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ChemicalBook CAS DataBase List 3-(3,4-DIFLUOROPHENYL)-3-OXO-PROPIONIC ACID ETHYL ESTER
252955-07-0

3-(3,4-DIFLUOROPHENYL)-3-OXO-PROPIONIC ACID ETHYL ESTER synthesis

5synthesis methods
-

Yield:252955-07-0 27 g

Reaction Conditions:

with lithium hexamethyldisilazane in tetrahydrofuran at -78; for 2 h;Inert atmosphere;

Steps:

63.2 Step 2: ethyl 3-(3,4-difluorophenyl)-3-oxo-propanoate

To a solution of ethyl acetate (31.0 mL, 278.9 mmol) in tetrahydrofuran (300 mL) was added lithium bis(trimethylsilyl)amide (1.0 M in tetrahydrofuran, 349.0 mL, 349.0 mmol) at -78° C. under nitrogen atmosphere, followed by methyl 3,4-difluorobenzoate (40.0 g, 232.4 mmol). After addition, the mixture was stirred at -78° C. for 2 h and quenched by addition of saturated aqueous ammonium chloride (100 mL). The resulting mixture was extracted with ethyl acetate (3*200 mL). The combined organic layers were dried over sodium sulfate and concentrated under reduced pressure. The residue was purified by column chromatography (silica gel, 100-200 mesh, 0 to 20% ethyl acetate in petroleum ether) to give ethyl 3-(3,4-difluorophenyl)-3-oxo-propanoate (27.0 g, 51%) as a brown oil. 1H NMR (400 MHz, CDCl3) δ 7.86-7.66 (m, 1H), 7.23 (s, 2H), 4.19-4.01 (m, 2H), 3.05-2.81 (m, 2H), 1.34-1.20 (m, 3H).

References:

US2019/127382,2019,A1 Location in patent:Paragraph 0439; 0441

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