2-氨基-3-溴-5-氯吡啶的制备及其应用

基本描述

2-氨基-3-溴-5-氯吡啶的CAS号是26163-03-1，分子式是C5H4BrClN2，分子量为207.46。熔点为82-83°C，沸点256.2±35.0°C(Predicted)，密度1.834±0.06g/cm3(Predicted)，酸度系数(pKa)是1.91±0.49(Predicted)。

图1 2-氨基-3-溴-5-氯吡啶的结构式[1]。

合成

图2 2-氨基-3-溴-5-氯吡啶的合成路线[2]。

将5-氯吡啶-2-胺(5000.0 mg, 38.90 mmol)溶于CHCl3 (78.0 mL)中，再加入Br2 (2.0 mL, 38.90 mmol)。反应混合物在室温下搅拌一小时，减压除去溶剂。残渣在乙酸乙酯中溶解，然后用饱和的NaHCO3水溶液和盐水洗涤，在无水Na2SO4上干燥，过滤，减压蒸馏。用硅胶柱层析(乙酸乙酯:n-Hex= 1:9)纯化残渣。收集含产物馏分，蒸发得到2-氨基-3-溴-5-氯吡啶。黄色固体，产率(7500.0 mg, 93%)。 LC/MS ESI(+): 207 (M+1), 209 (M+3) 1H-NMR (300 MHz, CDCl3); δ: 7.98 (d, 1H, J=2.1 Hz), 7.66 (d, 1H, J=2.1 Hz), 4.93 (bs, 2H).

向250ml圆底烧瓶中加入5-氯吡啶-2-胺（80g，622.3mmol）和CHCl3（100ml）。加入溴（31.98毫升，622.3毫摩尔）并在室温下搅拌30分钟；将反应混合物倒入饱和碳酸氢盐和NaHSO3中，用CH2Cl2萃取。有机层用硫酸钠干燥，过滤并浓缩，得到呈黄褐色固体的2-氨基-3-溴-5-氯吡啶（113.8g，88.1%产率）。1H NMR (d6-DMSO) δ 7.97 (d, 1H), 7.90 (d, 1H), 6.44 (bs, 2H)。

将2-氨基-5-氯吡啶(5.14 g, 40 mmol)和无水乙酸钠(3.29g> 40 mmol)的悬浮液(25 mL)机械搅拌，加热至45°C的浴温。加入溴(2.1 mL, 40 mmol)乙酸(2 mL)溶液1小时以上。得到的橙色混合物被冷却到15°C并过滤。固体加入400 mL水，加入1 N NaOH使悬浮液变碱，用乙酸乙酯(5 x 100 mL)提取悬浮液。用10% NaHSO3 (1×100 mL)洗涤组合提取物，并用MgSO4烘干。得到2-氨基-3-溴-5-氯吡啶。收益率(4 g, 48%)。熔点82 - 84°C。

应用

2-氨基-3-溴-5-氯吡啶的用途非常广泛，合成树脂、表面活性剂、塑料、橡胶、皮革、造纸、染料、制药、农药、照相胶片、炸药、建筑材料以及消毒、熏蒸和防腐过程中均需要其参与[3-6]。此外2-氨基-3-溴-5-氯吡啶是基础的有机化工原料和优质燃料[7]，主要应用于精细化工，塑料等领域。可以说2-氨基-3-溴-5-氯吡啶是化学工业中的多面手，但任何东西的使用都必须有个限量，有一个标准，一旦使用超越了标准和限量，就会带来不利的一面[8]。

参考文献

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