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Adv. Muter 1997, 9, No. 5 0 V C H Verlagsgesellschaff mbH, D-69469 Weinheim, 1997 0935-964~/97/0504-(1375 $17.50+.50/0 ADVANCED MATERIALS H.-7: Nguyen et al.lPhasmids and Polycatenar Mesogens Synthesis PrinciplesSymmetrical hexacatenars such as the first described phasmids were obtained as follows (Scheme 1): The threechain derivative 2 was obtained by etherification of ester 1 with three equivalents of the required n-alkyl bromide, followed by saponification and hydrolysis (a). Esterification of acid 2 chloride with p-nitrophenol (b) afforded nitroester 3, which was reduced to the corresponding aminoester 4 (c). Finally, phasmid 5 was obtained by reaction of two equivalents of 4 with terephthaldehyde.Compounds 5 were generally recrystallized from absolute ethanol. For different symmetrical phasmids and biforked mesogens, the synthetic route is similar with protected and deprotected phenols or anilines. The central ring moiety i s often terephthalic acid, 1,4-cyclohexanedi-carboxylic acid, or terephthaldehyde. With non-symmetric polycatenar mesogens, the different intermediate compounds are protected or deprotected phenols, anilines and acids or aldehydes. The same method is repeated to add a benzoate. The last step is often an esterification reaction (Scheme 2): unlike the imine derivatives, compounds with ester linkages can be easily purified by chromatography on silica gel with dichloromethane as eluent.