Synthesis of Nematic Liquid Crystals

This brief account of methods for the synthesis of nematic liquid crystals concentrates on the most frequently encountered core systems, linking and terminal groups the synthetic methods presented are often applicable to more unusual nematogens and to compounds showing other mesophases (see V. Vill in Volume 1, Chapter IV on General Synthetic Strategies). 

A vast number of liquid crystals showing nematic or other mesophases are obtained using benzene, biphenyl or terphenyl units as core systems, often with the rings connected by polarizable linkages such as ester or alkynyl functions or direct- 

The acid 2.8 is used to provide the acid chloride which gives a route to dimethylene linked-compounds by Friedel-Crafts acylation and reduction of the product ketone [34] and the alcohol 2.7 is used for the methyl-eneoxy-linked systems [36] by a direct DEAD reaction to a phenol [37] or by conversion into an alkyl halide or tosylate and reaction with a phenolate anion. 

Nematogenic, fused-cyclohexane systems with rra -ring junctions have been made based on decalins [38-40], perhydrophe-nanthrenes [40 -42], perhydrochrysenes [43], and perhydroanthracenes, perhydro-naphthacenes and perhydrobenza[a]anthra-cenes [44]. 

51] and directly linked aryl systems (3.1) [46, 51, 52] the bicyclo[2.2.2]octane core has also been compared with phenyl, cyclohexyl and a range of related cores [53, 54]. 

---

Synthesis of Nematic Liquid Crystals and Chiral Dopants... 

---