反应详情

3-(2-Bromo-3,5-difluorophenyl)propanoic acid (from Step 2, 3.0 g) is stirred with chlorosulfonic acid (10 mL) for 2 hours at ambient temperature. The mixture is then added dropwise to a vigorously stirred mixture of water and ice (200 mL) and further stirred for 15 minutes. Extraction with diethyl ether, subsequent washing of the organic layer with water, NaOH (0.2 M), and brine, drying (Na2SO4) and removal of the solvent under reduced pressure gives the crude product (Yield 2.7 g) that is used in the next step without further purification. LC (METHOD 7): tR=1.16 min.

1. extractionExtraction with diethyl ether
2. washsubsequent washing of the organic layer with water, NaOH (0.2 M), and brine
3. customdrying
4. custom(Na2SO4) and removal of the solvent under reduced pressure