title: Large-scale synthesis of a persistent trityl radical for use in biomedical EPR applications and imaging.
abstract: Tetrathiatriarylmethyl radicals are ideal spin probes for biological electron paramagnetic resonance (EPR) spectroscopy and imaging. The wide application of trityl radicals as biosensors of oxygen or other biological radicals was hampered by the lack of affordable large-scale syntheses. We report the large-scale synthesis of the Finland trityl radical using an improved addition protocol of the aryl lithium monomer to methylchloroformate. A new reaction for the formal one-electron reduction of trityl alcohols to trityl radicals using neat trifluoroacetic acid is reported as well. Initial applications show that the compound is very sensitive to molecular oxygen. It has already provided high-resolution EPR images on large aqueous samples and should be suitable for a broad range of in vivo applications.
authors.affiliation: Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Ilirian
authors.initials: I
authors.lastname: Dhimitruka
authors.forename: Murugesan
authors.initials: M
authors.lastname: Velayutham
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Bobko
authors.forename: Valery V
authors.initials: VV
authors.lastname: Khramtsov
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Villamena
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Hadad
authors.forename: Jay L
authors.initials: JL
authors.lastname: Zweier
mesh_terms: D020811:Biomedical Technology; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry; D015394:Molecular Structure; D014320:Triphenylmethyl Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D005609:Free Radicals; D014320:Triphenylmethyl Compounds