Reactions of 2,2-dialkyl-1,2-dihydroquinolines. Part VI. Further bromination studies

The product obtained by tetrabromination of 1,2-dihydro-2,2,4-trimethylquinoline in methanol described by Cliffe is not identical with 3,6,8-tribromo-4-bromomethyl-1,2-dihydro-2,2-dimethylquinoline, the tetrabromination product obtained in chloroform. It has been identified as the isomeric compound 3,6,8-tribromo-4-bromomethylene-1,2,3,4-tetrahydro-2,2-dimethylquinoline. This reacts with aqueous ethanolic alkali to yield an unusual fused aziridine. Further bromination, or nitration, yields dihydroquinolines, accompanied in the former case by a product of oxidative dimerisation which is also the main product of attempted tetrabromination of 1,2-dihydro-2,2,4-trimethylquinoline in sulphuric acid.