Carbon Dioxide → 2-(1-{[5-(Difluoromethoxy)-2-methylphenyl]carbonyl}piperidin-4-yl)-5-(3,4-dimethoxyphenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one

Participants

Reaction Steps

In a pressure vessel 0.47 g of 5-(3,4-dimethoxyphenyl)-2-{1-[(5-hydroxy-2-methylphenyl)carbonyl]piperidin-4-yl}-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one (compound described in example 85) and 37 mg tetrabutylammonium iodide are solved in a mixture of 20 ml methanol and 5 ml dioxane. After the reaction mixture has been frozen to a solid block upon cooling with dry ice, a layer of 4 ml THF is placed above the frozen reaction mixture and the pressure vessel is charged with 2.8 g of chloro(difluoro)methane. The pressure vessel is heated for 90 minutes to 70° C. and after the reaction mixture has reached RT, it is portioned between diethyl ether and water. After separation of the phases, the organic phase is washed with brine, dried over MgSO4, and the solvents are removed under reduced pressure. The crude product is purified by chromatography (silica gel and DCM) to yield the title compound.

Provenance & Evidence