Cyanobiphenyls synthesis

D. O., Micro-reactor synthesis synthesis of cyanobiphenyls using a modified Suzuki coupling of an aryl halide and aryl boronic acid, in Ehefeld, W. (Ed.), Microreaction Technology 3rd International Conference on Microreaction Technology, Proc. of... 

By using this method, 4-methyl-2 -cyanobiphenyl, an important intermediate for the synthesis of the antihypertensive drug Losartan, can be easily prepared.132 2-(t>-Chlorophenyl)-oxazoline reacts with excess of arylmagnesium halide without catalysis, as it was shown by Meyers for 2-(o-methoxyphenyl)-oxazolines.133 Cobalt(ll) salts catalyze the coupling of Grignard reagents with a-chloroazines at —40°C in ether (Scheme 47).134 135... 

Imrie, C. T., and Luckhurst, G. R., Liquid crystal trimers. The synthesis and characterisation of the 4,4 -bis[(u-(4-cyanobiphenyl-4 -yloxy)aIkoxy]biphenyls, J. Mater. Chem., 8, 1339-1343 (1998a). 

In Section 12.2, we describe the synthesis and properties of LC-PT derivatives, in which two kinds of LC groups, cyanobiphenyl (CB) and phenylcyclohexyl (PCH), are adopted as mesogenic cores [22-25] in LC side-chains. 

In the previous section, we described the synthesis of LC polythiophene (PT) and polythienylenevinylene (PTV) derivatives with a cyanobiphenyl (CB) or phenylcyclohexyl (PCH) group at the 3-position of the... 

Synthesis of monomers N-[n-(4 -cyanobiphenyl-4-yloxy)alkyl]maleimides (Mb) were prepared via the Mitsunobu reaction previously described for the condensation of alcohols with maleimide (yield 90-95%) and subsequent deprotection of the maleimide double bond by a retro-Diels-Alder reaction (yield 80-95%) as outlined in Scheme 1. 

Synthesis of polymers Poly N-[n-(4 -cyanobiphenyl-4-yloxy) alkyl] maleimide s (PMb) and poly[p-(4 -cyanobiphenyl-4-yloxy) methylstyrene-co- N-[3-(4 -cyanobiphenyl-4-yloxy)propyl] maleimide ] [PfCBMS-co-Ma)] were obtained by free radical polymerization (AIBN, 2 mol%) in DMSO ([monomer]=0.6 mol/L) under vacuum in sealed tubes at 70" C for 48 h. 

Although the above route differs slightly from the synthesis of the related chiral biphenyls [i.e. (5 )-(+)-4-(3-methylpentyl)-4 -cyanobiphenyl (41, n = 1 and /w = 1)], the other chiral methyl substituted alkanoic acids (37) are obtained by various transformations from (5)-(+)-2-methylbutyl bromide (18) the acyl groups are introduced into the aromatic core by conversion of the acids to their acid chlorides (38) followed by Friedel-Craft s acylation and subsequent Huang-Minion reduction of the chiral methyl substituted alkanoylbromobiphe-nyls (40). This general approach is demonstrated in Scheme 5. 

Synthesis of 4-Alkyl-and 4-alkoxy-4 -cyanobiphenyls Interdigitated Smectic A Materials (e.g., 8CB and (80CB)... 

The alkyl and alkoxy cyanobiphenyls (n-CB and n-OCB) derivatives synthesized by Gray and coworkers and the bicyclohexyl derivatives (PCH- and CCH-n), 4, bind rapidly to a variety of metals. The Sheffield Liquid Crystal group [12] used these compounds for the synthesis of metallomesogens with a linear geometry M = Pd, Pt, Rh. 

Q. Wang, X. Dong, T. Xiao, L. Zhou, PhI(OAc)2-mediated synthesis of 6-(trifluoromethyl)phenanthridines by oxidative cycUzation of 2-iso-cyanobiphenyls with Cp3SiMe3 under metal-free conditions, Org. Lett. 15 (2013) 4846-4849. 

Craig AA, Imrie CT. Effect of spacer length on the thermal properties of side-chain liquid-crystal polymethacrylates. 2. Synthesis and characterization of the poly[omega-(4 -cyanobiphenyl-4-yloxy)alkyl methacrylate]s. Macromolecules 1995 28 3617-24. 

---