The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 16, 1989
Filed:
May. 20, 1987
Richard Buchecker, Zurich, CH;
Hans-Jurgen Fromm, Lorrach, CH;
Stephen Kelly, Kaiseraugst, CH;
Martin Schadt, Seltisberg, CH;
Hoffmann-La Roche Inc., Nutley, NJ (US);
Abstract
Compounds of the formula ##STR1## wherein m represents is the number 0 or 1; A is a single covalent bond, --CH.sub.2 --CH.sub.2 --, --OCH.sub.2 --, --COO-- or --OOC--; rings B, C and D are 1,4-phenylene optionally substituted with cyano, halogen or lower alkyl; Y.sup.1 and Y.sup.2 are hydrogen or one of them also is cyano; and R.sup.1 and R.sup.2 each represents C.sub.1 -C.sub.18 -alkyl or C.sub.2 -C.sub.18 alkenyl, either of which is optionally halogen-substituted, in which one CH.sub.2 group or two non-adjacent CH.sub.2 groups is/are optionally replaced by oxygen; with the provisos that at least one of R.sup.1 and R.sup.2 has a chiral carbon atom or a C--C double bond or both when A is --COO-- and at least one of R.sup.1 and R.sup.2 has a C--C double bond when A is a single covalent bond, their preparation, liquid crystalline mixtures containing these compounds and their use for electro-optical purposes are described.