| Summary: | 碩士 === 國立高雄師範大學 === 化學系 === 87 === The new chiral terminal group with two chiral centers, 2(S)-[2(S)-methylhexoxy]propionic acid 6, was synthesized by the esterification of natural (S)-ethyl lactate and 1-iodo-2(S)-methylhexane 4 as well as the saponification of the ester 5 formed. The 1-iodo-2(S)-methylhexane 4 was prepared from 2-methylhexanoic acid by optical resolution、reduction、tosylation and iodination.
The new liquid crystal compound, 4-{2(S)-[2(S)-methyl-hexoxy] propionyloxy}biphenyl-4-n-decoxybenzoate 9d, was synthetized from the new chiral acid 6 . The research results indicate that it is a ferroelectric liquid crystal（FLC）. In comparison with the published papers and the corresponding study in our laboratory, some important research results are summarized as following：
1. The new chiral terminal group 6 is helpful for the formation of Sc* phase. Therefore, a new compound 9d containing 6 was prepared. It has a broad Sc* phase whose temperature range is from 73℃ up to 119℃ with a width of 46℃.
2. The Sc* phase temperature of the FLC 9d is ca. 10℃ lower than that of the similar compounds, but their temperature ranges of Sc* phase are more or less the same. They exhibit the same liquid crystal behavior, a wide Sc* phase and a narrow N* phase.
3. The change of the specific optical rotation within those new chiral compounds are similar to that within the corresponding chiral compounds studied before. This similarity could not been established within the corresponding chiral compounds with S,R-relative stereochemistry.
4. In addition, a series of new compounds, 4''-hydrobiphenyl-4-n-alkoxybenzoate 8, were synthesized and the results of DSC and polarizing microscope show that they possess N phase.
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