以2-氨基-3-取代的苯甲酸为起始原料,经重氮化-自偶联反应、酯化、还原、氧化、环合反应制备了4,5-二取代的菲衍生物,并以还原后的联苯中间体为原料经溴化、格氏化反应制备了4,5-二取代的9,10-二氢菲衍生物,以4,5-二取代的菲和4,5-二取代的9,10-二氢菲衍生物为原料经过卤化、偶联反应制备了液晶单体化合物.产物结构经过了1H NMR,13C NMR的确证,并对其性能进行了测试.研究结果表明,这类液晶具有较大的光学各向异性和介电各向异性. 4,5-disubstituted phenanthrene derivatives were prepared by diazotization-self-coupling reaction, esterification, reduction, oxidation and cyclization reaction using 2-amino-3-substituted benzoic acid as starting material The 4,5-disubstituted 9,10-dihydrophenanthrene derivative was prepared by bromination and Grignard reaction using the reduced biphenyl intermediate as starting material. The 4,5-disubstituted phenanthrene and 4,5 - disubstituted 9,10-dihydrophenanthrene derivatives as raw materials through halogenation, coupling reaction of liquid crystal monomer compounds were confirmed by 1H NMR, 13C NMR confirmation, and its performance was tested.Results It shows that this kind of liquid crystal has larger optical anisotropy and dielectric anisotropy.