反应详情

In a 100 mL round bottomed flask 4-bromo-3-chloroaniline (A, 2.06 g, 10.0 mmol) was dissolve in pyridine (30 mL) at room temperature. Methanesulfonyl chloride (1.72 g, 15.0 mmol, 1.5 equiv) was added under an ice-water bath cooling. The ice bath was removed immediately after addition of the reagent. After stirring for 1.5 h, another methanesulfonyl chloride (0.57 g, 5.0 mmol, 0.5 equiv) was added at room temperature for the reaction to go to completion. After stirring for 0.5 h, the mixture was treated with H2O (50 mL) and extracted with EtOAc (50 mL×3). Combined organic layers were washed with brine (50 mL×2) and dried over Na2SO4. The solvent was removed in vacuo to give the crude material (very light brown solid, 5.32 g). The crude product was purified by a silica gel column chromatography (SiO2=80 g, EtOAc/hexane=1:1, Rf=0.3) to give the desired product as colorless crystals. The obtained crystals were recrystallized from EtOAc/hexane=1:2 (24 mL) to give the desired material [N-(4-bromo-3-chlorophenyl)methanesulfonamide (B)].

1. temperaturecooling
2. customThe ice bath was removed immediately
3. additionafter addition of the reagent
4. stirringAfter stirring for 0.5 h
5. extractionextracted with EtOAc (50 mL×3)
6. washCombined organic layers were washed with brine (50 mL×2)
7. dry with materialdried over Na2SO4
8. customThe solvent was removed in vacuo
9. customto give the crude material (very light brown solid, 5.32 g)
10. customThe crude product was purified by a silica gel column chromatography (SiO2=80 g, EtOAc/hexane=1:1, Rf=0.3)