反应详情

To the solution of 0.4 g (0.93 mmol) of ethyl 8-iodo-7-methoxy-2-(trifluoromethyl)-2H-chromene-3-carboxylate in 8 mL of tetrahydrofuran was added a solution of 155 mg (3.7 mmol) of lithium hydroxide hydrate (LiOH—H2O) in 15 mL of water. The resulting solution was heated to reflux for one h. After cooling to room temperature, the volatiles were removed, the residue was acidified at 0° C. to pH=1.5 with dilute hydrochloric acid. The product was extracted with ethyl ether. The combined organic extracts were washed with brine, dried over anhydrous magnesium sulfate and concd in vacuo to afford 0.30 g (81%) of a light yellow solid: 1H NMR (CDCl3/400 MHz) 7.67(s, 1H), 7.18(d, J=8.4 Hz, 1H), 6.51(d, J=8.4 Hz, 1H), 5.78(q, J=6.8 Hz, 1H), 3.92(s, 3H). MS (ESI+) 400.9 (M+1, 100). MS(ES−) 398.9(M−H, 100). HRMS (ES−) m/z calcd for (M−H; C12H7F3O4): 398.9336, found 398.9368.

1. temperatureThe resulting solution was heated
2. temperatureto reflux for one h
3. customthe volatiles were removed
4. customwas acidified at 0° C. to pH=1.5 with dilute hydrochloric acid
5. extractionThe product was extracted with ethyl ether
6. washThe combined organic extracts were washed with brine
7. dry with materialdried over anhydrous magnesium sulfate and concd in vacuo