二氟环丙烷羧酸:卡宾策略、回收策略

文摘   2025-01-07 07:02   天津  
二氟环丙烷羧酸,分享的题目的确切名字是S-2,2-二氟环丙烷羧酸,结构和其他信息如下

卡宾策略
  • 二氟环丙烷羧酸,二氟环丙烷的构建采用双键和二氟卡宾反应;羧基的引入采用氧化双键或者原有酯的水解,方程式如下

  • 经过设计,羧基引入采用酯水解,二氟卡宾源采用化合物17-化合物22进行筛选。

卡宾源的研究
  • 卡宾源的筛选,经过对比选择化合物22

卡宾源的产生和副产物信息
  • 二氟卡宾的产生路径,需要溴离子参与反应,产出气体溴乙烷和二氧化碳。

  • 目标物合成方程式和副产物信息,注意有聚合物产生

拆分和回收策略
  • 动力学拆分不是想有就能有,但是经典拆分经常有。
  • 经典拆分的最大问题是,收率最多50%;经典拆分最大的起死回生策略,不要的部分继续消旋,再经典拆分。

经典拆分的方程式如下

回收的方程式流程如下
  • 以便宜为CDI为活性酯源,以DBU为碱,进行消旋处理。


构建二氟环丙烷的实验操作
To a vessel that has been purged with nitrogen was added a eutectic mixture of biphenyl/diphenyl ether (26.5% w/w biphenyl, 435 kg, 1.75 g/g), and the contents were heated to 135 °C. In a separate vessel, EBDFA (250 kg, 1.0 equiv), butyl acrylate (475 kg, 3.0 equiv), and TBAB (2 kg, 0.005 equiv) were added to a eutectic mixture of biphenyl/diphenyl ether (175 kg, 0.88 g/g) and stirred until the TBAB fully dissolved. The reaction is vented through an off-gas scrubber containing a solution of ethanolamine (210 kg), PEG400 (105 kg), and water (50 kg). The solution of reagents is added gradually over 7 h into the vessel containing the preheated  solvent at a rate to control gas generation and maintain a temperature of 130−140 °C. At the end of dosing, the addition vessel is rinsed with eutectic solvent (11 kg), and this added to the main batch. A second portion of TBAB (1 kg, 0.0025 equiv) is added, followed by a rinse with additional eutectic solvent (1 kg), and the mixture was stirred for 1 h. A third portion of TBAB (1 kg, 0.0025 equiv) is then added, followed by a solvent rinse (1 kg), and the reaction mixture was stirred for an additional 3 h. 
After cooling to room temperature, the reaction is diluted with 1,2-dichlorobenzene (581 kg, 2.3 g/g). The resulting solution is subjected to a crude distillation using a 11.3 m × 0.5 m column (20 theoretical plates) to remove volatiles (including product 14) from the residual biphenyl/diphenyl ether and polymer. The solution was distilled at reduced pressure (80−200 mbar) at a head temperature of 20−116 °C resulting in 807 kg of crude distillate. Two batches of crude distillate were combined and heated to 130−140 °C for 50 h to polymerize the remaining butyl acrylate until the level of remaining monomer had reached an acceptable level. The material was then subjected to fractional distillation (11.3m × 0.5 m column, 20 theoretical plates) under the following conditions: reflux ratio 10:1, sump temp 122−157 °C, head temp 55−130 °C, pressure 80−230 mbar. Collected fractions that were sufficiently pure were combined for further processing. This resulted in 182 kg of product 14, which was obtained as an ∼15% w/w solution in 1,2-DCB. Typical yield= 35−42%.

参考文献
https://doi.org/10.1021/acs.oprd.1c00171
Org. Process Res. Dev. 2022, 26, 683−697

原料药合成工艺开发
有机合成工艺文献分享和总结;有机合成工艺经验分享和交流;原料药研发的法规指导文件交流
 最新文章