1-Hydroxybenzotriazole → N-(9-methyl-9-azabicyclo[3.3.1]non-3-yl)-2-p-tolylbenzoxazole-4-carboxamide

Participants

Reaction Steps

A mixture of 2-p-tolylbenzoxazole-4-carboxylic acid (62 mg, 0.24 mmol), 3-amino-9-methyl-9-azabicyclo[3.3.1]nonane dihydrochloride (66 mg, 0.29 mmol), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (94 mg, 0.49 mmol) and 1-hydroxybenzotriazole (66 mg, 0.49 mmol) in DMF (5 mL) was stirred for 10 min at room temperature, then DIPEA (0.16 mL, 0.98 mmol) was added. The resulting reaction mixture was stirred at room temperature overnight. The mixture was diluted with ethyl acetate (20 mL), and then washed with a saturated solution of sodium bicarbonate. The aqueous layer was further extracted with ethyl acetate (2×50 mL). The combined organics were dried (Na2SO4), filtered and concentrated. The crude material was purified by column chromatography (silica gel, 90:9:1 ethyl acetate/methanol/concentrated ammonium hydroxide) to afford N-(9-methyl-9-azabicyclo[3.3.1]non-3-yl)-2-p-tolylbenzoxazole-4-carboxamide (25 mg, 27%) as a white solid: 1H NMR (500 MHz, CDCl3) δ 9.10 (d, J=7.0 Hz, 1H), 8.20 (dd, J=7.5, 0.5 Hz, 1H), 8.14 (d, J=8.5 Hz, 2H), 7.68 (dd, J=8.0, 1.0 Hz, 1H), 7.45 (t, J=7.0 Hz, 1H), 7.39 (d, J=8.0 Hz, 2H), 4.64-4.55 (m, 1H), 3.17-3.11 (m, 2H), 2.70-2.60 (m, 2H) 2.56 (s, 3H), 2.48 (s, 3H), 2.08-1.98 (m, 2H), 1.75-1.50 (m, 3H), 1.25-1.17 (m, 3H); MS (ESI+) m/z 390 (M+H); HPLC>99% (AUC), tR=13.37 min.

Provenance & Evidence