Spin labeled hydroxyproline analogues

The synthesis and properties of both epimers of 4-(N-hydroxyamino)-N-tosyl- L-proline methyl ester and derivatives thereof are reported. In the presenc e of air, the compounds bearing a free N-hydroxyamino group oxidized in sol ution to give the corresponding aminoxyl free radicals, EPR spectra of whic h were recorded. None of these compounds showed any interesting biological activity as such, but they constitute potential synthetic building blocks t owards spin labeled glycopeptide or oligopeptide analogues. (C) 1999 Elsevi er Science S.A. All rights reserved.