Cyclization—Decyclization of Sterically Hindered o-Iminobenzoquinone

摘要

Aryl-substituted o-iminobenzoquinones are widely used in coordination chemistry as redox-active ligands that can change its oxidation state when coordinated [1]. In a free state, they are labile compounds apt to cyclization reactions resulting in different phenoxazine derivatives [2-7]. The chiral derivatives of 4aH-phenoxazine supposed as intermediates in the thermal transformation of 4,6-di-tert-butyl-N-dialkylphenyl-o-iminobenzo-quinone undergo further transformations in solution on account of dimerization [5, 6] or oxidation [6]. In this work, we prepared for the first time 4aH-phenoxazine, a product of cyclization of 4,6-di-tert-butyl-N-2-hydroxy-5-tert-butylphenyl-o-iminobenzoquinone, and snowed a possibility of its decyclization.