Cu(I)/Fe(III) promoted dicarbonylation of aminopyrazole via oxidative C H coupling with methyl ketones

Abstract Cu(I)/Fe(III) promoted C4-dicarbonylation of 5-aminopyrazole is developed. The strategy involved radical triggered direct oxidative coupling of 5-aminopyrazoles with methyl ketones using aerial oxygen as a source of oxygen in newly generated carbonyl group. CuI is used as catalyst and FeCl 3 ·6H 2 O is used as additive and the reaction proceeded at 120 °C in DMSO for 9–12 h. It is found that use of Cu(II) catalyst gives the thiomethylated product by reacting with DMSO instead of oxidative coupling. A plausible mechanism is also given.