Ethyl Acetate → Ethyl 6-bromo-8-phenylimidazo[1,2-a]pyridine-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of ethyl 6,8-dibromoimidazo[1,2-a]pyridine-2-carboxylate hydrobromide (0.5 g, 1.2 mmol) and phenylboronic acid (0.15 g, 1.2 mmol) in toluene (10 mL) and ethanol (2 mL) was bubbled nitrogen for 20 mins. The mixture was then treated with Pd(PPh3)4 (30 mg, 0.026 mmol) and K3PO4 (2 M, 1 mL, 2 mmol) and heated at 80° C. overnight. The reaction was cooled, poured into ethyl acetate (200 mL), washed with brine, separated, and concentrated. The residue was purified by column chromatography on silica gel using ethyl acetate in hexanes (10%) as eluent. The product containing fractions were concentrated to give 0.23 g (58% yield) of ethyl 6-bromo-8-phenylimidazo[1,2-a]pyridine-2-carboxylate as a white solid. LCMS (Conditions C): 3.41 min (RT); (M+H)+=347.24 (100%), 345.24 (100%). 1H NMR, 400 MHz, CDCl3: δ 8.27 (d, J=1.6 Hz, 1 H), 8.19 (s, 1 H), 8.02 (m, 2H), 7.52-7.41 (m, 4 H), 4.45 (q, J=7.1 Hz, 2 H), 1.42 (t, J=7.0 Hz, 3 H).

Provenance & Evidence