Synthesis of Quinazolines from N,N'-Disubstituted Amidines via I/KI-Mediated Oxidative C-C Bond Formation.

An I/KI-promoted oxidative C-C bond formation reaction from C(sp)-H and C(sp)-H bonds has been used to construct quinazoline skeletons from N,N'-disubstituted amidines. The required substrates are readily prepared from the corresponding acyl chlorides, anilines, and alkyl/benzylamines by sequential amidation, chlorination, and amination reactions. Under the optimal oxidative cyclization conditions, all these amidines were conveniently transformed into the expected products in moderate to good yields. This practical and environmentally benign approach works well with crude amidine intermediates and can also be carried out on a gram scale.