Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants

• Tamás Zoltán Agócs,
• István Puskás,
• Erzsébet Varga,
• Mónika Molnár and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2016, 12, 2873–2882, doi:10.3762/bjoc.12.286

• oligosaccharides consisting of 6–8 glucose units (α-, β- and γ-CD) primarily used in the pharmaceutical, cosmetic and household chemical industry [8]. They form non-covalent inclusion complexes with a great number of the organic contaminants in soil (petroleum hydrocarbons, polycyclic aromatic hydrocarbons, etc

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

• Loïc Leclercq

Beilstein J. Org. Chem. 2016, 12, 2644–2662, doi:10.3762/bjoc.12.261

• been developed in the last two decades [29]. Nevertheless, the cheapest remains the β-CD whereas the most expensive is the γ-CD. The molecular shape of the native CDs can be represented as a truncated cone with “hydrophobic” cavity which can accommodate hydrophobic compounds (Scheme 1). In aqueous

• , the knowledge of the binding constants (Kass) is crucial because these values provide an index of host–guest binding forces. CDs can also form exclusion complexes where the CDs are bound to the guest through a H-bond network. For instance, the complexation of [PMo12O40] anion by β- and γ-CD results in

• modified cyclodextrins As safety and toxicity are important criteria for consideration before using CDs in pharmaceutical products, this section deals with toxicological issues. The native α- and β-CD, unlike γ-CD, cannot be hydrolyzed by pancreatic amylases and human salivary but can be fermented by the

Radical polymerization by a supramolecular catalyst: cyclodextrin with a RAFT reagent

• Kohei Koyanagi,
• Yoshinori Takashima,
• Takashi Nakamura,
• Hiroyasu Yamaguchi and
• Akira Harada

Beilstein J. Org. Chem. 2016, 12, 2495–2502, doi:10.3762/bjoc.12.244

• α-CD and AA in water, we obtained a powder precipitate of a complex between α-CD and AA, although the crystal structure of α-CD and AA was not solved. The formation of precipitate implied the formation of a host-guest complex between them. A mixture of CDs (α-CD, β-CD and γ-CD) and AAm did not

Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins

• Laszlo Jicsinszky,
• Marina Caporaso,
• Katia Martina,
• Emanuela Calcio Gaudino and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2016, 12, 2364–2371, doi:10.3762/bjoc.12.230

• -chloro-CDs [15] in solution. The solubility of per-6-halogeno-CDs is very limited in water and the majority of organic solvents, meaning that their preparation and purification is far from being environmentally friendly. Per-6-S-(3-mercapto)propionyl-γ-CD (Sugammadex, Bridion®) is not only the biggest

• the similar halogen/tosyl ratio used in the monotosylated case is not sufficient to lead to complete substitution. Owing to the lower reactivity of bromo-CD a higher TU/per-6-bromo-γ-CD ratio had to be used. The more ionic character of formed thiouronium bromide was seen not only in the higher yields

• stage, the sodium salt of octakis(6-deoxy-6-S-(3-mercapto)propionyl)-γ-CD has been slowly becoming an important surgical aid. The solution phase reaction is a dangerous process due to the use of sodium hydride. The relatively large number of possible side-reactions in solution brings further challenges

Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

• Vito Rizzi,
• Sergio Matera,
• Paola Semeraro,
• Paola Fini and
• Pinalysa Cosma

Beilstein J. Org. Chem. 2016, 12, 549–563, doi:10.3762/bjoc.12.54

• complexation mode of the inclusion complexes involving 4-thiothymidine (S4TdR, a known photosensitizer) and five CDs, namely 2-hydroxypropyl-α-cyclodextrin (2-HP-α-CD), 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD), 2-hydroxypropyl-γ-cyclodextrin (2-HP-γ-CD), heptakis-(2,6-di-O-methyl)-β-cyclodextrin (DIMEB CD

• CDs are α-, β- and γ-CD, and the differences among them are related to the number of α-D-glucopyranose units. While α-CD, characterized by a small cavity size, is hardly used and γ-CD is expensive, β-CD is extensively used because its cavity size is able to allocate a large number of guest molecules

• -CD, 2-HP-β-CD, 2-HP-γ-CD, DIMEB and TRIMEB. This is a preliminary work in order to (i) study, in the next future, its photochemical behavior in the presence of CDs, and to (ii) preserve it from oxidative degradation when irradiated during PDT treatments. In this work, absorption spectroscopic

New synthetic strategies for xanthene-dye-appended cyclodextrins

• Milo Malanga,
• Andras Darcsi,
• Mihaly Balint,
• Gabor Benkovics,
• Tamas Sohajda and
• Szabolcs Beni

Beilstein J. Org. Chem. 2016, 12, 537–548, doi:10.3762/bjoc.12.53

• glucopyranose units (α-, β- and γ-CD, respectively). Native CDs do not adsorb light in the UV–vis region (200–800 nm), but they can be converted into spectroscopically active compounds by modification with a chromophore/fluorophore unit. Fluorophore-appended CDs can be appropriate systems to detect

• later the same group reported on a fluorescein-modified γ-CD and its properties as a sensor and as a charge-changeable receptor for detecting organic acids [13]. The synthetic strategy was still based on the ester formation between the fluorophore and the CD scaffold, but the conditions were slightly

• modified. As a starting material, 6-monoiodo-γ-CD was chosen instead of the more labile 6-monotosyl-γ-CD and anhydrous DMF (under nitrogen atmosphere) substituted for the aqueous environment of the previous β-CD coupling. The first rhodamine-modified CD was reported by Harada [14]. 6-Monoamino-α-CD was

Optimized methods for preparation of 6^I-(ω-sulfanyl-alkylene-sulfanyl)-β-cyclodextrin derivatives

• Eva Bednářová,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2016, 12, 349–352, doi:10.3762/bjoc.12.38

• ability to form supramolecular inclusion complexes with a wide range of guest molecules [2]. From the native CDs (α-CD, β-CD, and γ-CD containing 6, 7, and 8 glucose units, respectively) the β-CD is studied the most due to its lowest price and the highest guest binding ability. A large number of CD

Enabling technologies and green processes in cyclodextrin chemistry

• Giancarlo Cravotto,
• Marina Caporaso,
• Laszlo Jicsinszky and
• Katia Martina

Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30

• friendly technique that is well suited to the selective chemical modification of CDs from native α-, β- and γ-CD. The use of this method in heterogeneous phase reactions, such as reductions and “click reactions” [14], is well known, as is its use in full CD derivatization in combination with MW irradiation

• performed in the presence of tosyl imidazole and molecular sieves under US irradiation. As shown in Table 1, the reaction time was shortened to 2 h for α-CD (yield: 36%), 1 h for β-CD (yield: 40%) and 45 min for γ-CD (yield: 46%) (Scheme 4) [21]. In Table 1 we compared the preparation of several

• synthetic procedure to graft viscose using a diisocyanate cross-linker was reported (Scheme 6) [32]. Sonochemical reticulation with HDI was used in the preparation of a new series of solid cross-linked α-, β- and γ-CD-based catalysts containing Cu(I) or Pd(II) [33]. Sonication breaks up intermicellar

Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds

• Sophie Letort,
• Sébastien Balieu,
• William Erb,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23

• chiral selectors has therefore been employed to discriminate the enantiomers of fenamiphos (3, Figure 3) in quantitative water analysis [45]. Neutral CDs such as β-CD, methyl-β-CD, hydroxyethyl-β-CD (HE-β-CD), hydroxypropyl-β-CD (HP-β-CD), and hydroxyethyl-γ-CD (HP-γ-CD) were evaluated in these

• Table 1. A 1:1 stoichiometry with close complexing ability was found for β-CD and HP-β-CD [46], while a 1:2 complex was found to be predominant in the case of G2-β-CD [39]. These results can be corroborated with the aqueous solubility studies of chlorpyrifos in the presence of α-CD, β-CD, γ-CD, HP-β-CD

• binding constant values and the hydrophobicity of the pesticides, suggesting that steric effects are probably predominantly involved in complex formation. The inclusion of the apolar heterocyclic ring into the CD cavity is the most likely situation to occur. γ-CD has the largest secondary alcohols rim

Thermal and oxidative stability of Atlantic salmon oil (Salmo salar L.) and complexation with β-cyclodextrin

• Daniel I. Hădărugă,
• Mustafa Ünlüsayin,
• Alexandra T. Gruia,
• Cristina Birău (Mitroi),
• Gerlinde Rusu and
• Nicoleta G. Hădărugă

Beilstein J. Org. Chem. 2016, 12, 179–191, doi:10.3762/bjoc.12.20

• 8 glucopyranose units for the corresponding α-, β-, and γ-CD types [34][35]. The specific structural architecture of CDs having a hydrophilic exterior and hydrophobic inner cavity allows for tin-containing FA moieties from fish oil [36] or other hydrophobic compounds and mixtures to be more easily

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• enzymes used are cyclodextrin glucosyltransferases which are produced by several microorganisms including Bacillus macerans and Bacillus circulans. The most common cyclodextrins are α-, β- and γ-cyclodextrin (α-, β- and γ-CD) which consist of 6, 7 and 8 α-1,4-linked D-glucopyranose subunits, respectively

• decreased upon addition of α-, β- or γ-CD due to decreased hydrophobic interaction between the n-alkyl substituents because of their cyclodextrin host–guest complexation [46]. Due to the differences in annular size (Table 1), the hydrophobe complexing abilities of α-, β- and γ-CD differ [44][45][46]. At low

• PAAodn 0.5 wt % concentration in aqueous solution, the viscosity decreases substantially to a minimum value at either 1:1 α-CD, β-CD or γ-CD host to n-C18H37 guest substituent mole ratio (Figure 3) [46]. This minimum viscosity value decreases on going from α-CD to γ-CD due to the stronger complexation of

Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

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

Beilstein J. Org. Chem. 2016, 12, 29–42, doi:10.3762/bjoc.12.5

• of 1 and 2 with six CDs (α-CD, β-CD, γ-CD, hydroxypropylated-β-CD (HP-β-CD), randomly methylated β-CD (RAMEB) and a low methylated-β-CD (CRYSMEB)) were determined by an UV–visible competitive method using methyl orange (MO) as competitor [34]. Firstly, Kf values of CD/MO inclusion complexes were

• recognized by β-CD and its derivatives as compared to α-CD and γ-CD. Our findings could be strengthened by the fact that the vigor of binding is highly influenced by the complementarity between guest and CD cavity. Molecules with aromatic ring structures would fit better within the β-CD cavity. When

• complex prepration and increase in formulation bulk [38]. Kf values obtained by UV–visible competitive studies showed that β-CD and its derivatives form more stable inclusion complexes with 1 and 2 than α-CD and γ-CD. Moreover, HP-β-CD is the only β-CD derivative cited in the FDA’s list of Inactive

Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

• Mino R. Caira,
• Susan A. Bourne,
• Halima Samsodien and
• Vincent J. Smith

Beilstein J. Org. Chem. 2015, 11, 2616–2630, doi:10.3762/bjoc.11.281

• hormones were among the first bioactive compounds whose aqueous solubilities were shown to be significantly enhanced via CD inclusion. For example, in an early study by Uekama et al. [14], the interactions between 18 steroid hormones and the native cyclodextrins α-, β- and γ-CD in aqueous solution were

• complexes, some of them having host–guest stoichiometric ratios of 2:1 and 3:2 with β-CD and γ-CD, respectively. An early attempt to acquire basic structural information from PXRD data for crystalline inclusion complexes of β-CD with a series of pregnanes as guests led to the estimation of crystal unit cell

• crystal structures containing the rocuronium ion, a well-known neuromuscular blocking agent consisting of a steroid nucleus that is highly functionalised [17], this species being encapsulated by specially designed CD derivatives [per-6-deoxy-per-6-carboxyethylsulfanyl-γ-CD and 6-perdeoxy-6-per(4

Aggregation behaviour of amphiphilic cyclodextrins: the nucleation stage by atomistic molecular dynamics simulations

• Giuseppina Raffaini,
• Antonino Mazzaglia and
• Fabio Ganazzoli

Beilstein J. Org. Chem. 2015, 11, 2459–2473, doi:10.3762/bjoc.11.267

• attracting an increasing attention [1][2][3][4][5][6][7][8], including also the new polymeric CD nanogels [9] and nanosponges [10][11][12][13]. Over the past twenty years, amphiphilic cyclodextrins (aCD) formed with α-, β-, or γ-CD have given rise to a wide interest in the scientific community because of

Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex

• Chompoonut Rungnim,
• Sarunya Phunpee,
• Manaschai Kunaseth,
• Supawadee Namuangruk,
• Kanin Rungsardthong,
• Thanyada Rungrotmongkol and
• Uracha Ruktanonchai

Beilstein J. Org. Chem. 2015, 11, 2306–2317, doi:10.3762/bjoc.11.251

• α-D-glucopyranose units and are depicted as α-CD, β-CD and γ-CD, respectively. CDs are able to bind non-polar molecules, including poorly soluble drugs, in their hydrophobic cavities to form binary inclusion complexes [10][11][12]. Inclusion of the drug can result in its enhanced solubility

Self-assemblies of γ-CDs with pentablock copolymers PMA-PPO-PEO-PPO-PMA and endcapping via atom transfer radical polymerization of 2-methacryloyloxyethyl phosphorylcholine

• Jing Lin,
• Tao Kong,
• Lin Ye,
• Ai-ying Zhang and
• Zeng-guo Feng

Beilstein J. Org. Chem. 2015, 11, 2267–2277, doi:10.3762/bjoc.11.247

• -assembled with varying amounts of γ-CDs to prepare poly(pseudorotaxanes) (PPRs). When the concentration of γ-CDs was lower, the central PEO segment served as a shell of the micelles and was preferentially bent to pass through the γ-CD cavity to construct double-chain-stranded tight-fit PPRs characterized by

• phosphorylcholine (MPC), these single-chain-stranded loose-fit PPRs were transformed into conformational identical polyrotaxanes (PRs). The structures of the PPRs and PRs were characterized by means of 1H NMR, GPC, 13C CP/MAS NMR, 2D 1H NOESY NMR, FTIR, WXRD, TGA and DSC analyses. Keywords: ATRP; γ-CD; double

• -chain-stranded; pentablock copolymer; poly(pseudorotaxane); polyrotaxane; single-chain-stranded; Introduction Cyclodextrins (CDs) are a series of macrocyclic molecules composed of 6, 7, or 8 (α-, β-, and γ-CD, respectively) glucopyranose units. Their hydrophilic surface and hydrophobic inner cavity

Qualitative evaluation of regioselectivity in the formation of di- and tri-6-O-tritylates of α-cyclodextrin

• Keisuke Yoshikiyo,
• Yoshihisa Matsui and
• Tatsuyuki Yamamoto

Beilstein J. Org. Chem. 2015, 11, 1530–1540, doi:10.3762/bjoc.11.168

• gives exclusively 6-O-substituted CD. CD is composed of six (α-CD), seven (β-CD), eight (γ-CD), or more Glu residues. Thus, a reaction of α-CD, for example, with trityl chloride (TrCl) gives mono- [7], di- [13][15][16], tri- [9][11], tetra- [18], and per-6-O-trityl derivatives [19]. The di-6-O-tritylate

Superstructures with cyclodextrins: Chemistry and applications II

• Gerhard Wenz

Beilstein J. Org. Chem. 2015, 11, 271–272, doi:10.3762/bjoc.11.30

• Gerhard Wenz Saarland University, Organic Macromolecular Chemistry, Campus C4 2, 66123 Saarbrücken, Germany 10.3762/bjoc.11.30 Keywords: cyclodextrins; Cyclodextrins (CDs) are cyclic α(1→4)-linked oligomeres of anhydroglucose. Since the 6-, 7- and 8-membered rings, called α-, β- and γ-CD

Properties of cationic monosubstituted tetraalkylammonium cyclodextrin derivatives – their stability, complexation ability in solution or when deposited on solid anionic surface

• Martin Popr,
• Sergey K. Filippov,
• Nikolai Matushkin,
• Juraj Dian and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2015, 11, 192–199, doi:10.3762/bjoc.11.20

• Villiers in 1891 [1]. They are composed of α-(1→4)-linked D-glucopyranose units forming a cycle with the shape of a hollow truncated cone. Naturally occurring CDs are α-, β- and γ-CD with 6, 7 and 8 glucopyranose units, respectively. Their inner cavity, which is relatively hydrophobic, creates a proper

Articulated rods – a novel class of molecular rods based on oligospiroketals (OSK)

• Pablo Wessig,
• Roswitha Merkel and
• Peter Müller

Beilstein J. Org. Chem. 2015, 11, 74–84, doi:10.3762/bjoc.11.11

• CDs. As expected, the addition of Me-β-CD (which was used instead of β-CD due to the scarce solubility of the latter) in MeOH clearly increases the IM/IEX ratio (Figure 6, green curve) whereas α- and γ-CD (blue and red curve) have hardly any influence on the fluorescence spectra of 32a. Remarkably

Effects of RAMEA-complexed polyunsaturated fatty acids on the response of human dendritic cells to inflammatory signals

• Éva Rajnavölgyi,
• Renáta Laczik,
• Viktor Kun,
• Lajos Szente and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2014, 10, 3152–3160, doi:10.3762/bjoc.10.332

• Solubilization of n−3 PUFAs Cyclodextrins (CDs) are efficient solubilizers of lipids [42]. The water-insoluble n−3 PUFAs were solubilized in aqueous solutions of randomly methylated α- and β-CD (RAMEA and RAMEB, respectively), but the similar γ-CD derivative, RAMEG was ineffective to modulate the solubility

• methylated β-cyclodextrin (RAMEB, the number of methyl groups/CD (DS) is 12) is the product of Wacker Chemie, Munich, Germany, while the α- and γ-CD analogues with DS 8.7 and 12.6 were produced by CycloLab, Hungary. Solubility measurement The solubility of fatty acids in CD solutions was determined by adding

Inclusion of trans-resveratrol in methylated cyclodextrins: synthesis and solid-state structures

• Lee Trollope,
• Dyanne L. Cruickshank,
• Terence Noonan,
• Susan A. Bourne,
• Milena Sorrenti,
• Laura Catenacci and
• Mino R. Caira

Beilstein J. Org. Chem. 2014, 10, 3136–3151, doi:10.3762/bjoc.10.331

• -solubility results for RSV with the native CDs β- and γ-CD. The phase-solubility profile resulting from the use of β-CD is of type AL and this host produces a guest solubility enhancement of 26-fold over the concentration range indicated. The results for the experiments with γ-CD were limited to a maximum CD

• , the negative deviation possibly being due to changes in the solubility of the complex and/or aggregation of the CD molecules. The solubility enhancement for RSV with γ-CD was only 3.4-fold. The solubility enhancements for RSV in the presence of the derivatised CDs are significant (Figure 17). With TMB

• used to calculate KC (up to 6 mM for γ-CD, 8 mM for DMB and 4 mM for HP-β-CD and RMB). The values obtained indicate relatively weak interactions between RSV and γ-CD, initially weak interaction with HP-β-CD and RMB, fairly strong binding with β-CD and TMB, and the formation of a very stable complex

Release of β-galactosidase from poloxamine/α-cyclodextrin hydrogels

• César A. Estévez,
• José Ramón Isasi,
• Eneko Larrañeta and
• Itziar Vélaz

Beilstein J. Org. Chem. 2014, 10, 3127–3135, doi:10.3762/bjoc.10.330

• copolymer. α-CD must surpass the outer PPO blocks to reach the PEO blocks and form stable structures known as (pseudo)polyrotaxanes. PEO chains and oligoethylenes of different molecular weights form inclusion complexes with α-CD. On the other hand, the wider PPO chains yield inclusion complexes with β and γ

• -CD. For reverse poloxamine 90R4, the enthalpy-driven complexation between α-CD and inner PEO blocks makes it possible to overcome the energy barrier of α-CD sliding over the relatively bulky PPO blocks [16]. Lactase molecules are entrapped within the supramolecular cross-linked gels which are formed

Synthetic strategies for the fluorescent labeling of epichlorohydrin-branched cyclodextrin polymers

• Milo Malanga,
• Mihály Bálint,
• István Puskás,
• Kata Tuza,
• Tamás Sohajda,
• László Jicsinszky,
• Lajos Szente and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2014, 10, 3007–3018, doi:10.3762/bjoc.10.319

• Cyclodextrins (CDs) are cyclic oligosaccharides consisting of 6, 7 or 8 glucopyranose units (α-, β- or γ-CD, respectively). The capability for complexation, as well as their ability to stabilize and solubilize guest compounds, makes these substances prime candidates for incorporation in delivery systems for

• was demonstrated for β-CD, but they can be easily adapted for the production of α- and γ-CD polymers as well. The applications of fluorescent labeled epichlorohydrin branched β-CD polymers span from the biological field and material science to the pure physicochemical investigations. TLC study of β-CD

Synthesis of uniform cyclodextrin thioethers to transport hydrophobic drugs

• Lisa F. Becker,
• Dennis H. Schwarz and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 2920–2927, doi:10.3762/bjoc.10.310

• -, β- and γ-CD, respectively [1]. CDs are well known to increase the bioavailability of active pharmaceutical ingredients (APIs) [2][3], and they are readily available in pharmaceutical purity and industrial quantities. Furthermore, they are water soluble and regarded as non-toxic in case of α- and γ

• compounds with very high binding potentials due to the higher hydrophobicity of sulfur compared to oxygen [21][22][23]. The octa-substituted carboxyethyl thioether of γ-CD is already in use under the name sugammadex (Bridion®) for the reversal of neuromuscular blockade, making use of its extremely high

• affinity towards rocuronium [24][25]. Furthermore, hydrophilic γ-CD thioethers show high affinities to other guests such as polycyclic aromatic hydrocarbons [26], botulin [27][28], and fullerene C60 [29]. Hydrophilic β-CD thioethers also tightly complex volatile benzene derivatives leading to a significant