Synthesis Of Chlorphyll-A Derivatives Substituted With Beta,Beta-Dicyanomethylene And Their Visible Spectra

Using methyl pyropheophorbide-a as starting material, the carbonyl structures were constructed in different positions of the chlorin periphery by oxidition of the 3-vinyl group, Grignard reaction and air oxidation and rearrangement of E-ring. Then the synthesis of chlorphyll-a derivatives substituted with beta,beta-dicyanomethylene having long wavelength absorption property was accomplished by Knoevenagel reaction of the carbonyl group on the chromophore with malononitrile. The effect of the peripheral conjugated substitutes oriented in different directions on the visible spectra was also discussed. The structures of all new chlorine derivatives were characterized by elemtntal analysis, UV, IR and H-1 NMR spectra.