2-Chlorobenzaldehyde → o-Chlorobenzaldoxime

To a stirred solution of 56.2 grams (0.40 mole) of 2-chlorobenzaldehyde and 55.6 grams (0.80 mole) of hydroxylamine hydrochloride in 225 ml of ethanol and 111 ml of water was added in portions over a 15 minute period a solution of 24.0 grams (0.60 mole) of sodium hydroxide in 24 ml of water. The addition caused a solid precipitate to form. The reaction mixture was heated to boiling, and water was added until the solid dissolved. Additional water was added until the solution became cloudy. The reaction mixture was allowed to cool, and as it cooled a crystalline solid formed. The solid, collected by filtration, was dissolved in methylene chloride, and the methylene chloride solution was dried with sodium sulfate. The filtrate was concentrated under reduced pressure to remove ethanol, yielding additional solid, which was collected by filtration. This solid, too, was dissolved in methylene chloride, and the solution was dried with sodium sulfate. The two methylene chloride solutions were filtered from the sodium sulfate and the filtrates combined and concentrated under reduced pressure to give a residual solid. The solid was recrystallized from ethanol-water to give 48.3 grams of 2-chlorobenzaldoxime; mp 73.5°-75.5° C. The nmr and the ir spectra were consistent with the assigned structure.

1. additionThe addition
2. customto form
3. temperatureThe reaction mixture was heated
4. dissolutiondissolved
5. temperatureto cool
6. temperatureas it cooled a crystalline solid
7. customformed
8. filtrationThe solid, collected by filtration
9. dissolutionwas dissolved in methylene chloride
10. dry with materialthe methylene chloride solution was dried with sodium sulfate
11. concentrationThe filtrate was concentrated under reduced pressure
12. customto remove ethanol
13. customyielding additional solid, which
14. filtrationwas collected by filtration
15. dissolutionThis solid, too, was dissolved in methylene chloride
16. dry with materialthe solution was dried with sodium sulfate
17. filtrationThe two methylene chloride solutions were filtered from the sodium sulfate
18. concentrationconcentrated under reduced pressure
19. customto give a residual solid
20. customThe solid was recrystallized from ethanol-water

ORD record

ord-f852b22885744828bd6413f4c8d9a698

Source dataset

uspto-grants-1981_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04302238