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

• Syed Mashhood Ali Kehkeshan Fatma Snehal Dhokale Department of Chemistry, Aligarh Muslim University, Aligarh-202002, India National Chemical Laboratory, Pune-411008, India 10.3762/bjoc.9.226 Abstract The complexation of xylazine with β-cyclodextrin was studied in aqueous medium. 1H NMR titrations

• 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

Space filling of β-cyclodextrin and β-cyclodextrin derivatives by volatile hydrophobic guests

• Sophie Fourmentin,
• Anca Ciobanu,
• David Landy and
• Gerhard Wenz

Beilstein J. Org. Chem. 2013, 9, 1185–1191, doi:10.3762/bjoc.9.133

• Saarbrücken, Germany 10.3762/bjoc.9.133 Abstract The inclusion of volatile derivatives of benzene and cyclohexane in β-cyclodextrin (β-CD), hydroxypropyl-β-CD, and hydrophilic β-CD-thioethers was investigated by static headspace gas chromatography (HS-GC) and molecular modelling. The obtained binding

• pressure; Introduction β-Cyclodextrin (β-CD, 1), the cyclic α(1→4) heptamer of glucose, is known to form inclusion compounds with a great variety of guests [1], such as derivatives of benzene [2][3], cyclohexane [4], adamantane [5][6], other alicyclic guests [7], and also inorganic molecules or ions [1][8

Superstructures of fluorescent cyclodextrin via click-reaction

• Arkadius Maciollek,
• Helmut Ritter and
• Rainer Beckert

Beilstein J. Org. Chem. 2013, 9, 827–831, doi:10.3762/bjoc.9.94

• , Humboldtstr. 10, 07743 Jena, Germany 10.3762/bjoc.9.94 Abstract Mono-(6-azido-6-deoxy)-β-cyclodextrin (CD) was covalently attached to an alkyne-modified 5-methyl-2-(pyridin-2-yl)thiazol-4-ol yielding a fluorophore containing CD in a click-type reaction. Intermolecular complexes were formed by poly(host–guest

• detection maintained at a constant value by power modulation. Reactions were performed in closed vessels. Synthesis of mono-(6-azido-6-deoxy)-β-CD (1): Mono-(6-azido-6-desoxy)-β-cyclodextrin was synthesized according to the known procedure [8]. Synthesis of 2-[5-methyl-4-(prop-2-yn-1-yloxy)-1,3-thiazol-2-yl

• ]pyridine (2): The alkyne modified thiazol was synthesized according to the literature procedure [2]. Synthesis of fluorescent β-cyclodextrin 3: 1.3 g (1.15 mmol) of mono-(6-azido-6-desoxy)-β-cyclodextrin (1), 396 mg (1.73 mmol) 2-[5-methyl-4-(prop-2-yn-1-yloxy)-1,3-thiazol-2-yl]pyridine (2), 29 mg (147

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

• 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

• )phosphorothioate] and the host compound heptakis(2,6-di-O-methyl)-β-cyclodextrin (DIMEB) was prepared and its structure elucidated by single-crystal X-ray diffraction. This revealed two independent host molecules in the asymmetric unit. In one of these, the cavity is occupied by two disordered guest components

• of DIMEB showed a remarkable reduction of 84% in the rate of this reaction relative to that for the free substrate, a value exceeding those previously attained with the native hosts, β- and γ-cyclodextrin, and fully methylated β-cyclodextrin. Keywords: crystal structure; cyclodextrin; fenitrothion

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

• recently reported, but the experimental data only partially revealed the structure of the supramolecular complex due to the limitations in understanding the intermolecular association mechanism. The present work describes the equilibrium molecular geometries of β-cyclodextrin/propiconazole and β

• 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

Influence of cyclodextrin on the solubility and the polymerization of (meth)acrylated Triton^® X-100

• Melanie Kemnitz and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 2176–2183, doi:10.3762/bjoc.8.245

• the absence and presence of randomly methylated β-cyclodextrin (RAMEB-CD). Triton®-polymers that were polymerized with RAMEB-CD in water were compared with polymers that were synthesized in organic solvents after the addition of RAMEB-CD. The polymers were characterized by 1H NMR and FTIR spectroscopy

• ®; randomly methylated β-cyclodextrin (RAMEB-CD); rheology; Triton® X-100 (poly(ethylene glycol)tert-octylphenyl ether); Introduction Triton® X-100 (1) is a macromolecular, nonionic surfactant with an average number of ethylene oxide units of 9.5. The tert-octylphenyl group is a hydrophobic moiety whereas

• a few minutes (Scheme 1). In the solid state, the complex formation could be proved by FTIR, as the ether-band shifted from 1102 to 1033 cm−1. By using 2D-ROESY NMR, the interactions between the inner protons H-3 and H-5 of 2,6-dimethyl-β-cyclodextrin (DIMEB-CD) and the protons of the tert-octyl and

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

• of a copolymer of 4-tert-butylphenol and 4-ferrocenylphenol by horse radish peroxidase (HRP) in the presence of H2O2 in a 1,4-dioxane/water system is described. Furthermore, polymer-analogous alkylation of the free hydroxy groups and subsequent click reaction with mono-6-azido-6-desoxy-β-cyclodextrin

• investigated until now. Hence, in the present paper we report the HRP-catalyzed synthesis of novel copolymers from 2 and 3. Click reaction of the propargyl modified polyphenol 5 with mono-(6-azido-6-deoxy)-β-cyclodextrin (6) was also investigated. Based on former studies, host–guest structures were created [24

• combined successfully with mono-6-azido-6-deoxy-β-cyclodextrin (6) in a click-type reaction to give copolymer 7 (Scheme 1). ROESY measurements show some weak interaction of the protons of β-CD with the protons of the ferrocene (Fc) moiety and the tert-butyl-moiety (Supporting Information File 1

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

• dialdehydes, epoxides, epichlorohydrin, diacyl chlorides, etc., the term cyclodextrin nanosponges were first used by DeQuan Li and Min Ma in 1998 [11] to indicate a cross-linked β-cyclodextrin with organic diisocyanates leading to an insoluble network that showed a very high inclusion constant with several

• . There are far more interaction sites available for incorporation within a nanosponge structure than in β-cyclodextrin molecules, and they also show different mesh polarities (hydrophobic cyclodextrin cavities surrounded by hydrophilic nanochannels of the polymeric network) thereby enabling significant

Cyclodextrin-induced host–guest effects of classically prepared poly(NIPAM) bearing azo-dye end groups

• Gero Maatz,
• Arkadius Maciollek and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 1929–1935, doi:10.3762/bjoc.8.224

• [4-(4’-aminophenylazo)phenyl]amine. This dye-end-group-labeled polymer showed acidochromic effects, depending on the pH and the presence of randomly methylated β-cyclodextrin (RAMEB-CD). Also higher cloud-point values for the lower critical solution temperature (LCST) in the presence of RAMEB-CD were

• functionalization by condensation with an azo dye. We also investigated the host–guest interaction of the azo-dye-labeled end group with randomly methylated β-cyclodextrin (RAMEB-CD), and with HPG bearing β-CD on top. Thus, the focus of the present study was directed towards the preparation and superstructure

Influence of intramolecular hydrogen bonds on the binding potential of methylated β-cyclodextrin derivatives

• Gerhard Wenz

Beilstein J. Org. Chem. 2012, 8, 1890–1895, doi:10.3762/bjoc.8.218

• Gerhard Wenz Organic Macromolecular Chemistry, Saarland University, Campus Saarbrücken C4.2, 66123 Saarbrücken, Germany 10.3762/bjoc.8.218 Abstract Various heptasubstituted derivatives of β-cyclodextrin (β-CD) bearing 1, 2 and 3 methyl substituents per glucose unit were synthesized by

• . Structural drawing of β-CD [43], according to structural data (CSD-ID BUVSEQ03) from Zabel et al. [38], generated by VMD 1.8.4 showing the intramolecular hydrogen bonds between OH-3 and O-2. Thermodynamics of the inclusion of 4-tert-butyl-benzoate in β-cyclodextrin 1 and its methyl derivatives 2–6

• . Thermodynamics of the inclusion of adamantane-1-carboxylate in β-cyclodextrin 1 and its methyl derivatives 2–6. List of the methylated β-CD derivatives used in this contribution. Acknowledgements The author thanks Andreas Steffen for drawing the structure of β-CD (Figure 3), and Annegret Engelke for performing

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

• -assembled material based on ferrite associated with β-cyclodextrin (Fe-Ni/Zn/βCD) at the nanoscale level. This MHM and pure ferrite (Fe-Ni/Zn) were used as an adsorbent system for Cr3+ and Cr2O72− ions in aqueous solutions. Prior to the adsorption studies, both ferrites were characterized in order to

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

• Polymers, “Gheorghe Asachi” Technical University of Iasi, 700050 Iasi, Romania 10.3762/bjoc.8.184 Abstract An ionic liquid based on polydimethylsiloxane with imidazolium salt brushes was synthesized as a good solvent for β-cyclodextrin-polydimethylsiloxane rotaxane. As expected the PDMS-Im/Br ionic liquid

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

• File 1. The analytical data for 1–4 are fully consistent with their molecular structure. The synthesis of amphiphilic β-cyclodextrin 5 has been reported previously [30]. Unilamellar vesicles with a diameter of 100–150 nm are obtained by extrusion [27][30]. To investigate the ability of adamantane

• functions to bind into the cavity of cyclodextrins, the synthesized guest molecules were investigated regarding their 1:1 complexation behavior towards β-cyclodextrin. Isothermal titration calorimetry (ITC) was carried out with β-cyclodextrin and each of the synthesized guest molecules 1–4. The

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

• 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

• photophysical properties of PFs by using persilylated γ-CD as a new host molecule [33]. Inclusion of bithiophene into persilylated β-cyclodextrin, randomly methylated β-cyclodextrin, or chemically modified CD derivatives, followed by copolymerization with fluorene monomers results in significant changes in the

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

• that the addition of randomly modified β-cyclodextrin (RAME-β-CD) in aqueous medium could have a beneficial impact on the catalytic performances of phosphane-based aggregates in the Pd-catalyzed cleavage of allyl carbonates (Tsuji–Trost reaction). The RAME-β-CD/phosphane supramolecular interactions

• demonstrate that the beneficial effect of CDs on a catalytic micellar system can be generalized to another reaction and other amphiphilic phosphanes. To this end, we undertook a study using the randomly methylated β-cyclodextrin (RAME-β-CD) as an additive in an aqueous Pd-catalyzed cleavage reaction of allyl

Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part II: Iridomyrmecins

• Robert Hilgraf,
• Nicole Zimmermann,
• Lutz Lehmann,
• Armin Tröger and
• Wittko Francke

Beilstein J. Org. Chem. 2012, 8, 1256–1264, doi:10.3762/bjoc.8.141

• mixture of OV1701 and heptakis(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin as an enantioselective stationary phase. Figure 3 shows the structures and retention times of all eight stereoisomers of trans-fused iridomyrmecins on both capillary column systems. Despite the small differences in

• Y and Z to show the same mass spectra and retention times as the two early eluting racemates of the synthetic iridomyrmecins, i.e., B/B' and A/A', respectively (Figure 3). Enantioselective gas chromatography on heptakis(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin showed that A and A

• ' were well separated with an α-value of A:A' = 1.05 (Figure 3). Consequently, the structure of Z could be easily determined to be A', namely (4S,4aS,7R,7aS)-iridomyrmecin. Under the same experimental conditions, B and B' were only poorly resolved, however, heptaiks(2,6-di-O-methyl-3-O-pentyl)-β

Stereoselective synthesis of trans-fused iridoid lactones and their identification in the parasitoid wasp Alloxysta victrix, Part I: Dihydronepetalactones

• Nicole Zimmermann,
• Robert Hilgraf,
• Lutz Lehmann,
• Daniel Ibarra and
• Wittko Francke

Beilstein J. Org. Chem. 2012, 8, 1246–1255, doi:10.3762/bjoc.8.140

• 1:1-mixture of OV1701 and heptakis-(6-O-tert-butyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin as an optically active stationary phase. Figure 3 shows the corresponding retention times of all eight stereoisomers that were obtained with the two used capillary column systems. Coupled GC/MS using FFAP

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

• cations from an aqueous solution increases in the order Na+< K+< Rb+< Cs+. According to these properties, compound 4 could be used as a selective transport system controlled by light. The β-cyclodextrin-type structure, schematically represented in Figure 9 as 5, acknowledges the bipyridinium fragment of

• 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

Low-generation dendrimers with a calixarene core and based on a chiral C₂-symmetric pyrrolidine as iminosugar mimics

• Marco Marradi,
• Stefano Cicchi,
• Francesco Sansone,
• Alessandro Casnati and
• Andrea Goti

Beilstein J. Org. Chem. 2012, 8, 951–957, doi:10.3762/bjoc.8.107

• interactions [10], the effect of iminosugar-based multivalent inhibitors on enzyme activity is difficult to rationalise. However, the introduction of several copies of an N-alkyl analogue of iminosugar 1-deoxynojirimycin onto a fullerene ball [8] or onto β-cyclodextrin [9] afforded the first pieces of evidence

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

• mesomeric betaine with randomly methylated (1.8) β-cyclodextrin were investigated by UV–vis spectroscopy. Furthermore, the reaction conditions were applied to poly(vinylimidazole) and 1,4-bis(1H-imidazol-1-yl)butane to obtain functionalized polymer networks and condensate polymers, respectively. Keywords

• ). 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

• functionalized polymer networks and oligomers, which were stable at temperatures up to 300 °C and 200 °C, respectively. Experimental Materials. Randomly methylated (1.8) β-cyclodextrin (m-β-CD) was obtained from Wacker-Chemie GmbH (Burghausen, Germany). Prior to use, m-β-CD was dried in a CEM Sam 255 microwave

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

• substituents with an aldoxime or a ketoxime moiety along the narrow opening of the β-cyclodextrin cavity was synthesized, and the ability of these compounds to reduce the inhibitory effect of the neurotoxic organophosphonate cyclosarin on its key target, acetylcholinesterase, was assessed in vitro. All

• compounds exhibited a larger effect than native β-cyclodextrin, and characteristic differences were noted. These differences in activity were correlated with the structural and electronic parameters of the substituents. In addition, the relatively strong effect of the cyclodextrin derivatives on cyclosarin

• phosphates and phosphonates [15][16][17][18], including the highly neurotoxic organophosphonates (OP) sarin and soman [19][20][21]. While α-cyclodextrin, the cyclodextrin containing six anhydroglucose units along the ring, was shown to be most effective for sarin [17][22], the larger β-cyclodextrin with the

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

• aromaticity and is pharmaceutically relevant (Scheme 1). Recently we described the monomer synthesis of mono-(6-azido-6-desoxy)-β-cyclodextrin with propargylmethacrylate and the copolymerization with N-isopropylacrylamide (NIPAAM) [20]. The properties of the polymer 1 were characterized further by use of size

• -exclusion chromatography (SEC), dynamic light scattering (DLS) and turbidity measurements. To confirm the formation of the proposed host–guest structure of β-cyclodextrin and ephedrine in principle, 2-D ROESY NMR spectroscopy was performed at room temperature with β-CD in excess. Thus the correlation

• )-(+)-Ephedrine hydrochloride and (1R,2S)-(−)-ephedrine hydrochloride were obtained from Acros Organics and used as received. β-Cyclodextrin (β-CD) was obtained from Wacker-Chemie GmbH, Burghausen, Germany and used after drying overnight in an oil-pump vacuum over P2O5. 1H NMR and ROESY experiments were performed

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

• Indra Bohm Susanne Katharina Kreth Helmut Ritter Institut für Organische und Makromolekulare Chemie II, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany Fax: (+49) 211 8115840 10.3762/bjoc.7.130 Abstract The release of anthraquinone dyes from β-cyclodextrin

• anionic groups can interact with the cationic hyperbranched structure of the polymeric matrix [14]. These components can be released by changing the pH value [15]. In this context we recently reported the synthesis of hyperbranched PEI bearing covalently attached β-cyclodextrin (CD) [16]. CD has been

• strongly indicates the formation of higher aggregates due to intermolecular interactions. DLS measurements of the complex of unmodified, randomly methylated, β-cyclodextrin (RAMEB-CD) and dye 2 were performed, giving a dH of 68 nm (Supporting Information File 1, Figure S6). The combination of RAMEB-CD and