Yield:-

Reaction Conditions:

in tetrahydrofuran;

Steps:

1.I

Example 1 A Facile Synthesis of a Series of 2-(4'-alkylphenyl)-5-cyanopyridine Liquid Crystal and Its Product AnalysisI. Facile Synthesis of 2-(4'-alkylphenyl)-5-cyanopyridine Liquid CrystalAdd dry magnesium particles 12 millimole to 20 ml of tetrahydrofuran (THF) solution containing 10 millimole of 4-butylbromobenzene in inert gas to form a Grignard reagent of 4-alkylphenylmagnesium bromides, then gradually add the Grignard reagent to 20 ml of tetrahydrofuran (THF) solution containing 10 millimole of N-phenyloxycarbonyl-3-cyanopyridinium chloride under low temperature (-20° C.), allow the mixed solution to gradually return to ambient temperature, stir the mixed solution for 8 hours, remove the tetrahydrofuran (THF), extract the remainder with ether, rinse it twice with 10% hydrochloric acid and once with saturated saline, then dry it with magnesium sulfate to obtain 1,2-dihydropyridine intermediate. (The yield rate of said intermediate is about 95%).Dissolve the 1,2-dihydropyridine intermediate in 20 ml dry toluene, add about 1.5 equivalent of o-chloronil to said 1,2-dihydropyridine intermediate to oxydize it, then heat the resultant solution in inert gas for a few hours under reflux, quench it with 25 ml of IN sodium hydroxide (NaOH) solution, extract with ether, then after filtering and usual aqueous phase post-treatment and separation with column chromatography, 2-(4'-alkylphenyl)-5-cyanopyridine liquid crystal compounds of formula (I) can be obtained.

References:

US2008/146813,2008,A1 Location in patent:Page/Page column 2