Synthesis and properties of novel purpurinimide derivatives from methyl pheophorbide-a

Qiong Li, Lelin Li, Meiyan Zhu

Abstract

The novel purpurinimide derivatives exhibiting long wavelength absorption and amphiphilicity were obtained from methyl pheophorbide-a (MPa) by modification of the peripheral functional groups. The vinyl group at 3-position was oxidized with OsO4 and NaIO4 to form the formyl group and the Grignard reaction of this aldehyde with the alkyl magnesium bromide was carried out to give the corresponding 3-(1-hydrroxylalkyl) pheophorbide-a. The E-ring of these chlorins was converted into imide ring to give purpurinimide derivatives by air oxidation and amidation reaction. These new compound have long wavelength absorption in the range of 726-727nm. In preliminary screening, the purpurinimides exhibit relatively high PDT effect than MPa.