1-溴-2,4,6-三甲氧基苯主要用于医药和农药领域,其合成方法多样,可通过不同底物和反应条件实现高效制备,具有较高的产率和绿色化学特性。
医药; 农药
合成路线 1(1. 合成:1131-40-4)
产率:97%
合成条件:With silver carbonate; copper(ll) bromide; palladium dichloride In tetrahydrofuran at 110℃; for 24 h;
实验步骤:一般步骤:将羧酸(1当量,0.5mmol),CuBr 2或CuCl 2(2当量,1mmol),Ag 2 CO 3(1当量,0.5mmol)和PdCl 2(0.1当量)的混合物在THF中加热(3) mL)在110℃回流24小时。 反应完成后,将混合物真空蒸发并通过柱色谱法纯化,得到所需产物。
参考文献:
- [1] Tetrahedron Letters, 2013, vol. 54, # 24, p. 3079 - 3081 [2] Journal of Organic Chemistry, 2016, vol. 81, # 7, p. 2794 - 2803
合成路线 2(2. 合成:1131-40-4)
产率:89 %Spectr.
合成条件:With tetrabutylammomium bromide; dihydrogen peroxide; trifluoroacetic acid In water at 25℃; for 24 h; Inert atmosphere
实验步骤:一般步骤:在装有回流冷凝器的10mL双颈烧瓶中,放置底物(0.25mmol)和四丁基溴化铵(161.2mg,0.50mmol)。 将烧瓶抽空并用Ar回填。 向混合物中加入超纯水(0.5mL),三氟乙酸(57.5μL,0.75mmol)和30%H 2 O 2(77μL,0.75mmol)。 将混合物在25℃下在Ar下搅拌,然后用1:1混合物的饱和Na 2 S 2 O 3水溶液和饱和NaHCO 3水溶液处理,并用乙醚萃取。 将有机层用Na 2 SO 4干燥,过滤,蒸发。 加入1,3,5-三甲氧基苯或六甲基苯作为内标,并进行1H NMR分析以确定NMR产率。 产品的光谱数据与市售和真实样品的光谱数据相同。
参考文献:
- [1] Journal of Organic Chemistry, 2008, vol. 73, # 17, p. 6849 - 6852 [2] ACS Catalysis, 2016, vol. 6, # 2, p. 1113 - 1121 [3] Chemistry - An Asian Journal, 2009, vol. 4, # 8, p. 1213 - 1216 [4] Tetrahedron Letters, 1996, vol. 37, # 47, p. 8609 - 8612 [5] Chemical Communications, 2009, # 42, p. 6460 - 6462 [6] Synlett, 2014, vol. 25, # 12, p. 1769 - 1775 [7] Chemistry Letters, 2017, vol. 46, # 12, p. 1708 - 1710
合成路线 3(3. 合成:1131-40-4)
产率:98%
合成条件:With N-Bromosuccinimide In neat (no solvent) at 20℃; for 0.75 h; Milling; Green chemistry
实验步骤:一般步骤:将1-甲氧基-3,5-二甲基苯(100mg,0.73mmol),N-溴代琥珀酰亚胺(NBS,260mg,1.46mmol)和一个球(5mm直径,不锈钢)转移到研磨罐中(10mL) , 不锈钢)。进行球磨操作,通过TLC / 1H NMR监测反应进程。[1]完成后,将反应混合物转移到30mL乙酸乙酯中并在0℃冷却。在纸过滤时将产物分离为滤液,并将废琥珀酰亚胺作为沉淀物分离。将所得滤液真空浓缩,分离出250mg(产率:85%)2b,为无色粉末。为了大规模测试效率,还进行了以1.3g规模对1-甲氧基-3,5-二甲基苯进行单溴化反应1小时的反应,并且以87%的收率分离产物[1]。停止研磨设备并从反应罐中收集小部分样品以研究TLC /质子NMR。接着,再次开始反应,排除该操作时间以报告反应时间。
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