Synthesis of β-Octaethylporphyrin Conjugates with Nitrogen and Sulfur Containing Heterocycles

Conjugates of Ni(II) P-octaethylporphyrin with nitrogen and sulfur containing heterocycles were obtained by meso-functionalization of the porphyrin. The meso-functionalization of Ni(II) P-octaethylporphyrin was performed by the Vilsmeier-Haack formylation reaction, followed by the Knoevenagel reaction of Ni(II) meso-formylP-octaethylporphyrin with CH-acids: malonic ester, thiohydantoin, and thiobarbituric acid. The product of condensation of the porphyrin with malonic ester was cyclized with hydrazine to the corresponding porphyrin conjugate with pyrazolidine-3,5-dione. The optical spectra of the obtained new dyes are modified compared to that of the initial compounds. The spectral changes of the porphyrin conjugate with thiobarbituric acid are particularly dramatic reflecting the considerable interaction between tetrapyrrolic and heterocyclic chromophores in the molecule.