2,6-Dichlorobenzoxazole → 2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)hex-5-enamide

Participants

Reaction Conditions

Reaction Steps

Hunigs base (2.5 mL) was added to a stirred suspension of 2-acetylamino-2-piperidin-4-yl-hex-5-enoic acid tert-butylamide hydrochloride (250 mg, 0.73 mmol) and 2,6-dichlorobenzoxazole (172 mg, 0.91 mmol) in anhydrous dimethylacetamide (5 mL). The reaction was stirred at 95° C. overnight under an atmosphere of nitrogen. After heating over night, the reaction mixture was cooled to room temperature and then diluted with diethyl ether. The organic layer was washed with saturated aqueous sodium chloride (3×), dried over MgSO4, filtered and concentrated. The crude product was purified by flash column chromatography (silica gel, 20-80% ethyl acetate in heptane) to give 2-acetamido-N-tert-butyl-2-(1-(6-chlorobenzo[d]oxazol-2-yl)piperidin-4-yl)hex-5-enamide as an off-white solid (240 mg, 72%). 1H NMR (CDCl3, 300 MHz) δ 7.24 (d, J=2 Hz, 1H), 7.21 (d, J=8.5 Hz, 1H), 7.12 (dd, J1=8.5 Hz, J2=2 Hz, 1H), 7.02 (s, NH, 1H), 5.79 (m, 1H), 5.50 (s, NH, 1H), 4.98 (m, 2H), 4.34 (m, 2H), 3.00 (m, 3H), 2.49 (tt, J1=12.5 Hz, J2=3 Hz, 1H), 2.10-1.96 (m, 1H), 2.03 (s, 3H), 1.74-1.93 (m, 3H), 1.49 (m, 1H), 1.33 (s, 9H), 1.18-1.28 (m, 2H).

Provenance & Evidence