反应详情

2-Amino-4-chloropyridine (5.00 g, 38.9 mmol, WO 02/32872) was dissolved in tetrahydrofuran (200 ml); and triethylamine (17.9 ml, 128 mmol) was added thereto. While stirring with a waterbath, phenyl chloroformate (14.6 ml, 117 mmol) was added thereto dropwise; the reaction mixture was stirred at room temperature for 1.5 hours. The reaction mixture was partitioned between water and ethyl acetate; the organic layer was washed with brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained residue was filtered by silica gel; the crystals obtained after the concentration were suspended in diethyl ether, filtered off, washed with diethyl ether, and dried to yield the title compound (3.77 g, 10.2 mmol, 26.3%) as pale yellow crystals. The mother liquor was concentrated under reduced pressure, which was then treated by the similar methods to yield the title compound (3.98 g, 10.5 mmol, 27.1%) as pale yellow crystals (secondary crystals).

1. additionwas added
2. customThe reaction mixture was partitioned between water and ethyl acetate
3. washthe organic layer was washed with brine
4. dry with materialdried over anhydrous sodium sulfate
5. concentrationconcentrated under reduced pressure
6. filtrationThe obtained residue was filtered by silica gel
7. customthe crystals obtained
8. concentrationafter the concentration
9. filtrationfiltered off
10. washwashed with diethyl ether
11. customdried