反应详情

3-[2-(2-Chloro-3,6-difluoro-phenyl)-acetylamino]-pyrazine-2-carboxylic acid methyl ester (4.15 g) (Example 1.1) was heated with potassium carbonate (1.67 g) in N,N-dimethylformamide (50 ml) at 110° C. for 2 hours and then stored at ambient temperature for 16 hours. Water was added and the reaction mixture was acidified with aqueous hydrochloric acid (concentrated). A precipitate formed which was isolated by filtration. The residue was washed successively with water and hexane to produce 7-(2-chloro-3,6-difluoro-phenyl)-8-hydroxy-5H-pyrido[2,3-b]pyrazin-6-one as a brown solid (2.88 g). 1H-NMR (400 MHz, d6-DMSO): 7.34-7.42 (m, 1H), 7.51-7.59 (m, 1H), 8.59 (d, 1H), 8.72 (d, 1H), 12.0 (bs, 1H), 12.4 (s, 1H) ppm.

1. customA precipitate formed which
2. customwas isolated by filtration
3. washThe residue was washed successively with water and hexane