Benzaldehyde → 2-(Benzylamino)-4-(4-benzoylpiperazin-1-yl)benzoic acid

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Reaction Steps

The obtained 4-(4-benzoylpiperazin-1-yl)-2-nitrobenzoic acid (0.40 g, 93%) was dissolved in 30 ml ethanol and 10 ml THF, followed by the addition of platinum oxide (20 mg, 5%) and stirred under hydrogen gas for 16 hours. The reaction was filtered with the aid of celite. 2-amino-4-(4-bezoylpiperazin-1-yl)benzoic acid (0.24 g, 70%) was obtained after removing of solvents. To a solution of 2-amino-4-(4-bezoylpiperazin-1-yl)benzoic acid (0.2 g, 0.6 mmol) and benzaldehyde (0.14 ml, 1.3 mmol) added sodium triacetoxyborohydride (0.4 g, 1.8 mmol) and stirred under argon atmosphere overnight. The reaction was quenched with 10 ml water and extracted with ethyl acetate (3×20 ml), followed by drying it over anhydrous sodium sulfate. 2-(benzylamino)-4-(4-benzoylpiperazin-1-yl)benzoic acid (0.11 g, 40%) was obtained after concentration. 1H NMR (500 MHz, CDCl3) δ (ppm) 3.25-3.88 (m, br, 8H), 4.48 (s, 2H), 6.20 (d, J=2.3 Hz, 1H), 6.22 (dd, J=2.3, 9.1 Hz, 1H), 7.30-7.45 (m, 10H), 7.48 (d, J=9.1 Hz, 1H), 8.25 (s, 1H), 10.65 (s, 1H).

Provenance & Evidence