Disclosed are novel active benzene derivatives represented by the general formula (I): ##STR1## (wherein X represents --COO--, --OCO--, --CH.sub.2 O-- or --OCH.sub.2 --; A represents a hydrogen atom, a halogen atom or an alkyl or alkoxyl group having 1 to 20 carbon atoms; R represents an alkyl group having 1 to 20 carbon atoms; l and m each represents a number of 1 or 2, n represents a number of 0 or 1, but when n is 0 the sum of l and m is 3 or less; and * indicates asymmetric carbon atom), a process for producing the same, liquid-crystalline substances containing said derivatives as active ingredient, and optical switching elements utilizing the liquid crystal compositions containing said liquid-crystalline substances.
揭示了由通式(I)表示的新型活性苯衍
生物:(其中X代表--COO--,--OCO--,--CH.sub.2 O--或--OCH.sub.2--;A代表氢原子,卤素原子或具有1至20个碳原子的烷基或烷氧基;R代表具有1至20个碳原子的烷基;l和m分别表示1或2的数字,n表示0或1的数字,但当n为0时,l和m的总和为3或更少;*表示不对称碳原子),以及生产该化合物的方法,含有上述衍
生物作为活性成分的液晶物质,以及利用含有上述液晶物质的液晶组合物的光学开关元件。