反应详情

Ethyl 5-methyl-2-pyrazinecarboxylate (10.0 g, 60.18 mmol), benzoyl peroxide (1.46 g, 6.02 mmol) and N-bromo succinimide (11.78 g, 66.19 mmol) in 80 mL CCl4 was heated to reflux while a 75 W tungsten lamp was shining on the reaction mixture. After 4 h the reaction mixture was cooled and the precipitate filtered off. The red filtrate was concentrated and the residue redissolved in EtOAc and washed with sat'd NaHCO3, 5% Na2S2O3, brine and the organics dried (Na2SO4), filtered and concentrated. Chromatography on silica gel using 1:1 Hexanes:EtOAc eluted the product. After concentration the title compound (6.64 g, 27.08 mmol, 45% yield) was isolated as a yellow oil: 1H NMR (CDCl3, 400 MHz) δ 9.22 (s, 1H), 8.80 (s, 1H), 4.58 (s, 2H), 4.49 (dd, J=14.3, 7.1 Hz, 2H), 1.43 (t, J=7.2 Hz, 3H).

1. temperatureAfter 4 h the reaction mixture was cooled
2. filtrationthe precipitate filtered off
3. concentrationThe red filtrate was concentrated
4. dissolutionthe residue redissolved in EtOAc
5. washwashed with sat'd NaHCO3, 5% Na2S2O3, brine
6. dry with materialthe organics dried (Na2SO4)
7. filtrationfiltered
8. concentrationconcentrated
9. washChromatography on silica gel using 1:1 Hexanes:EtOAc eluted the product