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

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 sp2 and sp3 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.