Sodium Chloride → 3-oxo-2-(4-pyrazol-1-ylbenzyl)thiobutyric acid S-tert-butyl ester

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Reaction Conditions

Reaction Steps

A solution of 3-oxothiobutyric acid S-tert-butyl ester (3.7 g) in 1,2-dimethoxyethane (5.0 mL) was added to a stirred suspension of sodium hydride (60% in oil, 0.92 g) in 1,2-dimethoxyethane (25 mL) at −10° C., and the resulting mixture was warmed to 15° C. over 15 minutes, cooled to −10° C. and then treated dropwise with a mixture of 1-(4-bromomethylphenyl)-1H-pyrazole (5.0 g) in 1,2-dimethoxyethane (20 mL) over a period of 30 minutes. The resulting mixture was warmed to room temperature and then stirred at this temperature for overnight. The mixture was diluted water, pH adjusted to 5 by the addition of glacial acetic acid and then saturated with sodium chloride. The mixture was extracted ethyl acetate and the combined extracts were dried over magnesium sulfate and then concentrated under reduced pressure. Purification of the residue purified by column chromatography on silica gel, eluting with a mixture of pentane, dichloromethane and ethyl acetate (1:3:0, 0:1:0 to 0:10:1 by volume) gave title compound as a colourless gum (0.6 g).

Provenance & Evidence