Hydrochloric Acid → 8-chloro-6-ethynyl-2-(trifluoromethyl)-2H-chromene-3-carboxylic Acid

Participants

Reaction Steps

To 450 mg (1.36 mmole) of ethyl 8-chloro-6-iodo-2-(trifluoromethyl)-2H-chromene-3-carboxylate was added 9 mL of a solvent mixture of THF/MeOH (7:2) followed by 172 mgs of LiOH—H2O in 1 mL of H2O. The mixture was stirred for 30 min at rt. The mixture was concd, treated with 10 mL of water and acidified with conc. HCl (approx. 0.4 mL). The producted oiled out of solution and was extracted three times with diethyl ether. Combined extracts were dried and concd to afford 0.32 g of a crude yellow solid. Chromatography (C18, Gilson 10×4 cm, 7 injections of 50 mgs each) afforded 0.18 g (43.7%) of a white solid: 1H NMR (d6-acetone/400 MHz) 3.74 (s, 1H), 6.03 (q, 1H, 6.8 Hz), 7.61 (m, 2H), 7.92 (s, 1H); 13C NMR (d6-acetone/400 MHz) 72.0 (q, J=33.2 Hz), 80.0, 81.6, 118.3, 119.6, 121.7, 121.8 (q, J=0.7 Hz), 124.2 (q, J=286.6 Hz), 132.5, 136.1, 136.7, 149.9, 164.6; 19F NMR (d6-acetone/400 MHz) −79.6 (d, 3F, J=6.5 Hz); MS (ES+) 303 (M+1, 27), 291 (65), 289 (51), 235 (100), 233 (79); MS(ES−) 301 (M−1, 100), 303 (35); HRMS (EI−) m/z calcd for (C13H5O3ClF3) 300.9874, found 300.9837.

Provenance & Evidence