A green approach to the synthesis of novel phytosphingolipidyl β-cyclodextrin designed to interact with membranes

• Yong Miao,
• Florence Djedaïni-Pilard and
• Véronique Bonnet

Beilstein J. Org. Chem. 2014, 10, 2654–2657, doi:10.3762/bjoc.10.278

• time in cyclodextrin chemistry via solvent-free substitution of aminocyclodextrin followed by the use of a new, more environmentally friendly peptide coupling agent known as COMU (1-cyano-2-ethoxy-2-oxoethylidenaminooxy)dimethylaminomorpholinocarbenium hexafluorophosphate). Finally, by optimized

• (ethyl (hydroxyimino)cyanoacetate), has been reported as a greener, safer and more efficient peptide coupling reagent [12]. It was decided that COMU would be used as a peptide coupling reagent in the modification of cyclodextrin using the described conditions in previous studies [9]. The carboxyl group

• (yield = 80%, see Scheme 1). Indeed, COMU is an efficient peptide coupling reagent and can be used in the synthesis of cyclodextrin derivatives. Insertion of fatty acid chain In previous work, the synthesis of the reaction of permethylated 6-amino-6-deoxy-β-cyclodextrin and vinyl ester catalyzed by

Cyclodextrin-grafted polymers functionalized with phosphanes: a new tool for aqueous organometallic catalysis

• Jonathan Potier,
• Stéphane Menuel,
• David Mathiron,
• Véronique Bonnet,
• Frédéric Hapiot and
• Eric Monflier

Beilstein J. Org. Chem. 2014, 10, 2642–2648, doi:10.3762/bjoc.10.276

• CNRS 3517, 33 rue St Leu, 80039 Amiens, France 10.3762/bjoc.10.276 Abstract New cyclodextrin (CD)-grafted polymers functionalized with water-soluble phosphanes were synthesized in three steps starting from polyNAS. Once characterized by NMR spectroscopy and size-exclusion chromatography, they were

• used as additives in Rh-catalyzed hydroformylation of 1-hexadecene. The combined supramolecular and coordinating properties of these polymers allowed increasing the catalytic activity of the reaction without affecting the selectivities. Keywords: biphasic catalysis; cyclodextrin; hydroformylation

• compartments [6]. We especially developed biphasic catalytic systems in which cyclodextrin (CD) derivatives acted as interfacial additives [7][8]. These torus-like macrorings proved to be appropriate to supramolecularly recognize C8–C10 alkenes within their cavity and convert them into their corresponding

Improving ITC studies of cyclodextrin inclusion compounds by global analysis of conventional and non-conventional experiments

• Eléonore Bertaut and
• David Landy

Beilstein J. Org. Chem. 2014, 10, 2630–2641, doi:10.3762/bjoc.10.275

• Eleonore Bertaut David Landy Univ Lille Nord de France, F-59000 Lille, France ULCO, UCEIV, F-59140 Dunkerque, France 10.3762/bjoc.10.275 Abstract The study of 1:1 cyclodextrin inclusion compounds by isothermal titration calorimetry was explored in a theoretical and experimental point of view to

• stability, enthalpy, or solubility. Keywords: cyclodextrins; global analysis; inclusion compounds; isothermal titration calorimetry; non-conventional experiments; Introduction The stability and thermodynamics of cyclodextrin inclusion compounds in solutions may be investigated with various analytical

• limited. As a consequence, most of these methods have not been applied to cyclodextrin complexes. Moreover, not all the non-conventional experiments have been described to date. Finally, while titration efficiency has been thoroughly studied [7][18][19], few is known about the efficiency of non

Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups

• Ji-Hun Seo,
• Shino Nakagawa,
• Koichiro Hirata and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2014, 10, 2623–2629, doi:10.3762/bjoc.10.274

• -soluble PRX crosslinker can be applied to design degradable photosetting plastics potentially used in the industrial or biomedical field. Keywords: α-cyclodextrin; composite resin; disulfide; polyrotaxane; Vickers hardness; Introduction Polyrotaxane (PRX) is a supermolecule containing host molecules

• , e.g., α-cyclodextrin (α-CD), threaded on a linear guest molecule, e.g., poly(ethylene glycol) (PEG) [1]. The threaded α-CD molecules are known to be reversibly disassembled when a cleavable end-capping group was introduced in the PEGs, and the cleavable reaction was triggered by proper signals [2][3

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

• : cyclodextrin; biocide; encapsulation; host–guest chemistry; pathogen; textile; Introduction Since the first reference to cyclodextrins (CDs) in 1891 by Villiers, CD has been of great interest to researchers [1]. Cyclodextrins are composed of several α-D-glucopyranose units linked 1→4 and arranged in a conical

• ]. Similarly, Priya et al. used sodium citrate as a reducing agent followed by capping with β-cyclodextrin for the preparation of silver nanoparticles [87] with an increased biocidal activity against P. aeruginosa and S. aureus of the β-CD capped silver nanoparticles compared to the uncapped ones. The proposed

• , the following antimicrobial mechanism was proposed: i) the carbon nanotube embedded in water-insoluble cyclodextrin polyurethane polymers pierce the bacterial cell membrane by direct contacts, and ii) the copper nanoparticles release copper inside the bacterial cell. The combination of these two steps

Synthesis and characterization of a hyper-branched water-soluble β-cyclodextrin polymer

• Francesco Trotta,
• Fabrizio Caldera,
• Roberta Cavalli,
• Andrea Mele,
• Carlo Punta,
• Lucio Melone,
• Franca Castiglione,
• Barbara Rossi,
• Monica Ferro,
• Vincenza Crupi,
• Domenico Majolino,
• Valentina Venuti and
• Dominique Scalarone

Beilstein J. Org. Chem. 2014, 10, 2586–2593, doi:10.3762/bjoc.10.271

• hyper-branched water-soluble polymer was synthesized by reacting β-cyclodextrin with pyromellitic dianhydride beyond the critical conditions that allow the phenomenon of gelation to occur. The molar ratio between the monomers is a crucial parameter that rules the gelation process. Nevertheless, the

• concentration of monomers in the solvent phase plays a key role as well. Hyper-branched β-cyclodextrin-based polymers were obtained performing the syntheses with excess of solvent and cross-linking agent, and the conditions for critical dilution were determined experimentally. A hyper-branched polymer with very

• high water solubility was obtained and fully characterized both as for its chemical structure and for its capability to encapsulate substances. Fluorescein was used as probe molecule to test the complexation properties of the new material. Keywords: β-cyclodextrin; complexation; gelation

Synthesis of graft polyrotaxane by simultaneous capping of backbone and grafting from rings of pseudo-polyrotaxane

• Kazuaki Kato,
• Katsunari Inoue,
• Masabumi Kudo and
• Kohzo Ito

Beilstein J. Org. Chem. 2014, 10, 2573–2579, doi:10.3762/bjoc.10.269

• (PEG) and the formation of inclusion complexes with α-cyclodextrin (α-CD). PEG with multiple functional groups at each end was prepared by the condensation of PEG-amine and D-gluconic acid; the PEG derivative formed an inclusion complex with α-CD. The polymerization of multiple hydroxy groups at the

• reaction yielded graft polyrotaxanes in a good yield, demonstrating a significant simplification of the synthesis of graft polyrotaxanes. Keywords: branch structure; cyclodextrin; end capping; graft polyrotaxane; polyrotaxane; Introduction Polyrotaxanes, interlocked molecules composed of polymer chains

• chromatography (SEC) with a calibration curve using PEG standards. The standard polymers for the calibration of the molecular weights by SEC were purchased from Polymer Source Inc. α-Cyclodextrin (α-CD) was purchased from Nihon Shokuhin Kako Co. Ltd. 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) was purchased from

Host–guest-driven color change in water: influence of cyclodextrin on the structure of a copper complex of poly((4-hydroxy-3-(pyridin-3-yldiazenyl)phenethyl)methacrylamide-co-dimethylacrylamide)

• Nils Retzmann,
• Gero Maatz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2480–2483, doi:10.3762/bjoc.10.259

• -yldiazenyl)phenethyl)methacrylamide-co-dimethylacrylamide) and its reversible optical and complex-forming properties due to copper and cyclodextrin (CD) interactions. Color changing effects are characterized by UV–vis spectroscopy and the supramolecular behavior is investigated by dynamic light scattering

• experiments. Keywords: cyclodextrin; copolymer; copper(II) sulfate; supramolecular; water complex; Introduction In recent years, the interest in stimuli-responsive polymers increased exponentially [1]. Many polymers have been described, showing sensitivity towards e.g. light, pH and heat [2][3][4

• ]. Accordingly, polymer-based fluorescent and colorimetric chemosensors have attracted great attention due to several important advantages such as their simplicity of use, or their versatile structural designs [5]. In this connection, also the interactions of suitable polymers with cyclodextrin (CD) have been

Towards the sequence-specific multivalent molecular recognition of cyclodextrin oligomers

• Michael Kurlemann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 2428–2440, doi:10.3762/bjoc.10.253

• . Furthermore, sequence-specific recognition motifs have been used in various artificial systems in the last years, e.g., to emulate biological processes or to build up new materials with highly specific recognition domains. In this article, we present the preparation of cyclodextrin (CD)-based strands and

• functionalized α- and β-CD, again followed by complete deprotection under Zemplén conditions (Figure 2). Based on MALDI mass spectra of the protected and unprotected cyclodextrin strands impurities by monomeric building blocks respectively dimeric species in the case of trivalent strands can be excluded (see

• 1:1 adduct is preferentially formed, with non-complementary CD strands host–guest adducts of higher stoichiometry are favored. Conclusion In this work we present our first successful attempt to realize the sequence-specific multivalent molecular recognition of cyclodextrin sequences and

A versatile δ-aminolevulinic acid (ΑLA)-cyclodextrin bimodal conjugate-prodrug for PDT applications with the help of intracellular chemistry

• Chrysie Aggelidou,
• Theodossis A. Theodossiou,
• Antonio Ricardo Gonçalves,
• Mariza Lampropoulou and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 2414–2420, doi:10.3762/bjoc.10.251

• , Aghia Paraskevi Attikis, 15310 Greece. Tel. +30210 6503796, Fax: +30 210 6511766 10.3762/bjoc.10.251 Abstract Grafting of δ-aminolevulinic acid (1) moieties on the narrow periphery of a β-cyclodextrin (β-CD) derivative through hydrolysable bonds was implemented, in order to generate a water-soluble

• -cyclodextrin, with an average degree of substitution, DS = 3. Delivery of water-soluble, colorless 2 to cells resulted in intense red fluorescence registered by confocal microscopy, evidently due to the engagement of the intracellular machinery towards formation of PpIX. Conjugate 2 was further complexed with

• , with inherently poor cell permeability and consequently challenging pharmaceutical formulations [5]. We have recently published [6] the covalent conjugation of PpIX to β-cyclodextrin (β-CD), a water-soluble cyclic oligosaccharide host capable of carrying hydrophobic molecules, such as drugs, in its

Phosphinocyclodextrins as confining units for catalytic metal centres. Applications to carbon–carbon bond forming reactions

• Matthieu Jouffroy,
• Rafael Gramage-Doria,
• David Sémeril,
• Dominique Armspach,
• Dominique Matt,
• Werner Oberhauser and
• Loïc Toupet

Beilstein J. Org. Chem. 2014, 10, 2388–2405, doi:10.3762/bjoc.10.249

• cavity-shaped ligands, HUGPHOS-1 and HUGPHOS-2, to generate exclusively singly phosphorus-ligated complexes, in which the cyclodextrin cavity tightly wraps around the metal centre, was explored with a number of late transition metal cations. Both cyclodextrin-derived ligands were assessed in palladium

• study dealing with the Mizoroki–Heck reactions, comparative tests were carried out with WIDEPHOS, a diphosphine analogue of HUGPHOS-2. Keywords: asymmetric hydroformylation; cyclodextrin; Heck reaction; homogeneous catalysis; palladium; phosphine; rhodium; Introduction Since the studies of Fu

Oligomerization of optically active N-(4-hydroxyphenyl)mandelamide in the presence of β-cyclodextrin and the minor role of chirality

• Helmut Ritter,
• Antonia Stöhr and
• Philippe Favresse

Beilstein J. Org. Chem. 2014, 10, 2361–2366, doi:10.3762/bjoc.10.246

• enzymatic catalyzed asymmetric enantiomer-differentiating oligomerizations was investigated. In addition, the poor influence of cyclodextrin on the enantioselectivity of enzymatic catalyzed asymmetric enantiomer-differentiating oligomerizations was studied. Keywords: cyclodextrin; enantioselectivity

• -cyclodextrin (CD) allows the oxidative coupling of poor water soluble phenol derivatives via complexation without using of organic solvents [6][7][8]. However, to the best of our knowledge, there were no studies published dealing with the potential enantioselective control of enzyme catalyzed oligomerization

• reaction of chiral phenol derivatives, respectively. Thus, the enantioselectivity of enzymatic asymmetric enantiomer-differentiating oligomerizations of a chiral mandeloamide-phenol derivative as model compound and the influence of cyclodextrin is a main subject of the present study. Results and Discussion

Effect of cyclodextrin complexation on phenylpropanoids’ solubility and antioxidant activity

• Miriana Kfoury,
• David Landy,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2014, 10, 2322–2331, doi:10.3762/bjoc.10.241

• , stability, release and bioavailability of natural compounds [10][11][12][13]. CDs are a family of cyclic oligosaccharides obtained from enzymatic degradation of starch. The most common native CDs are α-cyclodextrin (α-CD), β-cyclodextrin (β-CD) and γ-cyclodextrin (γ-CD) composed of six, seven and eight (α

• hydoxycinnamic acids (p-coumaric acid (5), caffeic acid (6) and ferulic acid (7)) (Figure 1) was investigated with α-CD, β-CD, hydroxypropyl-β-cyclodextrin (HP-β-CD), randomly methylated β-cyclodextrin (RAMEB) and a low methylated β-cyclodextrin (CRYSMEB). These PPs were selected mainly according to their

• considerably enhances the PPs solubility (up to 17 fold for 1 with a 10 mM RAMEB solution). Similar findings were found in literature [28][35][36][37][38][39]. The solubilizing effect of CDs can be evaluated using their complexation efficiency (CE), i.e., the concentration ratio between cyclodextrin in a

End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

• Carolin Fleischmann,
• Hendrik Wöhlk and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2263–2269, doi:10.3762/bjoc.10.235

• easily utilized in polymer analogous reactions, is presented. The subsequent cycloaddition reaction with propargyl-functionalized methoxypoly(ethylene glycol) yielded polymers bearing phenolphthalein as the covalently attached end group. In presence of per-β-cyclodextrin-dipentaerythritol, the formation

• spectroscopy and even the naked eye. Keywords: cyclodextrin; phenolphthalein; poly(ethylene glycol); supramolecular assembly; UV–vis spectroscopy; Introduction Over the past decades, polymers with well-defined and complex architectures gained increasing attention due to a broad variety of applications

• cyclodextrin (CD) and phenolphthalein (PP) moieties were introduced as the complex-forming groups. Regarding the formation of inclusion complexes, one of the major driving forces is the displacement of enthalpy-rich water molecules from the cyclodextrin cavity, which requires working in aqueous media, ideally

Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label

• Nattawut Yotapan,
• Chayan Charoenpakdee,
• Pawinee Wathanathavorn,
• Boonsong Ditmangklo,
• Hans-Achim Wagenknecht and
• Tirayut Vilaivan

Beilstein J. Org. Chem. 2014, 10, 2166–2174, doi:10.3762/bjoc.10.224

• interaction between the Nile red label and the bulge site. The addition of β-cyclodextrin to the bulged duplexes caused no change in the fluorescence of the Nile red label, whereas a marked blue shift was observed with single-stranded PNA (8 nm) (Figure S17, Supporting Information File 1). This experiment

• addition of cyclodextrin, which indicates possible interactions between the groove-bound Nile red and cyclodextrin. To better understand the effect of neighboring bases on the optical properties of the Nile red-labeled acpcPNA and its duplexes with DNA, four Nile red-labeled acpcPNA sequences (11merAA-Nr

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• polyrotaxanes (4a and 4b), which consist of electron-accepting 9,9-dicyanomethylenefluorene 1 as an inclusion complex in persilylated β- or γ-cyclodextrin (TMS-β-CD, TMS-γ-CD) (1a, 1b) and methyltriphenylamine as an electron-donating molecule. They are statistically distributed into the conjugated chains of 9,9

Photo, thermal and chemical degradation of riboflavin

• Muhammad Ali Sheraz,
• Sadia Hafeez Kazi,
• Sofia Ahmed,
• Zubair Anwar and
• Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

• studied for complexation with RF to achieve its stabilization [111][112][113][114][115][116][117]. In a comparative study of complexation between α- and β-cyclodextrins with RF, β-cyclodextrin was found to form more stable inclusion complexes with RF [116]. The formation of strong and stable inclusion

• complexes of RF with β- and γ-cyclodextrins have also been observed in other studies [111][112][113][114][115]. Such β-cyclodextrin complexes are suitable for fluorescent compounds for which the fluorescence intensity is influenced by the presence of cyclodextrins [113]. A non-inclusion complexation between

• RF and β-cyclodextrin or hydroxypropyl-β-cyclodextrin at low concentrations occurred through hydrogen bonding and resulted in a better solubility of RF along with an enhanced antitumor activity [117]. On the contrary, the formation of inclusion complexes between RF and hydroxypropylated α-, β-, and γ

Influence of cyclodextrin on the UCST- and LCST-behavior of poly(2-methacrylamido-caprolactam)-co-(N,N-dimethylacrylamide)

• Alexander Burkhart and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1951–1958, doi:10.3762/bjoc.10.203

• (LCST) in water and an upper critical solution temperature (UCST) in ethanol, 1-propanol, and 1-butanol. The solubility properties of the copolymers can be influenced significantly by the addition of randomly methylated β-cyclodextrin (CD). The complexation of the copolymers with CD, was confirmed by

• the use of ROESY-NMR-spectroscopy. Keywords: cyclodextrin; LCST; lysine; 2-methacrylamido-caprolactam; UCST; Introduction Recently, increasing interest has been spent on thermoresponsive polymer solutions, mainly because of their potential application in the field of drug delivery, gene delivery, or

• influenced significantly by supramolecular interactions with cyclodextrin [9]. Accordingly, we described in 2003 for the first time, that the LCST of a poly(N-adamantylacrylamide-co-N’-isopropylacrylamide) is influenced by CD [10]. Furthermore, the interaction of poly(pseudo-betaines) with CD leads to an

Orthogonal dual thiol–chloroacetyl and thiol–ene couplings for the sequential one-pot assembly of heteroglycoclusters

• Michele Fiore,
• Gour Chand Daskhan,
• Baptiste Thomas and
• Olivier Renaudet

Beilstein J. Org. Chem. 2014, 10, 1557–1563, doi:10.3762/bjoc.10.160

• successive attachment of sugar residues on a core scaffold such as sugar [6][7], peptide [8][9][10], dendrimer [11][12], cyclodextrin [13][14][15] and polymer [16]. The most common synthetic strategy to build such hGCs relies on a fragment-coupling approach using thiol–ene coupling [17], copper(I)-catalyzed

Synthesis of the first examples of iminosugar clusters based on cyclopeptoid cores

• Mathieu L. Lepage,
• Alessandra Meli,
• Anne Bodlenner,
• Céline Tarnus,
• Francesco De Riccardis,
• Irene Izzo and
• Philippe Compain

Beilstein J. Org. Chem. 2014, 10, 1406–1412, doi:10.3762/bjoc.10.144

• ], β-cyclodextrin [4][5] and porphyrin [7] cores, and with nanoparticles prepared by self-assembly of iminosugar-based glycopolypetides [6]. So far, the largest multivalent effect (up to 610-fold relative inhibition potency increase on a valency-corrected basis) has been achieved on jack bean α

• -mannosidase with β-cyclodextrin-based analogues displaying 14 copies of 1-deoxynojirimycin (DNJ) [4]. Applications of the inhibitory multivalent effect to glycosidases of therapeutic interest were promptly performed and promising results were obtained in the field of Gaucher disease, the most common lysosomal

• , evaluation of the inhibition potency of multivalent iminosugars 10 was performed on this peculiar enzyme (Table 1). Related monovalent controls 11 [3][4] as well as 7-valent β-cyclodextrin-based DNJ clusters 12 [4] have been included for comparative purposes (Figure 3). Our results clearly point out that all

A complete series of 6-deoxy-monosubstituted tetraalkylammonium derivatives of α-, β-, and γ-cyclodextrin with 1, 2, and 3 permanent positive charges

• Martin Popr,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2014, 10, 1390–1396, doi:10.3762/bjoc.10.142

• Prague, Hlavova 8, 128 40, Prague 2, Czech Republic 10.3762/bjoc.10.142 Abstract An efficient synthetic route toward the preparation of a complete series of monosubstituted tetraalkylammonium cyclodextrin (CD) derivatives is presented. Monotosylation of native CDs (α-, β-, γ-) at position 6 gave the

• ; regioselectivity; tetraalkylammonium derivatives; Introduction Cyclodextrins (CDs) are cyclic oligosaccharides with the shape of a hollow truncated cone, first described in 1891 by Villiers [1]. Naturally occurring CDs are named α-, β- and γ-cyclodextrin and are composed of 6, 7 or 8 D-glucopyranose units

• excellent chiral selectors in capillary zone electrophoresis (CZE) [18][19] and as catalysts of chemical reactions [20][21]. The synthesis of some cationic derivatives of β-CD have already been described in the literature (namely 6I-(N,N,N-trimethylammonio)-6I-deoxy-β-cyclodextrin [21] and 6I-(N,N,N’,N‘,N

Substitution effect and effect of axle’s flexibility at (pseudo-)rotaxanes

• Friedrich Malberg,
• Jan Gerit Brandenburg,
• Werner Reckien,
• Oldamur Hollóczki,
• Stefan Grimme and
• Barbara Kirchner

Beilstein J. Org. Chem. 2014, 10, 1299–1307, doi:10.3762/bjoc.10.131

• computational energy profile [22]. The formation of α-cyclodextrin-based [3]pseudorotaxanes in the gas phase was studied by means of density functional calculations [23]. Molecular mechanics calculations were used for a free energy calculation of an α-cyclodextrin rotaxane system and for the investigation of

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

Towards allosteric receptors – synthesis of β-cyclodextrin-functionalised 2,2’-bipyridines and their metal complexes

• Christopher Kremer,
• Gregor Schnakenburg and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 814–824, doi:10.3762/bjoc.10.77

• Abstract Herein, we present three new 2,2’-bipyridines that carry two β-cyclodextrin moieties in different substitution patterns. When coordinated by zinc(II) or copper(I) ions (or their complexes), these compounds undergo conformational changes and switch between “open” and “closed” forms and thereby

• bringing together or separating the cyclodextrin moieties from each other. Keywords: allosteric receptors; 2,2’-bipyridines; β-cyclodextrin; supramolecular chemistry; metal complexes; Introduction In biological systems, recognition events play a major role to guarantee the selectivity of essential

• on-state in the absence of the effector and changes its conformation to the open off-state upon binding of it. In this article we present the synthesis of three new cyclodextrin-functionalised 2,2’-bipyridines 1–3 differing in the bipyridine’s substitution pattern (Scheme 2) and their metal complexes

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

• , 15310 Greece. Tel. +30210 6503796, Fax: +30 210 6511766 10.3762/bjoc.10.73 Abstract β-Cyclodextrin (β-CD) dimers have been prepared using the bioorthogonal Staudinger ligation for the first time. In addition to a known linker, methyl 2-(diphenylphosphanyl)terephthalate, a doubly active linker was

• ) satisfactory aqueous solubility and independent binding capacity of the cavities. Keywords: calculations; conformations; cyclodextrin; dimer; inclusion; PM3; Staudinger ligation; Introduction The Staudinger reaction [1] is a classical method for the preparation of amines from phosphines and azides [2][3

• confirming the structure of dimer 5. However, while the excellent yield of the Staudinger ligation step to 4 showed its applicability and suitability for cyclodextrin substrates, the poor yield of CD-dimer 5 suggested the presence of impediments in the introduction of a second β-CD moiety. Examination of the