2-Aminopyridine → ethyl 2-methylimidazo[1,2-a]pyridine-3-carboxylate

Participants

Reaction Steps

To a stirred solution of 2-aminopyridine (15.0 g. 159.00 mmol) in dimethoxyethane (150 mL) was added NaHCO3 (14.72 g, 175 mmol) followed by ethyl 2-chloroacetoacetate (39.34 g, 239 mmol) at room temperature. After refluxing for 16 h the solvent was removed under reduced pressure. The residue was taken up in water (200 mL) and extracted with dichloromethane (2×200 mL). The combined organic layers were washed with water (100 mL), brine (100 mL), and dried over anhydrous Na2SO4. Evaporation of solvents under reduced pressure afforded crude product which was further purified by column chromatography to give 20 g of the product as an off-white solid; 1H NMR (300 MHz, CDCl3) δ 1.44 (t, J=6.9 Hz, 3H), 2.72 (s, 3H), 4.43 (q, J=7.2 Hz, 2H), 6.98 (t, J=6.6 Hz, 1H), 7.38 (t, J=8.7 Hz, 1H), 7.62 (d, J=8.7 Hz, 1H), 9.31 (d, J=6.9 Hz, 1H); ESI-MS (m/z) 205.13 (MH)+.

Provenance & Evidence