In vivo and in vitro preparation of divinyl-13 2 ,17 3 -cyclopheophorbide- a enol

Abstract Divinyl-13 2 ,17 3 -cyclopheophorbide- a enol was in vivo produced as a metabolite of divinyl-chlorophyll- a by protists and in vitro prepared by the intramolecular cyclization of methyl divinyl-pyropheophorbide- a , one of the divinyl-chlorophyll- a derivatives. The 1 H NMR spectra in CDCl 3 showed that the obtained product took exclusively its enol form in the solution. The intramolecular cyclization of chlorin π-system at the C13 2 and C17 3 positions affected the optical properties of such chlorophyll derivatives including the non-fluorescent emission of the enol.