This invention concerns compounds of the formula: ##STR1## wherein n is 1 and X is --COO--, --OOC-- or --CH.sub.2 CH.sub.2 --; or n is O and X is --CH.sub.2 CH.sub.2 --; ring A is p-phenylene or trans-1,4-cyclohexylene; R.sup.2 is cyano, p-cyanophenyl or, when X is --COO-- or --OOC--, R.sup.2 may also be p-R.sup.3 -phenyl or trans-4-R.sup.3 -cyclohexyl; and R.sup.1 and R.sup.3 each are straight-chain C.sub.1 -C.sub.10 -alkyl. their manufacture and their use for electro-optical purposes and in gas chromatography are described.
本发明涉及以下式的化合物: ##STR1## 其中n为1且X为--COO--,--OOC--或--CH.sub.2 CH.sub.2 --;或n为O且X为--CH.sub.2 CH.sub.2 --;环A为p-苯撑基或反-1,4-环己撑基;R.sup.2为
氰基,对-
氰基苯基或当X为--COO--或--OOC--时,R.sup.2还可以是对- R.sup.3 -苯基或反-4-R.sup.3 -环己基;R.sup.1和R.sup.3分别为直链C.sub.1-C.sub.10-烷基。描述了它们的制造方法以及它们在电光目的和气相色谱中的用途。