Synthesis, electrochemical and spectral properties of some omega-N-quinonyl amino acids.
Four series of omega-N-quinonyl amino acids were synthesized by Michael-like additions. The quinones include 2-phenylthio-1,4-benzoquinone, 1,4-naphthoquinone, 2-methyl-1,4-naphthoquinone and 2,3-dichloro-1,4-naphthoquinone. These modified amino acids can be used for post chain assembly modifications of biologically active peptides, which target the quinonic drug to a cancer damaged area. The electron-transfer capabilities of the modified amino acids were probed by cyclic voltammetry measurements. The results described in this paper show that the novel N-quinonyl amino acids are effective in producing semiquinone radicals similarly to the unconjugated quinones themselves. A direct relation was found between the first reduction potentials of the quinones and their reactivity towards the omega-amino acids. The successful generation of stable semiquinone radicals by the novel quinone derivatives is a prerequisite for the manifestation of site-directed antitumor activity of corresponding quinone-peptide conjugates.
Bittner
S
S
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel. bittner@bgumail.bgu.ac.il
Gorohovsky
S
S
Paz-Tal
Levi O
LO
Becker
J Y
JY
D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D004563:Electrochemistry; D010084:Oxidation-Reduction; D011809:Quinones / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods
D000596:Amino Acids; D011809:Quinones