Synthesis and characterization of low-molecular-weight π-conjugated polymers covered by persilylated β-cyclodextrin

• Aurica Farcas,
• Ana-Maria Resmerita,
• Andreea Stefanache,
• Mihaela Balan and
• Valeria Harabagiu

Beilstein J. Org. Chem. 2012, 8, 1505–1514, doi:10.3762/bjoc.8.170

• bulkier silylated groups, affecting the ability of the diborate groups from the DOF molecule to partially penetrate the PS-βCD cavity. Keywords: alternating fluorene-bithiophene copolymer; cyclodextrins; interlocked molecules; macrocycles; persilylated β-cyclodextrin; polyrotaxanes; Introduction Organic

• several known host molecules, e.g., crown ethers [32], cyclodextrins (CDs) have been employed for the synthesis of polyrotaxanes with π-conjugated polymers. As a result, many CD-based rotaxanes and polyrotaxanes have been reported until now [5][11][12][19][20][21][22][23][24][25][26][27][28][29][30][31

Impact of cyclodextrins on the behavior of amphiphilic ligands in aqueous organometallic catalysis

• Hervé Bricout,
• Estelle Léonard,
• Christophe Len,
• David Landy,
• Frédéric Hapiot and
• Eric Monflier

Beilstein J. Org. Chem. 2012, 8, 1479–1484, doi:10.3762/bjoc.8.167

• increase in the catalytic performances. Keywords: amphiphilic phosphanes; biphasic system; cyclodextrins; micelles; Introduction Facing the need of developing a greener chemistry, chemists have recently focused their investigations on clean transformation processes to convert organic molecules into

• substrates constitutes a real challenge not completely solved so far. Recently, we showed that an association of cyclodextrins (CDs) and amphiphilic phosphanes could significantly improve the catalytic performances in an aqueous rhodium-catalyzed hydroformylation of higher olefins [6]. Herein we clearly

• complexes. Acknowledgements Roquette Frères (Lestrem, France) is gratefully acknowledged for the generous donation of cyclodextrins.

Restructuring polymers via nanoconfinement and subsequent release

• Alan E. Tonelli

Beilstein J. Org. Chem. 2012, 8, 1318–1332, doi:10.3762/bjoc.8.151

• . In this review we summarize the behaviors and uses of coalesced polymers, and attempt to draw conclusions on the relationship between their behavior and the organization/structures/conformations of the constituent polymer chains achieved upon coalescence from their ICs. Keywords: cyclodextrins

• coalesced bulk polymer sample. This process is illustrated in Figure 1, in which the cyclic starches, cyclodextrins (CDs), are the host molecules used to form ICs with guest polymers [1][2]. In polymer ICs formed with CDs and other small-molecule hosts, such as urea, thiourea, cyclotriphosphazenes, and

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

• Gobancho, Chiyoda-ku, Tokyo 102-0076, Japan 10.3762/bjoc.8.150 Abstract The interaction of β- and γ-cyclodextrins (β-CD and γ-CD, respectively) with polyacrylamide modified with pyrenyl (Py) residues (pAAmPy) was investigated in a mixed solvent of water and dimethyl sulfoxide (DMSO) by steady-state

• , respectively. Using the fluorescence spectra, equilibrium constants of the formation of Py dimers and the complexation of β-CD and γ-CD with Py residues were roughly estimated based on simplified equilibrium schemes. Keywords: cyclodextrins; interaction; pyrene-modified polyacrylamide; steady-state

• fluorescence; water/DMSO mixed solvent; Introduction Cyclodextrins (CDs) are cyclic oligomers composed of glucopyranose units linked through α-1,4-glycoside bonding. They bear a tapered structure with a narrower rim of primary hydroxy groups and a wider rim of secondary hydroxy groups. CDs of 6, 7, and 8

Cyclodextrin nanosponge-sensitized enantiodifferentiating photoisomerization of cyclooctene and 1,3-cyclooctadiene

• Wenting Liang,
• Cheng Yang,
• Masaki Nishijima,
• Gaku Fukuhara,
• Tadashi Mori,
• Andrea Mele,
• Franca Castiglione,
• Fabrizio Caldera,
• Francesco Trotta and
• Yoshihisa Inoue

Beilstein J. Org. Chem. 2012, 8, 1305–1311, doi:10.3762/bjoc.8.149

• from that reported for the conventional sensitizer-appended monomeric cyclodextrins, affording chiral (E)-cyclooctene and (E,Z)-cyclooctadiene in enantiomeric excesses critically dependent on the solution pH and solvent composition employed, revealing the active roles of chiral void spaces of CDNS in

• the photochirogenic reaction. Keywords: cyclodextrins; 1,3-cyclooctadiene; cyclooctene; nanosponge; photochirogenesis; photoisomerization; Introduction The precise control of chiral photoreactions, or photochirogenesis, is one of the most challenging topics in current photochemistry [1][2][3]. Weak

• ], hydrogen-bonding templates [12], cyclodextrins [13][14][15][16][17][18][19][20][21] and serum albumins [22][23], have hitherto been employed to mediate chiral photoreactions. External factors, such as temperature [13], solvent [17], pressure [18] and irradiation wavelength [24], have also been found to

Superstructures with cyclodextrins: Chemistry and applications

• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 1303–1304, doi:10.3762/bjoc.8.148

• Helmut Ritter Institute of Organic Chemistry and Macromolecular Chemistry II, Heinrich-Heine-University of Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany 10.3762/bjoc.8.148 Keywords: cyclodextrins; superstructures; Cyclodextrins (CDs) are cyclic oligosaccharides consisting of 6 (α

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

• der Bundeswehr, Neuherbergstraße 11, D-80937 München, Germany 10.3762/bjoc.7.182 Abstract The potential of appropriately substituted cyclodextrins to act as scavengers for neurotoxic organophosphonates under physiological conditions was evaluated. To this end, a series of derivatives containing

• the nine compounds investigated, one exhibited remarkable activity, completely preventing acetylcholinesterase inhibition by the (−)-enantiomer of cyclosarin within seconds under the conditions of the assay. Thus, these investigations demonstrate that decoration of cyclodextrins with appropriate

• substituents represents a promising approach for the development of scavengers able to detoxify highly toxic nerve agents. Keywords: acetylcholinesterase; cyclodextrins; cyclosarin; neurotoxic organophosphonates; oximes; Introduction Cyclodextrins, cyclic oligosaccharides composed of α-1,4-linked D-glucose

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

• -containing polymer. The supramolecular structures obtained by complexation of ephedrine and cyclodextrin were verified by 2-D ROESY NMR measurements. Dynamic light scattering showed clear differences in the mean coil size. Keywords: chiral recognition; cyclodextrins; ephedrine; host–guest interaction

• , the use of cyclodextrins as chiral host molecules has been the focus of attention for many investigations [6][7]. β-Cyclodextrins (β-CDs) are widely used as selectors for the resolution of enantiomers of chiral drugs in both separation techniques and spectroscopic methods [8][9][10][11][12][13][14

• ]. Cyclodextrins are cyclic oligosaccharides comprising six, seven or eight α-1–4-linked D-glucopyranose units. They are used in pharmaceutical, medical and industrial applications, allowing even hydrophobic molecules to become water-soluble [15][16]. However, there are only a few works published dealing with

Supramolecular FRET photocyclodimerization of anthracenecarboxylate with naphthalene-capped γ-cyclodextrin

• Qian Wang,
• Cheng Yang,
• Gaku Fukuhara,
• Tadashi Mori,
• Yu Liu and
• Yoshihisa Inoue

Beilstein J. Org. Chem. 2011, 7, 290–297, doi:10.3762/bjoc.7.38

• ) 3 are chiral (Scheme 1). This chiral photoreaction turned out to be an ideal benchmark system for exploring and comparing the performance of various chiral hosts, such as cyclodextrins (CDs), proteins and chiral hydrogen-bonding templates. γ-CD can significantly accelerate the photocyclodimerization

• presence of native and modified γ-cyclodextrins (CDs)a. Supporting Information Supporting Information File 26: NMR and HR–MS data of compounds 6 and 7. Acknowledgements This work was supported by JST (CY and YI), JSPS (YI). QW thanks the Student Exchange Support Program of JASSO for financial support for

Effects of anion complexation on the photoreactivity of bisureido- and bisthioureido-substituted dibenzobarrelene derivatives

• Heiko Ihmels and
• Jia Luo

Beilstein J. Org. Chem. 2011, 7, 278–289, doi:10.3762/bjoc.7.37

• ], liquid crystals [18], chiral crystals [19][20][21][22][23], or cyclodextrins (CDs) [24][25][26] in such a way that the chiral environment within the binding site has an influence on preferential reaction pathways, thus inducing stereoselective photoreactions. Along these lines, the di-π-methane (DPM

Chiral recognition of macromolecules with cyclodextrins: pH- and thermosensitive copolymers from N-isopropylacrylamide and N-acryloyl-D/L-phenylalanine and their inclusion complexes with cyclodextrins

• Sabrina Gingter,
• Ella Bezdushna and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 204–209, doi:10.3762/bjoc.7.27

• of the side groups of copolymers 3D and 3L and their solubility behaviour were investigated by dynamic light scattering and 2D NMR spectroscopy, respectively. Keywords: amino acid; chiral recognition; cyclodextrins; LCST; stimuli-responsive polymers; Introduction Chiral recognition has attracted

• few papers exist dealing with recognition of chiral polymeric systems by use of cyclodextrins. One of the first published methods was the enantioselective inclusion of isotactic polylactides with cyclodextrin (CD) rings [2]. Cyclodextrins (CDs) are cyclic oligosaccharides comprising six, seven or

Cross-metathesis of allylcarboranes with O-allylcyclodextrins

• Ivan Šnajdr,
• Zbyněk Janoušek,
• Jindřich Jindřich and
• Martin Kotora

Beilstein J. Org. Chem. 2010, 6, 1099–1105, doi:10.3762/bjoc.6.126

• carborane-cyclodextrin conjugates. Herein, we report our preliminary results. Results and Discussion Although studies on the inclusion of carboranes into cyclodextrins have previously been reported [9][10][11][12][13], a synthesis of cyclodextrin-carborane conjugates connected by a linker has not been, to

• carried out according to the previously reported procedures [8]. O-Allylcyclodextrins 2 were prepared by allylation of β-cyclodextrins under various reaction conditions (2I-O-allyl-β-cyclodextrin for 2a [22], 3I-O-allyl-β-cyclodextrin for 2b [23], and 6I-O-allyl-β-cyclodextrin for 2c) followed by

• prepared carborane-cyclodextrin conjugates 3. Supporting Information Supporting Information File 164: Experimental details and characterisation data of peracetylated cyclodextrins 2a, 2b and 2c. Acknowledgements This work was supported by the Ministry of Education, Youth, and Sports (project No

Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine)

• Katja Hofmann,
• Ingolf Kahle,
• Frank Simon and
• Stefan Spange

Beilstein J. Org. Chem. 2010, 6, No. 79, doi:10.3762/bjoc.6.79

• solubility in organic solvents [26]. The use of cyclodextrins (CD) provides a further opportunity to solve these problems. Due to the formation of host–guest complexes with CD both reactants become completely soluble in water. According to Ritter et al., the 2,6-O-β-dimethylcyclodextrin (β-DMCD) derivative

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

• ]. Many types of synthetic ammonium ion receptors are available, ranging from crown ethers, calixarenes, porphyrins, cucurbiturils, cyclodextrins and cyclopeptides to tweezer ligands, sterically geared tripods and several types of metal complexes. The most important methods used for evaluating ammonium

• substance classes that have been mostly used in organic ammonium ion recognition: crown ethers, calixarenes [54], cyclodextrins [55][56][57], cucurbiturils, porphyrins, phosphonate based receptors, tripodal receptors, tweezer ligands, clefts, cyclopeptides and metal complexes. We have not included rotaxanes

(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

• tetramers of L-rhamno- and D-gulo-configured oxetane-SAAs 24 and 25 (Figure 12) have been synthesised by Fleet et al. [59] as mimics of naturally occurring cyclic peptides and cyclodextrins, although no further conformational and recognition studies on these compounds have currently been published. Urea

• phosphate were obtained from NMR titration experiments for both series of glucooligomers. The binding affinity of the thiourea and guanidine oligomers was stronger than in the case of the urea analogues. Stimulated by the interesting supramolecular properties and applications of cyclodextrins (CDs), a range

• of cyclodextrins. Determination of the inclusion capabilities towards a series of structurally diverse guests demonstrated that large-ring CTs are well suited for forming supramolecular complexes in water [77][79][88]. Guanidine-linked sugars The use of the guanidine functional group to connect