反应详情

To a vigorously stirred solution of 2-bromo-4,6-difluoro aniline (100 g, 0.48 mol) in pyridine (400 mL), at 0° C., is added ethyl chloroformate (70 ml, 0.73 mol) at a rate to keep the temperature below 5° C. When addition is complete, the mixture is stirred at 0° C.–5° C. an additional 2 hours while monitoring by TLC (20% ethyl acetate/hexane, UV). The reaction is then allowed to warm to room temperature, filtered and the filtrate concentrated. The residue is dissolved in diethyl ether/ethyl acetate (500 ml/250 ml) and washed with H2O, 2.5 N HCl, aqueous NaHCO3, brine, dried (Na2SO4), filtered, concentrated, and triturated with petroleum ether to give 126 g of 2-bromo-4,6-difluoro-N-carbethoxy aniline (94%).

1. customthe temperature below 5° C
2. additionWhen addition
3. filtrationfiltered
4. concentrationthe filtrate concentrated
5. dissolutionThe residue is dissolved in diethyl ether/ethyl acetate (500 ml/250 ml)
6. washwashed with H2O, 2.5 N HCl, aqueous NaHCO3, brine
7. dry with materialdried (Na2SO4)
8. filtrationfiltered
9. concentrationconcentrated
10. customtriturated with petroleum ether