Chlorosulfonic acid → HCID 21883691, compound

Participants

Reaction Conditions

Reaction Steps

Chlorosulfonic acid (50.0 mL) was cooled to 15° C. and ethyl 2-trifluoromethyl-2H-1-benzopyran-3-carboxylate (Example 10, Step 2) (6.21 g, 22.83 mmol) was added. After stirring at −15° C. for 1 hour, the solution was warmed to room temperature and stirred for 16 hours. The solution was added dropwise onto ice (500 mL) with vigorous stirring and extracted with diethyl ether (2×250 mL). The ether layers were combined, washed with water (2×250 mL), saturated sodium bicarbonate (2×250 mL), and brine (2×250 mL). Hexanes (50 mL) were added and the solution was dried over sodium sulfate. The solvent was removed in vacuo to afford the ester as a yellow solid (7.41 g, 87%): mp 97.2–98.4° C. 1H NMR (CDCl3, 300 MHz) 7.97 (dd, 1H, J=8.6, 2.2. Hz), 7.92 (d, 1H, J=2.2 Hz), 7.73 (s, 1H), 7.17 (d, 1H, J=2.2 Hz), 5.82 (qH-F, 1H, J=7.2 Hz), 4.28–4.39 (m, 2H), 1.35 (t, 3H, J=7.0 Hz). FABLRMS m/z 376 (M+Li+).

Provenance & Evidence