Investigations into the possibility of applying established synthetical methods in the carbazole group to the preparation of indolocarbazoles from derivatives of p-phenylenediamine, including 3-aminocarbazole and related substances, have culminated in the synthesis of 6-cyanoindolo(2' : 3'-3 : 4)carbazole.THIS communication describes attempts to apply known methods for the synthesis of carbazoles to the preparation of indolocarbazoles from various derivatives of 9-phenylenediamine. Manjunath ( J . Indian Chem. Soc., 1927, 4, 271) was unable to obtain an indolocarbazole by heating the phenylenebistriazole (I ; R = H), and we have confirmed his observations. The degree of success attending the Graebe-Ullmann reaction, however, can vary widely among closely related compounds, and it seemed desirable to investigate other substances of this type. Accordingly the bistriazoles (I ; R = C1, OMe, and CN) have been synthesised and then heated under a variety of conditions, but none gave the desired product.Carbazole has been obtained from 1-anilinocyclopentane-1-carboxylic acid (I1 ; R = H), and the 1-and 3-methylcarbazoles from the corresponding toluidino-compounds, by heating them with potassium hydroxide, sometimes with the addition of sodium ethoxide (Plant and Facer,
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