Sulfuric Acid → HCID 23048179, compound

Participants

Reaction Steps

A stirred mixture of 4-[1-[4-(trifluoromethyl)phenyl]-1H-indazol-3-yl]piperidine-1-carbonitrile of Example 101 (15 g, 0.041 moles) and 25% H2SO4 (100 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 13 g (93%) of 1-[4-(trifluoromethyl)phenyl]-3-(4-piperidinyl)-1H-indazole as an oil. A stirred mixture of the indazole (4.0 g, 0.012 moles), potassium carbonate (3.6 g, 0.026 moles) and chloromethyldimethyl phosphine oxide (3.96 g, 0.031 moles) in DMF (30 ml) was heated at 80° C. for 40 hours. The mixture was cooled, poured into H2O, extracted (CHCl3), dried (MgSO4) and concentrated to yield 4.8 g of an oil. The product was purified on the HPLC (silica gel, 5% methanol-CHCl3) and then recrystallized once from acetone-hexane to yield 2.2 g (35%) of 1-[4-(trifluoromethyl)phenyl]-3-[1-(dimethylphosphinylmethyl)-4-piperidinyl]-1H-indazole, m.p. 158°-160° C.

Provenance & Evidence