Potassium Carbonate → 5-(4-Methoxy-2-methyl-phenyl)-4-methyl-thiophene-2-carboxylic acid methyl ester

참여 물질

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To a mixture of 4-methoxy-2-methylphenylboronic acid (912 mg, 6 mmol), 5-bromo-4-methyl-thiophene-2-carboxylic acid methyl ester (1.1 g, 5 mmol) and K2CO3 (1.38 g, 10 mmol) in toluene (30 mL) and water (5 mL) is bubbled N2 for 15 minutes followed by addition of tetrakis(triphenylphosphine) palladium (289 mg, 0.25 mmol). The reaction mixture is stirred at 80° C. under N2 overnight. The reaction mixture is filtered through a diatomaceous earth pad eluting with EtOAc. The combined filtrate is concentrated and the residue is purified by column chromatography on silica gel eluting with 0-15% EtOAc in hexanes to give 5-(4-methoxy-2-methyl-phenyl)-4-methyl-thiophene-2-carboxylic acid methyl ester (540 mg, 39%). 1H NMR (CDCl3): δ 7.63 (s, 1H), 7.15 (d, 1H, J=8.4 Hz), 6.82 (d, 1H, J=2.8 Hz), 6.78 (dd, 1H, J=2.8, J=8.4 Hz), 4.79 (bs, 1H), 3.88 (s, 3H), 3.83 (s, 3H), 2.17 (s, 3H), 2.02 (s, 3H).

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