反应详情

To a solution of 2,5-dimethoxybenzoic acid (6.00 g, 33.0 mmol) in DCM (100 mL) was added oxalyl chloride (3.6 mL, 41.3 mmol) and then DMF (0.2 mL). The solution was stirred at room temperature for 2 h, and the solvent was removed under reduced pressure. The crude material was placed under vacuum for 30 min to remove all of the oxalyl chloride. To a mixture of the residue and N, O-dimethylhydroxylamine hydrochloride (4.03 g, 41.32 mmol) in DCM (100 mL) at 0° C., triethylamine (6.8 mL, 48.78 mmol) was added dropwise. The solution was stirred at 0° C. for 30 min and then at room temperature for additional 30 min. The reaction was diluted with DCM (50 mL), washed (2×100 mL H2O, 100 mL brine), dried over Na2SO4, and concentrated under reduced pressure. The crude material was purified on a silica gel column to yield N,2,5-trimethoxy-N-methylbenzamide (7.32 g, 99%) as clear oil which solidified over time. 1H NMR (CDCl3): δ 7.90 (m, 3H), 3.82 (s, 3H), 3.79 (s, 3H), 3.58 (br s, 3H), 3.32 (br s, 3H).

1. customthe solvent was removed under reduced pressure
2. waitThe crude material was placed under vacuum for 30 min
3. customto remove all of the oxalyl chloride
4. stirringThe solution was stirred at 0° C. for 30 min
5. waitat room temperature for additional 30 min
6. washwashed (2×100 mL H2O, 100 mL brine)
7. dry with materialdried over Na2SO4
8. concentrationconcentrated under reduced pressure
9. customThe crude material was purified on a silica gel column