Triethylamine → ethyl 6-chloro-8-(5-chloro-1-pentynyl)-2-(trifluoromethyl)-2H-1-benzopyran-3-carboxylate

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Reaction Steps

Ethyl 6-chloro-8-iodo-2-trifluoromethyl-2H-1-benzopyran-3-carboxylate (Example 73, Step 2) (1.50 g, 3.47 mmol), tetrakis(triphenylphosphine)palladium(0) (0.2 g, 0.174 mmol), copper(I)iodide (0.066 g, 0.347 mmol), and triethylamine (1.05 g, 10.4 mmol) were dissolved in toluene (50 mL). 5-Chloro-1-pentyne (0.53 g, 5.20 mmol) was added via syringe and the mixture stirred for 18 hours at room temperature. The reaction was diluted with diethyl ether (50 mL), extracted with 0.5 N HCl (2×25 mL), and water (2×25 mL). The organic phase was dried over MgSO4, filtered, and evaporated to yield an orange oil. The crude material was purified by flash chromatography in 2% ethyl acetate in hexane. Recrystallization from hexane afforded the ester as a white solid (0.96 g, 68%): mp 84.8–85.9° C. 1H NMR (CDCl3/300 MHz) 7.61 (s, 1H), 7.33 (d, 1H, J=2.6 Hz), 7.14 (d, 1H, J=2.6 Hz), 5.79 (q, 1H, J=6.7 Hz), 4.37−4.29 (m, 2H), 3.75 (t, 2H, J=6.7 Hz), 2.67 (t, 2H, J=6.7 Hz), 2.11–2.03 (m, 2H,), 1.35 (t, 3H, J=7.2 Hz). FABLRMS m/z 424.1 (M+NH4+). ESHRMS m/z 424.0694 (M+NH4+, Calc'd. 424.0694). Anal. Calc'd. for C18H15Cl2F3O3: C, 53.09; H,3.71;, Cl,17.41. Found: C, 53.02; H, 3.90; Cl, 17.63.

Provenance & Evidence