Sulfuric Acid → HCID 22397358, compound

Participants

Reaction Steps

A stirred mixture of 4-[1-(4-fluorophenyl)-1H-indazol-3-yl]piperidine-1-carbonitrile of Example 102 (30 g, 0.094 moles) and 25% H2SO4 (225 ml) was refluxed for 20 hours. The mixture was cooled, poured into H2O, and basified with a 25% NaOH solution. The product was extracted (dichloromethane), dried (MgSO4), and concentrated to yield 21 g (76%) of 1-(4-fluorophenyl)-3-(4-piperidinyl)-1H-indazole as an oil. To a stirred suspension of the indazole (3.5 g, 0.012 moles) and triethylamine (3.3 ml, 0.024 moles) in toluene (50 ml) was added methyl chloroformate (1.0 ml, 0.013 moles). The mixture was stirred for 17 hours at ambient temperature and was then poured into H2O. The product was extracted (ethyl acetate), dried (MgSO4), and concentrated to yield 4.6 g of an oil. The product was purified on the HPLC (silica gel:ethyl acetate-hexane, 1:2) which produced 3.0 g (72%) of 4-[1-(4-fluorophenyl)-1H-indazol-3-yl]piperidine-1-carboxylic acid methyl ester, m.p. 95°-97° C.

Provenance & Evidence