54978-91-5Relevant articles and documents
Highly Selective Aromatic Chlorination. Part 4. The Chlorination of Aromatic Hydrocarbons with N-Chloroamines in Acidic Solution
Smith, John R. Lindsay,McKeer, Linda C.,Taylor, Jonathan M.
, p. 1537 - 1544 (2007/10/02)
Benzene, toluene, some polymethylbenzenes, and naphthalene have been treated with N-chlorotrialkylammonium salts and N-chlorodialkylamines in trifluoroacetic acid at room temperature.With benzene, toluene, and 1,3,5-trimethylbenzene the major products arise from aromatic chlorination whereas with the other polymethylbenzenes side-chain reactions predominate.By controlling the acidity of the reaction and the nature of the N-chloroamine, the chlorination of toluene can be made to give preferentially 2- or 4-chlorination.However, the selectivities are not as great as reported previously with electron-rich aromatic compounds with a ?-donor substituent.The products from the reaction of naphthalene are very dependent on the structure of the N-chlorinated amine.The bulky N-chlorotrialkylammonium salts selectively chlorinate the 1-position, but in low yield, whereas the less hindered N-chloropiperidine gives good yields of 1-(1-piperidino)-naphthalene.The results from these studies are discussed in terms of arenium-ion and electron-transfer mechanisms.
