无水溴化锌催化合成反-4-苯乙烯基吡啶

Synthesis of trans-4-styryl pyridine with anhydrous zinc bromide as catalyst

以甲苯为溶剂,无水溴化锌为催化剂,苯甲醛与4-甲基吡啶进行缩合反应生成了反-4-苯乙烯基吡啶.最佳反应条件是,苯甲醛与4-甲基吡啶物质的量的比为1.0∶1.5,无水溴化锌与苯甲醛物质的量比为2.0∶3.0,反应温度为85℃,产物收率为68.32%.研究还发现,在相同条件下,以无水氯化锌为催化剂,可以得到一种晶体(4-甲基吡啶)氯化锌,X-单晶衍射分析表明,该晶体属单斜晶系,空间群为P2(1)/c,晶胞参数为a=1.434 1(4)nm,b=0.789 3(4)nm,c=1.350 4(9)nm,β=100.656 0(10)°,晶胞内分子数为4.作为配体4-甲基吡啶不与苯甲醛发生缩合反应.

Trans-4-styryl pyridine was prepared by use of toluene as a solvent,anhydrous zinc bromide as catalyst,from the condensation reaction of benzaldehyde and 4-methylpyridine.That best reaction conditions is,benzaldehyde and 4-methyl-pyridine molar ratio of 1.0∶1.5,anhydrous zinc bromide and benzaldehyde molar ratio of 2.0∶3.0,and the reaction temperature is 85 ℃,the product yield 68.32%.It is also found that,under the same conditions,by use of anhydrous zinc chloride as catalyst,a crystal is obtained： bis（4-methyl-pyridine） zinc chloride.Through the X-crystal diffraction analysis,the crystal is monoclinic system,space group P2（1） / c,unit cell parameters： a= 1.434 1（4）,b=0.789 3（4）,c=1.350 4（9） nm,β= 100.656 0（10） °,the number of molecular within unit cell is 4.As ligand,4-methylpyridine does not condense with benzaldehyde.