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) at room temperature. Then, DMF (0.2 mL) was added to the mixture. The resulting solution was stirred at room temperature for 2 h, and the solvent was removed on a rotary evaporator. The crude material was placed under vacuum for 30 minutes to remove the residual oxalyl chloride to give the crude acid chloride. Crude material was dissolved in DCM (100 mL) and cooled down to 0° C. To this solution, N,O-dimethylhydroxylamine hydrochloride (4.03 g, 41.32 mmol) and triethylamine (6.8 mL, 48.78 mmol) were added respectively. The resulting mixture 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 on a rotary evaporator. 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 on a rotary evaporator
2. waitThe crude material was placed under vacuum for 30 minutes
3. customto remove the residual oxalyl chloride
4. customto give the crude acid chloride
5. temperaturecooled down to 0° C
6. stirringThe resulting mixture was stirred at 0° C. for 30 min
7. waitat room temperature for additional 30 min
8. washwashed with H2O (2×100 mL)
9. washwashed with brine (100 mL)
10. dry with materialdried over Na2SO4
11. filtrationfiltered
12. concentrationconcentrated on a rotary evaporator
13. customThe crude material was purified by silica gel chromatography