Pyridine → Ethyl 3-(butanoylamino)-2-oxobutanoate

Participants

Reaction Conditions

Reaction Steps

The compound of formula VI (9.54 g, 0.06 mol) was dissolved into dried tetrahydrofuran (60 mL), and DMAP (0.24 g, 2.0 mmol) and pyridine (15 mL) were added therein. The mixture was heated for 30 minutes at 50° C., cooled, and slowly dropped with ethyl oxalyl monochloride (16.4 g, 0.12 mol) under an ice bath. After the dropping, the mixture was heated for 4 hours at 70° C., filtered to remove the solid, and evaporated to remove the solvent under reduced pressure. Water (100 mL) was added therein, and the product was extracted with ethyl acetate (120 mL×3). The liquid was separated, and the combined organic phase was washed by water (90 mL) and saturated saline (50 mL×2) respectively, dried over anhydrous sodium sulfate, and rotarily evaporated to remove the solvent. NaHCO3 (3.8 g, 0.045 mol) and methanol (50 mL) were added therein, and the reaction mixture was refluxed for 2 hours, filtered, and evaporated off the solvent under reduced pressure to obtain a yellow oil, i.e., ethyl 3-butyramido-2-oxo-butyrate, which was directly used in the next step without separation.

Provenance & Evidence