反应详情

A mixture of formic acid (14.361 g, 0.312 mol) and acetic anhydride (12.659 g, 0.124 mol) was stirred at room temperature for 1 h under an argon atmosphere. This mixture was added to a solution of 2-methylaniline (10.710 g, 0.1 mol) in dry dichloromethane (60 ml) at such a rate that the temperature of the reaction mixture was kept between 5 and 10° C. The reaction was stirred at room temperature for 16 h and then refluxed for 4 h. The solvent was evaporated under reduced pressure, the residue was dissolved in CHCl3 (200 mL) and washed with a saturated aqueous NaHCO3 solution (3×200 mL), and water (200 mL). The organic layer was dried over Na2SO4 and the solvent was evaporated under reduced pressure. The remaining yellow solid was washed with a mixture of hexanes/diethyl ether (2×10 mL) and then with hexanes (3×5 mL) to afford N-formyl-2-methylaniline 8b as a white solid (9.70 g, 72%). 1H NMR (CDCl3, 300 MHz): δ=9.03-8.18 (m, 2H, CHO, NH), 7.77-7.03 (m, 4H), 2.30-2.22 (m, 3H); 13C{1H}NMR (CDCl3, 75 MHz): δ=164.41, 160.32, 135.50, 134.99, 131.45, 130.82, 130.50, 129.87, 127.25, 126.80, 126.34, 125.84, 123.75, 121.32, 18.05, 17.99; HRMS (FAB+) calculated for C8H10NO [M]+ 136.0762, observed 136.0783.

1. customwas kept between 5 and 10° C
2. stirringThe reaction was stirred at room temperature for 16 h
3. temperaturerefluxed for 4 h
4. customThe solvent was evaporated under reduced pressure
5. dissolutionthe residue was dissolved in CHCl3 (200 mL)
6. washwashed with a saturated aqueous NaHCO3 solution (3×200 mL), and water (200 mL)
7. dry with materialThe organic layer was dried over Na2SO4
8. customthe solvent was evaporated under reduced pressure
9. washThe remaining yellow solid was washed with a mixture of hexanes/diethyl ether (2×10 mL)