Triethylamine → 5-(3-Methanesulfonylamino-prop-1-ynyl)-thiophene-2-carboxylic acid methyl ester

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Reaction Steps

To a solution of 5-bromo-thiophene-2-carboxylic acid methyl ester (1.66 g, 8.0 mmol), N-prop-2-ynyl-methanesulfonamide (1.09 g, 8.2 mmol), Et3N (1.7 mL, 12.1 mmol), and CH3CN (30 mL) was added Pd(PPh3)4 (462 mg, 0.4 mmol) followed by CuI (76 mg, 0.4 mmol). The reaction was heated at reflux for 24 h and was cooled to room temperature. The volatiles were removed in vacuo and the residue was purified via flash chromatography (20% EtOAc in hexanes to 33% EtOAc in hexanes) to yield 5-(3-methanesulfonylamino-prop-1-ynyl)-thiophene-2-carboxylic acid methyl ester as a pale yellow solid (1.1 g). 1H NMR (300 MHz, CDCl3) δ 7.64 (d, 1H), 7.14 (d, 1H), 4.60 (m, 1H), 4.22 (d, 2H), 3.88 (s, 3H), 3.10 (s, 3H); MS 274 (M+1).

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