Triethylamine → Ethyl 3-(3-fluoro-4-nitrophenyl)-3-oxopropanoate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A 2 L round bottomed flask was fitted with a mechanical stir motor and nitrogen inlet. To a 10° C. solution of potassium 3-ethoxy-3-oxopropanoate (55.15 g, 324 mmol) in THF (500 mL) was added MgCl2 (38.56 g, 405 mmol) and Et3N (45 mL, 324 mmol). The reaction mixture was allowed to warm to 23° C. and stir for 3 h. A solution of 3-fluoro-4-nitrobenzoyl chloride (˜162 mmol) in THF (200 mL) was added. The reaction turned yellow instantly and a precipitate formed. THF (200 mL) was added to ensure that stirring was not impeded. TLC analysis indicated that the reaction had gone to completion however the reaction was allowed to stir over night. The reaction was quenched with 2 N HCl (1 L) and extracted with EtOAc (2×500 mL). The organic layer was washed with saturated NaHCO3 (500 mL), H2O (300 mL) and brine (200 mL). The organic layer was dried (Na2SO4) and concentrated in vacuo. The desired product (37.65 g, 147 mmol) was isolated by flash column chromatography in 91% yield (1:1 Hex EtOAc) as a yellow solid as a mixture of keto (75%) and enol (25%) tautomers. 1H-NMR (DMSO-d6) Keto tautomer δ 8.29 (dd, J=8.6, 7.4 Hz, 1H), 8.10 (dd, J=11.6, 2.0 Hz, 1H), 7.94 (m, 1H), 4.30 (s, 2H), 4.11 (q, J=7.2 Hz, 2H), 1.17 (t, J=7.2 Hz, 3H); Enol tautomer δ 12.44 (br s, 1H), 8.22 (app t, J=8.2 Hz, 1H), 8.05 (dd, J=12.6, 2.0 Hz, 1H), 7.90 (m, 1H), 6.22 (s, 1H), 4.25 (q, J=7.2 Hz, 2H), 1.26 (t, J=7.2 Hz, 3H); LCMS RT=3.14 min; MS {M+H]+=311.0.

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