Transformation of 6′‐aminosubstituted spironaphthoxazines induced by Pb(II) and Eu(III) cations

Abstract

Abstract The transformation of spiroindolinonaphth[2,1‐ b ][1,4]oxazines (SNOs) conjugated with aza‐15(18)‐crown‐5(6) ether moieties or morpholine in the presence of Pb 2+ or lanthanoid cations in MeCN solution was studied by UV–Vis, NMR and surface‐enhanced resonance Raman scattering spectroscopy methods. The Pb 2+ or Eu 3+ cations induce the formation of the betaine merocyanine form of SNO. When the merocyanine complexes are kept in the dark, the corresponding oxazole derivatives are formed irreversibly and regioselectively. Copyright © 2005 John Wiley & Sons, Ltd.