Synthesis and phase behaviour of liquid crystals containing a 2(S)[2(S)-methylbutoxy]propionate group

Abstract

4-nS-Alkyloxyphenyl 4-{2(S)-[2(S)-methylbutoxy]propionyloxy}benzoate (4a-f), 4-(4-n-alkyloxyphenyl)phenyl 4-{2(S)-[2(S)methylbutoxy]propionyloxy}benzoate (5a-f) and 4-n-alkyloxyphenyl 4-(4-{2(S)-[2(S)-methylbutoxy]propionyloxy]phenyl) benzoate (6a-f) were synthesized and characterized. They all contain two chiral centres. Compounds 4a-f are not liquid crystals. Compounds 5a-f either exhibit both an S_c* and an N* or only an S_c* phase, depending on the length of the side-chain alkyl group, whereas compounds 6a-f all possess both S_c* and N* phases. The K-S_c* phase-transition temperature of 6a-f is not only lower than that of the corresponding 5a-f, but the S_c* phase temperature range is also wider.