反应详情

A solution of 3,5-dichloro-4-ethoxybenzoic acid (1) (285 mg, 1.21 mmol) and DIPEA (1.05 mL, 6.05 mmol) in DMF (2.5 mL) was added to HATU (690 mg, 1.82 mmol) and the orange mixture was stirred for 5 min prior to the addition of methyl 4-amino-2-methylbenzoate (2) (200 mg, 1.21 mmol) in DMF (1 mL). The resulting dark orange solution was stirred overnight for 18 h. 2 M HCl (10 mL) was added and stirring continued for 10 min, and then the mixture was extracted with diethyl ether. The organic layer was washed with water (3×15 mL), dried over MgSO4, filtered and the solvent was evaporated in vacuo. The yellow residue was purified by silica gel chromatography (40 g, 0-100% EtOAc in isohexane) to afford methyl 4-(3,5-dichloro-4-ethoxybenzamido)-2-methylbenzoate (3) (267 mg, 56%): m/z 380 (M−H)− (ES−). 1H NMR (400 MHz, CDCl3) δ: 7.97 (1H, s), 7.80 (3H, m), 7.54 (1H, dd), 7.51 (1H, d), 4.18 (2H, q), 3.89 (3H, s), 2.63 (3H, s), 1.49 (3H, t).

1. stirringThe resulting dark orange solution was stirred overnight for 18 h
2. stirringstirring
3. waitcontinued for 10 min
4. extractionthe mixture was extracted with diethyl ether
5. washThe organic layer was washed with water (3×15 mL)
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. customthe solvent was evaporated in vacuo
9. customThe yellow residue was purified by silica gel chromatography (40 g, 0-100% EtOAc in isohexane)