Methanol → 2'-Methyl-2-oxo-1,2-dihydro-3,4'-bipyridine-6-carboxylic acid, hydrochloride salt

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Reaction Steps

Synthesis of methyl 5-bromo-6-methoxypyridine-2-carboximidoate (C29). Sodium hydride (60% dispersion in mineral oil, 3.57 g, 93.8 mmol) was added portion-wise over a 20 minute period to a stirred solution of methanol (7.1 mL) in tetrahydrofuran (123 mL) under argon; the reaction was then stirred for an additional 55 minutes. A solution of 5-bromo-6-chloropyridine-2-carbonitrile (C28) (8.16 g, 37.5 mmol) in tetrahydrofuran (71 mL) was then added drop-wise and the reaction mixture was stirred for 18 hours. After being quenched with saturated aqueous ammonium chloride solution (200 mL), the mixture was extracted with ethyl acetate (2×400 mL). The combined organic layers were washed with saturated aqueous sodium chloride solution (200 mL), dried over magnesium sulfate and concentrated in vacuo to give the crude title compound (9.42 g, quantitative) as an orange solid, which was used in the next step without further purification, as it was found to be unstable on silica gel. LCMS m/z 247.1 (M+1). 1H NMR (400 MHz, CDCl3) δ 3.99 (s, 3H), 4.09 (s, 3H), 7.32 (d, J=7.8 Hz, 1H), 7.90 (d, J=7.8 Hz, 1H).

Provenance & Evidence