反应详情

To a stirred solution of 3-amino-5-bromo-2-chloropyridine (5.0 g, 24 mMol) in CH2Cl2 (50 mL) was added pyridine (3.0 mL, 37 mMol) followed by benzenesulfonyl chloride (4.5 mL, 35 mMol) drop wise over 5 minutes. The reaction was stirred at RT for 18 h and evaporated to dryness under vacuum. Purified by flash chromatography on silica gel (15% hexanes in CH2Cl2 then 0 to 5% EtOAc in 15% hexanes in CH2Cl2). During evaporation of the solvents the product crashed out. The resultant slurry was diluted with hexane, filtered and dried under vacuum to give the title compound (2.89 g, 34%) as a white solid. [An overlap fraction which contained 30% starting amine (2.60 g) was also obtained.]: 1H NMR (400 MHz, DMSO-d6) δ ppm 10.61 (br. s., 1 H), 8.41 (d, J=2.27 Hz, 1 H), 7.91 (d, J=2.27 Hz, 1 H), 7.73-7.77 (m, 2 H), 7.67-7.72 (m, 1 H), 7.56-7.64 (m, 2 H); MS (ES) m/e 346.7 (M+H)+.

1. customevaporated to dryness under vacuum
2. customPurified by flash chromatography on silica gel (15% hexanes in CH2Cl2
3. customDuring evaporation of the solvents the product
4. additionThe resultant slurry was diluted with hexane
5. filtrationfiltered
6. customdried under vacuum