Key words rhodium catalysis - C–H functionalization macrocyclic peptides tryptophan-containing

The addition of partially dehydroxylated silica (PDS) to a solution of the Wilkinson WMe6 as well as the Schrock W neopentylidyne tris neopentyl complex catalyzes linear or cyclic alkanes to produce respectively a distribution of linear alkanes from methane up to triacontane or a mixture of cyclic and macrocyclic hydrocarbons. This single catalytic system transforms also linear α-olefins into h...

A facile synthesis of a highly preorganized tripodal enterobactine-type ligand 1a-H₃ consisting of a chiral C₃-symmetric macrocyclic peptide and three tridentate 2-amido-8-hydroxyquinoline coordinating units is presented. Complex formation with various metal ions (Al(³+), Ga(³+), Fe(³+), La(³+) and Eu(³+)) was investigated by spectrophotometric methods. Only in the case of La(³+) and Eu(³+) wer...

The title compound, [CoCl(2)(C(15)H(24)N(6))(C(3)H(7)NO)], crystallizes as a monomeric complex. The coordination environment around the Co(II) center could be described as a distorted octa-hedron consisting of three N donors from the facially coordinating triaza macrocyclic ligand, one O donor from dimethyl-formamide and two Cl(-) ions. Neutral complex mol-ecules are associated via inter-molecu...

Threading of a polymer through a macrocyclic ring may occur directly, that is, by finding the end of the polymer chain, or by a process in which the polymer chain first folds and then threads through the macrocyclic ring in a hairpin-like conformation. We present kinetic and thermodynamic studies on the threading of a macrocyclic porphyrin receptor (H2 1) onto molecular threads that are blocked...

Synthetic superoxide dismutase mimetics have emerged as a potential novel class of drugs for the treatment of oxidative stress related diseases. Among these agents, metal complexes with macrocyclic ligands constitute an important group. In this work we synthesized five macrocyclic copper(II) complexes and evaluated their ability to scavenge the superoxide anions generated by the xanthine-xanthi...

The membrane lipid of a new deep-sea hydrothermal vent methanogen, Methanococcus jannaschii, was isolated, purified, and structurally characterized. The total lipid extract, amounting to 32.2 micrograms/mg, dry cell weight, was fractionated on silica gel into a neutral lipid and polar lipid fraction. The neutral lipid fraction consisted of a series of isoprenoid hydrocarbons and free (nonphosph...

Infections caused by nontuberculous mycobacteria (NTM) are increasing worldwide, resulting in a new global health concern. NTM treatment is complex and requires combinations of several drugs for lengthy periods. In spite this, disease often associated with poor outcomes. The anti-parasitic family macrocyclic lactones (ML) (divided two subfamilies: avermectins milbemycins) was previously describ...

In the title compound, [Cd(C(8)H(4)O(4))(C(36)H(44)N(4)O(4))]·C(8)H(6)O(4), the Cd(II) atom is six-coordinated by four N atoms from the macrocyclic ligand and two O atoms from a benzene-1,3-dicarboxyl-ate ligand. The complex mol-ecules are linked by N-H⋯O hydrogen bonds, forming a one-dimensional chain structure along the b axis. The chains are further connected through N-H⋯O and O-H⋯O hydrogen...

[reaction: see text]. The copper acetate mediated intramolecular O-arylation of phenols with phenylboronic acid pseudopeptides is the key step in the preparation of macrocyclic biphenyl ether hydroxamic acid inhibitors of collagenase 1 and gelatinases A and B. The intramolecular macrocyclization was found to be mild and tolerant of common chemical functionality. This methodology should provide ...