Water → Ethyl N-(8-bromo-2-methylimidazo[1,2-a]pyridin-7-yl)carbamate

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Reaction Steps

A mixture of sodium bicarbonate (0.74 g, 8.81 mmol) and amine 18 (1.00 g, 4.42 mmol) in 50 mL of dry CH2Cl2 was treated over a period of fifteen minutes with ethyl chloroformate (2.40 g, 22.1 mmol). 4-Dimethylaminopyridine (0.08 g, 0.65 mmol) was added and the reaction mixture was stirred at room temperature for 20 h. Then, water (25 mL) was added and the solution was extracted with CH2Cl2 (3×25 mL). The extracts were dried (Na2SO4), filtered and evaporated under vacuum. The residue was purified by chromatography using CH2Cl2/EtOAc (4/1, v/v) as eluent to afford in order of elution: compound 19 (461 mg, yield: 35%); mp 137-138° C.; 1H NMR (200 MHz, CDCl3) δ 1.34 (t, 3H, J=7 Hz), 2.45 (s, 3H), 4.26 (q, 2H, J=7 Hz), 7.24 (brs, 1H), 7.31 (s, 1H), 7.81 (d, 1H, J=7.4 Hz), 7.92 (d, 1H, J=7.4 Hz); 13C NMR (100 MHz, DMSO-d6) δ 14.1, 14.4, 60.8, 102.5, 109.7, 111.3, 125.1, 133.3, 142.4, 143.0, 153.8. Starting material 18 (0.31 g, 31%).

Provenance & Evidence