Planar-bilayer activities of linear oligoester bolaamphiphiles

• Jonathan K. W. Chui,
• Thomas M. Fyles and
• Horace Luong

Beilstein J. Org. Chem. 2011, 7, 1562–1569, doi:10.3762/bjoc.7.184

• voltage-dependent. The varied and irregular activities were summarized with the aid of a recently developed “activity-grid” method. Keywords: activity grid; single-molecule studies; synthetic ion channels; voltage clamp experiment; Introduction Ion channels modulate conductance in cell membranes, and

Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• achieved without immobilization or addition of charged polymer, but by using nanofiltration membranes instead of ultrafiltration ones [25]. The reactor for the synthesis of L-tert-leucine (11) from trimethylpyruvate (10) catalyzed by leucine dehydrogenase (Scheme 4) was operated for 10 days with a total

• continuous multistep enzymatic synthesis of fine chemicals, where cofactor regeneration is required. In such cases the whole-cell in vivo approach is advantageous over in vitro approaches, because it is not necessary to use immobilization or nanofiltration membranes for the retention of small cofactor

Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

• Alicja Schlange,
• Antonio Rodolfo dos Santos,
• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2011, 7, 1412–1420, doi:10.3762/bjoc.7.165

• , 20 wt % Ru) supported on Vulcan® XC-72R carbon. Catalyst coated membranes (CCM) were fabricated by spraying catalyst ink (water:catalyst:Nafion® ionomer (15 wt %) at a weight ratio of 9:1:1.175) on the Nafion® 117 membrane. After application of catalyst ink the membrane was hot-pressed at 120 °C at a

Synthesis of enantiomerically enriched (R)-¹³C-labelled 2-aminoisobutyric acid (Aib) by conformational memory in the alkylation of a derivative of L-alanine

• Stephen P. Fletcher,
• Jordi Solà,
• Dean Holt,
• Robert A. Brown and
• Jonathan Clayden

Beilstein J. Org. Chem. 2011, 7, 1304–1309, doi:10.3762/bjoc.7.152

• common component of several fungal and bacterial antibiotic metabolites [14], and the helix-forming properties of these metabolites, which encourage them to embed themselves into cell membranes, are at the origin of their biological activity. The methods available for the asymmetric synthesis of

NMR studies of anion-induced conformational changes in diindolylureas and diindolylthioureas

• Damjan Makuc,
• Jennifer R. Hiscock,
• Mark E. Light,
• Philip A. Gale and
• Janez Plavec

Beilstein J. Org. Chem. 2011, 7, 1205–1214, doi:10.3762/bjoc.7.140

• of anions in biological and chemical processes drives much of this research. Biomolecules such as the sulfate binding protein [14] and phosphate binding protein [15] employ hydrogen bonds as the key driving force to bind or transport anions through cell membranes. Hydrogen bonding interactions are

Multicomponent synthesis of artificial nucleases and their RNase and DNase activity

• Anton V. Gulevich,
• Lyudmila S. Koroleva,
• Olga V. Morozova,
• Valentina N. Bakhvalova,
• Vladimir N. Silnikov and
• Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2011, 7, 1135–1140, doi:10.3762/bjoc.7.131

• and 5g, the most hydrophobic among synthesized substances, might potentially penetrate through cellular or viral membranes and therefore the dependence of RNA cleavage on the concentration of the peptidomimetics was studied in detail. The concentration of compounds 5e and 5g, optimal for RNA cleavage

Advances in synthetic approach to and antifungal activity of triazoles

• Kumari Shalini,
• Nitin Kumar,
• Sushma Drabu and
• Pramod Kumar Sharma

Beilstein J. Org. Chem. 2011, 7, 668–677, doi:10.3762/bjoc.7.79

• triazoles Triazoles have been suggested as water replacements in proton conductors used in fuel cells. Once doped into membranes, these triazoles improve the conductivity of the membranes under anhydrous conditions. Due to their amphoteric nature, these compounds act as proton acceptors and donors. Their

Pyridinium based amphiphilic hydrogelators as potential antibacterial agents

• Sayanti Brahmachari,
• Sisir Debnath,
• Sounak Dutta and
• Prasanta Kumar Das

Beilstein J. Org. Chem. 2010, 6, 859–868, doi:10.3762/bjoc.6.101

• the difference in the lipid composition as well as in the membrane potential gradient between the target prokaryotic and the non-target eukaryotic cell membranes [41][42]. Conclusion We have utilized a combination of a quaternary pyridinium unit and hydrophobic long chain to build a scaffold, which

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

• membranes and creates opportunities for the modification of known and new drugs. Thus this group is a useful substituent in agrochemicals and pharmaceuticals [2][3][4]. Examples of bioactive compounds containing SCF3, SOCF3 and SO2CF3 groups are shown in Figure 1 and Figure 2. The synthesis of a large

Functionalized copolyimide membranes for the separation of gaseous and liquid mixtures

• Nadine Schmeling,
• Roman Konietzny,
• Daniel Sieffert,
• Patrick Rölling and
• Claudia Staudt

Beilstein J. Org. Chem. 2010, 6, 789–800, doi:10.3762/bjoc.6.86

• plasticization since it has been shown that this phenomenon leads to a significant increase in permeability with a dramatic loss in selectivity. Plasticization effects occur with most polymer membranes at high CO2 concentrations and pressures, respectively. Plasticization effects are also observed with higher

• /aliphatics; copolyimides; cross-linking; gas separation; membranes; natural gas treatment; olefins/paraffins; pervaporation; Introduction Over 50% of energy costs in the chemical industry are used for the separation of gaseous or liquid mixtures [1]. Separations in petrochemical processes, e.g. low

• removal of polar low molecular weight components in equilibrium reactions [7]. Background and theory In general, membranes are very thin layers, which can have different structures. They are divided into porous membranes and solution-diffusion membranes. Porous membranes are well established in typical

Synthesis, characterization and photoinduced curing of polysulfones with (meth)acrylate functionalities

• Cemil Dizman,
• Sahin Ates,
• Lokman Torun and
• Yusuf Yagci

Beilstein J. Org. Chem. 2010, 6, No. 56, doi:10.3762/bjoc.6.56

• important components of UV curable formulations for obtaining networks that could have application in coatings and membranes. Experimental Materials Bisphenol A and bis(p-chlorophenyl) sulfone (Hallochem Pharma Co. Ltd, China), methanol (Merck), dimethylacetamide (DMA, 99%, Merck) were used without any

Functionalized polymers: synthesis and properties

• Helmut Ritter

Beilstein J. Org. Chem. 2010, 6, No. 55, doi:10.3762/bjoc.6.55

• chromatography), for membranes and in the solid phase synthesis of peptides and oligonucleotides. Focusing on the constantly developing medical field, only specifically elaborated functional polymer materials can fulfill the specific challenges required of them for use as, for example, surgical sutures, dental

Chemical aminoacylation of tRNAs with fluorinated amino acids for in vitro protein mutagenesis

• Shijie Ye,
• Allison Ann Berger,
• Dominique Petzold,
• Oliver Reimann,
• Benjamin Matt and
• Beate Koksch

Beilstein J. Org. Chem. 2010, 6, No. 40, doi:10.3762/bjoc.6.40

• , enabling better diffusion across the membranes [16]. Koksch and co-workers have developed a model peptide system based on the coiled-coil folding motif. They used it to show that the impact of fluorine substitution on structure and stability is strongly dependent on the position and the number of fluorine

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties

• José L. Jiménez Blanco,
• Fernando Ortega-Caballero,
• Carmen Ortiz Mellet and
• José M. García Fernández

Beilstein J. Org. Chem. 2010, 6, No. 20, doi:10.3762/bjoc.6.20

• -oligomers of mannose- and glucose-derived furanoid SAAs [58] in order to constrain their conformational degrees of freedom and to induce desirable structural elements essential for their biological activities, such as tubular structures for transporting ions or molecules across membranes. Detailed ROESY

• , temperature coefficient (Δδ/ΔT) measurements of amide protons and constrained MD simulations revealed that all the cyclic oligomers had symmetrical structures, although none of the unprotected cyclic oligomers displayed any ability to transport ions across model membranes according to ion flux studies. Cyclic

An enantiomerically pure siderophore type ligand for the diastereoselective 1 : 1 complexation of lanthanide(III) ions

• Markus Albrecht,
• Olga Osetska,
• Thomas Abel,
• Gebhard Haberhauer and
• Eva Ziegler

Beilstein J. Org. Chem. 2009, 5, No. 78, doi:10.3762/bjoc.5.78

• . Therefore microorganisms have to develop strategies how to solubilise and take up charged ions through highly non-polar membranes [1][2]. An important class of natural products which is responsible for the uptake of iron are the siderophores [3][4][5]. The probably most prominent example of this class is

Thematic series on supramolecular chemistry

• Christoph A. Schalley

Beilstein J. Org. Chem. 2009, 5, No. 76, doi:10.3762/bjoc.5.76

• , molecular containers, elevators, valves and springs, supramolecular catalysts and many more. Fixing such functional supramolecules in a suitable way, for example on nanoparticles, at interfaces or in membranes can be a way to generate even novel materials with interesting macroscopic effects. This exciting

Synthesis and properties of calix[4]arene telluropodant ethers as Ag⁺ selective sensors and Ag⁺, Hg²⁺ extractants

• Yang Lu,
• Yuanyuan Li,
• Song He,
• Yan Lu,
• Changying Liu,
• Xianshun Zeng and
• Langxing Chen

Beilstein J. Org. Chem. 2009, 5, No. 59, doi:10.3762/bjoc.5.59

• + selectivity of phenyltelluride functionalized calix[4]arene 6–8, 10 and 12 was evaluated by the potentiometric selectivity coefficients (logK) (Table 1). As shown in Table 1, the polymer membranes containing calix[4]arenes 6–8, 10 and 12 as ionophores gave excellent logK values (≤−3.3) against most of the

Functional properties of metallomesogens modulated by molecular and supramolecular exotic arrangements

• Alessandra Crispini,
• Mauro Ghedini and
• Daniela Pucci

Beilstein J. Org. Chem. 2009, 5, No. 54, doi:10.3762/bjoc.5.54

• 4 position, and chosen for many different purposes, including its universal affinity for cell membranes and its ability to self order into liquid crystalline state [48]. The functionalised 2-phenylquinoline ligand has firstly been cyclopalladated and then conjugated to a number of O,O chelating β

An expedient synthesis of 5-n-alkylresorcinols and novel 5-n-alkylresorcinol haptens

• Kirsti Parikka and
• Kristiina Wähälä

Beilstein J. Org. Chem. 2009, 5, No. 22, doi:10.3762/bjoc.5.22

• biological effects including antimutagenic activity [3][4][5][6], antibacterial properties [7], inhibition of enzymes [8][9][10][11][12] and interaction with biological membranes by incorporation to the membrane structure [13][14]. Whole grain rye and wheat products, linked to a healthy diet, are the most

Stereoselective synthesis of (2S,3S,4Z)-4-fluoro- 1,3-dihydroxy- 2-(octadecanoylamino)octadec- 4-ene, [(Z)-4-fluoroceramide], and its phase behavior at the air/water interface

• Gergana S. Nikolova and
• Günter Haufe

Beilstein J. Org. Chem. 2008, 4, No. 12, doi:10.3762/bjoc.4.12

• Gergana S. Nikolova Gunter Haufe Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstr. 40, D-48149 Münster, Germany 10.3762/bjoc.4.12 Abstract Background Sphingolipids belong to the most important constituents of the membranes of eukaryotic cells. As intermediates

• to stronger intermolecular interactions between the hydrophobic chains of neighboring molecules, and therefore to increasing stability of the monolayer of 4-fluoroceramide at the air water interface. Introduction Sphingolipids belong to the most important constituents of the membranes of eukaryotic