4-Chlorobenzoic Acid → (2r,3r)-n-(2-((3-Pyridinyl)methyl)-1-azabicyclo[2.2.2]oct-3-yl)benzofuran-2-carboxamide p-chlorobenzoate salt

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Reaction Steps

Solid p-chlorobenzoic acid (46.8 mg, 0.299 mmol) was added in one portion to a solution of the earlier eluting isomer of N-(2-((3-pyridinyl)methyl)-1-azabicyclo[2.2.2]oct-3-yl]benzofuran-2-carboxamide from Example 15 (108 mg, 0.299 mmol) in acetone (10 mL). This mixture was warmed to near reflux for 30 min and cooled to ambient temperature. No precipitate formed, so the solution was concentrated to about 20% of its former volume (hot plate), at which point crystals began to form. The mixture was cooled and diluted with isopropanol (2 mL). This mixture was concentrated by slow evaporation of solvent at ambient temperature, and the resulting solids were collected and dried. This produced 145 mg (94% yield) of light yellow crystals, mp 150-152° C. 1H NMR (300 MHz, CDCl3) δ 8.49 (s, 1H), 8.38 (d, 1H), 7.93 (d, 2H, p-chlorobenzoic acid), 7.67 (m, 2H), 7.57 (d, 1H), 7.45 (m, 1H), 7.36 (d, 2H, p-chlorobenzoic acid), 7.30 (m, 1H), 7.27 (s, 1H), 7.16 (m, 1H), 7.00 (d, 1H, amide), 6.90 (broad s, quaternary ammonium), 4.62 (m, 1H), 3.85 (dd, 1H), 3.36 (m, 1H), 2.95-3.25 (m, 5H), 2.16 (s, 1H), 1.70-2.10 (m, 4H).

Provenance & Evidence