Access to 1,4-Dihydrobenzo[e][1,2,4]triazin-4-yl Derivatives

A simple, one-pot method for the preparation of 1 -aryl-3-phenyl-1,4-dihydrobenzo[e][1,2,4]triazin-4-yl radicals by addition of aryllithium to the readily available 3-phenylbenzo[e][1,2,4]triazine followed by aerial oxidation is described. The intermediate anion is also trapped as an N-benzyloxycarbonyl derivative and purified prior to deprotection and oxidation to the radical. The method was demonstrated for nine (het)arenes, and the regioselectivity of nucleophilic addition to the benzo [e] [1,2,4]triazine and trapping of the intermediate anion with electrophiles was assessed computationally.