Acetone → 3-Chloro-4,5-diethoxybenzoic acid

Temperature

60 °C

To a solution of methyl 3-chloro-4,5-dihydroxybenzoate (D68) (1.0 g) in acetone (50 mL) stirred at room temp was added K2CO3 (6.9 g) and bromoethane (5.5 g). The reaction mixture was stirred at 60° C. for 18 h. After filteration, the filtrate was concentrated under reduced pressure. The residue was dissolved in tetrahydrofuran (20 mL) and methanol (20 mL), a solution of NaOH (1.0 g) in water (20 mL) was added to the above solution. The resulted mixture was stirred for 4 h and then the organic solvent was removed in vacuo. The aqueous layer was acidified with concentrated HCl to pH around 1. The solid was filtered and dried in vacuo to afford 3-chloro-4,5-bis(ethyloxy)benzoic acid (D69) (769 mg). δH (DMSO-d6, 400 MHz): 1.29 (3H, t), 1.36 (3H, t), 4.08-4.15 (4H, m), 7.46 (1H, d), 7.53 (1H, d), 13.16 (1H, br s). MS (ES): C11H13ClO4 requires 244; found 245.1 (M+H+).

1. concentrationAfter filteration, the filtrate was concentrated under reduced pressure
2. dissolutionThe residue was dissolved in tetrahydrofuran (20 mL)
3. additionmethanol (20 mL), a solution of NaOH (1.0 g) in water (20 mL) was added to the above solution
4. stirringThe resulted mixture was stirred for 4 h
5. customthe organic solvent was removed in vacuo
6. filtrationThe solid was filtered
7. customdried in vacuo

ORD record

ord-54fcef7f06c644c1884b7b24617130a0

Source dataset

uspto-grants-2012_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08217028B2