Acetic Acid → 1-Methyl-1,5,6,7-tetrahydro-4H-indazol-4-one

Participants

Reaction Steps

To a solution of 2-((dimethylamino)methylene)cyclohexane-1,3-dione (55 g crude, 300 mmol) in t-BuOH (400 ml) was added methylhydrazine solution (35 g, 40% aqueous solution, 304 mmol) and AcOH (20 ml) at room temperature. The resulting mixture was heated to reflux for 3 h under nitrogen protection. After cooling, the mixture was concentrated in vacuo and the residue was purified by column chromatograph on silica gel (petroleum ether/ethyl acetate=1/1 v/v %) to give 1-methyl-6,7-dihydro-1H-indazol-4(5H)-one (20 g, two steps: 44%). MS-ESI (m/z): 151 (M+1)+ (Acq Method: 0-60AB_2 min; Rt: 0.90 min)

Provenance & Evidence