Facile Approach to the N,O,S-Heteropentacycles via Condensation of Sterically Crowded 3H-Phenoxazin-3-one with ortho-amino-, hydroxy- and mercaptoanilines

A convenient method for the synthesis of a series of 2-arylamino-3H-phenoxazin-3-ones based on the nucleophilic substitution reaction between sterically crowded 3H-phenoxazin-3-one and arylamines performed by short-term heating of the melted reactants at 230-250 °C is described and the compounds are characterized by means of single-crystal X-ray crystallography, NMR, UV/vis, IR spectroscopy and cyclic voltammetry. Involvement into the reaction of arylamines with o -amino-, o -hydroxy and o -mercapto-substituents widens its scope and provides for an access to derivatives of N,O- and N,S-heteropentacyclic quinoxalinophenoxazine, triphenodioxazine and oxazinophenothiazine systems.