In a 5-ml three-necked flask, dissolve 74 mg of 4-(3H-imidazo[4,5-c]pyridin-2-yl)-fluorene-9(R,S)-amine, isolated as the dihydrochloride, in 0.5 ml of ethanol, add 45 mg of 5-formyl-indole and 70 μL of diisopropylethylamine and stir for 2 hours 30 minutes at room temperature. Then add 28 mg of sodium hydroborate and stir for 18 hours at room temperature. Pour the reaction mixture into 5 ml of a saturated aqueous solution of potassium dihydrogen phosphate, then extract 3 times with 10 ml of dichloromethane. After purification on silica gel, eluting with mixtures of dichloromethane and methanol (98-2, then 96-4 by volume), we obtain 34 mg of N-[4-(3H-imidazo[4,5-c]pyridin-2-yl)-9H-fluoren-9(R,S)-yl]-(1H-indol-5-yl-methyl)-amine, in the form of a white solid with the following characteristics:
