Development of New Double-Stranded Phenylalanyl Chelators Using .ETA.-.CHI. Diagrams and Binding Constants for Chelators and Lanthanide Ions

Potent 2,2-Diphenyl-1-picrylhydrazyl Radical-Scavenging Activity of Novel Antioxidants, Double-Stranded Tyrosine Residues Conjugating Pyrocatechol

“…19,20) Boc (Boc, tert-butoxycarbonyl)-protected tyrosine residue, Boc-LTyr(OBzl) was conjugated to a triethylenedioxide spacer to yield protected 2a by the C-activating method using N,N-carbonyldiimidazole (CDI) in dry CHCl 3 (Chart 1). The crude compound 2a was purified using chromatography over neu-tral silica gel and the Boc-protecting group was removed by treatment with 90% trifluoroacetic acid (TFA) to produce the free form 3a.…”

“…Rather, we have reported that compounds 5a and 5b are applicable to the inhibitors of Alzheimer's disease-related b-amyloid protein aggregation 27) and chelators. 19) The antioxidant activities of 5a and 5b may provide useful pharmacological properties as model compounds, such as free radical scavenging molecules.…”

“…We aimed to design and synthesize novel antioxidants using a chemically soft catechol (ϭpyrocatechol, pyrCat) ligands, selected based on the chemical hardness concept. 19) The present work extends the synthesis, structure, antioxidant activity, and kinetics of novel antioxidants (1) conjugated with pyrCat to two N-termini of modified amino acid residues. The h values of the potent antioxidant active compound 1 are distributed to 2.23-2.34 (eV), between the values of ˙OH and DPPH˙ radicals.…”

“…19,20) The peptide and related ligands were detected on thin-layer chromatography (TLC) plates using iodine vapor or UV absorption. Silica gel column chromatography was performed on silica gel 60N (100 mesh, neutral; Kanto Chemical Co., Tokyo, Japan).…”

Superoxide Scavenging Effects of Some Novel Bis-Ligands and Their Solvated Metal Complexes Prepared by the Reaction of Ligands with Aluminum, Copper and Lanthanum Ions

“…We previously reported the synthesis and chemical properties of the solved complex of bis(amino acid)catechol derivatives with lanthanoid (Ln 3+ ) ions [11,15,16]. We paid attention to the fact that Al 3+ and Cu 2+/+ ions, besides amyloid β protein misfolding and self-assembly, are causative compounds of Alzheimer’s disease [17,18].…”