Selective N(1)-arylation of benzotriazole with activated aryl halides under conditions of phase transfer catalysis

Arylation of 1H-1,2,3-benzotriazole with activated aryl halides in a medium of aromatic hydrocarbons under conditions of phase transfer catalysis with the use of inorganic bases and cetyltrimethylammonium bromide as a phase-t ransfer catalyst was studied. Arylation affords both N(1)- and N(2)-arylati on products. Their ratio depends on the nature of the base and the reactivi ty of the arylating agent. In the presence of catalytic amounts of copper p henylcyclopropanecarboxylate, arylation proceeds regioselectively at the N( 1) atom.