2-Acetylthiophene → Rac-alpha-hydroxy-alpha-propyl-gamma-oxo-2-thiophenebutyric acid

Beteiligte Stoffe

Reaktionsschritte

11.2 g (200 mmol) of potassium hydroxide in 75 ml of water are added at 0° dropwise to a suspension of 11.6 g (100 mmol) of 2-oxo-n-valeric acid and 12.6 g (100 mmol) of 2-acetylthiophene in 75 ml of ethanol and the suspension is held at 0° for 48 hours. After evaporation of the ethanol the residue is made acidic with 25% hydrochloric acid and extracted three times with ethyl acetate. The combined ethyl acetate extracts are dried, filtered and evaporated. After chromatography on silica gel using a 5:1 mixture of methylene chloride and methanol as the eluent and crystallisation from ether there are obtained 10.0 g (41%) of rac-α-hydroxy-α-propyl-γ-oxo-2-thiophenebutyric acid as a colorless powder, melting point 128°-131°, MS: 197 (M-COOH)+.

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