Novel heterocyclization of 3-(2-aminophenylamino)- 5,5-dimethyl-2-cyclohexen-1-one

4-(1,2,3,4,10,10a-Hexahydro-3,3-dimethyl-1-oxophenazin-10a-yl)-2,6-di-tert-butylphenol [10a-(3,5-di-tert-butyl-4-hydroxyphenyl)-3,3-dimethyl-1,2,3,4,10,10a-hexahydro-1H-phenazin-1-one] was obtained by the condensation of 3-(2-aminophenylamino)-5,5-dimethyl- 2-cyclohexen-1-one and 2,6-di-tert-butyl-1,4-benzoquinone.