反应详情

(−)3-(3-bromo-4-hydroxy-6-methyl-2-oxopyridin-1(2H)-yl)-4-methylbenzoic acid (10) (1.50 kg, 4.44 moles), 1,1′-carbonyldiimidazole (1.08 kg, 6.66 moles) and N,N-dimethylformamide (3 mL) were mixed together at ambient temperature. Once the activation reaction was deemed complete, 2 M methylamine solution in tetrahydrofuran (5.5 L, 11.1 moles) was added at a rate that maintained the temperature below 30° C. The mixture became homogeneous as the reaction reached completion. A solution of 1 N hydrochloric acid solution (15.4 kg) was added to reach pH 3 or less. The acidification precipitated the product. The product was filtered, washed with water and vacuum dried at 60° C. overnight to give (−)3-(3-bromo-4-hydroxy-6-methyl-2-oxopyridin-1(2H)-yl)-N,4-dimethylbenzamide (9) (1.56 kg, 4.44 moles, 97% purity).

1. customOnce the activation reaction
2. temperaturemaintained the temperature below 30° C
3. customThe acidification precipitated the product
4. filtrationThe product was filtered
5. washwashed with water and vacuum
6. customdried at 60° C. overnight