反应详情

Oxalyl chloride (3.6 mL, 41.3 mmol) was added to a solution of 2,5-dimethoxybenzoic acid (6.00 g, 33.0 mmol) in DCM (100 mL). Then DMF (0.2 mL) was added to the mixture. 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 the residual oxalyl chloride. Triethylamine (6.8 mL, 48.78 mmol) was added dropwise to the mixture of the residue and N,O-dimethylhydroxylamine hydrochloride (4.03 g, 41.32 mmol) in DCM (100 mL) at 0° C. 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 with H2O (2×100 mL), washed with brine (100 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude material was purified by silica gel chromatography 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 the residual oxalyl chloride
4. stirringThe solution was stirred at 0° C. for 30 min
5. waitat room temperature for additional 30 min
6. washwashed with H2O (2×100 mL)
7. washwashed with brine (100 mL)
8. dry with materialdried over Na2SO4
9. filtrationfiltered
10. concentrationconcentrated under reduced pressure
11. customThe crude material was purified by silica gel chromatography