23978-55-4Relevant articles and documents
The syntheses and structural characterizations of some monoaza- and diaza-crown ethers
Fewings, Kym R.
, p. 1109 - 1114 (1999)
Several aza-crown ethers have been synthesized and their structures determined by X-ray crystallography. In a modified synthesis of diaza-18-crown-6 we isolated two of the intermediates, viz. the NaI salt (1) of N,N′-dibenzyldiaza-18-crown-6 and the salt-free macrocycle (2), and determined their stuctures. In compound (1) a hydrated crown-encapsulated sodium cation was revealed with both benzyl groups folded down and away from the water molecule while in compound (2) a centrosymmetric crown with the benzyl groups splayed out from the ring was found. In addition, we have determined the X-ray crystal structures of monoaza-18-crown-6 and the hydrochloride salt of monoaza-15-crown-5. In the former, the crown resides on an inversion centre showing N/O disorder, and in the latter the protonated amine hydrogen bonds with the chloride anion. CSIRO 1999.
Copper and zinc complexes of a diaza-crown ether as artificial nucleases for the efficient hydrolytic cleavage of DNA
Li, Fang-Zhen,Xie, Jia-Qing,Feng, Fa-Mei
, p. 5654 - 5660 (2015)
Artificial nucleases are a kind of new non-enzymatic breakage tool, which mimic the function of a restricted enzyme and can catalyze nucleic acid cleavage highly efficiently and selectively. Some metal complexes are highly efficient cleavage agents for DNA. In this report, a diaza-crown ether (L) was synthesized and its copper and zinc complexes (CuL and ZnL) were prepared to serve as artificial nucleases. The compositions of the two metal complexes were confirmed by LC-MS analysis, and the nuclease activity of the complexes towards pUC19 DNA cleavage was studied using agarose gel electrophoresis. The results indicate that the two metal complexes can accelerate the breakage of DNA from the supercoiled (form I) to the nicked form (form II) under appropriate conditions; the optimal pH value for the DNA catalytic cleavage is 8.01 for both CuL and ZnL; the complex ZnL was a better catalyst in the DNA cleavage process than the complex CuL at low concentrations; and unreactive μ-hydroxo dimers were formed hampering the DNA cleavage process at high concentrations. In the presence of free radical scavengers, the supercoiled plasmid DNA cleavage catalyzed by these complexes has been performed and the catalytic mechanism has been investigated.
DIAZA-CROWN ETHERS-VI A MECHANISM FOR METAL ION PROMOTED FORMATION OF MACROCYCLIC DIAZAOLIGOETHERS
Kulstad, S.,Malmsten, L. A.
, p. 521 - 524 (1980)
The mechanism of the formation of 1,7,10,16-tetraoxa-4,13-diazacyclooctadecane has been studied from both a thermodynamic and a kinetic point of view.The cyclisation is favoured by the presence of an alkali metal ion, which forms a complex with the ring precursor.Both this intermediate and the complex react with starting material, but only the complex forms a cyclic product.The rate constants of these reactions have been determined by using simulation methods.
Selective mono-alkylation of N-methoxybenzamides
Chen, Zenghua,Hu, Le'an,Zeng, Fanyun,Zhu, Ranran,Zheng, Shasha,Yu, Qingzhen,Huang, Jianhui
supporting information, p. 4258 - 4261 (2017/04/21)
We report our latest discovery of norbornene derivative modulated highly mono-selective ortho-C-H activation alkylation reactions on arenes bearing simple mono-dentate coordinating groups. The reaction features the use of readily available benzamides and alkyl halides. During the study, we prepared 30 mono-alkylated aryl amides in good yields with good mono-selectivity. We have also demonstrated that structurally rigid alkenes such as norbornene and its derivatives are a good class of ligand and could be used for future direct C-H functionalizations. The utilization of norbornene type ligands for assistance in C-H activation processes has opened a new window for future molecular design using direct C-H functionalization strategies.
Synthetic ion channel activity documented by electrophysiological methods in living cells
Leevy, W. Matthew,Huettner, James E.,Pajewski, Robert,Schlesinger, Paul H.,Gokel, George W.
, p. 15747 - 15753 (2007/10/03)
Hydraphiles are synthetic ion channels that use crown ethers as entry portals and that span phospholipid bilayer membranes. Proton and sodium cation transport by these compounds has been demonstrated in liposomes and planar bilayers. In the present work, whole cell patch clamp experiments show that hydraphiles integrate into the membranes of human embryonic kidney (HEK 293) cells and significantly increase membrane conductance. The altered membrane permeability is reversible, and the cells under study remain vital during the experiment. Control compounds that are too short (C8-benzyl channel) to span the bilayer or are inactive owing to a deficiency in the central relay do not induce similar conductance increases. Control experiments confirm that the inactive channel analogues do not show nonspecific effects such as activation of native channels. These studies show that the combination of structural features that have been designed into the hydraphiles afford true, albeit simple, channel function in live cells.
