Synthesis
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]+.
References
[1] Patent: US2012/178748, 2012, A1. Location in patent: Page/Page column 52-53
[2] Bioorganic and Medicinal Chemistry Letters, 2009, vol. 19, # 5, p. 1329 - 1331
[3] Journal of Organic Chemistry, 1988, vol. 53, # 11, p. 2589 - 2593
[4] Journal of Medicinal Chemistry, 2016, vol. 59, # 3, p. 1116 - 1139
[5] Tetrahedron, 2013, vol. 69, # 2, p. 474 - 480
