Allomerization of Methyl Pheophorbide-a and Synthesis of Chlorin Derivatives

The allomerization of methyl pyropheophorbide-a, used as starting material, was carried out under the alkaline condition to separate a series of oxidized and rearranged products at exocyclic E-ring and C-12-methyl group.The same reaction of chlorinated methyl pyropheophorbide-a also came through similar processes.The further oxidations of C-13 2 -and C-12-oxidized products gave two different results, the former reacted quickly and produced complicated compounds, the latter H H basicallyH H unchanged under the same condition.The structures of all new chlorin derivatives were characterized by elemental analysis, UV, IR and 1 H NMR spectra.The possible mechanisms about corresponding reactions were tentatively proposed.Keywords chlorophyll-a;