Two-steps synthesis of hexasubstituted porphyrins at the β-pyrrolic positions

meso-Tetraarylporphyrin chelates are easily available from parent porphyrins.Their reactions with nitric acid (yellow fuming HNO3, d = 1.52), under optimized conditions in CHCl3 at room temperature, can be carried out selectively, thus giving mainly ,,-trinitro-substituted moieties (usually two or three isomers of the above complexes).These intermediates (Cu 2+ -derivatives; obtained in overall yields of up to 38%), upon the reaction with carbanions bearing a leaving group X at the reactive centre afforded the target products, the ones of vicarious nucleophilic substitution of hydrogen (VNS).This approach allows the synthesis of porphyrin derivatives exhaustively -substituted in three pyrrole rings (in yields of up to 69%), starting from a simple mesotetraarylporphyrin complexes.The above two-steps procedure including very attractive VNS reaction gives hydrophilic or amphiphilic moieties that seem to be potential agents in anticancer photodynamic therapy (PDT), practically unavailable by alternative methods.