The Bromination of Methyl Pyropheophorbide-a with N-bromosuccinimide(NBS)

Methyl pyropheophorbide-a is used as starting material and reactions with N- bromosuccinimide were carried out in dichloromethane at different temperature. The electrophilic substitution,electrophilic addition,hydrolysis and dehydrogenation occurron the chlorinchromophore,respectively. toisolate four new chlorophllouschlorin derivatives. The reaction mechanisms about brominationare proposed and regioselectivities in bromination of methyl pyropheophorbide- aare explained and summarized. The structuresof all new compoundsare assignedbasedonthedatafrom IR,~1HNMRandelementalanalysis.