钯催化氰基化反应合成对氰基苯甲酸

Synthesis of 4-cyanobenzoic acid by palladium catalyzed cyanation reaction

目的合成对氰基苯甲酸,并考察其催化反应条件。方法以对溴苯甲酸为原料、K4Fe（CN）6·3H2O为氰基化试剂、双（O-二苯基膦苯甲酸）钯配合物[（O-Ph2PC6H4COO）2Pd]为催化剂,经溴代芳烃的氰基化反应合成对氰基苯甲酸;考察K4Fe（CN）6·3H2O、钯配合物和K3PO4的用量、温度、时间和溶剂等对反应的影响。结果目标产物的化学结构经1HNMR、13CNMR确证,收率为82.3%,HPLC纯度〉94.6%。最佳反应条件为：对溴苯甲酸、K4Fe（CN）6·3H2O、（O-Ph2PC6H4COO）2Pd及K3PO4的比例为1.0∶0.3∶0.02∶2.0,溶剂为N,N-二甲基甲酰胺,温度为125~130℃,时间12 h。结论所用方法具有原料易得、条件温和、操作简便、收率高等优点。

OBJECTIVE To synthesize 4 - cyanobenzoic acid and to investigate the catalytion reaction conditions. METHODS 4 - cyanobenzoic acid was synthesized from 4 - bromobenzoic acid and potassium hexacyanoferrate （ Ⅱ ） , via cyanation reaction with the palladium complex catalyst of （0 -Ph2PC6H4CO0） 2Pd. The effects of potassium hexacyanoferrate（Ⅱ） dosage ,catalyst dosage ,tripotassi- um phosphate trihydrate dosage, reaction temperature, reaction time and reaction solvent on the yield of 4 - cyanobenzoic acid were investigated. RESULTS The target compound was confirmed by t HNMR and 13 CNMR. The yield of 4 - cyanobenzoic acid was 82. 3% , and the HPLC purity was higher than 94.6%. The optimization conditions for 4 - cyanobenzoic was N, N - Dimethylformamide as the reaction solvent,the ratio of 4 - bromobenzoic acid, potassium hexacyanoferrate （Ⅱ）, and the ratio of palladium catalyst and tripotassium phosphate trihydrate was 1.0 ： 0.3 ： 0.02 ： 2.0, reaction temperature 125 - 130 ℃ and reaction time 12 h. CONCLUSION The method possesses the adventages such as easily available stock,mild condition simple manipulation and high yeild.