Triethylamine → 2-(4-Bromo-3-methyl-phenyl)-pyrazolidin-3-one

Temperature

80 °C

Triethylamine (625 μL, 13.1 mmol) and acrylic acid ethyl ester (1.82 mL, 5.74 mmol) were added to a solution of (4-bromo-3-methyl-phenyl)-hydrazine (1.05 g, 5.22 mmol) in EtOH (26.1 mL) at room temperature in a nitrogen atmosphere, and the mixture was stirred at 80° C. for 18 hours. The reaction solution was cooled, and 50% NaH (501 mg, 10.4 mmol) was then added to the reaction solution at 0° C. The mixture was stirred at 0° C. for 30 minutes, and 50% NaH (251 mg, 5.20 mmol) was then further added, followed by further stirring for 30 minutes. The reaction mixture was quenched with a saturated aqueous ammonium chloride solution and extracted with ethyl acetate three times. The organic layers were combined and washed with a mixed solution of water:saturated brine (1:1). After separation, the organic layer was dried over sodium sulfate and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane-ethyl acetate) to give 2-(4-bromo-3-methyl-phenyl)-pyrazolidin-3-one as a brown form (684 mg, 60%).

1. temperatureThe reaction solution was cooled
2. stirringThe mixture was stirred at 0° C. for 30 minutes
3. stirringby further stirring for 30 minutes
4. customThe reaction mixture was quenched with a saturated aqueous ammonium chloride solution
5. extractionextracted with ethyl acetate three times
6. washwashed with a mixed solution of water
7. customAfter separation
8. dry with materialthe organic layer was dried over sodium sulfate
9. concentrationconcentrated under reduced pressure
10. customThe resulting residue was purified by silica gel column chromatography (hexane-ethyl acetate)

ORD record

ord-682c16d3e9054108acb13036ad0960a9

Source dataset

uspto-grants-2015_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09169254B2