Reusable copper iron oxide for heterogeneously oxidative cyclization of (hetero)aryl methyl ketones and 2-phenylglycines

Abstract

Annulation of methyl C–H bonds in acetophenone derivatives with 2-phenylglycines to furnish 2,5-diphenyloxazoles under the assistance of heterogeneous catalyst is firstly reported. Successes are attributed to the use of commercially available copper iron oxide, in combination with molecular iodine, p-toluenesulfonic acid, and DMSO. The efficiency of our method is somewhat proven as 19 examples were isolated with yields varied from 32 % to 84 %. The copper iron oxide could be recovered and reused up to 4 times with nearly identical catalytic activity.