反应详情

To a stirred solution of 2,5-dimethoxybenzoic acid (6.61 g, 36.3 mmol) in 50 ml of CH2Cl2 was added a solution of (COCl)2 in CH2Cl2 (2.0M, 20 ml, 40.0 mmol) at 0° C. under argon. After addition of catalytic amount of pyridine (0.2 ml) an evolution of gas was observed. The reaction was warmed up to room temperature and stirred for 3 hours. The volatile were removed and the residue was dissolved in 300 ml of diethyl ether. Diethylamine (5.26 ml, 50.8 mmol) was introduced dropwise at 0° C. under argon. The resulting mixture was stirred at room temperature for another 3 hours, and then quenched with saturated K2CO3 solution. The organic layer was washed with 2N NaOH and water, dried over MgSO4, filtered and then evaporated. Flash chromatography of the residue with CH2Cl2 and CH3CO2Et (1:1) provided pure title compound (8.34 g, 35.1 mmol) in 97% yield as white solid. 1H NMR (CDCl3) δ:1.05 (3H, t, J=7.1 Hz), 1.24 (3H, t, J=7.1 Hz), 3.16 (2H, q, J=7.1 Hz), 3.56 (2H, m), 3.77 (3H, s), 3.78 (3H, s), 6.77 (1H, m), 6.84 (2H, m).

1. customThe volatile were removed
2. dissolutionthe residue was dissolved in 300 ml of diethyl ether
3. stirringThe resulting mixture was stirred at room temperature for another 3 hours
4. customquenched with saturated K2CO3 solution
5. washThe organic layer was washed with 2N NaOH and water
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. customevaporated