4,5,6,7-tetrahydro-1H-indazol-4-one → HCID 59252674, compound

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Reaction Steps

According to Scheme 1 Step 3: Pyridinium tribromide (25.7 mmol, 8.22 g) was added to a solution of 6,7-dihydro-1H-indazol-4(5H)-one (25.7 mmol, 3.50 g) in acetic acid (60 mL) and the reaction mixture was stirred under reflux for 2 hours. After evaporation of the solvent, the crude residue was partitioned between DCM and a saturated solution of Na2S2O3. The organic phase was washed with a saturated solution of Na2CO3 and with water, was dried over Na2SO4 and concentrated to yield 5-bromo-6,7-dihydro-1H-indazol-4(5H)-one (23.3 mmol, 5.00 g, 90%).

Provenance & Evidence