20443-98-5Relevant articles and documents
Continuous photochemical benzylic bromination using: In situ generated Br2: Process intensification towards optimal PMI and throughput
Steiner, Alexander,Williams, Jason D.,De Frutos, Oscar,Rincón, Juan A.,Mateos, Carlos,Kappe, C. Oliver
, p. 448 - 454 (2020)
The detailed development of photochemical benzylic brominations using a NaBrO3/HBr bromine generator in continuous flow mode is reported. Optimization of the bromine generator enables highly efficient mass utilization by HBr recycling, coupled with fast interphase transfer within a microstructured photochemical reactor (405 nm LEDs). Intensification of the reaction system, including complete removal of organic solvent, allowed a reduction in PMI from 13.25 to just 4.33. The photochemical transformation achieved exceptionally high throughput, providing complete conversion in residence times as low as 15 s. The organic solvent-free preparation of two pharmaceutically relevant building blocks was demonstrated with outstanding mass efficiency, by monobromination (1.17 kg scale in 230 min, PMI = 3.08) or dibromination (15 g scale in 20 min, PMI = 3.64).
Photocatalytic continuous bromination method
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Paragraph 0041-0059; 0072, (2021/04/03)
The invention provides a photocatalytic continuous bromination method. The method comprises the following steps: carrying out a first-stage photocatalytic continuous bromination reaction on a materialcontaining an aromatic substrate with a structural general formula I and a bromination reagent in a first continuous illumination reactor to form a first continuous system; overflowing the obtained first continuous system into a second continuous illumination reactor for a second-stage photocatalytic continuous bromination reaction to form a second continuous system; and purifying the second continuous system, wherein the structural general formula I is shown in the specification, R is selected from any one of carboxyl, ester group, NO2, CN, C1 to C8 alkyl and alkoxy, and R1 is C1 to C8 alkyl; n is 1 or 2; X is N or C, and the bromination reagent is Nbromo succinimide or dibromohydantoin. According to the bromination reagent, the selectivity of a product is improved, so the yield of the product is improved; the photocatalytic continuous bromination reaction of the two stages effectively relieves the reaction heat accumulation, and enhances the yield of the target product.
Silver-Catalyzed Decarboxylative Bromination of Aliphatic Carboxylic Acids
Tan, Xinqiang,Song, Tao,Wang, Zhentao,Chen, He,Cui, Lei,Li, Chaozhong
supporting information, p. 1634 - 1637 (2017/04/11)
The silver-catalyzed Hunsdiecker bromination of aliphatic carboxylic acids is described. With Ag(Phen)2OTf as the catalyst and dibromoisocyanuric acid as the brominating agent, various aliphatic carboxylic acids underwent decarboxylative bromination to provide the corresponding alkyl bromides under mild conditions. This method not only is efficient and general but also enjoys wide functional group compatibility. An oxidative radical mechanism involving Ag(II) intermediates is proposed.