2-Aminopyridine → 2-Chloromethyl-imidazo(1,2-A)pyridine

Participants

Reaction Steps

1,3-Dichloroacetone (22.9 g, 180.3 mmol) was added to a solution of 2-amino pyridine (10 g, 106.3 mmol) in acetonitrile (200 ml). The mixture was heated at reflux for 14 h (the reaction was monitored by TLC). Upon completion of the reaction, the volatiles were removed under reduced pressure. The residue was diluted with water and adjusted the pH to 7.5 with sodium bicarbonate solution which was extracted with EtOAc. The combined organics were dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified by flash column chromatography using 12% ethyl acetate in n-hexanes and silica gel (230-400 mesh) to afford 2-(chloromethyl) imidazo[1,2-a]pyridine (8.0 g, 47.9%) as pale yellow solid. 1H NMR: 200 MHz, CDCl3: δ 8.15 (d, 1H), 7.6 (dd, 2H), 7.1 (t, 1H), 6.8 (t, 1H), 4.75 (s, 2H). MS: [M+H]+: m/z=167.2.

Provenance & Evidence