[CH3:1][C:2]1[N:3]=[CH:4][C:5]([C:8]([O:10][CH2:11][CH3:12])=[O:9])=[N:6][CH:7]=1.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1.[Br:31]N1C(=O)CCC1=O>C(Cl)(Cl)(Cl)Cl.[W]>[Br:31][CH2:1][C:2]1[N:3]=[CH:4][C:5]([C:8]([O:10][CH2:11][CH3:12])=[O:9])=[N:6][CH:7]=1Ethyl 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).
Loading…
