CAS 19652-14-3: 3-(4-Chlorophenyl)-1-phenyl-1H-pyrazol-5-amine

5-(4-Chlorophenyl)-2-phenyl-2H-pyrazol-3-ylamine (CAS# 53865-06-8) is a hydrofluoric acid precursor that is used in the synthesis of various organic compounds. The compound has two asymmetric carbons and can be synthesized by the intramolecular reaction of hydrofluoric acid with an amide. This reaction is catalyzed by a base such as potassium hydroxide or sodium hydroxide. Disulfide exchange reactions are possible when the carboxylic acid group is present on the molecule, but this can be avoided by adding cysteine to the reaction mixture. The solubility of this material can be increased by adding a surrogate such as ethyl acetate or ethanol to the solution. The yield for this process is typically quite high, with yields ranging from 50% to over 95%.