Methanol → 4-Ethynyl-1-(4-methoxybenzyl)-1H-pyrazole

Participants

Reaction Steps

A vigorously stirred solution of 4-iodo-1-(4-methoxy-benzyl)-1H-pyrazole (1.0 g, 3.18 mmol) and Pd(Ph3P)2Cl2 (60 mg, 3 mol %) in a mixture of DCM (10 mL) and triethylamine (3 mL) was evacuated and backfilled with nitrogen three times and then treated sequentially with trimethylsilylacetylene (0.53 mL, 3.83 mmol) and copper (I) iodide (70 mg, 12 mol %). The reaction rapidly became dark and after stirring for 3 h the solvents were removed in vacuo and the residue treated with methanol (10 mL) and potassium hydroxide (300 mg, 5.35 mmol). After stirring for 30 minutes the mixture was concentrated onto silica gel and purified by flash column chromatography (eluent-hexane:diethyl ether 2:1) to afford the title compound as a white solid (550 mg, 81% yield over two steps). 1H-NMR (CDCl3) δ 7.61 (s, 1H), 7.46 (s, 1H), 7.17 (d, J=8.6 Hz, 2H), 6.86 (d, J=8.6 Hz, 2H), 5.18 (s, 2H), 3.78 (s, 3H), 2.96 (s, 1H).

Provenance & Evidence