Catalyst‐ and Base‐Controlled Site‐Selective sp² and sp³ Direct Arylation of 5,7‐Dimethyl‐2‐phenylpyrazolo[1,5‐<i>a</i>]pyrimidine Using Aryl Bromides

Abstract

Abstract The palladium‐catalyzed direct C–H arylation of various heterocyclic is now recognized to be the most effective methodology for making aromatic compounds. In this paper, we present a new approach to control the site‐selective direct C–H arylation of both sp 2 and sp 3 sites in 5,7‐dimethyl‐2‐phenylpyrazolo[1,5‐ a ]pyrimidine by using aryl bromides. The desired compounds were obtained in satisfactory yields. The effects of each reaction parameter including catalyst, base, and solvent were investigated.