Triethylamine → 5-(4-Hydroxy-but-1-ynyl)-thiophene-2-carboxylic acid methyl ester

Participants

Reaction Steps

To a 20-mL vial for microwave reaction, were added a mixture of palladium chloride (57 mg, 0.32 mmol), triphenylphosphine (104 mg, 0.32 mmol), copper iodide (243 mg, 1.28 mmol), triethylamine (8.08 g, 80 mmol), 5-bromo-thiophene-2-carboxylic acid methyl ester (1.77 g, 8 mmol) and anhydrous acetonitrile (10 mL). To the stirred mixture, were added copper iodide (243 mg, 1.28 mmol) and but-3-yn-1-ol, 1 (588 mg, 8.4 mmol), and the vial was sealed and put into the microwave reactor at 100° C. for 10 min. After evaporation of solvent under reduced pressure, MeOH (20 mL) was added followed by silica gel (5 g). The resulting plug was loaded on to a silica gel column (3.5×12 cm) and eluted with hexane followed by 20% EtOAc in hexane. Fractions with an Rf=0.42 (hexane/EtOAc 4:1) were pooled and evaporated to afford 1.17 g of 2 as yellow oil. 1H NMR (DMSO-d6): δ 2.59-2.63 (t, J=6.4 Hz, 2H), 3.56-3.59 (t, J=6.4 Hz, 2H), 3.81 (s, 3H), 4.95-4.98 (t, J=5.6 Hz, 1H), 7.27-7.28 (d, J=4.0 Hz, 1H), 7.69-7.70 (d, J=4.0 Hz, 1H).

Provenance & Evidence