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

• Hai Ming Wang Gerhard Wenz Organic Macromolecular Chemistry, Saarland University, Campus Saarbrücken C4 2, 66123 Saarbrücken, Germany 10.3762/bjoc.9.217 Abstract The formation of soluble 1:2 complexes within hydrophilic γ-cyclodextrin (γ-CD) thioethers allows to perform photodimerizations of

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

• host molecules such as tris(o-phenylenedioxy)cyclotriphosphazene (TPP) [10], cyclodextrin (CD) [11], or cucurbituril (CB) derivatives [12] but the inclusion compound derived from AZADO is still unknown. Here in this paper we wish to report the apparent difference of reactivity between AZADO (2) and

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

• cyclodextrin and ferrocene as a representative of metallocenes has been the subject of numerous works. Especially Takahashi and Harada were engaged in the analysis of ferrocene complexes with different cyclodextrins [5], which could be obtained in aqueous solution in high yields. In addition, the crystal

• structure of the α-CD:ferrocene complex has been analyzed by X-ray-diffraction [6]. These studies showed that the ferrocene molecule is encapsulated by two α-CD rings in a tail-to-tail orientation, where all carbon atoms of the cyclopentadienyl rings are in close contact with the cavity of the cyclodextrin

• –CH3 groups of the siloxane backbones at 0 ppm. In addition, the signals of the cyclodextrin-substituents appear in the area of 3.50 to 6.00 ppm. New peaks at 0.43 and 1.25 ppm of the resulting dimethylene bridge between the siloxane and α-CD are detectable. Signals for the double bond of the vinyl

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

• and Discussion The water-soluble fluorescent cyclodextrin was synthesized via copper-catalyzed cycloaddition (Scheme 1). The existence of the resulting product was confirmed by MALDI–TOF spectrometry, 1H NMR and IR spectroscopy. The formation of host–guest structures between the thiazole functionality

• of a fluorescent cyclodextrin via click reaction. The changes in the spectroscopic properties of the fluorescent cycloadduct were investigated in the presence and absence of the competitive guest potassium adamantane-1-carboxylate. The intermolecular formation of polymeric structures with elongated

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

• when it was positioned vertically. The AM1 HOMO/LUMO gap of the empty β-CD with about 12 eV is lowered to about 10 eV in the complex, in agreement with data from the literature. AM1 IR spectra displayed a splitting of the O–H frequencies of cyclodextrin upon complex formation. At the BP/TZVP-DISP3

• 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

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

• presence of DIMEB (2 mM) the signal appears at 66.82 ppm, in agreement with data reported for 1 in water [6][12][13][14]. The shift observed indicates that a complex is formed. The 1H NMR spectrum shows that the protons H3 and H5 of the cyclodextrin rings that are located inside the cavity are slightly

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

• -cyclodextrin/protonated propiconazole, established by the AM1 and PM3 semi-empirical methods. The affinity between different parts of the guest molecule and the cyclodextrin cavity was studied considering that propiconazole possesses three residues able to be included into the host cavity through primary or

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

• (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

• 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

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

• Francesco Trotta Marco Zanetti Roberta Cavalli Dipartimento di Chimica. University of Torino, Via Pietro Giuria 7 10125 Torino, Italy Dipartimento di Scienza e Tecnologia del Farmaco. University of Torino, Via Pietro Giuria 9 10125 Torino, Italy 10.3762/bjoc.8.235 Abstract Cyclodextrin-based

• nanosponges, which are proposed as a new nanosized delivery system, are innovative cross-linked cyclodextrin polymers nanostructured within a three-dimensional network. This type of cyclodextrin polymer can form porous insoluble nanoparticles with a crystalline or amorphous structure and spherical shape or

• biodegradable material with negligible toxicity on cell cultures and are well-tolerated after injection in mice. Cyclodextrin-based nanosponges can form complexes with different types of lipophilic or hydrophilic molecules. The release of the entrapped molecules can be varied by modifying the structure to

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

• Gero Maatz Arkadius Maciollek Helmut Ritter Institute of Organic Chemistry and Macromolecular Chemistry, Heinrich-Heine-University Duesseldorf, Universitaetsstraße 1, D-40225 Duesseldorf, Germany 10.3762/bjoc.8.224 Abstract A thermo-, pH- and cyclodextrin- (CD) responsive poly(N

• [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

• : binding constant; cyclodextrin; hydrogen bond; methylation; regioselective; Introduction Cyclodextrins (CDs) are a well-known class of organic hosts able to include various guests, preferably in aqueous solution [1][2][3]. Inclusion is mainly driven by hydrophobic and van der Waals interactions [4][5][6

• ]. The host–guest complexes, so-called cyclodextrin inclusion compounds, find many applications such as solubilization of pharmaceutical drugs, dispersion of cosmetics, catalysis, or chromatographic separation of enantiomers [2][7][8]. Application of β-CD 1 is hampered by its low solubility of 18.8 g L−1

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

• function of pH. Zeta potential measurements identified an amphoteric behavior for the Fe-Ni/Zn/βCD, suggesting its better capability to remove ions (cations and anions) from aqueous solutions compared to that of Fe-Ni/Zn. Keywords: assembled particles; colloids; cyclodextrin; ferrite; hybrid materials

• /cyclodextrin (Fe-Ni/Zn/βCD) were prepared by coprecipitation reaction of their metal sulfates at 80 °C and pH > 12 (with a sodium hydroxide concentration of 15 g L–1), following the method described in the literature [21]. In the Fe-Ni/Zn/βCD synthesis, 5.0 g L–1 of βCD was used during the preparation process

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

• Hai Ming Wang Gerhard Wenz Organische Makromolekulare Chemie, Saarland University, Campus Geb. C4.2, D-66123, Saarbrücken, Germany 10.3762/bjoc.8.188 Abstract Various hydrophilic γ-cyclodextrin (CD) thioethers, containing neutral or ionic side arms were found to form molecular disperse solutions

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

• 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

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

• employs cyclodextrin (CD) as a host molecule, because CD effectively forms polyrotaxanes with polymers. Herein we report the formation of supramolecular hydrogels with an α-CD dimer (α,α-CD dimer) as a topological linker molecule, and a viologen polymer (VP) as the polymer chain. The supramolecular

• 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

• viologen derivatives Figure 1 depicts the chemical structures of the cyclodextrin dimers (α,α-CD dimer, α,β-CD dimer, and β,β-CD dimer) and pyridyl derivatives (PyC10Py and viologen polymer (VP)). The α,α-CD and β,β-CD dimers are prepared by reacting the corresponding 6-amino-CDs and terephthalic acid

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

• Ulrike Kauscher Bart Jan Ravoo Organic Chemistry Institute, Westfälische Wilhelms-Universität Münster, Correnstraße 40, 48149 Münster, Germany 10.3762/bjoc.8.175 Abstract Cyclodextrin vesicles are versatile models for biological cell membranes since they provide a bilayer membrane that can easily

• be modified by host–guest interactions with functional guest molecules. In this article, we investigate the multivalent interaction of the lectin concanavalin A (ConA) with cyclodextrin vesicles decorated with mannose–adamantane conjugates with one, two or three adamantane units as well as one or two

• mannose units. The carbohydrate–lectin interaction in this artificial, self-assembled glycocalyx was monitored in an agglutination assay by the increase of optical density at 400 nm. It was found that there is a close relation between the carbohydrate density at the cyclodextrin vesicle surface and 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

• ß-cyclodextrin in water. Via radical ring-opening copolymerization of 5 and NiPAAm a graft copolymer 8 with a clouding point of 32 °C was synthesized. The branched unsaturated polymer was treated with ozone to cleave the double bonds of the main chain. Keywords: branched poly(NiPAAm); cloud point

• 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

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

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

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

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

• )-cyclooctene and (Z,Z)-1,3-cyclooctadiene were performed by using the pyromellitate-linked cyclodextrin network polymer, termed “cyclodextrin nanosponge (CDNS)”, as a supramolecular sensitizing host. The photochirogenic behavior of the nanosponges incorporating β- or γ-cyclodextrin was significantly different

• play crucial roles in controlling supramolecular photochirogenesis. Amongst the chiral supramolecular hosts that have been applied to photochirogenesis, cyclodextrin (CD) is undoubtedly the most frequently employed, probably due to its ready availability, modifiability, inherently chiral cavity, and

• photochirogenesis to use pyromellitate-linked polymeric β- and γ-CDs, termed “cyclodextrin nanosponges” (CDNSs) [25][26][27][28][29][30][31][32][33], as sensitizing hosts for the enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) [34][35][36][37] and (Z,Z)-1,3-cyclooctadiene (2ZZ) [38][39][40

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

• retention times between B and B' on the cyclodextrin column, the enantiomers could be well distinguished under the experimental conditions. Structure assignment of volatile components Y and Z in the parasitoid wasp Alloxysta victrix Comparison of mass spectra and GC retention times of synthetic

• 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

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

• as the stationary phase revealed the target natural iridoid lactone X to show the same mass spectrum and the same retention time as a/a', the first eluting pair of the synthetic dihydronepetalactones (Figure 3). Enantioselective gas chromatography on a cyclodextrin column showed X to coelute with a

• the iridoid X, a component of the volatile secretions of the parasitoid wasp Alloxysta victrix. Structures and gas chromatographic retention times of trans-fused dihydronepetalactones on a conventional FFAP column (FFAP) and on an enantioselective cyclodextrin column (cyclo). For experimental details