Triethylamine → Ethyl 6-trimethylsilylethynyl-1,2-dihydro-2-(trifluoromethyl)-3-quinolinecarboxylate

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Reaction Steps

The ethyl 6-iodo-1,2-dihydro-2-(trifluoromethyl)-3-quinolinecarboxylate (Example 160, Step 1) (750 mg, 1.89 mmol), trimethylsilylacetylene (925 mg, 9.44 mmol), dichlorobis(triphenylphosphine)palladium(II) (35 mg, 0.05 mmol), copper(I)iodide (9.5 mg, 0.05 mmol), and triethylamine (953 mg, 9.44 mmol) were mixed at room temperature for 2 h in acetonitrile (10 mL). The resulting black heterogeneous mixture was poured into ethyl acetate(50 mL) and extracted with water (2×25 mL), 1 N aqueous hydrochloric acid (25 mL), and saturated aqueous ammonium chloride (2×25 mL). The organic layer was dried over sodium sulfate and solvent removed at reduce pressure. The product was purified by flash chromatography (0–25% ethyl acetate/hexanes, silica gel). A black semisolid was isolated which upon trituration with hexanes afforded ethyl 6-trimethylsilylethynyl-1,2-dihydro-2-(trifluoromethyl)-3-quinolinecarboxylate as a yellow solid(267 mg,38%): mp 117–119° C. 1H NMR (CDCl3, 300 MHz) 7.65 (s, 1H), 7.24–7.32 (m, 2H), 6.55 (d, 1H, J=8.0 Hz), 5.08–5.18 (m, 1H), 4.66 (brs, 1H), 4.24–4.64 (m, 2H), 1.34 (t, 3H, J=7.1 Hz) 0.22 (s, 9H). ESHRMS m/z 368.1306 (Calc'd for M+H 368.1293).

Provenance & Evidence