Synthesis of β-Hexasubstituted Porphyrins by Vicarious Nucleophilic Substitution of Hydrogen. Closing Research
Stanisław Ostrowski,
Sylwia Ostrysz
Meso-Tetraarylporphyrin chelates in the electrophilic reactions with nitric acid, under optimized
conditions, can give mainly β,β,β-trinitro-substituted moieties. These intermediates (Cu2+- and Zn2+-
derivatives; obtained in overall yields of up to 38%), upon the reaction with carbanions bearing a
leaving group X at the reactive centre afford the target products, the ones of vicarious nucleophilic
substitution of hydrogen (VNS). This approach allows the synthesis of hydrophilic or amphiphilic
porphyrin derivatives exhaustively β-substituted in three pyrrole rings that seem to be potential agents
in anticancer photodynamic therapy (PDT). The above two-step procedure including very attractive
VNS reaction leads to moieties practically unavailable by alternative methods.
