Hydrochloric Acid → Benzoic acid, 4-amino-3-hydroxy-, methyl ester

4-amino-3-hydroxybenzoic acid (5.0 g, 32.6 mmol) was added dropwise to a 0° C. solution of an HCl 1.25 M solution in MeOH (100 mL) and MeOH (100 mL). After 5 min of final addition the mixture was allowed to warm up to room temperature and stirred overnight. HPLC monitoring of the reaction showed remaining starting material and the mixture was stirred at ambient temperature for 48 hours. The solvent was then removed under reduced pressure and the residue was treated with saturated aqueous bicarbonate solution and the aqueous phase was extracted with AcOEt (2 x). The combined organic extracts were washed with brine, dried over anhydrous sodium sulphate, filtered and concentrated to dryness obtaining the title compound (5.37 g, 97% yield) as a crystalline solid.

1. additionAfter 5 min of final addition the mixture
2. stirringthe mixture was stirred at ambient temperature for 48 hours
3. customThe solvent was then removed under reduced pressure
4. additionthe residue was treated with saturated aqueous bicarbonate solution
5. extractionthe aqueous phase was extracted with AcOEt (2 x)
6. washThe combined organic extracts were washed with brine
7. dry with materialdried over anhydrous sodium sulphate
8. filtrationfiltered
9. concentrationconcentrated to dryness

ORD record

ord-e93d1bf0d5c84255b009974db7229a0b

Source dataset

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09233108B2