Sulfuric Acid → 1H-Pyrazole, 3,5-diphenyl-

Participants

Reaction Steps

490 parts (3 mol) of 60% strength by weight sulfuric acid were initially introduced into the stirring flask. 46.9 parts (0.75 mol) of 80% strength by weight hydrazine hydrate, 90 parts (0.75 mol) of acetophenone, 79.5 parts (0.75 mol) of benzladehyde and 1.5 parts (0.01 mol) of sodium iodidewere metered in in succession at room temperature. The reaction mixture wasbrought to 120° C. by distilling off water and kept at 120° C. for 2.5 hours. 110 parts of water were distilled off. The mixture was diluted with the distilled-off water and neutralized with 717 parts (4.5 mol) of 25% strength by weight sodium hydroxide solution. The precipitate was filtered off at room temperature, and the filter residue was washed with water and dried. 160.6 parts of 3,5-diphenylpyrazole having a purity of 94.4% (HPLC) were obtained, which corresponds to a yield of 91.9% of theory. M.p.: 194° C.

Provenance & Evidence