Bis-Spiro-Oxetane and Bis-Spiro-Tetrahydrofuran Pyrroline Nitroxide Radicals: Synthesis and Electron Spin Relaxation Studies

J Org Chem. 2021 Oct 1;86(19):13636-13643. doi: 10.1021/acs.joc.1c01670. Epub 2021 Sep 21.

Abstract

Synthesis of bis-spiro-oxetane and bis-spiro-tetrahydrofuran pyrroline nitroxide radicals relies on the Mitsunobu reaction-mediated double cyclizations of N-Boc protected pyrroline tetraols. Structures of the nitroxide radicals are supported by X-ray crystallography. In a trehalose/sucrose matrix at room temperature, the bis-spiro-oxetane nitroxide radical possesses electron spin coherence time, Tm ≈ 0.7 μs. The observed enhanced Tm is most likely associated with strong hydrogen bonding of oxetane moieties to the trehalose/sucrose matrix.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electron Spin Resonance Spectroscopy
  • Electrons*
  • Ethers, Cyclic
  • Furans*
  • Nitrogen Oxides
  • Pyrroles

Substances

  • Ethers, Cyclic
  • Furans
  • Nitrogen Oxides
  • Pyrroles
  • pyrroline
  • nitroxyl
  • oxetane