反应详情

Tosyl chloride (7.7 g, 40.4 mmol) was added to a solution of 2-chloro-5-bromo picolinic acid (4 g, 17 mmol) and pyridine (9.2 mL, 114 mmol) in 33 mL of t-BuOH at 0° C. The reaction was then stirred at room temperature for 12 hours. NaHCO3 (sat.) was then added and the mixture was extracted with ethyl acetate (3 times). The combined organic phases were washed with brine and dried over Na2SO4. Evaporation of the organic solvent afforded the desired compound 94A, which is used in the next step without further purification: 1H NMR (300 MHz, DMSO-d6) δ ppm 8.27 (1H, d), 7.63 (1H, d), 1.57 (9H, s).

1. extractionthe mixture was extracted with ethyl acetate (3 times)
2. washThe combined organic phases were washed with brine
3. dry with materialdried over Na2SO4
4. customEvaporation of the organic solvent