Palladium‐Catalyzed Cyclization Reaction of o ‐Haloanilines, CO 2 and Isocyanides: Access to Quinazoline‐2,4(1 H ,3 H )‐diones

Quinazoline‐2,4(1 H ,3 H )‐diones are core structural subunits frequently found in many biologically important compounds. The reaction of 2‐aminobenzonitrile and CO 2 , which was frequently studied, only provided N 3‐unsubstituted quinazoline‐2,4(1 H ,3 H )‐dione compounds. Herein we report palladium‐catalyzed cyclization reactions of o ‐haloanilines, CO 2 and isocyanides to prepare N 3‐substituted quinazoline‐2,4(1 H ,3 H )‐diones. Electron‐rich o ‐bromoanilines participated in the cyclization reaction using Cs 2 CO 3 at high temperature, and electron‐deficient o ‐bromoaniline or o ‐iodoaniline substrates conducted the reaction using CsF as base to deliver corresponding quinazoline‐2,4(1 H ,3 H )‐dione products in good yields.