Synthesis of deuterated chlorophyll derivatives and their physical properties

Abstract

The 3-vinyl group of methyl pyropheophorbide-a, one of the chlorophyll-a derivatives, was chemically transformed into partially or fully deuterated vinyl, 1-hydroxyethyl, acetyl, formyl, and hydroxymethyl groups via oxidation, oxidative cleavage, reduction, dehydration, or Grignard reaction. Using commercially available sodium borodeuteride and trideuteromethyl iodide as deuterium sources, a variety of regioselectively deuterated pyropheophorbides were obtained with either no or a slight loss of the deuteration degree compared with those of the starting deuterated materials. The deuteration affected largely the related infrared vibrational bands, slightly the chemical shifts of specific proton signals, and no change of visible absorption bands in a solution.