Diisopropylethylamine → Methyl 5-((2,4-difluorobenzyl)carbamoyl)-1-(2,2-dimethoxyethyl)-3-methoxy-4-oxo-1,4-dihydropyridine-2-carboxylate

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Reaction Steps

1-(2,2-dimethoxyethyl)-5-methoxy-6-(methoxycarbonyl)-4-oxo-1,4-dihydropyridine-3-carboxylic acid (1-A, 0.300 g, 0.95 mmol), prepared as described in WO2011/119566 A1, was evaporated once from dry toluene, suspended in acetonitrile (4 mL) and treated with N,N-diisopropylethylamine (DIPEA) (0.329 mL, 1.90 mmol), 2,4-difluorobenzylamine (0.125 mL, 1.05 mmol) and HATU (0.433 g, 1.14 mmol). The reaction mixture was stirred for 10 minutes and concentrated. The residue was purified by flash chromatography on silica gel (10 to 60% ethyl acetate:dichloromethane) to afford the compound methyl 5-(2,4-difluorobenzylcarbamoyl)-1-(2,2-dimethoxyethyl)-3-methoxy-4-oxo-1,4-dihydropyridine-2-carboxylate, 1-B. 1H-NMR (400 MHz, DMSO-d6) δ 10.28 (t, J=6.0 Hz, 1H), 8.46 (s, 1H), 7.42 (dd, J=15.4, 8.6 Hz, 1H), 7.24 (m, 1H), 7.06 (m, 1H), 4.52 (m, 3H), 4.22 (d, J=4.4 Hz, 2H), 3.92 (s, 3H), 3.80 (s, 3H), 3.29 (d, 6H). LCMS-ESI+ (m/z): [M+H]+ calculated for C20H23F2N2O7: 441.15; found: 441.2.

Provenance & Evidence