SYNTHESIS OF 2,7-DISUBSTITUTED 5,10-DIARYL-5,10-DIHYDROPHENAZINES VIA IRON-CATALYZED INTRAMOLECULAR RING-CLOSING C-H AMINATION (Dedicated to Professor Isao Kuwajima on the occasion of his 77th birthday)

Abstract

A novel iron-catalyzed intramolecular ring-closing C–H amination reaction of o-phenylenediamines was developed, affording the corresponding 2,7-disubstituted 5,10-diaryl-5,10-dihydrophenazines in acceptable yields. The reaction proceeded via the in-situ generation of the magnesium amides of the starting secondary amines in the presence of a catalytic amount of an iron salt and a stoichiometric amount of 1,2-dibromoethane as the terminal oxidant. The substituted dihydrophenazine derivatives can potentially be used as hole-injection materials in organic electroluminescence (OEL) devices and also offer scaffolds for further synthetic elaborations of OEL materials. This paper is dedicated to Professor Dr. Isao Kuwajima on the occasion of his 77th birthday. HETEROCYCLES, Vol. 90, No. 2, 2015 893