反应详情

Preparation of 2-(4-bromo-2-fluorophenylamino)-6-chloronicotinic acid methyl ester: To a suspension of 2-(4-bromo-2-fluorophenylamino)-6-chloronicotinic acid (5.00 g, 14.5 mmol) in methanol/benzene (1:1, 100 mL) under N2 was added (trimethylsilyl)diazomethane (2.0 M solution in hexanes) dropwise until the bubbling caused by gas evolution ceased. Solids precipitated out of solution. The reaction was allowed to stir for 1 hour. Excess (trimethylsilyl)diazomethane was quenched by the dropwise addition of glacial acetic acid. The precipitated solids were filtered and washed with methanol. The filtrate was concentrated to a smaller volume and additional solids precipitated out of solution that were filtered and washed with methanol. The solids were combined and dried under vacuum to yield 4.82 g (93%) of pure desired product as a dark pink solid.

1. customSolids precipitated out of solution
2. customExcess (trimethylsilyl)diazomethane was quenched by the dropwise addition of glacial acetic acid
3. filtrationThe precipitated solids were filtered
4. washwashed with methanol
5. concentrationThe filtrate was concentrated to a smaller volume and additional solids
6. customprecipitated out of solution that
7. filtrationwere filtered
8. washwashed with methanol
9. customdried under vacuum