Hydroxylamine → 2-Hydroxyimino-2-(3-hydroxyphenyl)acetic acid

A mixture of 3-hydroxyphenylglyoxylic acid (3.32 g.) and 1 N-methanol solution of hydroxylamine (45 ml.) was refluxed with stirring, for 25 minutes. The reaction mixture was concentrated to dryness. The residue was dissolved in 1 N-sodium hydroxide aqueous solution (50 ml.) and the solution was washed with ether, acidified with hydrochloric acid under cooling and extracted with ethyl acetate. The extract was washed with a saturated sodium chloride aqueous solution, dried and concentrated to give yellow oil. To the oil was added benzene and benzene was distilled off. The residue was crystallized with petroleum ether and the crystals were collected by filtration, washed with petroleum ether and dried to give 2-hydroxyimino-2-(3-hydroxyphenyl)acetic acid (a mixture of syn and anti isomer) (2.9 g.).

1. temperaturewas refluxed
2. concentrationThe reaction mixture was concentrated to dryness
3. dissolutionThe residue was dissolved in 1 N-sodium hydroxide aqueous solution (50 ml.)
4. washthe solution was washed with ether
5. temperatureunder cooling
6. extractionextracted with ethyl acetate
7. washThe extract was washed with a saturated sodium chloride aqueous solution
8. customdried
9. concentrationconcentrated
10. customto give yellow oil
11. distillationwas distilled off
12. customThe residue was crystallized with petroleum ether
13. filtrationthe crystals were collected by filtration
14. washwashed with petroleum ether
15. customdried

ORD record

ord-b7ff8020748c44bca6482fc0bcc7cc8c

Source dataset

uspto-grants-1981_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04254117