhexane, C 1 -C 6 Me: [18] DEAD (1.32 g, 7.6 mmol) was added dropwise to a solution of triphenylphosphine (2 g, 7.6 mmol), (S)-2-butanol (0.56 g, 7.6 mmol) and 1,6-bis(4-hydroxy-49-biphenylcarbonyloxy)-3-methylhexane (4 g, 7.6 mmol) in 50 mL anhydrous THF at room temperature and under vigorous stirring. After refluxing overnight, the solvent was evaporated and dichloromethane was added in order to precipitate triphenylphosphine oxide and diethyl hydrazinedicarboxylate which were filtered off.…”

“…1 A 15% fraction of the disubstituted D 2 1C 6 Me product was also obtained and purified by a second chromatographic process (silica gel, dichloromethane/hexane/diethyl ether 5 : 4 : 1). 1 Oxetanes, Ox 1 1C 6 Me1C 6 Me: [21] 3-[(4-Methyl-6-bromohexyloxy)methyl]-3-methyloxetane (1.4 g, 5 mmol) was stirred overnight with 1-(4-[(R)-2-butoxy]-49-biphenylcarbonyloxy)-6-(4-hydroxy-49-biphenylcarbonyloxy)-(R)-3-methylhexane (3.1 g, 5 mmol) in DMF (40 mL) at 80 8C in the presence of anhydrous K 2 CO 3 (0.7 g). [23] The reaction mixture was cooled to room temperature and then DMF was removed under reduced pressure.…”

“…[1] Most of them consist of a calamitic rigid core, containing at least two ring systems, which is linked at both ends to flexible chains or small polar groups. Other non-conventional geometries have been published where several mesogens are connected in such a way that they are still able to build phases with orientational order.…”