Lithium hydride → 4-(4-Bromo-2-fluorophenylamino)-5-fluoro-6-oxo-1-pyridin-3-ylmethyl-1,6-dihydropyridine-3-carboxylic acid methyl ester

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Reaction Steps

Lithium hydride (14 mg, 1.64 mmol) was added to a stirred solution of 4-(4-bromo-2-fluorophenylamino)-5-fluoro-6-oxo-1,6-dihydropyridine-3-carboxylic acid methyl ester (0.190 g, 0.529 mmol) in DMF (5 mL) at 0° C. After stirring for 30 minutes, 3-bromomethyl-pyridine hydrobromide (0.14 g, 0.53 mmol) was added. The reaction mixture was warmed to room temperature and stirred for 16 hours. After quenching with ice water, the reaction mixture was extracted with ethyl acetate. The combined organic extracts were dried (MgSO4) and concentrated under reduced pressure. Purification by flash column chromatography (1% MeOH in methylene chloride) yielded 4-(4-bromo-2-fluorophenylamino)-5-fluoro-6-oxo-1-pyridin-3-ylmethyl-1,6-dihydropyridine-3-carboxylic acid methyl ester. The methyl ester was dissolved in 4:1 THF:MeOH (5 mL) and 1 M LiOH solution (1.1 mL) was added. After 1 hour, the reaction mixture was acidified to pH 1 with 10% aqueous HCl solution and extracted with ethyl acetate. The combined organic extracts were washed with brine, dried (MgSO4) and concentrated under reduced pressure. Trituration with diethyl ether gave 0.160 g (69% two step yield) clean desired product. MS APCI (−) m/z 434, 436 (M−, Br pattern) detected; 1H NMR (400 mHz, DMSO-d6) δ 9.40 (bs, 1H), 8.65 (s, 1H), 8.61 (s, 1H), 8.51 (d, 1H), 7.74 (d, 1H), 7.58 (d, 1H), 7.39 (m, 1H), 7.34 (s, 1H), 7.16 (m, 1H), .525 (s, 1H).

Provenance & Evidence