反应详情

A solution of 2,4-dimethoxyphenyl acetic acid (7.9 g, 38 mmol) in CH2Cl2 (50 mL) plus a few drops of DMF was treated with SOCl2 (5.0 mL, 76 mmol) and the reaction was allowed to stir for 3 h at rt. The reaction mixture was then concentrated and taken up in a small amount of dichloroethane and added dropwise, at 0° C., to a solution of 1,3,5-trimethoxybenzene (12.8 g, 76 mmol) and AlCl3 (7.3 g, 57 mmol) in 50 mL dichloroethane. After 20 minutes at 0° C., the reaction was carefully quenched with 2 N HCl aq. The organic layer was separated, dried over MgSO4, filtered and concentrated to give a dark oil which was chromatographed on SiO2 (3:7 EtOAc/hexanes to 1:1 EtOAc/hexanes) to yield the desired product as a white solid (6.2 g): Mp 109-111° C.; 1H NMR (CDCl3) δ 7.06 (d, 1H, J=8.1 Hz), 6.41 (dd, 1H, J=8.1Hz, 2.4Hz), 6.39 (d, 1H, J=2.4Hz), 6.04 (s, 2H), 3.97 (s, 2H), 3.80 (s, 3H), 3.78 (s, 3H), 3.74 (s, 6H), 3.71 (s, 3H); MS FI 347 (M+H)+.

1. concentrationThe reaction mixture was then concentrated
2. waitAfter 20 minutes at 0° C.
3. customthe reaction was carefully quenched with 2 N HCl aq. The organic layer
4. customwas separated
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated
8. customto give a dark oil which
9. customwas chromatographed on SiO2 (3:7 EtOAc/hexanes to 1:1 EtOAc/hexanes)