Sodium hydride → 6-chloro-5-hydroxvl-2-(trifluoromethyl)-2H-chromene-3-carboxylic acid

Participants

Reaction Steps

To the mixture of ethyl 6-chloro-5-fluoro-2-(trifluoromethyl)-2H-chromene-3-carboxylate (2g, 6.2 mmol) and 2-methylsulfonylethanol (2.3 g, 18.5 mmol) in 40 mL of dry DMF at 0° C. was added sodium hydride (60% mineral oil suspesion, 1.48 g, 37.2 mmol) slowly with stirring. Bubbling was observed during the process. Then the resulting black solution was stirred at room temperature for three hrs. LC-MS indicated that no any more starting material was observed. The reaction was poured into ice/aqueous ammonium chloride mixture. The product was extracted with ethyl acetate, and the resulting organic solution was washed with brine, and dried over anhydrous magnesium sulfate. After removing the volatiles, the residue was purified on silica gel column with 1:1 EtOAc/hexane+1% HOAc. The product was obtained as colorless oil, 0.8 g. Part of the product was further purified on reverse phase HPLC and gave an off-white solid. LC-MS (ES+) 295.2(M+1, 100). 1H NMR (CD3OD/300 MHz) 8.11(s, 1H), 7.30(d, J=8.7 Hz, 1H), 6.53(d, J=9.0 Hz, 1 H), 5.75(q, J=7.5 Hz, 1 H),. 19F NMR(CDCl3/300 MHz) −80.31 (d, J=7.1 Hz). High resolution MS (ES−): m/e calc. For C15H6ClF3O4: 292.9828(M−H), found: 292.9853.

Provenance & Evidence