Carbolines

Two methods of synthesizing 4-aryl- and 4-hetaryl--carbolines are proposed. The reaction of indole with aryl- and hetarylnitroolefins leads to the formation of -aryl- and -hetaryl-nitroethylindoles, which are reduced to the corresponding tryptamines. The latter can be converted by the usual methods into 3,4-dihydro- and 1,2,3,4-tetrahydro--carbolines. The second route is illustrated by the reaction of indole with 3-phenylaziridine-2-carboxylic acid ester. The resulting -phenyltryptophan, on subsequent treatment with acetaldehyde in potassium dichromate solution, is smoothly converted into 4-phenylharman.For Communication V, see 1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1523–1527, November, 1973.