Triethyl phosphite → Diethyl 2-(4-benzyloxyphenyl)-1-(hydroxyimino)ethylphosphonate

To a solution of 4-benzyloxyphenylacetyl chloride (4.0 g, 16.2 mmol) in THF (10.0 mL) at room temperature was slowly added triethyl phosphite (3.33 mL, 19.5 mmol). The reaction mixture was stirred at room temperature for 16 h and the solvent was removed under reduced pressure. The residue was treated with hexanes (20 mL) and the mixture was filtered. White solid was collected and air-dried. The solid was dissolved in pyridine (25.0 mL) and hydroxylamine hydrochloride (1.96 g, 28 mmol) was added. The reaction mixture was stirred at room temperature for 72 h and the solvent was removed under reduced pressure. The crude product was purified by column chromatography on silica gel, eluting with ethyl acetate-hexanes (7:3) to afford diethyl 2-(4-benzyloxyphenyl)-1-(hydroxyimino)ethylphosphonate as a colorless oil (5.2 g, 85%): 1H NMR (300 MHz, CDCl3): δ 7.18-7.38 (m, 7H), 6.80 (d, J=6.2 Hz, 2H), 4.94 (s, 2H), 3.80-4.10 (m, 4H), 3.80 (s, 1H), 3.76 (s, 1H), 1.16 (t, J=6.0 Hz, 6H); TLC conditions: Uniplate silica gel, 250 microns; Mobile phase=hexanes-ethyl acetate (2:3); Rf=0.55.

1. customat room temperature
2. customthe solvent was removed under reduced pressure
3. additionThe residue was treated with hexanes (20 mL)
4. filtrationthe mixture was filtered
5. customWhite solid was collected
6. customair-dried
7. dissolutionThe solid was dissolved in pyridine (25.0 mL)
8. stirringThe reaction mixture was stirred at room temperature for 72 h
9. customthe solvent was removed under reduced pressure
10. customThe crude product was purified by column chromatography on silica gel
11. washeluting with ethyl acetate-hexanes (7:3)

ORD record

ord-91f3f16cceb04694aa9f70037cd7e512

Source dataset

uspto-grants-2009_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07514419B2