Bromine → Methyl 4-bromoacetyl-2,6-dichlorophenoxyacetate
反応式
[Br:1]Br.[C:3]([C:6]1[CH:17]=[C:16]([Cl:18])[C:9]([O:10][CH2:11][C:12]([O:14][CH3:15])=[O:13])=[C:8]([Cl:19])[CH:7]=1)(=[O:5])[CH3:4]>C(Cl)(Cl)Cl>[Br:1][CH2:4][C:3]([C:6]1[CH:7]=[C:8]([Cl:19])[C:9]([O:10][CH2:11][C:12]([O:14][CH3:15])=[O:13])=[C:16]([Cl:18])[CH:17]=1)=[O:5]参加物
4
反応条件
- 温度
- 40 °C
実験手順
A solution of bromine (0.77 ml) in chloroform (10 ml) was added dropwise over 15 minutes to a stirred solution of the product from step (i) (4.16 g) in chloroform (40 ml) at 25° C. The temperature was raised to 40° C. for 1 hour and then stirring continued for a further 18 hours at ambient temperature. The solvent was removed in vacuo and the residual oil purified by flash chromatography on silica, eluting with dichloromethane, to give a crystalline solid. Recrystallisation from methanol gave methyl 4-bromoacetyl-2,6-dichlorophenoxyacetate, 1.88 g, as white crystals: m.p. 89°-90° C.; NMR (d6DMSO) δ8.06 (2H, s), 4.93 (2H, s), 4.82 (2H, s), 3.72 (3H s); m/e 355/357 (M+H)+, 1 Br pattern; calculated for C11H9BrCl2O4 : C, 37.1; H, 2.3. found: C, 36.8; H, 2.4%.