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

• -1,4)-linked α-D-glucopyranose units, respectively. Owing to their molecular structure, consisting of a hydrophilic outer surface and a hydrophobic cavity, CDs can form inclusion complexes with organic compounds which enter partly or entirely into their cavity. Inclusion complexes can be obtained

• either in solution or in solid state [14]. The relative stabilities of inclusion complexes are governed by different factors such as hydrogen bonding, hydrophobic interactions, solvation effects as well as the guest molecule's space filling ability [15][16]. CD derivatives are also of great importance

• , since they generally have higher aqueous solubility than native CDs and enhanced binding affinities and selectivity [17]. The aim of this study was to investigate the binding ability of five CDs with seven naturally occurring PPs. Formation constants (Kf) of CD/PP inclusion complexes were calculated by

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

• of stable inclusion complexes was observed, representing an interesting approach towards the formation of star shaped polymers. The decolorization of a basic polymer solution caused by the complexation was of great advantage since this behavior enabled following the complex formation by UV–vis

• 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

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

• spectroscopy (see details in Figures S1 and S2 in Supporting Information File 1). To clarify whether the guest molecule 1 can be accommodated inside the permodified CDs cavities, the approximated stability constant (Ks) was investigated. The Ks of 1a and 1b inclusion complexes in toluene cannot be measured

• reaction of acceptor moieties, which were either in the form of inclusion complexes into TMS-β-CD or TMS-γ-CD cavities (1a, 1b) or non-complexed state 1 with 2 and 3 units in molar ratios 5:4:1 with toluene as a solvent. This was followed by the termination of the growing chains with Br–Ph to yield 4a and

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

• 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

• 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

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

• , respectively. The most commonly utilized feature of native CDs is their ability to form noncovalent inclusion complexes with a wide range of guest molecules [2]. In the majority of industrial applications, natural CDs serve as encapsulation agents with a high affinity toward suitable lipophilic organic guests

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

• Information File 1, Figure S2), anticipated due to the lack of molecular symmetry, while the spectrum of 6 (Figure S2) was simpler reflecting a rather symmetrical structure. The 2D ROESY NMR spectra of 4 and 5 suggested formation of self-inclusion complexes via the phenyl groups of the linker, since strong

• formation in one step. Despite the well verified formation of intra- as well as intermolecular inclusion complexes, the compounds proved to be effective in encapsulating a suitable external guest in each cavity. The data were fully supported by theoretical calculations that confirmed the energetic

• with the cavity exterior H1, H2 and H4. The above are in line with the experimental findings in the 2D ROESY NMR data in D2O. Intermolecular arrangements (Supporting Information File 1, Figure S8), verified by the experimentally observed aggregation, may also incorporate phenyl group inclusion

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

• addition the solution properties of polymers 8a–d and 9a–d as a function of temperature were also evaluated in the presence of different amounts of RAMEB-CD. In general, the 4-tert-butylphenyl as well as the 4-tert-octylphenyl end-group are able to build host-guest inclusion complexes with the RAMEB-CD

Oligomeric epoxide–amine adducts based on 2-amino-N-isopropylacetamide and α-amino-ε-caprolactam: Solubility in presence of cyclodextrin and curing properties

• Julian Fischer and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2803–2811, doi:10.3762/bjoc.9.315

• [5]. The Tc can be influenced for example through copolymerization with hydrophobic or hydrophilic comonomers and further through supramolecular interactions of these comonomers with cyclodextrins (CD) [6][7][8][9][10]. Generally, CDs are water soluble and their ability of forming inclusion complexes

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

• the cavity is hydrophobic [2][3]. The encapsulation of a guest into the CD cavity has a profound effect on the chemical, physical and biological properties of the guest. The structure establishment of CD inclusion complexes in solution state is a challenging task considering the fact that the

• inclusion phenomenon is a dynamic process, the included guest being in fast exchange between the free and bound state, and hence deriving instantaneous information with regard to structural changes is not easy. NMR spectroscopy has evolved as a method of choice for studying inclusion complexes in solution

• the use of molecular dynamic techniques with no prior knowledge about the existence or geometry of CD inclusion complexes [8], accurate and reliable predictions can be made regarding the possible formation and other aspects of inclusion process by following a general simulation protocol [9]. We report

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2013, 9, 1858–1866, doi:10.3762/bjoc.9.217

• inclusion complexes were transferred into 50 mL quartz round-bottomed flasks and bubbled with nitrogen gas for 20 min with stirring before photo-irradiation. Photodimerization of the samples was carried out using a medium-pressure mercury lamp (166.5 W, Heraeus Noblelight GmbH, UVB) as a light source. After

Structures of the reaction products of the AZADO radical with TCNQF₄ or thiourea

• Hideto Suzuki,
• Yuta Kawahara,
• Hiroki Akutsu,
• Jun-ichi Yamada and
• Shin’ichi Nakatsuji

Beilstein J. Org. Chem. 2013, 9, 1487–1491, doi:10.3762/bjoc.9.169

• conditions with thiourea (4), but each component was recovered. This was a rather unexpected result, because some precedent examples of TEMPO-based inclusion complexes are actually known [10][11][12], but this is supposed to be due to the steric hindrance of the extra methyl substituents of the TEMPO radical

Linkage of α-cyclodextrin-terminated poly(dimethylsiloxanes) by inclusion of quasi bifunctional ferrocene

• Helmut Ritter,
• Berit Knudsen and
• Valerij Durnev

Beilstein J. Org. Chem. 2013, 9, 1278–1284, doi:10.3762/bjoc.9.144

• attached are of increasing interest in recent years. For example, polymers bearing β-CD as side or terminal groups and their interaction with classical guest groups such as adamantane or azo-dyes have been intensively studied [1][2][3][4]. The characterization of the inclusion complexes between

• -terminated poly(dimethylsiloxanes) to create novel supramolecular linear or macrocyclic siloxan structures based on double inclusion complexes with ferrocene. Results and Discussion The syntheses of α-CD-terminated poly(dimethylsiloxanes) 4 and 5 were performed by hydrosilylation of mono-((6-N-allylamino)-6

• the derivatives mechanically. In addition, the successful complexation of the α-CD-modified siloxanes and the formation of supramolecular structures via inclusion complexes with ferrocene can be illustrated in the TEM images of 4 (Figure 5). Figure 5A (α-CD-disiloxane 4) shows a majority of globular

The β-cyclodextrin/benzene complex and its hydrogen bonds – a theoretical study using molecular dynamics, quantum mechanics and COSMO-RS

• Jutta Erika Helga Köhler and
• Nicole Grczelschak-Mick

Beilstein J. Org. Chem. 2013, 9, 118–134, doi:10.3762/bjoc.9.15

• shows multiple topologies/configurations (guest up/down) in MD with λ-dynamics [14]. The association constant Ka for α- and β-CD inclusion complexes with several benzene derivatives was investigated by a genetic algorithm [15] and neuronal networks [16]. An overview of quantum mechanical methods to

• ΔEcomplexation values, up to BCDbenzeneverticalO23lO6r with +9.69 kcal mol−1, and thus are endothermic, Table 3. IR spectra of empty β-CD conformers and their inclusion complexes The most important lines of the calculated AM1 IR spectra are given in Table 4. The IR bands of benzene at 744, 1145, 1579 and 3194 cm

• many inclusion complexes and remarkable influence on reactions, catalysis and supramolecular structures. Crystal structure of heptakis(6-O-triisopropylsilyl)-β-cyclodextrin benzene pyrene solvate; [C105H210O35Si7,0.5(C16H10),3.5(C6H6)], taken from The Cambridge Crystallographic Data Centre CCDC [9

Inclusion of the insecticide fenitrothion in dimethylated-β-cyclodextrin: unusual guest disorder in the solid state and efficient retardation of the hydrolysis rate of the complexed guest in alkaline solution

• Dyanne L. Cruickshank,
• Natalia M. Rougier,
• Raquel V. Vico,
• Susan A. Bourne,
• Elba I. Buján,
• Mino R. Caira and
• Rita H. de Rossi

Beilstein J. Org. Chem. 2013, 9, 106–117, doi:10.3762/bjoc.9.14

• ]. In our recent reports on the interaction between CDs and the organophosphorus insecticide 1 we gave an account of the X-ray crystal structures and thermal decomposition profiles of two solid inclusion complexes between permethylated α- and β-cyclodextrins, hexakis(2,3,6-tri-O-methyl)-α-CD (TRIMEA

• TRIMEA [9], whereas for β-CD, γ-CD and TRIMEB the association constants for the inclusion complexes of 1 had the respective values 417, 99 and 511 M−1 [6], the hydrolytic decomposition of 1 being significantly retarded by all three CDs. The present study relates to the interaction between 1 and heptakis

• few exceptions, the values of the torsion angles ω (O5–C5–C6–O6) indicate (−)-gauche conformations, with the C6–O6 bonds thus directed away from the centres of the respective cavities. This results in relatively open cavities, contrary to the usual situation in inclusion complexes of the fully

Theoretical study on β-cyclodextrin inclusion complexes with propiconazole and protonated propiconazole

• Adrian Fifere,
• Narcisa Marangoci,
• Stelian Maier,
• Adina Coroaba,
• Dan Maftei and
• Mariana Pinteala

Beilstein J. Org. Chem. 2012, 8, 2191–2201, doi:10.3762/bjoc.8.247

• secondary hydroxyl rims. The results have revealed that the most stable complex is formed when the azole residue of the propiconazole enters the cavity of the cyclodextrin through the narrow hydroxyl’s rim. Keywords: β-cyclodextrin; inclusion complexes; PM3; propiconazole; Introduction The occurrence of

• units joined in a truncated cone-shaped structure [5]. They exhibit a hydrophobic cavity delimited by two rims, a wide and a narrow one, composed of secondary and primary hydroxy groups. By virtue of this structure, CDs are able to generate inclusion complexes with a wide variety of hydrophobic organic

• theoretically investigates the interaction between PP, PPH+ and β-CD molecules by means of AM1 and PM3 semi-empirical quantum-mechanical calculations, to examine in detail the insertion pathways and to determine the intimate configurations of the β-CD/propiconazole (β-CD/PP and β-CD/PPH+) inclusion complexes

New enzymatically polymerized copolymers from 4-tert-butylphenol and 4-ferrocenylphenol and their modification and inclusion complexes with β-cyclodextrin

• Adam Mondrzyk,
• Beate Mondrzik,
• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2118–2123, doi:10.3762/bjoc.8.238

• (N3-β-CD) was carried out. The formation of inter- and intramolecular inclusion complexes was investigated by DLS measurement. Keywords: copolymer; ß-cyclodextrin; enzymatic polymerization; 4-ferrocenylphenol; polyphenol; 4-tert-butylphenol; horseradish peroxidase; HRP oxidative coupling; inclusion

• . Dimethylsulfoxide-d6 (99.9 atom % D) and CDCl3 were obtained from Deutero GmbH, Germany. 4-Ferrocenylphenol was prepared according to synthetic routes reported in the literature [31]. The inclusion complexes of potassium adamantylcarboxylate were formed by stirring a solution of the β-CD-containing polymer in DMSO

• complexes; polymer-analogous modification; Introduction Polyphenols in general play an important role in nature, e.g., lignin and suberin. In industry, Bakelite represents the first practically successful polyphenol resin [1]. In the latter case, the phenol moieties are covalently connected by formaldehyde

Cyclodextrin-based nanosponges as drug carriers

• Francesco Trotta,
• Marco Zanetti and
• Roberta Cavalli

Beilstein J. Org. Chem. 2012, 8, 2091–2099, doi:10.3762/bjoc.8.235

• . Cyclodextrins are able to include compounds whose geometry and polarity are compatible with that of their cavity. However, native cyclodextrins are not able to form inclusion complexes with certain molecules, such as hydrophilic or high-molecular-weight drugs. Moreover, β-cyclodextrin, the cheapest type, has

• . Many drugs show poor solubility, low permeability, a short half-life, low stability, and/or high molecular weight, and as a consequence their formulation is challenging. Nanosponges have the capacity to incorporate drugs within their structure, either as inclusion complexes or as noninclusion complexes

• drugs are poorly soluble in water, which hinders their clinical application. The formulation of poorly water-soluble drugs constitutes a problem that is difficult to solve. Many technological approaches have been investigated. The ability of cyclodextrins to form inclusion complexes with various

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

• eight α(1→4) linked-D-glucopyranoside units, named αCD, βCD and γCD, respectively. These macromolecules have a rigid and well-defined structure with a toroidal shape, in which a variety of organic and inorganic guest molecules can be inserted into their cavities, resulting in the formation of inclusion

• complexes [14][15][16][17]. Beyond these characteristics, it has been reported in the literature that CDs self-assemble into large aggregates [18][19][20], suggesting their uses as size-modulator molecules [21], similar to other amphiphilic molecules [22][23][24][25]. Based on these interesting properties

Molecular solubilization of fullerene C₆₀ in water by γ-cyclodextrin thioethers

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2012, 8, 1644–1651, doi:10.3762/bjoc.8.188

• ][25]. CDs form water-soluble inclusion complexes with many hydrophobic or amphiphilic guest molecules [26], mainly driven by hydrophobic interactions [27]. Among the commercially available CDs, γ-CD with a clear width of d = 0.74 nm [28] is only large enough to partially accommodate C60, which has a

Polysiloxane ionic liquids as good solvents for β-cyclodextrin-polydimethylsiloxane polyrotaxane structures

• Narcisa Marangoci,
• Rodinel Ardeleanu,
• Laura Ursu,
• Constanta Ibanescu,
• Maricel Danu,
• Mariana Pinteala and
• Bogdan C. Simionescu

Beilstein J. Org. Chem. 2012, 8, 1610–1618, doi:10.3762/bjoc.8.184

• supermolecules formed by ILs with different host molecules), leading to interesting phenomena, properties and applications [7][8][9][10][11][12]. This includes the dissolution of cellulose and cyclodextrins (CDs) with ILs [12], synthesis of ILs containing slide-ring gels [7], synthesis of IL-CD inclusion

• complexes [10], etc. Polyrotaxane structures based on cyclodextrins and different linear (co)polymers are well known as supramolecular ensembles. They consist of cyclodextrin molecules whose hydrophobic cavities are penetrated by a linear polymer chain terminating with bulky stoppers, which prevent the

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

• and extrusion through a 0.1 μm polycarbonate membrane [27]. The cavities of each cyclodextrin are available to form inclusion complexes with hydrophobic guest molecules. Adamantane is known to be an excellent guest for β-cyclodextrin cavities (Ka = (2–3) × 104 M−1). We were able to recently

• , the guest molecules are expected to form inclusion complexes at the surface of vesicles of amphiphilic cyclodextrin 5. More importantly, guest molecules 2–4 are expected to form multivalent host–guest complexes with a much higher effective binding constant than the monovalent binding constant reported

Restructuring polymers via nanoconfinement and subsequent release

• Alan E. Tonelli

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

• accomplished by first forming noncovalently bonded inclusion complexes (ICs) between these small-molecule hosts and guest polymers, followed by the careful removal of the host crystalline lattice to obtain a coalesced bulk polymer. We have repeatedly observed that such coalesced polymer samples behave

• means to reorganize polymers by nanoprocessing them into solids with unique properties is presented. This is achieved by first forming noncovalently bonded inclusion complexes (ICs) between certain small-molecule hosts and guest polymers, followed by the careful removal of the host molecules to obtain a

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

• glucopyranose units are called α-CD, β-CD, and γ-CD, respectively. CDs have a hydrophilic exterior and a rather hydrophobic cavity, and thus, recognize guest compounds of a size and shape matching their cavity, to form inclusion complexes [1][2][3][4][5]. Since CDs are nontoxic, they have been utilized in a

• variety of fields, including food additives, cosmetics, and personal care items [6][7][8][9][10][11][12]. In the past decade, the formation of inclusion complexes of CDs with guest residues attached on water-soluble polymers has attracted increasing interest from a number of research groups because these

• and excimer states [32][33]. Since pyrene is very hydrophobic, it may tend to form aggregates, e.g., dimers, in aqueous solutions. It is also known that pyrene forms inclusion complexes with β-CD and γ-CD in different manners; β-CD includes monomeric pyrene whereas γ-CD includes dimeric pyrene [34][35

Synthesis of mesomeric betaine compounds with imidazolium-enolate structure

• Nina Gonsior,
• Fabian Mohr and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 390–397, doi:10.3762/bjoc.8.42

• 10.3762/bjoc.8.42 Abstract The synthesis of a heterocyclic mesomeric betaine by quaternization reaction of 1-butylimidazole and tetrabromo-1,4-benzoquinone is presented. The structure was verified by means of X-ray single-crystal analysis, NMR and IR spectroscopy. Inclusion complexes of the heterocyclic

• ). Regarding our interest in supramolecular chemistry and the enhancement of water solubility, the ability of 3 to form inclusion complexes with randomly methylated (1.8) β-cyclodextrin (m-β-CD) was investigated by means of UV–vis spectroscopy. Therefore, the type of inclusion complex and the complex formation

• mesomeric betaine. Inclusion complexes of 3 with m-β-CD were investigated by UV–vis spectroscopy. The Higuchi–Connors phase diagram indicated the formation of weak 1:1 and 1:2 complexes. In addition, the reaction conditions were applied to poly(vinylimidazole) and 1,4-bis(1H-imidazol-1-yl)butane to obtain

Hyperbranched polyethylenimine bearing cyclodextrin moieties showing temperature and pH controlled dye release

• Indra Böhm,
• Susanne Katharina Kreth and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 1130–1134, doi:10.3762/bjoc.7.130

• exploited to complex various hydrophobic guests such as proteins, dyes and anti tumor drugs [17][18][19][20][21][22]. Inclusion complexes with, e.g., adamantane derivates, are relatively stable due to their high binding constants [23][24]. These kinds of supramolecular complexes become less stable under