Ethyl chloroformate → Ethyl 3-(4-methylphenyl)-3-oxopropanoate

Participants

Reaction Steps

Lithium bis(trimethylsilyl)amide (20% in tetrahydrofuran, 203.6 ml, 217 mmol) was added dropwise to a stirred solution of 4-methylthioacetophenone (20.2 g, 121 mmol) in dried tetrahydrofuran (300 ml) at −20° C. and stirring was continued for 1 hour at −20° C. Ethylchloroformate (19.8 g, 182 mmol) was added dropwise to the stirred reaction mixture at −20° C. and stirring was continued for 3 hours. The reaction was quenched with saturated ammonium chloride solution and extracted with ethylacetate. The organic extract was washed with water, brine, dried over anhydrous sodium sulphate and concentrated to dryness in vacuum. The crude product thus obtained was purified by column chromatography to yield the title compound as viscous oil (16.45 g, 56.8%). 1H-NMR (DMSO-d6): δ 1.15–1.19 (t, 3H), 2.54 (s, 3H), 4.07–4.11 (q, 2H), 4.13 (s, 2H), 7.36–7.39 (d, 2H), 7.85–7.88 (d, 2H). MS m/z: 239 (M+). Preparation 4 Synthesis of 2-amino-6-(4-methylphenyl)-1,3-oxazin-4-one

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