Studies on the reaction of benzoyl peroxide with NN-disubstituted aromatic amines and other related compounds. Part IV. A novel formation of 1,2,3,4-tetrahydroquinoline derivatives

Abstract

The reaction of benzoyl peroxide with NN-dimethylaniline in cumene or chloroform at ca. 0° in the presence of N-phenylmaleimide gives 1,2,3,4-tetrahydro-1-methylquinoline-N-phenyl-3,4-dicarboximide, formed via the N-methylanilinomethyl radical. This reaction provides a convenient way of differentiating between the PhNMe·ĊH₂ radical and the (PhNMe:CH₂)⁺ cation as intermediates. The latter does not react with N-phenylmaleimide, although it reacts with ethyl vinyl ether to give 4-ethoxy-1,2,3,4-tetrahydro-1-methylquinoline. The formation of quinoline derivatives by use of benzoyl peroxide succeeds also with N-methylmaleimide (instead of the N-phenyl compound) and with a number of other aromatic tertiary amines, including N-phenyl- and N-p-tolyl-pyrrolidine; yields of products obtained are of preparative value. Reduction of the products gives 2,3,3a,4,5,9b-hexahydro-5-methyl-2-phenyl-1H-pyrrolo[3,4-c]quinoline, 2,3,3a,3b,4,5,6,11b-octahydro-2-phenyl-1H-dipyrrolo[1,2a,3,4-c]quinoline, and derivatives thereof.