Water → HCID 21949857, compound

Participants

Reaction Steps

Sodium periodate (1.00 g, 4.60 mmol), osmium tetroxide (1.5% solution in tert-butanol, 190 mg, 0.02 mmol) and the pyrazole from Example 156 (600 mg, 1.86 mmol) were dissolved in acetone (9 ml) and water (3 ml) under nitrogen at room temperature, and the reaction was stirred for 5 hours. The acetone was removed under reduced pressure and the residue was extracted with ethyl acetate (30 ml). The organic phase was washed with water (2×30 ml) then brine (30 ml), dried over magnesium sulphate and concentrated under reduced pressure. The crude aldehyde was then dissolved in methanol (15 ml) and sodium borohydride (84 mg, 2.22 mmol) was added portionwise at room temperature under nitrogen. The reaction was stirred for 3 hours and the solvent was removed under reduced pressure. The residue was partitioned between ethyl acetate (10 ml) and water (10 ml) and the organic phase was washed with water (2×10 ml) then brine (10 ml), dried over magnesium sulphate and concentrated under reduced pressure. The residual oil was purified by flash chromatography on silica gel eluting with a solvent gradient of pentane changing to ethyl acetate:pentane (50:50, by volume) to provide the title compound (250 mg) as a colourless oil.

Provenance & Evidence