Diisopropylethylamine → (R)-methyl 5-(1-(2,4-difluorophenyl)ethylcarbamoyl)-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, 0.315 g, 1.00 mmol), was suspended in acetonitrile (4 ml) and treated with N,N-diisopropylethylamine (DIPEA) (0.348 mL, 2.00 mmol), (R)-1-(2,4-difluorophenyl)ethanamine HCl salt (0.213 mg, 1.10 mmol) and HATU (0.418 g, 1.10 mmol). The reaction mixture was stirred for 1 hour and partitioned between dichloromethane and HCl (10% aq). The organic layer was separated and washed sodium bicarbonate (1M aq), dried over sodium sulfate, filtered and concentrated to afford crude (R)-methyl 5-(1-(2,4-difluorophenyl)ethylcarbamoyl)-1-(2,2-dimethoxyethyl)-3-methoxy-4-oxo-1,4-dihydropyridine-2-carboxylate which was used without purification in the next step. LCMS-ESI+ (m/z): [M+H]+ calculated for C21H25F2N2O7: 455.16; found: 455.1.

Provenance & Evidence