Hydrogen Bromide → 6-Bromo-1,3-dihydro-2-benzofuran-1-one

Reaktionsgleichung

N([O-])=O.[Na+].N[C:6]1[CH:14]=[C:13]2[C:9]([CH2:10][O:11][C:12]2=[O:15])=[CH:8][CH:7]=1.[BrH:16]>O>[Br:16][C:6]1[CH:14]=[C:13]2[C:9]([CH2:10][O:11][C:12]2=[O:15])=[CH:8][CH:7]=1

Komponenten

Versuchsvorschrift

A solution of NaNO2 (2.2 g, 0.040 mol) in H2O (22 mL) was added to a mixture of 6-aminoisobenzofuran-1(3H)-one (5.0 g, 0.030 mol) in HBr (70 mL, 48%) over 5 min at 0° C. The mixture was stirred for 20 minutes and was then pipetted into an ice cold solution of CuBr (22.0 g, 0.210 mol) in HBr (48%, 23 mL). The resulting dark brown mixture was stirred for 20 min and was then diluted with H2O (200 mL) to produce an orange precipitate. The precipitate was filtered off and was treated with saturated NaHCO3. The mixture was extracted with ethyl acetate (20 mL×3). The organic layer was dried over Na2SO4 and evaporated in vacuo to give 6-bromoisobenzofuran-1(3H)-one (5.4 g, 84%). 1H NMR (300 MHz, CDCl3) δ 8.05 (d, J=1.8, 1H), 7.80 (dd, J=8.1, 1.8, 1H), 7.39 (d, J=8.1, 1H), 5.28 (s, 2H).