反应详情

To a mechanically stirred solution of 3.9 g (0.05 mol) dimethyl sulfoxide in 30 ml dry methylene chloride at -78° under nitrogen is added 13.1 g (0.046 mol) trifluoromethanesulfonic anhydride dropwise to afford a white precipitate. To this is added a solution of 5.0 g (0.039 mol) 2-amino-3-chloropyrazine (1) in 30 ml methylene chloride/15 ml dimethyl sulfoxide and the resulting solution is stirred at -78° for 2 hours and at -55° for 1 hour. The reaction mixture is then quenched with 50 ml of 5% aqueous sodium bicarbonate solution and stirred at -5° for 5 minutes. The reaction mixture is diluted with 200 ml methylene chloride and the phases are separated. The aqueous phase is extracted with 250 ml methylene chloride and the combined organic phases are washed with 3×75 ml portions of water and dried over anhydrous sodium sulfate. The solvent is removed from the rotary evaporator to give 5.8 g (79%) of 2 as yellow crystals, m.p. 106°-108°.

1. customto afford a white precipitate
2. customThe reaction mixture is then quenched with 50 ml of 5% aqueous sodium bicarbonate solution
3. stirringstirred at -5° for 5 minutes
4. additionThe reaction mixture is diluted with 200 ml methylene chloride
5. customthe phases are separated
6. extractionThe aqueous phase is extracted with 250 ml methylene chloride
7. washthe combined organic phases are washed with 3×75 ml portions of water
8. dry with materialdried over anhydrous sodium sulfate
9. customThe solvent is removed from the rotary evaporator