Hydrochloric Acid → 5-methoxy-4-methyl-1H-indazole

Acetic anhydride (1.46 ml, 15.52 mmol), tetrabutylammonium bromide (83 mg, 0.259 mmol), potassium acetate (1.02 g, 10.35 mmol) and isoamyl nitrite (0.904 ml, 6.73 mmol) were added to a solution of N-(4-methoxy-2,3-dimethylphenyl)acetamide (1.0 g, 5.175 mmol) in ethyl acetate (10 ml) at room temperature, and the resulting mixture was refluxed. After 6 hours, the ethyl acetate was distilled off with heating, and a 6M-aqueous sodium hydroxide solution (10.35 ml, 62.1 mmol) was added dropwise to the residue at 60° C. After 1 hour, the reaction solution was adjusted to pH 8 to 9 with a 3M-aqueous hydrochloric acid solution and extracted with chloroform (50 ml×2), and the organic layer was dried over anhydrous magnesium sulfate. The organic layer dried was concentrated under reduced pressure and the resulting residue was purified by a silica gel column chromatography (eluent: hexane/ethyl acetate) to obtain 5-methoxy-4-methyl-1H-indazole (456 mg, 54%).

1. temperaturethe resulting mixture was refluxed
2. distillationthe ethyl acetate was distilled off
3. temperaturewith heating
4. waitAfter 1 hour
5. extractionextracted with chloroform (50 ml×2)
6. dry with materialthe organic layer was dried over anhydrous magnesium sulfate
7. customThe organic layer dried
8. concentrationwas concentrated under reduced pressure
9. customthe resulting residue was purified by a silica gel column chromatography (eluent: hexane/ethyl acetate)

ORD-Eintrag

ord-2ab3688cd5574c57885c9877549899e4

Quelldatensatz

uspto-grants-2007_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07199147B2