2,5-二取代-1,4-二醛基苯的合成

Synthesis of 2, 5-Disubstituted-1, 4-Benzenedicarboxaldehyde

2,5-二甲基-1,4-二溴苯和N,N-二甲基甲酰胺在四甲基乙二胺和叔丁基锂的作用下,发生Bouveault反应氧化得到2,5-二甲基-1,4-二醛基苯。其结构经^(1)HNMR、^(13)CNMR和ESI-MS表征。通过对反应条件研究,确定当反应条件为:n(2,5-二甲基-1,4-二溴苯)∶n(N,N-二甲基甲酰胺)=1∶3、n(2,5-二甲基-1,4-二溴苯):n(叔丁基锂)=1∶2.1、n(2,5-二甲基-1,4-二溴苯)∶n(四甲基乙二胺)=1∶0.05时,以四氢呋喃为溶剂,室温反应50min,产物收率最高,可达82.5%。同时,该方法被用于2,5-二乙基-1,4-二醛基苯(5)和2,5-二乙氧基-1,4-二醛基苯(6)的合成,收率分别为82.0%和78.3%。

2,5-dimethyl-1,4-Dibromobenzene reacted with dimethylformamide by Bouveault reaction in the presence of Tetramethylethylenediamine and tert butyl lithium to afford 2,5-dimethyl-1,4-p-phenylenedialdehyde.The structure of the target product was confirmed by 1HNMR,13CNMR and ESI-MS.The optimal synthsis conditions were discussed.When n(2,5-dimethy-1,4-dibromobenzene):n(N,N-dimethylformamide)=1∶3,n(2,5-dimethy-1,4-dibromobenzene):n(t-BuLi)=1∶2.1,n(2,5-dimethy-1,4-dibromobenzene):n(tetramethylethylenediamine)=1∶0.05,and tetrahydrofuran was used as solvent at room temperature for 50min,the Bouveault reaction yield is the highest,which can reach 82.5%.Also,2,5-diethylterephthalaldehyde and 2,5-diethoxyterephthalaldehyde were obtained with this process in yields of 82.0%and 78.3%,respectively.