Search results for "Aza Compound"
showing 10 items of 37 documents
Designing binuclear transition metal complexes: a new example of the versatility of N,N′-bis(2-aminobenzyl)-4,13-diaza-18-crown-6
2005
[Abstract] N,N′-Bis(2-aminobenzyl)-4,13-diaza-18-crown-6 (L) is a versatile receptor able to adapt to the coordinative preferences of different metal cation guests. With first-row transition metal ions, L tends to form binuclear complexes but, depending on the nature of the particular metal ion, the structure of the binuclear complex may be very different. Herein we report a study of the structure and magnetic properties of the corresponding nickel(II) and cobalt(II) complexes. The X-ray crystal structure of the nickel complex (1), with formula [Ni2(L)(CH3CN)4](ClO4)4·CH3CN, shows that this compound presents a symmetric coordination environment with L adopting an anti arrangement. Each Ni(I…
Molecular Rearrangement of an Aza-Scorpiand Macrocycle Induced by pH: A Computational Study †
2016
Rearrangements and their control are a hot topic in supramolecular chemistry due to the possibilities that these phenomena open in the design of synthetic receptors and molecular machines. Macrocycle aza-scorpiands constitute an interesting system that can reorganize their spatial structure depending on pH variations or the presence of metal cations. In this study, the relative stabilities of these conformations were predicted computationally by semi-empirical and density functional theory approximations, and the reorganization from closed to open conformations was simulated by using the Monte Carlo multiple minimum method Financial support by the Spanish Ministerio de Economía y Competitiv…
Experimental and Theoretical Study on the Cycloreversion of a Nucleobase-Derived Azetidine by Photoinduced Electron Transfer.
2018
[EN] Azetidines are interesting compounds in medicine and chemistry as bioactive scaffolds and synthetic intermediates. However, photochemical processes involved in the generation and fate of azetidine-derived radical ions have scarcely been reported. In this context, the photoreduction of this four-membered heterocycle might be relevant in connection with the DNA (6-4) photoproduct obtained from photolyase. Herein, a stable azabipyrimidinic azetidine (AZT(m)), obtained from cycloaddition between thymine and 6-azauracil units, is considered to be an interesting model of the proposed azetidine-like intermediate. Hence, its photoreduction and photo-oxidation are thoroughly investigated throug…
Identifying three-way DNA junction-specific small-molecules
2012
Three-way junction DNA (TWJ-DNA, also known as 3WJ-DNA) is an alternative secondary DNA structure comprised of three duplex-DNAs that converge towards a single point, termed the branch point. This point is characterized by unique geometrical properties that make its specific targeting by synthetic small-molecules possible. Such a targeting has already been demonstrated in the solid state but not thoroughly biophysically investigated in solution. Herein, a set of simple biophysical assays has been developed to identify TWJ-specific small-molecule ligands; these assays, inspired by the considerable body of work that has been reported to characterize the interactions between small-molecules an…
Equilibrium, Kinetic, and Computational Studies on the Formation of Cu2+ and Zn2+ Complexes with an Indazole-Containing Azamacrocyclic Scorpiand: Evi…
2015
Cu(2+) and Zn(2+) coordination chemistry of a new member of the family of scorpiand-like macrocyclic ligands derived from tris(2-aminoethyl)amine (tren) is reported. The new ligand (L1) contains in its pendant arm not only the amine group derived from tren but also a 6-indazole ring. Potentiometric studies allow the determination of four protonation constants. UV-vis and fluorescence data support that the last protonation step occurs on the indazole group. Equilibrium measurements in the presence of Cu(2+) and Zn(2+) reveal the formation of stable [ML1](2+), [MHL1](3+), and [ML1(OH)](+) complexes. Kinetic studies on the acid-promoted decomposition of the metal complexes were carried out usi…
Antibiotic susceptibility of cocultures in polymicrobial infections such as peri-implantitis or periodontitis: an in vitro model.
2011
Although polymicrobial infections, such as peri-implantitis or periodontitis, were postulated in the literature to be caused by synergistic effects of bacteria, these effects remain unclear looking at antibiotic susceptibility. The aim of this study is to compare the antibiotic susceptibilities of pure cultures and definite cocultures.Laboratory strains of Aggregatibacter actinomycetemcomitans (Aa) (previously Actinobacillus actinomycetemcomitans), Capnocytophaga ochracea (Co), and Parvimonas micra (Pm) (previously Peptostreptococcus micros) were cultivated under anaerobic conditions, and their susceptibilities to 10 antibiotics (benzylpenicillin G, ampicillin, amoxicillin, ampicillin/sulba…
Synthesis of Bioactive 2-Aza-Analogues of Ipecac and Alangium Alkaloids
2010
HPMA-Based Nanoparticles for Fast, Bioorthogonal iEDDA Ligation
2019
Contains fulltext : 216143.pdf (Publisher’s version ) (Open Access) Fast and bioorthogonally reacting nanoparticles are attractive tools for biomedical applications such as tumor pretargeting. In this study, we designed an amphiphilic block copolymer system based on HPMA using different strategies to introduce the highly reactive click units 1,2,4,5-tetrazines (Tz) either at the chain end (Tz-CTA) or statistical into the hydrophobic block. This reactive group undergoes a rapid, bioorthogonal inverse electron-demand Diels-Alder reaction (iEDDA) with trans-cyclooctenes (TCO). Subsequently, this polymer platform was used for the preparation of different Tz-covered nanoparticles, such as micell…
Aza- and Azo-Stilbenes: Bio-Isosteric Analogs of Resveratrol
2020
Several series of natural polyphenols are described for their biological and therapeutic potential. Natural stilbenoid polyphenols, such as trans-resveratrol, pterostilbene and piceatannol are well-known for their numerous biological activities. However, their moderate bio-availabilities, especially for trans-resveratrol, prompted numerous research groups to investigate innovative and relevant synthetic resveratrol derivatives. This review is focused on isosteric resveratrol analogs aza-stilbenes and azo-stilbenes in which the C=C bond between both aromatic rings was replaced with C=N or N=N bonds, respectively. In each series, synthetic ways will be displayed, and structural sights will be…
2-Alkenoyl Pyridine N-Oxides, Highly Efficient Dienophiles for the Enantioselective Cu(II)−Bis(oxazoline) Catalyzed Diels−Alder Reaction
2007
2-Alkenoyl pyridine N-oxides are introduced as a new kind of efficient dienophiles for the Cu(II)−bis(oxazoline) (BOX) catalyzed enantioselective Diels−Alder reaction affording higher reactivity and enantioselectivity (ee's up to 96%) than the corresponding nonoxidized 2-alkenoyl pyridines.