A mixture of (S)-2-((5-hydroxy-1-methyl-4-oxo-1,4-dihydropyridin-2-yl)methylamino)-N-methylpropanamide (3.13 g, 13.1 mmol), trifluoroacetaldehyde methyl hemiacetal (3.6 mL, 38.0 mmol) and potassium carbonate (2.62 g, 19.0 mmol) in CH3CN (35 mL) was heated at 75-80° C. for overnight. Analysis of the reaction mixture by TLC using a solvent mixture of 28-30% conc. NH4OH in IPA as eluant indicated incomplete consumption of the starting material. A further portion of trifluoroacetaldehyde methyl hemiacetal (4 mL) was added, and the mixture was heated at 95-100° C. for another 24 h. On cooling to room temperature, the mixture was purified by column chromatography on silica gel using a mixture of MeOH and ethyl acetate as eluant (solvent gradient of 10, 15 and 20% MeOH in ethyl acetate). Thus, the title compound N2-{[5-hydroxy-1-methyl-4-oxo-6-(2,2,2-trifluoro-1-hydroxyethyl)-1,4-dihydropyridin-2-yl]methyl}-N-methyl-L-alaninamide, Apo7033, was obtained as a yellowish solid (1.53 g) in 35% yield. 1H NMR (DMSO-D6) δ (ppm): 7.79 (t, J=4.4 Hz, 1H, NH), 6.30 (s, 1H), 5.87 (q, J=8.7 Hz, 1H, CHCF3), 3.82 (s, 3H, NCH3), 3.61-3.65 (dd, 2J=14.5 and 4J=1.9 Hz, 1H, 0.5 NHCH2), 3.47-3.52 (apparent t, J=15.2 Hz, 1H, 0.5 NHCH2), 3.08 (q, J=6.8 Hz, 1H, CHCH3), 2.59 (d, J=4.2 Hz, 3H, NHCH3), 1.12 (dd, 2J=6.8 and 4J=2.3 Hz, 3H, CHCH3); 13C NMR (DMSO-D6) δ (ppm): 175.0 (C═O), 169.6 (C═O), 149.2, 147.3, 125.6, 125.0 (q, J=283 Hz, CHCF3), 113.1 (CH), 65.2 (q, J=33 Hz, CHCF3), 56.9 (CH), 48.9 (CH2), 36.6 (NCH3), 25.8 (NHCH3), 19.6 (CH3); MS m/z 360 [M+Na]+, 338 (100%) [M+1]+, 236.
