- Rhodium(I) and Iridium(I) N-Heterocyclic carbene complexes of imidazolium functionalized amino acids and peptides
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The conjugation of organometallic complexes to peptides is generally achieved through covalent organic linkages of the metal's ligand to the peptide. Examples of direct coordination to metal centers by amino acid side chain residues remain rare. In one such example, side chain methylation of the natural amino acid histidine (His) resulted in an imidazolium functionalized amino acid which was used for the synthesis of rhodium(I), iridium(I), iridium(III), palladium(II) and ruthenium(III) N-heterocyclic carbene (NHC) complexes of the single amino acid and peptides containing this amino acid. Here, we have synthesized two new, non-natural imidazolium functionalized amino acid derivatives, which were used for solid phase peptide synthesis and for the synthesis of [M(COD)(NHC)Cl] (COD = 1,5 cyclooctadiene) complexes of Rh(I) and Ir(I). In total, six new complexes of the single amino acids and four complexes where the amino acids are present in a peptide environment were synthesized. Their characterization provides convincing evidence of conversion of the imidazolium moiety to an NHC ligand and thus the presence of a direct metal-carbon bond between the metal center and the amino acid side chain. Therefore, our compounds represent unique examples of peptide-conjugated complexes that bear the potential to be used for the synthesis of N-heterocyclic carbene complexes conjugated to cancer cell targeting peptides.
- Daubit, Isabelle Marie,Wolf, Jonas,Metzler-Nolte, Nils
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- Synthesis of Imidazole and Histidine-Derived Cross-Linkers as Analogues of GOLD and Desmosine
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Amino acid derivatives with a central cationic heterocyclic core (e.g., imidazolium) are biologically relevant cross-linkers of proteins and advanced glycation end (AGE) products. Here, imidazolium-containing cross-linkers were synthesized from imidazole or histidine by N-alkylation employing aspartate- and glutamate-derived mesylates as key step. Biological investigations were carried out to probe the biocompatibility of these compounds.
- Sch?del, Nicole,Icik, Esra,Martini, Maike,Altevogt, Luca,Ramming, Isabell,Greulich, Andreas,Baro, Angelika,Bilitewski, Ursula,Laschat, Sabine
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p. 2260 - 2268
(2021/03/04)
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- Nα-Fmoc-protected ω-azido- and ω-alkynyl-L- amino acids as building blocks for the synthesis of "clickable" peptides
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The growing interest in the 1,4-disubstituted-1,2,3-triazolyl moiety as an amide bond surrogate and its formation through very mild, chemoselective, and bioorthogonal CuI-catalyzed Huisgen 1,3-dipolar [3+2] cycloaddition of an alkynyl to an azi
- Isaad, Alexandra Le Chevalier,Barbetti, Francesca,Rovero, Paolo,D'Ursi, Anna Maria,Chelli, Mario,Chorev, Michael,Papini, Anna Maria
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experimental part
p. 5308 - 5314
(2009/06/18)
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- P38 inhibitors and methods of use thereof
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This invention relates to inhibitors of p38, and methods for producing these inhibitors. The invention also provides pharmaceutical compositions comprising the inhibitors of the invention and methods of utilizing the inhibitors and pharmaceutical compositions in the treatment and prevention of various disorders mediated by p38.
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- An efficient procedure for the preparation of 4-substituted 5-aminoimidazoles
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The preparation of O-methylimidates from α-aminonitriles and their subsequent co-cyclization with primary amines to afford 4-substituted 5-aminoimidazoles was studied. It was found that the mildly acidic pyridinium p-toluenesulfonate efficiently catalyzed each stage of the reaction sequence: (a) the formation of the O-methylimidates, (b) their co-cyclization with a variety of primary amines, and (c) certain derivatizations of the resultant heterocycles. The developed reaction conditions tolerate a wide variety of α-aminonitriles and primary amine co-reactants. Thus, it is possible to easily prepare a diverse array of substituted heterocyclic compounds in good yield. The requisite α-aminonitriles were synthesized either from amino acids or by phase-transfer alkylation of a glycine anion equivalent. The unstable free 5-aminoimidazoles were normally protected in situ to provide derivatives (methyl imidates or N,N-dimethylamidines) that were amenable to characterization.
- McLaughlin, Mark,Mohareb, Rafat M.,Rapoport, Henry
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- AGENTS FOR IMAGING AND DIAGNOSTIC METHODS USING THEM
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The present invention provides novel compounds that bind selectively to cells undergoing perturbations and alterations of the normal organization of their plasma membrane, while binding to a lesser degree to cells having membranes of normal organization,
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