Sodium Hydroxide → HCID 178515621, compound

Temperature

5 °C

Sodium hydroxide (10.9 g) was dissolved in methanol (110 ml), and a solution of hydroxylamine hydrochloride (4.2 g) in water (10 ml) was added dropwise thereto at 5° C. with stirring. A solution of α,β-dibromo-2,4-difluorocinnamic acid ethyl ester (19.6 g) in tetrahydrofuran (20 ml) was added dropwise to the mixture, and the resulting mixture was stirred at room temperature for 2 hours, followed by reflux for 5 hours. The solvent was evaporated under reduced pressure and the residue was poured into ice-cold water. The pH of the reaction mixture was adjusted to a value of 2 with conc. hydrochloric acid, and the reaction mixture was extracted with ethyl acetate. The extract was washed with a saturated aqueous NaCl solution, and the organic layer was dried over anhydrous magnesium sulfate. After filtration, the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: cyclohexane/ethyl acetate=1/1) to obtain the title compound (8.2 g, 79%) as colorless crystals.

1. stirringthe resulting mixture was stirred at room temperature for 2 hours
2. temperatureby reflux for 5 hours
3. customThe solvent was evaporated under reduced pressure
4. additionthe residue was poured into ice-cold water
5. extractionthe reaction mixture was extracted with ethyl acetate
6. washThe extract was washed with a saturated aqueous NaCl solution
7. dry with materialthe organic layer was dried over anhydrous magnesium sulfate
8. filtrationAfter filtration
9. customthe solvent was evaporated under reduced pressure
10. customThe residue was purified by silica gel column chromatography (eluent: cyclohexane/ethyl acetate=1/1)

ORD record

ord-e7553bf0af9b49cebc4966a01fe2e187

Source dataset

uspto-grants-1999_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06005116