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

• inclusion complex with CDs, 3) end capping, 4) chemical modification of CDs, and 5) grafting. The first three steps constitute the synthesis of polyrotaxane. The fourth process is necessary to dissociate the columnar crystal of CDs formed by hydrogen bonds and to disperse the CDs within the backbone

• ; without this step the grafting reaction hardly occurs or produces insoluble products [10][14]. When the modification process is carried out prior to the second process and the modified CDs are used for the complexation, an inclusion complex is not obtained because the hydrogen bonds, the main driving

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

• inclusion complex is formed first. In the second step the intramolecular complexation between the n-butyl moiety of 9 and the α-CD of 2, (Ki ≈ 102 M−1) has to appear to build a double stranded structure. Here again a negative chelate cooperativity is present (Ki·EM ≈ 0.03), preventing the intramolecular

• to a negative chelate cooperativity (Ki·EM ≈ 0.03). Therefore only one inclusion complex is formed, leading to an open 1:1 adduct of 5/12. This assumption is confirmed by the modeling of the ITC data with a 1:1 overall binding model. Here a binding constant of ca. 3 × 104 M−1 is calculated. This

• guest strands show a specific 1:1 interaction with the complementary CD strand as soon as one adamantyl moiety is included. The monoadamantyl substituted guest strand 12 forms an open 1:1 adduct with the complementary CD trimer 5. Because of negative chelate cooperativity only the inclusion complex

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

• . This result could be explained by the higher hydrophobic character of its cavity which favors inclusion complex formation [31]. It is well known that complexation with CDs depends on guest hydrophobicity (expressed by different descriptors) [32][33][34][35]. However, in our study, no clear correlation

• hydroxylation. This could explain why 1 and 2, which carry no hydroxy group, reacted little with DPPH•. The activity of 3, 4, 5, 6 and 7 was kept unchanged upon complexation with CDs. This indicated that CDs did not interfere with the active groups of these PPs during inclusion complex formation which was still

• CD concentration. Kf value of CD/PP inclusion complex was calculated from the linear segment of the phase–solubility diagrams using the following equation: where S0 is the intrinsic solubility of PP in the absence of CD and the Slope is the slope of the phase–solubility profile. The solubilizing

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

• , since this nature strongly supports the inclusion complex formation. With respect to both requirements, methoxypoly(ethylene glycol) with an average molecular weight of 350 g/mol was chosen, which should generally allow working in aqueous media while preserving the hydrophobic nature of the PP moiety

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

• confirmed that the Nile red label is buried well within the hydrophobic pocket of the bulged duplexes and therefore not available to form an inclusion complex with the cyclodextrins [17]. Less pronounced shifts were observed with complementary and mismatched duplexes (2 and 4 nm, respectively) upon the

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

N,N'-(Hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide): Synthesis via cyclodextrin mediated N-alkylation in aqueous solution and further Prilezhaev epoxidation

• Julian Fischer,
• Simon Millan and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2834–2840, doi:10.3762/bjoc.9.318

• with two equivalents of randomly methylated β-cyclodextrin (β-CD) to give 3β, water solubility could be increased distinctively. Characterization of the inclusion complex of β-CD with 3 in D2O solution was conducted using 2D NMR ROESY spectroscopy (Figure 1). Thereby, proton signals at 7.0 and 7.4 ppm

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

• confirmed the formation of a 1:1 inclusion complex. A ROESY spectrum was recorded with long mixing time which contained TOCSY artifacts. It only confirmed the presence of xylazine aromatic ring in the β-cyclodextrin cavity. No information regarding the mode of penetration, from the wide or narrow side

• and molecular dynamics analysis. On the other hand, a ROESY spectrum with no spin diffusion can only compliment an averaged ensemble conformation obtained by molecular dynamics which is generally considered ambiguous. Keywords: β-cyclodextrin; inclusion complex; ROESY; simulation studies; xylazine

• combination of quantitative ROESY analysis and molecular dynamics in vacuum, highly accurate structural information regarding the whole conformation of the inclusion complex can be obtained which otherwise only confirms the inclusion of the guest in the cavity. Studies on the determination of the absolute

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

• configuration of the dimeric inclusion complex of the guest. Anti-parallel orientation of acenaphthylene within the CD cavity led to the exclusive formation of the anti photo-dimer in quantitative yield. Parallel orientation of coumarin within the complex of a CD thioether led to the formation of the syn head

• aqueous solution of the inclusion complex of ACE with γ-CD thioether. Molecular modeling: A previously described procedure was used [25]. The geometries of the orientational isomers of the COU gas-phase dimer were fully optimized without any symmetry restriction at the MP2/6-31G* level of theory by using

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

• macrocycles. The size of the ferrocene molecule is too large to penetrate completely into the α-CD cavity. Only a single cyclopentadienyl ring of the ferrocene is included. The binding mode, thermal stability, formation constants, and dielectric properties [7] of this inclusion complex were also investigated

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

• Jutta Erika Helga Kohler Nicole Grczelschak-Mick Wacker Chemie AG, Consortium für elektrochemische Industrie, Zielstattstrasse 20, D-81379 München, Germany 10.3762/bjoc.9.15 Abstract Four highly ordered hydrogen-bonded models of β-cyclodextrin (β-CD) and its inclusion complex with benzene were

• certainly no longer displayed the highly ordered hydrogen bonds of β-CD and benzene occupied many different positions inside the cavity, before it left the β-CD finally at its O2/O3 side. Keywords: AM1; benzene; COSMO-RS; cyclodextrin; hydrogen bonds; inclusion complex; molecular dynamics; quantum

• vertical position (higher in energy by only 0.29 kcal mol−1); both conformers were thermodynamically allowed. The HOMO/LUMO gap of the empty β-CD with about 12 eV was lowered to about 10 eV in the complex. The β-CD/benzene inclusion complex was formed only by weak noncovalent interactions, which influence

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

• Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, Córdoba, Argentina 10.3762/bjoc.9.14 Abstract An anhydrous 1:1 crystalline inclusion complex between the organophosphorus insecticide fenitrothion [O,O-dimethyl O-(3-methyl-4-nitrophenyl

• ; hydrolysis; inclusion complex; Introduction Whereas cyclodextrins (CDs) have been employed for many years in the pharmaceutical industry to modify drug-delivery properties, the application of CD technology to the improvement of agrochemicals is a more recent innovation [1][2]. Nevertheless, very significant

• ]. A crystalline inclusion complex (TRIMEA)2·1 was isolated and shown by X-ray analysis to contain a novel capsule formed by head-to-head contact of the secondary rims of two TRIMEA molecules [5]. The encapsulated fenitrothion molecule showed minor disorder in the form of two rotamers (with respect to

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

• , “Gheorghe Asachi” Technical University of Iasi, 700050 Iasi, Romania Faculty of Chemistry, “Al. I. Cuza” University Iasi, Iasi 700506, Romania 10.3762/bjoc.8.247 Abstract The synthesis of the β-cyclodextrin/propiconazole nitrate inclusion complex and the advantages of the encapsulation of this drug were

• molecule, respectively. The higher the negative value of the stabilization energy, the more thermodynamically favorable is the pathway of inclusion-complex formation. The particular shape of the PP molecule allows its inclusion into the β-CD cavity following three different ways. Additionally, each residue

• of PP can be well accommodated either by the secondary or the primary face of the β-CD cavity (Figure 1a). Therefore, six configurations must be considered in pursuing the most stable molecular structure of the inclusion complex. For simplicity, let us note each PP residue as it is shown in Figure 1b

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

• CDs (see Figure 1, [29]). Andersson et al. reported that C60 formed a water-soluble 1:2 inclusion complex with γ-CD after heating under reflux in water [21]. Mixing of an aqueous solution of γ-CD with a methanolic solution of C60 led to a C60 dispersion with a concentration of ca. 70 mg/L [30]. Even

• then the obtained inclusion complex dissolved in water after evaporation of the solvents. Procedure d: C60 stirred in water/CS2 (v/v 1:1) at rt for 7 d with 6 mM γ-CD thioether, and then the obtained inclusion complex dissolved in water after evaporation of the solvents. nC60 was prepared following a

Supramolecular hydrogels formed from poly(viologen) cross-linked with cyclodextrin dimers and their physical properties

• Yoshinori Takashima,
• Yang Yuting,
• Miyuki Otsubo,
• Hiroyasu Yamaguchi and
• Akira Harada

Beilstein J. Org. Chem. 2012, 8, 1594–1600, doi:10.3762/bjoc.8.182

• reports of supramolecular complexes with cyclodextrin (CD) dimers. A supramolecular hydrogel, which was constructed by the formation of an inclusion complex between the copolymer with an adamantyl group and CD dimer, showed a lower critical solution temperature (LCST) [11]. Another report indicated that

• ] = 60 mM), because the α-CD unit of the α,α-CD dimer forms an inclusion complex with PyC10Py. This inclusion-complex formation causes the cross-links between the α,α-CD dimer and VP to decompose. 1H NMR study of complexation of the α,α-CD dimer/VP To observe the competitive effect of PyC10Py, we

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

• the formation of a 1:1 inclusion complex of each adamantane unit with β-cyclodextrin. Based on the effective adamantane concentration, the stoichiometry, the binding constants, and the thermodynamic parameters (negative ΔH and positive ΔS) are very similar for each guest, with the exception of guest 3

Influence of cyclodextrin on the solubility of a classically prepared 2-vinylcyclopropane macromonomer in aqueous solution

• Helmut Ritter,
• Jia Cheng and
• Monir Tabatabai

Beilstein J. Org. Chem. 2012, 8, 1528–1535, doi:10.3762/bjoc.8.173

• solubility of 5 at room temperature (about 25 °C). However, the turbid dispersion becomes completely clear by the addition of methylated β-cyclodextrin (Me2-β-CD). This means that a water-soluble inclusion complex 7 of 5 with Me2-β-CD is formed (Figure 3). The 2D ROESY NMR spectrum of 7 indicates the

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

• -dioctylfluorene)-alt-5,5'-bithiophene/PS-βCD] (PDOF-BTc) polyrotaxane copolymer, through a Suzuki coupling reaction between the 5,5'-dibromo-2,2'-bithiophene (BT) inclusion complex with persilylated β-cyclodextrin (PS-βCD), and 9,9-dioctylfluorene-2,7-bis(trimethylene borate) (DOF) as the blocking group. The

• ]. In spite of the extended use of new compounds as hosts for inclusion-complex formation, CD derivatives have received less attention when compared to native CDs. Very few polyrotaxanes within CD derivatives were reported [12][33][34]. Recently, we have exemplified such improvements on the

• )-alt-5,5'-bithiophene/PS-βCD] (PDOF-BTc), was synthesized by Suzuki cross-coupling reaction between 5,5'-dibromo-2,2'-bithiophene (BT), as an inclusion complex in PS-βCD cavities, and the bulky molecule 9,9-dioctylfluorene-2,7-bis(trimethylene borate) (DOF), (Scheme 1). Of particular interest is the

Restructuring polymers via nanoconfinement and subsequent release

• Alan E. Tonelli

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

• as drug delivery and suture manufacturing. However, its relatively poor physical properties limit its use in load-bearing applications. An attempt to improve the strength of PCL was made by processing with α-cyclodextrin (α-CD). First an inclusion complex (IC) between PCL and α-CD was formed, and

• reorganize both morphologically and conformationally, either by formation of a crystalline inclusion complex (IC) between guest PET and host γ-cyclodextrin (γ-CD), followed by removal of the host γ-CD and coalescence of the guest PET (c-PET), or by precipitation (p-PET) from its solution in trifluoroacetic

• cyclodextrin inclusion complex [2]. Crystal structures and wide-angle X-ray diffractograms of neat (a) cage and (b) columnar IC γ-CD [20]. DSC cooling scans of as-received (upper) and coalesced N-6 (lower) [58]. DSC heating scans for asr-PVAc (upper) and c-PVAc coalesced from its γ-CD IC (lower) [72]. Melt

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

• pAAmPy. For the β-CD/pAAmPy system (Figure 3a), I480/I376 decreases with increasing [CD]0 at xDMSO = 0.1–0.6. For the γ-CD/pAAmPy system (Figure 3b), on the other hand, I480/I376 increases with [CD]0 at xDMSO = 0–0.2. Discussion Detailed study of the equilibria of the inclusion complex formation of CDs

• described in the Supporting Information File 1, the concentrations of all species can be calculated by using the equilibrium constant (Kβ) for the inclusion complex formation, and I480/I376 can be also obtained as given in Equation 3. Here [Py], [Py°], [CD], [CD·Py], and [CD·Py°] denote the concentrations

• inclusion complex formation, and I480/I376 can be also obtained as given in Equation 4. Here [CD·Py2] denotes the concentration of the complex of CD with Py2, and A'2,480 is a constant. It is also likely that A2,376 = A'2,376 = 0. When Kγ and A'2,480/A1,376 are chosen appropriately, the I480/I376 values

Control over molecular motion using the cis–trans photoisomerization of the azo group

• Estíbaliz Merino and
• María Ribagorda

Beilstein J. Org. Chem. 2012, 8, 1071–1090, doi:10.3762/bjoc.8.119

• diarylazobenzene 6 by formation of an inclusion complex of trans-5+6. This inclusion complex evolves in a reversible way when it is irradiated. The process is especially interesting for the translation of the optical signals recorded by the bipyridinium azobenzene 6 via a β-cyclodextrin single phase prepared on a

• guanidinium ion by a cis,cis-bis-azo derivative 3. Recognition of cesium ions by cis-azo derivative 4. Photocontrolled formation of an inclusion complex of cyclodextrin trans-azo 5+6. Pseudorotaxane-based molecular machine. Molecular hinge. Reprinted (adapted) with permission from Org. Lett. 2004, 6, 2595

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

• ). 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

• temperature range between 30 and 800 °C under an argon atmosphere. The heating rate was 10 °C min−1. All measurements were baseline corrected and analyzed by Pyris software. Determination of the type of inclusion complex and the complexation constant was achieved by UV–vis spectroscopy. The UV–vis spectra

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

• , acetylcholinesterase (AChE). Moreover, the results indicate that the mode of action of these cyclodextrin derivatives involves the formation of an inclusion complex with the OP. The question thus arises as to whether suitable cyclodextrin derivatives could also be used in vivo as antidotes against OP poisonings. Such

Intraannular photoreactions in pseudo-geminally substituted [2.2]paracyclophanes

• Henning Hopf,
• Vitaly Raev and
• Peter G. Jones

Beilstein J. Org. Chem. 2011, 7, 658–667, doi:10.3762/bjoc.7.78

• common disadvantage of solid-state photoreactions is the difficulty in predicting and controlling reaction selectivity. It remains a challenge to find the suitable crystal, co-crystal, or inclusion complex for the desired regio- or stereoselective outcome of a given reaction. Therefore, an attractive

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