2-Amino-6-methylpyridine → Ethyl 5-methylimidazo[1,2-a]pyridine-2-carboxylate

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Reaction Steps

A solution of 6-methyl-2-pyridinamine (10 g, 93 mmol) [Aldrich, A75706] and ethyl bromopyruvate (15 mL, 110 mmol) in ethanol (93 mL) was heated at 90° C. for 4 h. The reaction mixture was concentrated, diluted with dichloromethane (250 mL), and washed with 10% aqueous potassium carbonate (200 mL). The aqueous layer was separated and extracted with additional dichloromethane (100 mL). The combined organic layers were washed with brine, dried with sodium sulfate, filtered, and concentrated to a crude solid. The solid was treated with diethyl ether (300 mL) and, after several minutes, the diethyl ether was decanted to give the desired product (19 g, quantitative) as a solid after drying under reduced pressure. This material was used without further purification. LCMS for C11H13N2O2 (M+H)+: m/z=205.1.

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