7-Nitro-9-oxo-4-fluorenecarboxylic acid → 5-(1H-benzimidazol-2-yl)-2-nitro-9H-fluoren-9-one

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Reaction Conditions

Reaction Steps

The procedure used in Example 68 is followed. In a 100 ml round-bottomed flask under an argon atmosphere, heat, at 130° C. for 4 hours, a suspension of 1.6 g of (2-aminophenyl)amide of 7-nitro-9-oxo-9H -fluorene-4-carboxylic acid, obtained in the previous stage, in 30 ml of acetic acid. After cooling, the insoluble material that formed is filtered off, and washed successively with water, with a saturated aqueous solution of sodium hydrogen carbonate and then with water. After purification by flash chromatography on silica gel (40-63 μm), eluting with a mixture of dichloromethane and 7N ammoniacal methanol (9/1 by volume), then formation of a paste in diisopropyl ether, in this way we obtain 550 mg of 5-(1H-benzimidazol-2-yl)-2-nitro-9H-fluoren-9-one, in the form of a yellow powder, which is used as it is in the following stage, with the following characteristics:

Provenance & Evidence