Sodium Bicarbonate → 2-tert-Butyl-5-methyl-oxazole-4-carboxylic acid methyl ester

Participants

Reaction Steps

A solution of methyl 3-oxo-2-(pivalamido)butanoate (0.22 g, 1.0 mmol) in phosphorus oxychloride (1.5 mL) was heated at 110° C. for 30 min. The reaction was cooled in an ice bath, and saturated aqueous NaHCO3 was slowly added until the mixture was basic. The reaction was extracted with CH2Cl2, and the extracts were washed with saturated aqueous NaHCO3 and water, dried over Na2SO4, and concentrated under vacuum. The residue was purified by silica gel chromatography (0%-40% EtOAc-hexanes) to obtain methyl 2-tert-butyl-5-methyloxazole-4-carboxylate (44 mg, 22% yield). 1H NMR (400 MHz, CDCl3) δ 3.90 (s, 3H, 2.60 (s, 3H), 1.39 (s, 9H) ppm. LC/MS: m/z 198.3 (M+H)+ at 2.83 min (10%-99% CH3CN (0.035% TFA)/H2O (0.05% TFA)).

Provenance & Evidence