Potassium Hydroxide → 4-Amino-N-hydroxy-2-methoxybenzamide

Methyl 2-methoxy-4-aminobenzoate (10 g, 55.25 mmol) and hydroxylamine hydrochloride (15.36 g, 221 mmol) were taken up in MeOH (80 ml) and a solution of KOH (15.4 g, 275 mmol) in MeOH (55 ml) was added carefully. The resultant mixture was stirred at reflux for 36 hrs. The volatiles were removed in vacuo The residue was taken up in 1M NaOH (50 ml) and washed with ethyl acetate (EtOAc, 50 ml). Concentrated HCl was added slowly until precipitation of a solid (pH was 10). The solid was filtered off, washed with H2O, then methyl-tert-butyl ether (MTBE) and dried under vacuum. 1H NMR showed the solid contained approx. 1/3 molar equivalent of ethyl acetate. The solid was taken up in 1M NaOH (100 ml) and the EtOAc was removed in vacuo. Concentrated HCl was added carefully until precipitation of a solid (pH was 8). The solid was collected by filtration, washed with H2O, then MTBE and dried under vacuum to give 4.67 g (47%) of the title compound as a dark red solid.

1. temperatureat reflux for 36 hrs
2. customThe volatiles were removed in vacuo The residue
3. washwashed with ethyl acetate (EtOAc, 50 ml)
4. additionConcentrated HCl was added slowly until precipitation of a solid (pH was 10)
5. filtrationThe solid was filtered off
6. washwashed with H2O
7. dry with materialmethyl-tert-butyl ether (MTBE) and dried under vacuum
8. customthe EtOAc was removed in vacuo
9. additionConcentrated HCl was added carefully until precipitation of a solid (pH was 8)
10. filtrationThe solid was collected by filtration
11. washwashed with H2O
12. dry with materialMTBE and dried under vacuum

ORD record

ord-931047eac5b4489cb82c7d0ec372e888

Source dataset

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08450506B2