Benzaldehyde → 1H-Pyrazole, 3,5-diphenyl-

Participants

Reaction Steps

490 parts (3 mol) of 60% strength by weight sulfuric acid and 1.5 parts (0.01 mol) of sodium iodide 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 and 79.5 parts (0.75 mol) of benzaldehyde were simultaneously added dropwise at 120° C. in the course of 2 hours. By distilling off 120 parts of water the temperature was kept at 120° C. for 2 hours. The reaction mixture obtained was diluted with the distilled-off water and neutralized with 936 parts (4.7 mol) of 20% strength by weight sodium hydroxide solution. The precipitate was filtered off at room temperature, and the filter residue was washed with water and dried. 162.7 parts of 3,5-diphenylpyrazole having a purity of 96.1% (HPLC) were obtained, which corresponds to a yield of 94.8% of theory. M.p.: 196° C.

Provenance & Evidence