Triethylamine → 4-(3-Dimethylamino-prop-1-ynyl)-3-methyl-benzofuran-2-carboxylic acid ethyl ester

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Reaction Steps

To the product of Example 20, Step 1, 3-methyl-4-trifluoromethanesulfonyloxy-benzofuran-2-carboxylic acid ethyl ester (900 mg, 2.56 mmol, 1 eq), under nitrogen was added 1-dimethylamino-2-propyne (425 mg, 5.11 mmol, 2 eq), PdCl2(PPh3)2 (90 mg, 0.13 mmol, 0.05 eq), and triethylamine (1.4 mL, 10.23 mmol, 4 eq), in 25 mL of toluene. The reaction mixture was heated at reflux for 16 h until the reaction was complete by TLC. After work up and column chromatography (0-10% MeOH/dichloromethane), 4-(3-dimethylamino-prop-1-ynyl)-3-methyl-benzofuran-2-carboxylic acid ethyl ester was obtained in 65% yield (474 mg). 1H NMR (400 MHz, DMSO-d6) δ ppm 1.4 (t, J=7.1 Hz, 3 H) 2.3 (s, 6 H) 2.8 (s, 3 H) 3.6 (s, 2 H) 4.4 (q, J=7.1 Hz, 2 H) 7.4 (dd, J=7.3, 1.0 Hz, 1 H) 7.5 (m, 1 H) 7.7 (dd, J=8.2, 0.9 Hz, 1 H).

Provenance & Evidence