Benzocaine → 4-(Methylsulfonamido)benzoic acid

Temperatur

0 °C

Ethyl 4-amino-benzoate (5 g, 30 mmol, 1.0 equiv) was mixed in 50 mL of CH2Cl2 with Et3N (6.1 g, 60 mmol, 2.0 equiv). The solution was cooled to 0° C. and methanesulfonyl chloride (3.8 g, 33 mmol. 1.1 equiv) was added as a solution in 15 mL of CH2Cl2 dropwise over a 15 min period. The reaction was stirred for 4 h at which time it was diluted with 50 mL of water. Layers were separated and the organic layer was washed with 50 mL of saturated sodium bicarbonate solution and concentrated. The resulting ester was dissolved in 50 mL of MeOH and treated with 50 mL of 5 N NaOH for 4 h. The reaction solution was extracted with Et2O and the aqueous layer was acidified to give a white precipitate that was collected by filtration. The solid was dried and used without further purification.

1. customLayers were separated
2. washthe organic layer was washed with 50 mL of saturated sodium bicarbonate solution
3. concentrationconcentrated
4. dissolutionThe resulting ester was dissolved in 50 mL of MeOH
5. additiontreated with 50 mL of 5 N NaOH for 4 h
6. extractionThe reaction solution was extracted with Et2O
7. customto give a white precipitate that
8. filtrationwas collected by filtration
9. customThe solid was dried
10. customused without further purification

ORD-Eintrag

ord-24d1b58da3704a99a5c164dd93147823

Quelldatensatz

uspto-grants-2004_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06756372B2