Yield:57965-21-6 86%

Reaction Conditions:

Stage #1: 1-(3-Methoxyphenyl)ethanonewith sodium hydride in tetrahydrofuran at -5 - 0; for 0.5 h;Inert atmosphere;
Stage #2: ethyl trifluoroacetate, in tetrahydrofuran at 20; for 6 h;

Steps:

8.1

(1) in 100 ml round bottom flask is added in 3 - methoxy hypnone (compound 3g) 14.9mmol, dry THF 30 ml, lowering the temperature to - 5 - 0 °C, under the protection of nitrogen addition of NaH 0.715g (29.8mmol), in this particularity stirring 30min, adding trifluoro ethyl acetate 3.175g (22.4mmol), stirring at the room temperature reaction 6h, evaporating the solvent under reduced pressure, adding ice water dilution solution, for 1 mol/L HCl solution of adjusting PH value to 6, extracted with ethyl acetate three times (10 ml × 3), recovery, combined with the organic layer, the organic layer using 5 ml water washing, and the anhydrous magnesium sulfate drying, desolvation, the concentration of the product after the drying, to obtain the compound 4g (4, 4, 4 - trifluoro -1 - (3 - methoxyphenyl) - 1, 3 - Butanedione), yield 86%;

References:

CN104974135,2017,B Location in patent:Paragraph 0167