b. Sulfuric acid (1 mL) was slowly added to a solution of 2-oxobutanoic acid (6.0 g, 58.8 mmol) in ethanol (100 mL) at room temperature. The reaction mixture was heated to reflux and stirred continuously for 4 hours. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was diluted with distilled water (50 mL) and the pH was adjusted with 1 N sodium hydroxide solution to about 7. Subsequently, extraction was performed with ethyl acetate (100 mL × 3). The organic layers were combined, dried with anhydrous sodium sulfate, filtered and concentrated to give ethyl 2-oxobutyrate (7.5 g, 98% yield). The product was confirmed by electrospray mass spectrometry (ESI MS), m/z 131 [M + H]+.
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