Hydrochloric Acid → 2,5-Dihydroxy-3-methylbenzoic acid

The synthesis was performed with reference to the known literature (Canadian Journal of Chemistry, Vol. 50, p. 1276, 1972). 3-Methylsalicylic acid (6.0 g, 39 mmol) was added with 10% aqueous sodium hydroxide (80 mL), and the mixture was stirred at room temperature. The reaction mixture was added portionwise with a suspension of potassium peroxodisulfate (10.8 g, 40 mmol) in water (150 mL), and then the mixture was stirred at room temperature for 12 hours. The reaction mixture was made acidic with concentrated hydrochloric acid, and then extracted with diethyl ether to remove the unreacted starting material. Then, the aqueous layer was added with concentrated hydrochloric acid (40 mL), and the mixture was refluxed by heating for 2 hours. The reaction mixture was cooled to room temperature, and extracted with diethyl ether, and then the organic layer was washed successively with water and saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, the solid formed was suspended in ethyl acetate, and then collected by filtration to obtain 2,5-dihydroxy-3-methylbenzoic acid (4.7 g, 71%).

1. stirringthe mixture was stirred at room temperature for 12 hours
2. extractionextracted with diethyl ether
3. customto remove the
4. additionThen, the aqueous layer was added with concentrated hydrochloric acid (40 mL)
5. temperaturethe mixture was refluxed
6. temperatureby heating for 2 hours
7. temperatureThe reaction mixture was cooled to room temperature
8. extractionextracted with diethyl ether
9. washthe organic layer was washed successively with water and saturated brine
10. dry with materialdried over anhydrous magnesium sulfate
11. customThe solvent was evaporated under reduced pressure
12. customthe solid formed
13. filtrationcollected by filtration

ORD record

ord-94a5db8e8dfb44f1821d59118d63a1f3

Source dataset

uspto-grants-2015_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09156827B2