p-Toluenesulfonic acid → 2-(4,5-Dimethylpyridin-2-yl)-4-pyridin-3-yl-1,2-dihydro-3H-pyrazol-3-one

Participants

Reaction Steps

220 mg (1.0 mmol) of the compound from Example 2A are initially charged in 5 ml of ethanol. 137 mg (1.0 mmol) of the compound from Example 21A and 38 mg (0.2 mmol) of p-toluenesulfonic acid are added, and the mixture is stirred under reflux for 16 h. The mixture is then allowed to cool to RT, and the solid formed is filtered off, washed with tert-butyl methyl ether and dried under high vacuum. This gives 28 mg of the title compound. The mother liquor is put aside and used for preparing the hydrochloride (see Example 87).

Provenance & Evidence