Triethylamine → (Azetidin-1-yl)(5-chloropyrazin-2-yl)methanone

Participants

Reaction Steps

Oxalyl chloride (1.55 mL, 17.5 mmol), followed by DMF (2 drops), was added to a mixture of 5-chloropyrazine-2-carboxylic acid (CAS no. 36070-80-1, Intermediate 33) (2.31 g, 14.6 mmol) in DCM (40 mL). The reaction was stirred at RT for 2 hours after which time the volatiles were removed under reduced pressure. The residue was taken up DCM (40 mL) and azetidine (1.08 mL, 16.03 mmol) and triethylamine (4.46 mL, 32.06 mmol) added. The mixture was stirred at RT for 72 hours. The volatiles were removed under reduced pressure and ethyl acetate (100 mL) added to the residue. The organics were washed with water (100 mL), citric acid (50 mL), saturated sodium bicarbonate solution (50 mL) and brine (50 mL), dried (MgSO4), filtered and the solvent removed under reduced pressure. The residue was purified by flash chromatography, eluting with a gradient of 50-100% ethyl acetate in isohexane, to afford the product (2.38 g, 82%). 1HNMR δ (400 MHZ, CDCl3): 2.35-2.42 (2H, m), 4.26 (2H, t), 4.67 (2H, t), 8.52 (1H, d), 9.09 (1H, d); m/z 198 (M+H)+.

Provenance & Evidence