79985-01-6Relevant academic research and scientific papers
A scalable procedure for light-induced benzylic brominations in continuous flow
Cantillo, David,De Frutos, Oscar,Rincon, Juan A.,Mateos, Carlos,Oliver Kappe
supporting information, p. 223 - 229 (2014/01/17)
A continuous-flow protocol for the bromination of benzylic compounds with N-bromosuccinimide (NBS) is presented. The radical reactions were activated with a readily available household compact fluorescent lamp (CFL) using a simple flow reactor design based on transparent fluorinated ethylene polymer (FEP) tubing. All of the reactions were carried out using acetonitrile as the solvent, thus avoiding hazardous chlorinated solvents such as CCl4. For each substrate, only 1.05 equiv of NBS was necessary to fully transform the benzylic starting material into the corresponding bromide. The general character of the procedure was demonstrated by brominating a diverse set of 19 substrates containing different functional groups. Good to excellent isolated yields were obtained in all cases. The novel flow protocol can be readily scaled to multigram quantities by operating the reactor for longer time periods (throughput 30 mmol h-1), which is not easily possible in batch photochemical reactors. The bromination protocol can also be performed with equal efficiency in a larger flow reactor utilizing a more powerful lamp. For the bromination of phenylacetone as a model, a productivity of 180 mmol h -1 for the desired bromide was achieved.
Photolysis of a series of α-brominated ortho-xylenes in apolar solvents
Rezende, Daisy de B.,Campos, Ivan P. de Arruda,Toscano, Vicente G.,Catalani, Luiz H.
, p. 1857 - 1862 (2007/10/02)
The α-brominated ortho-xylenes have been subjected to 254 nm irradiation in deaerated benzene, isooctane and benzene-cyclohexene.The product analysis revealed that homolysis of the C-Br bond is followed by a series of hydrogen abstraction and radical recombination reactions resulting in xylenes more and less brominated than the starting compound.The less brominated products are formed with higher quantum yield when cyclohexene is present, due to hydrogen abstraction by the o-benzyl radical formed initially, together with cyclohexene dimers.Additionally, the formation of 2-bromo-2,4,4-trimethylpentane is observed when isooctane is the solvent.The quantum yields observed for the photolysis of 1 and 2 are higher in benzene than in isooctane, suggesting sensitization by benzene.A biradical intermediate of the type o-quinodimethane was expected in the case of (a) photolysis of the o-benzyl radical formed (biphotonic process) or (b) intramolecular hydrogen abstraction.However, the addition of cyclohexene failed to produce the expected Diels-Alder adduct.The synthesis of the novel α,α-dibromo-o-xylene 3 is reported.
REACTION OF THIONYL BROMIDE WITH AROMATIC ALDEHYDES
Saraf, S. D.
, p. 7 - 14 (2007/10/02)
Reaction of thionyl bromide with aromatic aldehydes resulted in the conversion of CHO group into CHBr2.Tolualdehyde gave the corresponding bromomethylbenzal bromides, whereas anisladehyde afforded p-anisic acid as the sole product.
