Water → 13-(2-Cyanoethyl)-6,7,12,13-tetrahydro-3-hydroxy-12-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole

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Reaction Conditions

Reaction Steps

200 mg (0.45 mmol) 13-(2-cyanoethyl)-6,7,12,13-tetrahydro-3-methoxy-12-methyl-5,1-dioxo-5H-indolo-[2,3-a]pyrrolo[3,4-c]carbazole (Example 1) in 15 ml dichloromethane are cooled to -10° C. and 0.1 ml (0.7 mmol) of a 1M solution of boron tribromide in dichloromethane added dropwise thereto. Since, after 3 hours at -10° C., no reaction is shown (TLC), 1.4 ml of the 1M solution of boron tribromide are again added thereto, followed by stirring for 16 hours at 20° C. 100 ml of water and 100 ml tetrahydrofuran are added thereto and the organic phase is separated off, washed with 100 ml of water and dried over anhydrous sodium sulphate. After filtration and evaporation, the residue is first chromatographed with dichloromethane/methanol (95:5 v/v) and then again with toluene/tetrahydrofuran (4:1 v/v). The fraction with the Rf 0.3 in toluene/tetrahydrofuran (2:1 v/v) is isolated, stirred with diisopropyl ether/acetone and the crystals formed are filtered off. 13-(2-Cyanoethyl)-6,7,12,13-tetrahydro-3-hydroxy-12-methyl-5,7-dioxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole is obtained in the form of yellow crystals which decompose from about 315° C.

Provenance & Evidence