4-甲基二苯并噻吩的合成与表征

SYNTHESIS AND CHARACTERIZATION OF 4-METHYLDIBENZOTHIOPHENE

采用将二苯并噻吩先锂化、再烷基化的方法 ,可以合成 4 甲基二苯并噻吩 (4 MDBT)。优化的合成条件如下 :正丁基锂 (n BuLi)与二苯并噻吩 (DBT)的摩尔比为 3∶1,正丁基锂己烷溶液的浓度为 1.5mol/L ,磺甲烷与DBT的摩尔比为 3∶1,在 - 35℃下进行锂化、烷基化反应。在此条件下 ,DBT的转化率最高 ,达 90 %以上 ;4 MDBT的色谱收率达 82 .3%。粗产品经活性白土脱色及在 - 2 0℃下用 95 %甲醇重结晶 2次后 ,产品纯度达 96 .1% ,产率为6 1 6 %。对合成产品 4 MDBT进行的GC MS、1H NMR、FT IR、XRD分析表征结果表明 ,合成产物的确为 4 MDBT。

The synthesis of 4 methyldibenzothiophene (4 MDBT) was carried out on the reaction of dibenzothiophene (DBT) with n butyl lithium to form 4 lithio dibenzothiophene, which then reacts with methyl iodide. The optimized synthesis conditions are as follows:① The molar ratio of n butyl lithium to dibenzothiophene is three to one. ② The concentration of solution of n butyl lithium in hexane is 1.5 molars per litre. ③ The reaction temperature of lithiation and alkylation is -35 ℃. Under above conditions, the transformation ratio of DBT is more than 90%, and the chromatographic yield is 82.3%. The activated clay is the best decolourization reagent to the crude product, and 95% methanol is the best solvent for recrystallization. The 4 MDBT with 96.1% in purity and 61.6% in yield was obtained. The purified 4 MDBT was identified and characterized with GC MS, 1H NMR, FT IR and XRD methods.