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

HRID 887758Notes

Reaction equation

[H-].[Na+].COC(=O)[CH2:6][CH2:7][C:8]1[CH:16]=[CH:15][C:14]2[C:10](=[CH:11][N:12]([CH3:17])[N:13]=2)[C:9]=1[C:18]([O:20]C)=O.Cl.[OH-].[Na+]>O1CCCC1.CO>[CH3:17][N:12]1[CH:11]=[C:10]2[C:14]([CH:15]=[CH:16][C:8]3[CH2:7][CH2:6][C:18](=[O:20])[C:9]=32)=[N:13]1

Participants

Conditions

Temperature: 100 °C

Procedure

To a suspension of 60% sodium hydride (145 mg, 3.62 mmol) in tetrahydrofuran (10 mL) were added a solution of methyl 5-(3-methoxy-3-oxopropyl)-2-methyl-2H-indazole-4-carboxylate (500 mg, 1.81 mmol) in tetrahydrofuran (10 mL) and methanol (1 drop), and the mixture was heated under reflux for 3 hr. The reaction solution was concentrated to dryness to give yellow-brown crystals. The obtained crystals were gradually added to 12M hydrochloric acid (5 mL) heated to 100° C., and the mixture was stirred 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 magnesium sulfate. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (ethyl acetate) to give the title compound (285 mg, yield 85%).

Workup

temperaturethe mixture was heated
temperatureunder reflux for 3 hr
concentrationThe reaction solution was concentrated to dryness
customto give yellow-brown crystals
extractionthe mixture was extracted with ethyl acetate
washThe extract was washed with saturated brine
dry with materialdried over anhydrous magnesium sulfate
customThe solvent was evaporated under reduced pressure
customthe residue was purified by silica gel column chromatography (ethyl acetate)

Sources & evidence

ORD record: ord-5b657eb32109495f9491a7f461851472
Source dataset: uspto-grants-2012_08
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08247429B2

Reaction notes

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