Phthalic Anhydride → 2-[(4-{2-[3-(2-methyl-1H-benzimidazol-1-yl)-8-azabicyclo[3.2.1]oct-8-yl]ethyl}-4-phenylpiperidin-1-yl)carbonyl]benzoic acid

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Reaction Steps

To a stirred solution of 2-methyl-1-{8-[2-(4-phenylpiperidin-4-yl)ethyl]-8-azabicyclo[3.2.1]oct-3-yl}-1H-benzimidazole dihydrochloride II (25.3 mg, 0.05 mmol) in 1,2-dichloroethane (3 mL) was added triethyl amine (14 μL, 0.1 mmol) and phthalic anhydride (7.4 mg, 0.05 mmol). The resulting mixture was stirred at ambient temperature for 4 hours. After evaporation of the solvents, the residue was purified by flash chromatography on silical gel, eluting with a gradient of 10-30% methanol in ethyl acetate to afford 2-[(4-{2-[3-(2-methyl-1H-benzimidazol-1-yl)-8-azabicyclo[3.2.1]oct-8-yl]ethyl}-4-phenylpiperidin-1-yl)carbonyl]benzoic acid as amorphous solid (29 mg, quant.). 1H NMR (300 MHz, DMSO-d6) δ 7.94 (d, J=6.6 Hz, 1H), 7.53-7.50 (m, 1H), 7.48-7.36 (m, 7H), 7.25-7.21 (m, 1H), 7.17-7.09 (m, 3H), 4.61-4.54 (m, 1H), 3.26 (br, 4H), 3.95 (br, 1H), 3.09 (br, 1H), 2.46 (s, 3H), 2.42-2.32 (m, 3H), 2.24-2.06 (m, 1H), 2.00-1.86 (m, 5H), 1.86-1.76 (m, 5H), 1.61 (d, J=7.7 Hz, 2H). HRMS m/z (M+H)+ calcd 577.3179; obsd 577.3176.

Provenance & Evidence