Ngic-I → 12-(2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-5H-indolo(2,3-a)pyrrolo(3,4-c)carbazole

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Reaction Steps

36 mg (1.2 mmole) sodium hydride (80% in mineral oil) are suspended under an atmosphere of nitrogen in 50 mL dry dimethylformamide and 365 mg (1 mmole) 12-(2-cyanoethyl)-6,7,12,13-tetrahydro-5-oxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole added portionwise thereto at ambient temperature. After subsidence of the gas evolution, stirring is continued for 1 hour at 20° C. 0.08 mL (1.25 mmole) methyl iodide is then added thereto and stirring continued for 16 hours at ambient temperature. The solvent is distilled off in a vacuum and the residue is chromatographed on silica gel with toluene/ethanol (95:5 v/v). The fraction with an Rf of 0.3 in dichloromethane/methanol (95:5 v/v) is isolated and recrystallized from tetrahydrofuran. 12-(2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole is obtained in the form of pale yellow crystals which decompose above 270° C.

Provenance & Evidence