反应详情

温度

55 °C

Concentrated sulfuric acid (18 M; 6.0 mL) was added to N-benzyl-2,2-dimethoxypropionamide (1.38 g, 6.18 mmol) at ambient temperature, and the solution was stirred at ambient temperature for 30 min and at 55° C. overnight. The reaction mixture was added to ≈100 mL of ice, and the pH of the yellow solution was adjusted to 7-8 with NaHCO3 solution. Small amounts of a brown solid that precipitated very soon during the addition (pH was still <2) were filtered off, and neutralization was continued. The yellow precipitate was filtered off, washed with water, and dried in vacuo, giving the title compound as yellow solid. It was used in the next step without further purification. 1H NMR (400 MHz, DMSO-d6): δ=10.6 (very brs, 1H), 8.74 (s, 1H), 7.91 (d, J=8.4 Hz, 1H), 7.83 (dd, J=0.8, 8.6 Hz, 1H), 7.61 (ddd, J=1.6, 6.4, 8.4 Hz, 1H), 7.31 (ddd, J=0.8, 6.4, 8.0 Hz, 1H), 2.37 (d, J=0.4 Hz, 3H). MS(ES+): m/z=160.10 (100) [MH+]. HPLC: tR=2.3 min (polar—5 min, ZQ3).

1. customSmall amounts of a brown solid that precipitated very soon during the addition (pH
2. filtrationwere filtered off
3. filtrationThe yellow precipitate was filtered off
4. washwashed with water
5. customdried in vacuo