Reaction #70235

Reaction equation

3-fluoro-4-methoxyacetophenone

O-(4-nitrobenzyl)hydroxylamine hydrochloride

pyridine

→

3′-fluoro-4′-methoxyacetophenone-O-4-nitrobenzyloxime

Yield 65.3%

Solvents

ethanol

Conditions

Workup

1. 1
   Temperatureat reflux under nitrogen for 4 h
2. 2
   ConcentrationThe solution was concentrated to a yellow oil which
3. 3
   workup.ADDITIONwas diluted with water/dichloromethane
4. 4
   ExtractionThe suspension was extracted with dichloromethane (×3)
5. 5
   WashThe combined organic phases were washed with water and brine
6. 6
   Dryingdried over magnesium sulphate
7. 7
   Filtrationfiltered
8. 8
   Concentrationconcentrated to a yellow oil
9. 9
   OtherThe crude product was purified by column chromatography (SiO2)
10. 10
    Washeluting with 9:1 petrol/ethyl acetate
11. 11
    Otherto give a yellow oil which
12. 12
    Otherwas triturated with petrol
13. 13
    Washthe resultant off white solid was further washed with petrol

Procedure

A solution of 3-fluoro-4-methoxyacetophenone (0.064 g, 0.380 mmol), O-(4-nitrobenzyl)hydroxylamine hydrochloride (0.111 g, 0.552 mmol) and pyridine (0.14 ml, 1.73 mmol) in ethanol (7 ml) was stirred at reflux under nitrogen for 4 h and cooled to room temperature. The solution was concentrated to a yellow oil which was diluted with water/dichloromethane. The suspension was extracted with dichloromethane (×3). The combined organic phases were washed with water and brine, dried over magnesium sulphate, filtered and concentrated to a yellow oil. The crude product was purified by column chromatography (SiO2), eluting with 9:1 petrol/ethyl acetate, to give a yellow oil which was triturated with petrol, and the resultant off white solid was further washed with petrol to give 3′-fluoro-4′-methoxyacetophenone-O-4-nitrobenzyloxime (CP9-123) as a white solid (0.079 g, 65%), m.p. 67-68°.

Source