反应详情

温度

-78 °C

3.50 g (24.8 mmol) of 2,2,6,6-tetramethylpiperidine and 15.50 ml (24.80 mmol) of 1.6 M n-butyllithium solution in hexane are stirred at 0° C. for 0.5 hour in 80 ml of tetrahydrofuran, 250 ml of tetrahydrofuran are added, and the mixture is cooled to -78° C. 5.00 g (16.5 mmol) of 2-fluoro-6-(4-octyloxyphenyl)pyrazine in 150 ml of tetrahydrofuran and, after the mixture has been stirred for one hour, 0.85 ml of bromine are subsequently added dropwise at -78C. The reaction mixture is stirred overnight, during which it warms to room temperature, and is partitioned between ether and aqueous sodium chloride solution, the aqueous phase is washed with aqueous sodium chloride solution, dried over sodium sulfate, filtered and freed from the solvent, and the residue is purified by chromatography (silica/hexane: ethyl acetate = 9:1). 4.68 g of 2-bromo-3-fluoro-5-(4-octyloxyphenyl)pyrazine are obtained. ##STR16## 1d

1. customwarms to room temperature
2. customis partitioned between ether and aqueous sodium chloride solution
3. washthe aqueous phase is washed with aqueous sodium chloride solution
4. dry with materialdried over sodium sulfate
5. filtrationfiltered
6. customthe residue is purified by chromatography (silica/hexane: ethyl acetate = 9:1)