Abstract
Synthesis of 1,3-diarylpyrazoles from commercial substrates and/or simple transformations
is still underrated. In this report, we have developed a method for copper-promoted
coupling of propiophenones and arylhydrazines. The reactions afforded substituted
pyrazoles in the presence of TEMPO oxidant, acetic acid additive, and DMF solvent.
A number of functionalities were compatible with reaction conditions, including halogens,
methoxy, trifluoromethyl, and nitro groups. An indazole could be obtained if an electron-poor
propiophenone was used.
Key words
copper - 1,3-diarylpyrazoles - TEMPO - oxidative - dehydrogenation