title: Diazaphenoxazines and Diazaphenothiazines: Synthesis of the "Correct" Isomers Reveals They Are Highly Reactive Radical-Trapping Antioxidants.
abstract: The preparation of 2,4-diazaphenothiazines and 2,4-diazaphenoxazines via a copper-catalyzed intramolecular amination is described. Literature approaches which utilize easily accessed (2'-aminophenyl) 4-pyri(mi)dyl sulfides undergo a Smiles rearrangement that gives rise to the 1,3-diaza derivatives instead, confirmed by X-ray crystallography. Inversion of the polarity of the cyclization avoids the rearrangement and affords the desired products. Preliminary kinetic studies suggest that 2,4-diazaphenothiazines and diazaphenoxazines, but not the 1,3-diaza isomers, are remarkably potent radical-trapping antioxidants.
authors.affiliation: Department of Chemistry and Biomolecular Sciences, University of Ottawa , Ottawa, Ontario, Canada K1N 6N5.
authors.forename: Evan A
authors.initials: EA
authors.lastname: Haidasz
authors.affiliation: Department of Chemistry and Biomolecular Sciences, University of Ottawa , Ottawa, Ontario, Canada K1N 6N5.
authors.forename: Derek A
authors.identifier: 0000-0002-7305-745X
authors.initials: DA
authors.lastname: Pratt