反应详情

温度

40 °C

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%.

1. customThe solvent was removed in vacuo
2. customthe residual oil purified by flash chromatography on silica
3. washeluting with dichloromethane
4. customto give a crystalline solid
5. customRecrystallisation from methanol