4-Aminobenzoic Acid → Methyl 4-aminobenzoate

Into a 1000 mL 3-necked round bottom flask, was placed a solution of 4-aminobenzoic acid (20 g, 145.99 mmol) in methanol (600 mL). To the above was added H2SO4 (30 mL) dropwise with stirring. The resulting solution was stirred at reflux overnight. The reaction progress was monitored by TLC (EtOAc/PE=1:5). After completion, the volatile components were removed under reduced pressure and the residue was dissolved in 300 mL of water. Adjustment of the pH to 9 was accomplished by the addition of and aqueous sat. Na2CO3 solution. The resulting solution was extracted three times with 600 mL of EtOAc and the organic layers were combined and dried over Na2SO4. Removal of the volatile components under reduced pressure afforded the crude product methyl 4-aminobenzoate (vii) (20.4 g, 93% yield) as a yellow solid which was used directly in the next step without further purification.

1. customInto a 1000 mL 3-necked round bottom flask, was placed
2. stirringThe resulting solution was stirred
3. temperatureat reflux overnight
4. customAfter completion, the volatile components were removed under reduced pressure
5. dissolutionthe residue was dissolved in 300 mL of water
6. additionAdjustment of the pH to 9 was accomplished by the addition of and aqueous sat. Na2CO3 solution
7. extractionThe resulting solution was extracted three times with 600 mL of EtOAc
8. dry with materialdried over Na2SO4
9. customRemoval of the volatile components under reduced pressure

ORD record

ord-71689d81e5b44102abe48dd4bc61f6a7

Source dataset

uspto-grants-2012_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08324219B2