2-羟基-4-(5,6-二硝基-1H-苯并[2,3-d]咪唑-2-基)苯甲酸甲酯的 合成探索

以4,5-二硝基邻苯二胺和2-羟基对苯二甲酸单甲酯为起始原料，设计并成功采用一锅法合成出2-羟 基-4-(5,6-二硝基-1H-苯并[2,3-d]咪唑-2-基)苯甲酸甲酯（MHDIB）。以50 mL二乙二醇二甲醚为溶剂，1.5 g的2-羟基对苯二甲酸单甲酯和2.5 g SOCl2在80 ℃反应2 h制2-羟基-4-氯羰基苯甲酸甲酯。室温下快速向反应体系中加入1.56 g 4,5-二硝基邻苯二胺，并于85 ℃反应1 h后加入3.52 g 多聚磷酸，回流反应1 h后水析出粗产品，经乙醇重结晶得到纯度为93.67%的黄色针状产物，产率为17.82%。产物经IR、MS、1H NMR的准确定性和表征，作为AB型新单体的前体可应用于羟基改性PBI纤维即聚2-羟基-1,4-亚苯基-2,6-苯并[2,3-d：5',6'-d']二咪唑（H-PBI）的创新研究。

Synthesis of methyl 2-hydroxyl-4-(5,6-dinitro-1H-benzo[2,3-d] imidazole-2-yl)benzoate

A novel compound，methyl 2-hydroxyl-4-(5,6-dinitro-1H-benzo[2,3-d]imidazole-2- yl)benzoate（MHDIB），was designed and synthesized from 4,5-dinitro-1,2-benzenediamine and methyl 2-hydroxy-4-carboxybenzoate.The one-pot synthesis method was adopted in synthesis of MHDIB . With 50mL diethylene glycol dimethyl ether as vehicle，methyl 2 - hydroxy-4-(chlorocarbonyl)benzoate was synthesized from 1.5 g methyl 2-hydroxy-4-carboxybenzoate and 2.5 g SOCl2 at 80 ℃，reaction time was 2 hours. At room temperature，1.56 g 4,5-Dinitro-o-phenylenediamine was added rapidly into the reaction system and 2 hours reaction time at 85 ℃. 3.52 g polyphosphoric acid was added and MHDIB was synthesized at reflux temperature for 1h。The preciptate formed was recrystallized with ethanol and yellow needles were obtained. Product yield was 17.82% and purity was 93.67%.The product was qualitatively exact and the structure was characterized by IR，ESI-MS，1H NMR. It was used to prepare a new AB-type monomer of high-performance polymer modified by orderly hydroxy ，poly 2-hydroxy-1,4-phenylene-2,6-benzo[2,3-d：5',6'-d'] diimidazole(H-PBI).