Sulfuric Acid → 5-chloro-2-methyl-6,7-dihydrocyclopenta[e]indazol-8(2H)-one

Temperature

100 °C

To a solution of methyl 6-chloro-5-(3-methoxy-3-oxopropyl)-2-methyl-2H-indazole-4-carboxylate (295 mg, 0.948 mmol) in tetrahydrofuran (10 mL) was added 28% sodium methoxide methanol solution (390 μL), and the mixture was heated under reflux for 2 hr. The reaction solution was concentrated to dryness to give crystals. The obtained crystals were added to 10% sulfuric acid (10 mL) heated to 100° C., and the mixture was heated under reflux for 4 hr. The reaction solution was neutralized with 8M aqueous sodium hydroxide solution, and the mixture was extracted with ethyl acetate. The extract was washed with saturated brine, and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to give the title compound (174 mg, yield 83%).

1. temperaturethe mixture was heated
2. temperatureunder reflux for 2 hr
3. concentrationThe reaction solution was concentrated to dryness
4. customto give crystals
5. temperaturethe mixture was heated
6. temperatureunder reflux for 4 hr
7. extractionthe mixture was extracted with ethyl acetate
8. washThe extract was washed with saturated brine
9. dry with materialdried over anhydrous sodium sulfate
10. customThe solvent was evaporated under reduced pressure

ORD record

ord-7580bd1ba07f4eb096f7e5f5f514f18d

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08247429B2