Hydrochloric Acid → HCID 20197235, compound

Participants

Reaction Steps

11 g 5-methyl-1-(4-methoxycarbonylphenyl)-2-{3-[4-(4-methyl-pyrid-2-yl)-piperazin-1-yl]-propyl}-pyrazolin-3-one hydrochloride (see Example No. 48 infra, produced in an analogous manner to Example 2A and B starting from 5-methyl-1-(4-methoxycarbonylphenyl) pyrazolin-3-one) are dissolved in 100 ml 85% ethanol, and the solution is mixed with 5 g potassium hydroxide with stirring at ambient temperature. After completion of the reaction, the reaction mixture is neutralized by the addition of pure hydrochloric acid, and the ethanol is distilled off. The remaining aqueous solution is acidified to a pH of 2 with hydrogen chloride, then the water is distilled off and the residue is dissolved in ethanol. The precipitated mineral salts are removed by suction filtration, and the filtrate is cooled, whereupon the dihydrochloride of the title compound crystallizes out. 6.3 g 5-methyl-1-(4-carboxyphenyl)-2-{3-[4-(4-methyl-pyrid-2-yl)-piperazin-1-yl]-propyl}-pyrazolin-3-one dihydrochloride are obtained, melting point: 205°-225° C.

Provenance & Evidence