Synthesis of 4-Alkoxy-phenyl-4-alkoxybenzoates Smectic C Materials

5 Synthesis of 4-Alkoxy-phenyl 4-Alkoxybenzoates Smectic C Materials 

Esters provide a wide range of stable smectic materials which are suitable for physical studies. In many instances they are more useful for investigations than Schiff s bases (nOms and TBnAs) because of their better stability and purity. Simple 4-alkoxy-phenyl 4-alkoxybenzoates are an intere.sting class of materials because they provide low temperature smectic C variants (often with the addition of smectic A and nematic phases). 

A synthetic pathway to the 4-alkoxyphe-nyl 4-alkoxybenzoates is shown in Fig. 32. The pathway involves two alkylations one of 4-hydroxybenzoic acid using an alkyl halide in the presence of sodium hydroxide and ethanol, and the other of 1,4-dihydroxyben-zene using an alkyl halide in the presence of sodium hydroxide and dioxane. Activation of the acid with thionyl chloride to give the acid chloride and reaction with the alkoxy-phenol in the presence of a base such as tri-ethylamine yields the final esters. 

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Synthesis of 4-Alkoxy-phenyl-4-alkoxybenzoates Smectic C Materials. . . 429... 

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