Synthesis of 5,10,15,20‐Tetra[4‐(N‐ethylpiperazinyl)phenyl]‐porphyrin and Its Interaction with DNA

Piperazinyl-porphyrin, 5,10,15,20-tetra[4-(N-ethylpiperazinyl)phenyl]porphyrin (TEPPH2), was synthesized based on the special affinity of porphyrin to cancer cells and the antitumor activity of piperazine compounds. Its structure was characterized by UV-vis and 1H NMR spectra and elemental analysis. A model for the interaction between TEPPH2 and calf thymus DNA was built, and the binding mechanism was investigated by UV-vis and fluorescence spectra. The results indicated that TEPPH2 could intercalate into the base pairs of DNA strongly. One calf thymus DNA molecule could bind 88 TEPPH2 molecules, and the binding constant K is 8.4×106 L·mol-1. The binding number and binding constant of TEPPH2 with DNA are higher than those of the known anti-tumor drugs, tetrakis(4-N-methylpyridyl)porphine and the Schiff bases Ca/sal-his and Ni/sal-aln.