Iodine → 2-(5-Iodo-1H-pyrazol-1-yl)ethan-1-ol

Participants

Reaction Conditions

Reaction Steps

To a cold (0° C.) solution of 2-pyrazol-1-yl-ethanol (0.5 g, 4.46 mmol) in tetrahydrofuran (15 mL), under an atmosphere of nitrogen, was added N,N,N′,N′-tetramethyl-ethylenenediamine (1.34 ml, 8.92 mmol, 2.0 eq.) followed by n-butyllithium (2.5M in hexane, 4.0 ml, 10 mmol, 2.2 eq.) at such a rate as to maintain the temperature below 5° C. The resulting yellow solution was stirred at 0° C. for 0.5 hr before adding a solution of iodine (1.36 g, 5.35 mmol, 1.2 eq.) in tetrahydrofuran (10 mL). The resulting mixture was stirred for 20 min before concentrating the mixture by evaporation under reduced pressure. The residue was partition between ethyl acetate (50 mL) and aqueous citric acid (1M, 100 ml). The organic phase was washed with 10% aqueous sodium thiosulphate solution, saturated brine (20 mL) and dried over sodium sulphate. The resulting mixture was filtered and the filtrate concentrated under reduced pressure to give a brown oil. The crude oil was purified by chromatography on silica gel (60 g) eluting with a gradient of ethyl acetate in heptane (50:50) to give the title compound as a white solid (0.4 g, 38%).

Provenance & Evidence