Potassium Hydroxide → HCID 10680480, compound

Temperature

50 °C

Methyl 2,4-dichloro-5-methoxy-3-methylbenzoate (238 mg, 0.96 mmol) was dissolved in MeOH (30 mL) and flushed with argon. Potassium hydroxide (308 mg, 4.78 mmol) was added and the reaction mixture was stirred at 50° C. for 19 h. The solvent was evaporated and the residue was dried in vacuum. Hydrobromic acid 30 mL, 48%, aq) was added and the mixture was heated to 110° C. After 3 days most of the HBr was removed by vacuum-distillation. The crude product was mixed with H2O (10 mL), concentrated NH3 (1 mL) and EtOAc (40 mL) were added, the aqueous phase (pH 1) was extracted with EtOAc (2×20 mL) and the combined organic phase was washed with brine (10 mL) and dried (MgSO4). Evaporation of the solvent gave 202 mg of the title compound. 1H NMR (DMSO-D6): δ 10.68 (br, 1H), 7.15 (s, 1H), 2.42 (s, 3H); 13C NMR (DMSO-d6): δ 166.68, 151.82, 135.87, 131.24, 123.70, 121.17, 114.36, 17.93; MS (EI, 70 eV): m/z (rel.int.) 222/220 (M+, 56/100), 205/203 (36/59), 185(26).

1. customflushed with argon
2. customThe solvent was evaporated
3. customthe residue was dried in vacuum
4. additionHydrobromic acid 30 mL, 48%, aq) was added
5. temperaturethe mixture was heated to 110° C
6. customAfter 3 days most of the HBr was removed by vacuum-distillation
7. additionThe crude product was mixed with H2O (10 mL), concentrated NH3 (1 mL) and EtOAc (40 mL)
8. additionwere added
9. extractionthe aqueous phase (pH 1) was extracted with EtOAc (2×20 mL)
10. washthe combined organic phase was washed with brine (10 mL)
11. dry with materialdried (MgSO4)
12. customEvaporation of the solvent

ORD record

ord-4078b437d3714819985b6eaffab0a25d

Source dataset

uspto-grants-1997_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05661183