2-(Ethoxymethylene)propanedinitrile → 5-Cyano-1-(indol-5-yl)benzimidazole

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Reaction Steps

5-(4-Cyano-2-nitrophenylamino)-1H-indole (0.56 g, 2.0 mmoles) was reduced by catalytic hydrogenation, to form 5-(4-cyano-2-aminophenylamino)-1H-indole (0.50 g, 2.0 mmole). The 5-(4-cyano-2-aminophenylamino)-1H-indole was cyclized using ethoxymethylenemalononitrile (0.49 g, 2.0 mmoles) in propanol, and the cyclization reaction was heated for 24 hours. Column chromatography using ethyl acetate/hexanes [1:1] afforded the title compound (94%) as a yellow solid. Mp, 263.0°-264.0° C.; 13C NMR (DMSO-d6) δ147.2, 143.5, 137.5, 135.8, 128.5, 128.1, 127.3, 127.0, 125.3, 120.2, 118.2, 116.7, 113.1, 112.6, 104.8, 102.2; HRMS calculated for C16H10N4 258.0904, found 258.0904. Analytical calculated for C16H10N4 : C, 74.40; H, 3.90; N, 21.69. Found: C, 74.20; H, 3.92; N, 21.69.

Provenance & Evidence