Lithium hydroxide, monohydrate → 8-iodo-7-methoxy-2-(trifluoromethyl)-2H-chromene-3-carboxylic acid

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Reaction Steps

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.

Provenance & Evidence