反应详情

温度

0 °C

A solution of the aldehyde 11 (50 g, 0.197 mol) in acetic anhydride (150 mL) was slowly added to a mixture of 70% nitric acid (900 mL) and acetic anhydride (200 mL) at 0° C. and was then left to stir for 2.5 hours at 0° C. The solution was then poured onto ice in a 5 L flask and the volume adjusted to 5 L with ice and water. The resulting light sensitive pale yellow precipitate was immediately filtered (the ester is slowly hydrolysed at room temperature in those conditions) and washed with cold water. The product 12 was used directly in the next step. TLC analysis (50/50 EtOAc/Pet Et) proved the product pure. 1H NMR (CDCl3) δ 10.4 (2H, s), 7.61 (1H, s), 7.4 (1H, s), 4.21 (2H, t, J=6.2 Hz), 4.00 (3H, s), 3.71 (2H, s), 2.58 (2H, t, J=7.1 Hz), 2.23 (2H, p, J=6.3 Hz); 13C NMR (CDCl3) δ 188.5, 172.8, 152.7, 151.0, 143.5, 124.7, 110.1, 108.2, 68.4, 56.4, 51.3, 29.7, 23.8; MS (ES+) m/z (relative intensity) 298 ([M+H]+, 100).

1. waitwas then left
2. additionThe solution was then poured onto ice in a 5 L flask
3. filtrationThe resulting light sensitive pale yellow precipitate was immediately filtered (the ester
4. customis slowly hydrolysed at room temperature in those conditions
5. washwashed with cold water