Boron tribromide → Methyl 5-hydroxybenzofuran-2-carboxylate
反応式
[CH3:1][O:2][C:3]([C:5]1[O:6][C:7]2[CH:13]=[CH:12][C:11]([O:14]C)=[CH:10][C:8]=2[CH:9]=1)=[O:4].B(Br)(Br)Br>C(Cl)Cl>[CH3:1][O:2][C:3]([C:5]1[O:6][C:7]2[CH:13]=[CH:12][C:11]([OH:14])=[CH:10][C:8]=2[CH:9]=1)=[O:4]参加物
4
実験手順
A solution of 5-methoxy-benzofuran-2-carboxylic acid methyl ester (5.0 g, 24 mmol) in 50 mL DCM at 0° C. was treated portionwise with boron tribromide (4.4 mL of a 1 M solution in DCM). After 3 hours, the reaction mixture was carefully quenched with 50% NH4OH. The organic layer was separated and washed 1×50 mL brine, dried (Na2SO4), and concentrated in vacuo to give 2 g (43%) of the title compound pure enough for subsequent use. 400 MHz 1H NMR (DMSO-d6) δ 9.47 (s, 1H), 7.56 (s, 1H), 7.45 (d, 1H, J=8.8 Hz), 7.00 (s, 1H), 6.91 (d, 1H, J=8.8 Hz), 3.81 (s, 3H). Preparation of 5-Dimethylthiocarbamoyloxy-benzofuran-2-carboxylic acid methyl ester (Compound 6B)