Molecular recognition of isomeric protonated amino acid esters monitored by ESI-mass spectrometry

• Andrea Liesenfeld and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 825–831, doi:10.3762/bjoc.10.78

• protonated amino acid esters. Keywords: amino acids; isomer labelled guest method (ILGM); mass spectrometry; molecular recognition; 9,9’-spirobifluorenes; template; Introduction The separation of constitutionally isomeric amino acids is of practical interest. This is particularly true for leucine (Leu

• achieve amino acid recognition by an artificial host [6][7][8][9][10][11] with regard to isomer separation upon isomer-selective molecular recognition by a concave template acting as a host, thereby avoiding the necessity to establish or break additional covalent chemical bonds. Hence, we have prepared

• target compounds 1 and 2 in moderate yields (Scheme 2). Molecular recognition studies With our crown ether derivatives 1 and 2 in hands we studied their recognition behaviour towards the L-leucine isomers. Usually, spectroscopic techniques like NMR or UV–vis spectroscopy are used for this purpose

Staudinger ligation towards cyclodextrin dimers in aqueous/organic media. Synthesis, conformations and guest-encapsulation ability

• Malamatenia D. Manouilidou,
• Yannis G. Lazarou,
• Irene M. Mavridis and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 774–783, doi:10.3762/bjoc.10.73

• specific guest molecules. The oligomers are reported to display improved to significantly enhanced binding capacity as well as superior molecular recognition ability [12][13][14], compared to the natural CDs. Suitable design has resulted in better hosts for applications as sensors and catalysts [15], hosts

End-group-functionalized poly(N,N-diethylacrylamide) via free-radical chain transfer polymerization: Influence of sulfur oxidation and cyclodextrin on self-organization and cloud points in water

• Sebastian Reinelt,
• Daniel Steinke and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 680–691, doi:10.3762/bjoc.10.61

• interactions in living systems [3][4]. Since then, the field of self-assembly through molecular recognition has attracted much attention also in the design of smart materials. In this context, cyclodextrins (CD) are of interest as ring shaped host molecules, e.g., for the design of stimuli-responsive hydrogels

Novel supramolecular affinity materials based on (−)-isosteviol as molecular templates

• Christina Lohoelter,
• Malte Brutschy,
• Daniel Lubczyk and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2013, 9, 2821–2833, doi:10.3762/bjoc.9.317

• ][6][7][8][9][10]. Particular interest was given to C3-symmetric structures, serving e.g. as templates in asymmetric catalysis or molecular recognition [11][12][13][14]. A specific but potent subclass of such C3-symmetric architectures is represented by triphenylene ketals [15]. They have found

Synthesis of enantiopure sugar-decorated six-armed triptycene derivatives

• Paola Bonaccorsi,
• Maria Luisa Di Gioia,
• Antonella Leggio,
• Lucio Minuti,
• Teresa Papalia,
• Carlo Siciliano,
• Andrea Temperini and
• Anna Barattucci

Beilstein J. Org. Chem. 2013, 9, 2410–2416, doi:10.3762/bjoc.9.278

• chemistry. Moreover, they have been investigated for their potential applications in molecular recognition, showing powerful complexation abilities toward different kinds of organic guests [3][4]. Many biological processes, such as cell–cell communication, immune response and cancer metastasis, are

• cluster effect [7][8][9][10][11]. These glycoconjugates showed their potentialities not only in the interpretation of molecular recognition events but also in biotechnological, pharmaceutical and medical fields [12]. Our research interest is focused on the synthesis of new glycoconjugates and the study of

• tool for the study of molecular recognition. Experimental General methods. All commercial reagents and solvents (AR, LabScan Ltd.; SpS, Romil Ltd.) were used without further purification. All syntheses were carried out under atmospheric conditions unless otherwise noted. Analytical TLC was performed on

Structure elucidation of β-cyclodextrin–xylazine complex by a combination of quantitative ¹H–¹H ROESY and molecular dynamics studies

• Syed Mashhood Ali,
• Kehkeshan Fatma and
• Snehal Dhokale

Beilstein J. Org. Chem. 2013, 9, 1917–1924, doi:10.3762/bjoc.9.226

• science and is the basis for most of the vital biological processes [1]. The basis of supramolecular chemistry is molecular recognition where host and guest species interact with each other and exist as a single system. These host–guest systems symbolize simplest examples of supramolecular systems in

Molecular assembly of amino acid interlinked, topologically symmetric, π-complementary donor–acceptor–donor triads

• M. B. Avinash,
• K. V. Sandeepa and
• T. Govindaraju

Beilstein J. Org. Chem. 2013, 9, 1565–1571, doi:10.3762/bjoc.9.178

• realized by modulating the chemical functionality of interlinking amino acids. Keywords: amino acids; charge transfer; designer functional molecules; molecular assembly; molecular recognition; Findings Geometric shapes, size and patterns have attracted the inquisitive human mind since time immemorial [1

• ][2]. The significance of geometric complementarity and chemical functionality can be exemplified by the well-known “lock and key” mechanism of enzymes as well as the prototypal molecular recognition manifested in biochemical processes [1][2][3][4]. It is this elementary yet elegant design strategy

• symmetric and π-complementary pyrene and NDI. Consequently, free-floating high-aspect-ratio supercoiled nanofibres and hierarchical helical bundles of triads are realized by modulating the chemical functionality of interlinking amino acids. Such molecular-recognition processes embodied in pertinent designer

The diketopiperazine-fused tetrahydro-β-carboline scaffold as a model peptidomimetic with an unusual α-turn secondary structure

• Francesco Airaghi,
• Andrea Fiorati,
• Giordano Lesma,
• Manuele Musolino,
• Alessandro Sacchetti and
• Alessandra Silvani

Beilstein J. Org. Chem. 2013, 9, 147–154, doi:10.3762/bjoc.9.17

• are structural motifs commonly found in bioactive peptides, which, besides being fundamental in protein folding, play a central role as molecular-recognition elements [31][32][33][34]. In addition to the most frequently occurring β and γ-turns, reversal of the polypeptide chain direction in globular

Self-assembled organic–inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles

• Ângelo M. L. Denadai,
• Frederico B. De Sousa,
• Joel J. Passos,
• Fernando C. Guatimosim,
• Kirla D. Barbosa,
• Ana E. Burgos,
• Fernando Castro de Oliveira,
• Jeann C. da Silva,
• Bernardo R. A. Neves,
• Nelcy D. S. Mohallem and
• Rubén D. Sinisterra

Beilstein J. Org. Chem. 2012, 8, 1867–1876, doi:10.3762/bjoc.8.215

• (CDs) can be associated with the inorganic matrix as an interesting strategy, since these macromolecules have been used for several devices with different properties, from light-responsive matrices to molecular recognition materials [12][13]. CDs are oligosaccharides commonly formed by six, seven or

Mannose-decorated cyclodextrin vesicles: The interplay of multivalency and surface density in lectin–carbohydrate recognition

• Ulrike Kauscher and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2012, 8, 1543–1551, doi:10.3762/bjoc.8.175

• ; cyclodextrins; lectins; molecular recognition; multivalency; vesicles; Introduction The surface modification of materials with carbohydrates has attracted much attention due to the fact that such materials can be compared to and compatible with the cell surface [1]. The “glycocalyx” is a dense layer on the

Interaction of cyclodextrins with pyrene-modified polyacrylamide in a mixed solvent of water and dimethyl sulfoxide as studied by steady-state fluorescence

• Akihito Hashidzume,
• Yongtai Zheng and
• Akira Harada

Beilstein J. Org. Chem. 2012, 8, 1312–1317, doi:10.3762/bjoc.8.150

• hydrogels [22][23][24][25][26][27] and macroscopic assemblies based on molecular recognition [28][29][30][31]. Aromatic residues absorb light to become excited, and subsequently they can transfer energy and electrons. The interaction of CDs with water-soluble polymers carrying aromatic residues may allow

• one to construct functional systems that convert photo energy based on molecular recognition. Among aromatic compounds, pyrene is the most examined as a fluorescence probe or label because it shows a relatively high fluorescence quantum yield and a relatively long fluorescence lifetime in both monomer

• ][36]. Recently, we have demonstrated this selectivity switching on macroscopic molecular recognition for polyacrylamide-based gels carrying pyrenyl (Py) and CD residues, by changing the composition of a mixed solvent of water and dimethyl sulfoxide (DMSO) [37]. In the present study, the interaction of

The effect of the formyl group position upon asymmetric isomeric diarylethenes bearing a naphthalene moiety

• Renjie Wang,
• Shouzhi Pu,
• Gang Liu and
• Shiqiang Cui

Beilstein J. Org. Chem. 2012, 8, 1018–1026, doi:10.3762/bjoc.8.114

• nucleosides and molecular recognition properties of nucleic acids with the light sensitivity of diarylethenes [34]. Recently, Wu et al. designed and synthesized a novel diarylethene-containing dithiazolethene, which exhibited a gated photochromic reactivity controlled by complexation/dissociation with BF3 [35

Parallel and four-step synthesis of natural-product-inspired scaffolds through modular assembly and divergent cyclization

• Hiroki Oguri,
• Haruki Mizoguchi,
• Hideaki Oikawa,
• Aki Ishiyama,
• Masato Iwatsuki,
• Kazuhiko Otoguro and
• Satoshi Ōmura

Beilstein J. Org. Chem. 2012, 8, 930–940, doi:10.3762/bjoc.8.105

• groups and hydrogen-bond donors or acceptors. The incorporation of multiple sp3-centers on the scaffold creates a unique three-dimensional shape of the surface, which is responsible for specific molecular recognition with biomacromolecules in the cellular context [1][2][3]. To generate diverse

Investigation of the network of preferred interactions in an artificial coiled-coil association using the peptide array technique

• Raheleh Rezaei Araghi,
• Carsten C. Mahrenholz,
• Rudolf Volkmer and
• Beate Koksch

Beilstein J. Org. Chem. 2012, 8, 640–649, doi:10.3762/bjoc.8.71

• close to and within the interhelical core (a,d,e,g), which are most important for molecular recognition, were mutated. More specifically, hydrophobic (a15,d18) and electrostatic (e19,g21) positions were mutated simultaneously (Figure 2). The 35mer mutants on the membrane only differ in the positions

Enantioselective supramolecular devices in the gas phase. Resorcin[4]arene as a model system

• Caterina Fraschetti,
• Matthias C. Letzel,
• Antonello Filippi,
• Maurizio Speranza and
• Jochen Mattay

Beilstein J. Org. Chem. 2012, 8, 539–550, doi:10.3762/bjoc.8.62

• life's supramolecular systems in which the guest molecule (e.g., amino acids, neurotransmitters, drugs) is selectively captured into the host macromolecular structure (molecular recognition) and transformed catalytically at a specific “active site” (enzyme catalysis) [1][2][3]. Furthermore, the

• the effective probability that the necessary proton transfer from T to B occurs. Rigid resorcin[4]arenes as chiral selectors of amino acids and neurotransmitters. Further insights into the molecular recognition of basket resorcin[4]arene V towards representative chiral molecules were gathered. For

Synthesis of multivalent host and guest molecules for the construction of multithreaded diamide pseudorotaxanes

• Nora L. Löw,
• Egor V. Dzyuba,
• Boris Brusilowskij,
• Lena Kaufmann,
• Elisa Franzmann,
• Wolfgang Maison,
• Emily Brandt,
• Daniel Aicher,
• Arno Wiehe and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2012, 8, 234–245, doi:10.3762/bjoc.8.24

• these concepts are not only molecular recognition and the noncovalent bonds themselves, but also self-assembly, self-sorting, templation and multivalent binding [1][2][3][4][5][6][7][8]. Consequently, the reductionist investigation of synthetic supramolecules can help us to understand biological systems

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• -substituted phenol; however, in host–guest chemistry an asymmetric macrocycle can provide a site for enantioselective molecular recognition. In the case of p-tert-butylcalix[n]arenes the tert-butyl substituent can be removed, as mentioned previously, through a retro-Friedel–Crafts acylation, and replaced by

• function as a molecular recognition centre. The cavity created by the lipophilic phenolic units, particularly when held in place through allosteric effects of lower-rim substituents bound to metals, can accommodate a number of quaternary ammonium ions or buckminsterfullerene, C60. Consequently, the ability

Binding of group 15 and group 16 oxides by a concave host containing an isophthalamide unit

• Jens Eckelmann,
• Vittorio Saggiomo,
• Svenja Fischmann and
• Ulrich Lüning

Beilstein J. Org. Chem. 2012, 8, 11–17, doi:10.3762/bjoc.8.2

• ; macrocycle; molecular recognition; Introduction In the last decade, isophthalamide derivatives have become attractive neutral hosts as anion receptors [1][2]. Some of these derivatives show a high selectivity for one anion over others [3]. Isophthalamide units have also been incorporated into macrocycles [4

(How) does 1,3,5-triethylbenzene scaffolding work? Analyzing the abilities of 1,3,5-triethylbenzene- and 1,3,5-trimethylbenzene-based scaffolds to preorganize the binding elements of supramolecular hosts and to improve binding of targets

• Xing Wang and
• Fraser Hof

Beilstein J. Org. Chem. 2012, 8, 1–10, doi:10.3762/bjoc.8.1

• Xing Wang Fraser Hof University of Victoria, Department of Chemistry, Victoria, BC, V8W 3V6, Canada 10.3762/bjoc.8.1 Abstract 1,3,5-triethylbenzenes have been widely used as supramolecular templates to organize molecular-recognition elements. It is believed that the steric-gearing effect of the

• methyl groups, but the size of this advantage can be small and is dependent on the groups involved. Keywords: binding affinity; entropy; molecular recognition; scaffolds; supramolecular hosts; triethylbenzene; trimethylbenzene; Introduction Supramolecular hosts use arrays of multiple weak interactions

• of preorganization [3][4]. As a nonmacrocyclic alternative, 1,3,5-triethylbenzenes are widely used as an easy-to-synthesize and general scaffold for presenting molecular-recognition elements in a convergent manner (Figure 1) [1][5]. These systems were spawned by the work of Mislow, who studied the

Highly efficient cyclosarin degradation mediated by a β-cyclodextrin derivative containing an oxime-derived substituent

• Michael Zengerle,
• Florian Brandhuber,
• Christian Schneider,
• Franz Worek,
• Georg Reiter and
• Stefan Kubik

Beilstein J. Org. Chem. 2011, 7, 1543–1554, doi:10.3762/bjoc.7.182

• cyclodextrins goes beyond molecular recognition since the recognition event can in some cases be coupled with the chemical transformation of a substrate. This property was already realized in 1959 when it was shown that native cyclodextrins accelerate the cleavage of some acetic acid esters [12]. Subsequent

Supramolecular chemistry II

• Christoph A. Schalley

Beilstein J. Org. Chem. 2011, 7, 1541–1542, doi:10.3762/bjoc.7.181

• cell. But the same concepts are useful for generating materials with function, when for example the building blocks are programmed appropriately to find their places in a larger, noncovalent architecture. The basis for all these concepts is molecular recognition. Recently, many studies have been

Chiral recognition of ephedrine: Hydrophilic polymers bearing β-cyclodextrin moieties as chiral sensitive host molecules

• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 1516–1519, doi:10.3762/bjoc.7.177

• ; stimuli-responsive polymer; Findings Chiral recognition is an important topic in medical and pharmaceutical applications. The sheer number of publications dealing with chiral and molecular recognition systems underlines the importance of finding reliable recognition systems [1][2][3][4][5]. Particularly

pH-Responsive chromogenic-sensing molecule based on bis(indolyl)methene for the highly selective recognition of aspartate and glutamate

• Litao Wang,
• Xiaoming He,
• Yong Guo,
• Jian Xu and
• Shijun Shao

Beilstein J. Org. Chem. 2011, 7, 218–221, doi:10.3762/bjoc.7.29

• )methene; colorimetric sensor; molecular recognition; proton transfer; Introduction The development of artificial receptors for the selective recognition of biologically important species has attracted much attention [1][2]. However, compared to the large number of chromo/fluororeceptors for cations or

• anions [3][4][5][6][7], the development of artificial receptors for amino acids is quite limited. The effective and selective molecular recognition or sensing of unprotected amino acids in aqueous solution is still a challenging problem due to their highly hydrophilic character [8]. Several studies have

An easy assembled fluorescent sensor for dicarboxylates and acidic amino acids

• Xiao-bo Zhou,
• Yuk-Wang Yip,
• Wing-Hong Chan and
• Albert W. M. Lee

Beilstein J. Org. Chem. 2011, 7, 75–81, doi:10.3762/bjoc.7.11

• developed fluorescent probes for detecting dicarboxylates and trifunctional aminoacids [17][18]. To continue our interest in this research direction, we report here the facile synthesis and molecular recognition properties of two new sensing probes 1 and 2. Trimethyl- or triethylbenzene have been widely

• used building blocks to prepare both tripodal or ditopic supramolecular systems for molecular recognition [19][20][21][22][23][24]. An obvious incentive for the use of the mesitylyl moiety is that the required 1,3,5-trimethyl-2,4-bis(bromomethyl)benzene and 1,3,5-trimethyl-2,4,6-tri(bromomethyl)benzene

Gelation or molecular recognition; is the bis-(α,β-dihydroxy ester)s motif an omnigelator?

• Peter C. Griffiths,
• David W. Knight,
• Ian R. Morgan,
• Amy Ford,
• James Brown,
• Ben Davies,
• Richard K. Heenan,
• Stephen M. King,
• Robert M. Dalgliesh,
• John Tomkinson,
• Stuart Prescott,
• Ralf Schweins and
• Alison Paul

Beilstein J. Org. Chem. 2010, 6, 1079–1088, doi:10.3762/bjoc.6.123

• gelation of liquids by low molecular weight solutes at low concentrations gives an insight into many molecular recognition phenomena and also offers a simple route to modifying the physical properties of the liquid. Bis-(α,β-dihydroxy ester)s are shown here to gel thermoreversibly a wide range of solvents

• based on hydrogen bonding of the end-group was confirmed by IR and circular dichroism (CD) spectroscopic characterisation. The specific stereochemistry of the gelator end-groups is a crucial factor, providing an obvious analogy to molecular recognition phenomena. Small-angle neutron scattering provided

• universality of the radius would seem to be a feature of the gelator structure rather than the solvent, i.e., self-association driven by a molecular recognition process, as opposed to a classical aggregation such as that observed in surfactants. There is a negligible variation in the scattering behavior with