2,5-DISUBSTITUTED FLUORINE-CONTAINING PYRIDINE DERIVATIVE

摘要

NEW MATERIAL:A compound shown by formula I (R is 1-20C straight-chain alkyl or straight-chain alkoxy; X is F or H). EXAMPLE:A compound shown by formula II. USE:A liquid crystal substance useful as a material for a liquid crystal display cell having low-voltage driving properties and high-temperature driving properties since the liquid crystal substance can lower a threshold voltage and raise N-I transition temperature of mixed liquid crystal as a parent material by adding the liquid crystal substance to the mixed liquid crystal. PREPARATION:A compound shown by formula II is reacted with Vilsmeier reagent prepared from N,N-dimethylformamide and phosphorus oxychloride, then reacted with perchloric acid or magnesium perchlorate to give a compound shown by formula III. Then this compound is reacted with a compound shown by formula IV in a basic solvent such as pyridine in the presence of sodium alcoholate to give a compound shown by formula V. Further this compound is reacted with ammonium acetate in acetic acid to give a compound shown by formula I.