| abstract |
PURPOSE: To obtain a new chloro tolane useful as a stable liquid crystal compound or component of liquid crystalline media, having a low viscosity, high nematic liquid crystal property as well as an advantageous optical parameter and dielectric anisotropy. n CONSTITUTION: A compound of formula I (R 1 is 1-12C alkyl in which one or two non-adjacent CH 2 groups may be replaced by -O-, -O-CO-, -COO-, and/or -CH=CH-; A is trans-1,4-cyclohexylene or 1,4-phenylene; r, s are 0-1; either of L 1 and L 2 is F, and the other H or F; and when s is 0 and R 1 is 2-12C alkyl, L 1 =L 2 =H), e.g. 4-pentyl-3'-fluoro-4'-chloro tolane, is produced from 4-substituted phenylacetylene, an aryl halide and copper iodide, preferably in the presence of Pd catalyst. n COPYRIGHT: (C)1992,JPO |