title: Synthesis and characterization of copper(II) complexes of cysteinyldopa and benzothiazine model ligands related to pheomelanin.
abstract: A new cysteinyldopa model ligand Cydo {3-[(2-aminoethyl)sulfanyl]-4,6-di-tert-butylbenzene-1,2-diol} was prepared and its reactivity with Cu(II) explored. Under anaerobic conditions, tetranuclear [Cu4(Cydo)4] is isolated, but in the presence of O2, a benzothiazine intermediate accumulates that is trapped as the Cu(II) complex [Cu(zine)2]. Under slightly different reaction conditions, the benzothiazine further oxidizes to benzothiazole (zole). All three compounds were characterized by X-ray crystallography, and the reactions were monitored spectrophotometrically.
authors.affiliation: Department of Chemistry, Duke University, Box 90346 Durham, NC 27708, USA.
authors.forename: Yohannes T
authors.initials: YT
authors.lastname: Tesema
authors.forename: David M
authors.initials: DM
authors.lastname: Pham
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Franz
mesh_terms: D001555:Benzene Derivatives / Q000138:chemical synthesis / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D003548:Cysteinyldopa / Q000031:analogs & derivatives* / Q000138:chemical synthesis; D008024:Ligands; D008543:Melanins / Q000737:chemistry*; D013843:Thiazines / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D001555:Benzene Derivatives; D008024:Ligands; D008543:Melanins; D013843:Thiazines; C018362:pheomelanin; D003548:Cysteinyldopa; D003300:Copper