4,6-二甲基二苯并噻吩的合成研究

Study on the Synthesis of 4,6-Dimethyldibenzothiophene

二苯并噻吩与正丁基锂在四甲基乙二胺作用下发生锂化反应生成二锂化DBT,二锂化DBT与碘甲烷发生烷基化反应生成4,6-二甲基二苯并噻吩。整个反应过程采用氩气保护,对反应温度进行了优化,对反应粗产物的收集方法做了改进,粗产品经减压蒸馏提纯,再经重结晶获得产品,对重结晶溶剂、重结晶温度进行了考察。各种改进措施的采用,提高了4,6-二甲基二苯并噻吩的产品纯度,获得较高的实际产率,实现了4,6-二甲基二苯并噻吩的规模化合成,最终得到纯度为98.8%的4,6-二甲基二苯并噻吩,产率45.8%。对4,6-二甲基二苯并噻吩产品进行了熔点、元素分析、NMR、FT-IR、XRD等分析表征,确认合成得到的产品为4,6-二甲基二苯并噻吩。

Dibenzothiophene reacts with n-butyl lithium under tetramethylethylenediamine to form bis-lithi-dibenzothiophene. Then bis-lithi-dibenzothiophene reacts with methyl iodide to form 4,6-dimethyldibenzothiophene. The whole reaction process is under argon atmosphere. The reaction temperature was optimized,and the collection method of crude products was improved. Crude products were purified by vacuum distillation and then recrystallized to obtain the product. The recrystallization solvent and recrystallization temperature were investigated. The adoption of various improvement measures improved the purity of 4,6-dimethyldibenzothiophene,obtained high actual yield,realized the scale synthesis of 4,6-dimethyldibenzothiophene,and finally got the purity of 98. 8% 4,6-dimethyldibenzothiophene,with a yield of 45. 8%. The products of 4,6-dimethyldibenzothiophene were characterized by melting point,elemental analysis,NMR,FT-IR,XRD and so on. It was confirmed that the synthesized products were 4,6-dimethyidibenzothiophene.