A self-assembled cyclodextrin nanocarrier for photoreactive squaraine

• Ulrike Kauscher and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2016, 12, 2535–2542, doi:10.3762/bjoc.12.248

• significant potential for photodynamic therapy. Herein we report that squaraines can be immobilized on a self-assembled nanocarrier composed of amphiphilic cyclodextrins to enhance their photochemical activity. To this end, a squaraine was equipped with two adamantane moieties that act as anchors for the

• aqueous solution of the vesicle [30]. The hydrophobic cyclodextrin cavities are well known to form size-selective inclusion complexes with apolar compounds such as adamantane [31]. In several publications, we have shown that CDVs retain this ability by keeping the cavity available for host–guest

• squaraines can also be immobilized onto CDVs. For this purpose, the squaraines are equipped with two adamantane functions that bind into the cavities of cyclodextrin on the surface of the CDVs (Figure 1). The resulting divalent host–guest interaction should lead to a higher binding affinity of the squaraine

Diradical reaction mechanisms in [3 + 2]-cycloadditions of hetaryl thioketones with alkyl- or trimethylsilyl-substituted diazomethanes

• Grzegorz Mlostoń,
• Paulina Pipiak and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2016, 12, 716–724, doi:10.3762/bjoc.12.71

• -tetrasubstituted isomers exclusively. In other studies, performed with cycloaliphatic thioketones, e.g. with adamantane-2-thione or 2,2,4,4-tetramethyl-3-thioxocyclobutanone, the growing stability of the corresponding 1,3,4-thiadiazolines obtained in reactions with diazomethane, diazoethane, and 2-diazopropane was

Cupreines and cupreidines: an established class of bifunctional cinchona organocatalysts

• Laura A. Bryant,
• Rossana Fanelli and
• Alexander J. A. Cobb

Beilstein J. Org. Chem. 2016, 12, 429–443, doi:10.3762/bjoc.12.46

• oxidative coupling – initially between 3-methoxycatechol (100) and tert-butyl 1-oxoindan-2-carboxylate (101) using an adamantane derivative of cupreidine CPD-102 to give the corresponding adduct 103 in 84% yield and 81% ee (Scheme 24a) [69]. An attempt to develop this methodology towards an asymmetric total

Supramolecular structures based on regioisomers of cinnamyl-α-cyclodextrins – new media for capillary separation techniques

• Gabor Benkovics,
• Ondrej Hodek,
• Martina Havlikova,
• Zuzana Bosakova,
• Pavel Coufal,
• Milo Malanga,
• Eva Fenyvesi,
• Andras Darcsi,
• Szabolcs Beni and
• Jindrich Jindrich

Beilstein J. Org. Chem. 2016, 12, 97–109, doi:10.3762/bjoc.12.11

• as competitive host molecule to the aqueous solution of isomer 3 did not decrease significantly the aggregate size distribution, which indicates that α-CD is not able to inhibit the intermolecular interactions between the molecules of 3-O-Cin-α-CD. Potassium adamantane-1-carboxylate (AdCOOK) was a

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

• octamethylene-linked β-CD dimer c (Figure 10a, b and c) [78] and related β-CD [79][80] dimers in aqueous solution. It was determined from ITC experiments that while β-CD formed a 1:1 host–guest complex with adamantane carboxylate, only one annulus of the β-CD dimer b and β-CD dimer c complexed adamantane

• )). Nevertheless, upon pressing the two halves together self-healing still occurs through β-CD substituent/adamantyl substituent complexation. Finally, if adamantane carboxylate is applied to one of the cut surfaces in sufficient quantity and the two halves are pressed together, competitive β-CD substituent

• /adamantane carboxylate complexation prevents self-healing ((c) and (e)). The properties of this hydrogel can also be utilized in controlling expansion and contraction and shape memory. The practical applications which potentially flow at the macroscopic level from such host–guest chemistry are substantial

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

• adamantane standard. Wide angle X-ray diffraction (WXRD) patterns were recorded on a Shimadzu XD-D1 X-ray diffractometer with Ni-filtered Cu Kα (1.54 Å) radiation (20 kV, 40 mA). Powder samples were scanned from 2θ = 4.5–60° at a speed of 5°/min. FTIR spectra were measured using a Shimadzu IR Prestige-21

Cholesterol lowering effects of mono-lactose-appended β-cyclodextrin in Niemann–Pick type C disease-like HepG2 cells

• Keiichi Motoyama,
• Yumi Hirai,
• Rena Nishiyama,
• Yuki Maeda,
• Taishi Higashi,
• Yoichi Ishitsuka,
• Yuki Kondo,
• Tetsumi Irie,
• Takumi Era and
• Hidetoshi Arima

Beilstein J. Org. Chem. 2015, 11, 2079–2086, doi:10.3762/bjoc.11.224

• adamantane, which is often used as a guest molecule for β-CyD, using the quartz crystal microbalance method (QCM) in phosphate-buffered saline (PBS, pH 7.4) at 37 °C. As a result, the dissociation constant of Lac-β-CyD with adamantane was 9.8 × 10−7 M due to the potent complex formation. Therefore, this

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• compounds. Notably, Bard and co-workers investigated the photo-Kolbé reaction, in which simple carboxylic acids RCO2H were decarboxylatively reduced to the corresponding alkanes RH on irradiation with platinized TiO2 in CH3CN under anaerobic conditions [35][36][37]. Only adamantane, from adamantane-1

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• and chloroacetyl chloride. The crude nitrile product 81 was then collected in a batch vessel and isolated in pure form after crystallisation and washing with n-heptane. Alkylation of 81 with the corresponding amino-adamantane derivate in the presence of excess K2CO3 following an existing batch

• adamantane-derived aminoester 119 [95] completed this flow synthesis. Meclinertant (103) was subsequently obtained after batch deprotection using polymer supported sulfonic acid. Overall, this study showcases how flow chemistry can be applied to gain benefits when faced with problems during mesoscale

Synthesis of tripodal catecholates and their immobilization on zinc oxide nanoparticles

• Franziska Klitsche,
• Julian Ramcke,
• Julia Migenda,
• Andreas Hensel,
• Tobias Vossmeyer,
• Horst Weller,
• Silvia Gross and
• Wolfgang Maison

Beilstein J. Org. Chem. 2015, 11, 678–686, doi:10.3762/bjoc.11.77

• catecholates on TiO2 and steel, we explored their use for the functionalization of ZnO NPs. Synthesis of tripodal catecholates A common synthetic precursor for the synthesis of suitable tripodal catecholates is the AB3-scaffold 1 [40][41][42] (Scheme 1) which is readily available in a few steps from adamantane

• an effector was prepared. This triscatecholate might be useful for the construction of diamandoid hydrophobic coatings [44] or for the reversible attachment of cyclodextrins to NPs by the formation of cyclodextrin/adamantane inclusion complexes [45]. Alternatively, acrylamide 4 and bromide 12 [42

• and sulfobetaine) or switchable hydrophobic/hydrophilic layers (reversible formation of adamantane/cyclodextrin inclusion complexes) on bulk metal surfaces or NPs. The potential of these conjugates has been demonstrated through the immobilization of the tripodal PEG-catecholate 3 on ZnO NPs and a

Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and β-cyclodextrin polymers

• Thorbjørn Terndrup Nielsen,
• Catherine Amiel,
• Laurent Duroux,
• Kim Lambertsen Larsen,
• Lars Wagner Städe,
• Reinhard Wimmer and
• Véronique Wintgens

Beilstein J. Org. Chem. 2015, 11, 147–154, doi:10.3762/bjoc.11.14

• of nanoparticles. It has been shown that CD polymers can form nanoparticles when associated with various amphiphilic polymers such as dextran modified with fatty acid chains [15] or adamantane [16] in aqueous solution. Simply by mixing solutions of β-CD polymers and the hydrophobic-modified dextrans

• can be loaded with hydrophobic molecules and are stable for several days [15]. Here we report an alternative approach where instead of using biological inactive side chains, e.g., adamantane, CPT is applied. This was achieved by the synthesis of two series of novel CPT-polymers by conjugation of CPT

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

Conjugates of methylated cyclodextrin derivatives and hydroxyethyl starch (HES): Synthesis, cytotoxicity and inclusion of anaesthetic actives

• Lisa Markenstein,
• Antje Appelt-Menzel,
• Marco Metzger and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 3087–3096, doi:10.3762/bjoc.10.325

• forms inclusion compounds with derivatives of benzene, naphthalene, adamantane, and many other moieties of similar sizes [3]. Applications of β-CD as complexing agents are limited because of low aqueous solubilities of β-CD and its complexes. Furthermore, the toxic potential of β-CD is known for a long

• much lower binding potential to sevoflurane than all other CD derivatives. Low binding affinities of TRIMEB are also known towards other guest molecules, such as tert-butyl benzoate and adamantane-1-carboxylate, and had been rationalized by the lack of intramolecular hydrogen bonds which would

Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

• Florian Hamon,
• Claire Blaszkiewicz,
• Marie Buchotte,
• Estelle Banaszak-Léonard,
• Hervé Bricout,
• Sébastien Tilloy,
• Eric Monflier,
• Christine Cézard,
• Laurent Bouteiller,
• Christophe Len and
• Florence Djedaini-Pilard

Beilstein J. Org. Chem. 2014, 10, 2874–2885, doi:10.3762/bjoc.10.304

• configurations, respectively. In these conditions, using azobenzene as a linker between two β-CD can lead to a modulation of the inclusion properties, such as a cooperative effect. The cavity of each CD is available to form an inclusion complex with a hydrophobic guest molecule. Among these, adamantane is known

• to be an excellent guest for the β-CD cavity, with an association constant Ka ranging from 2·104 M−1 to 4·104 M−1 [35]. This is because the adamantyl residue fits perfectly inside the β-CD cavity. In this present work, we investigated how the affinity between the dimer of adamantane and switchable

Loose-fit polypseudorotaxanes constructed from γ-CDs and PHEMA-PPG-PEG-PPG-PHEMA

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

Beilstein J. Org. Chem. 2014, 10, 2461–2469, doi:10.3762/bjoc.10.257

• and tetramethylsilane (TMS) as an internal standard. 13C cross-polarization magic-angle spinning (CP/MAS) NMR spectra were measured on a Bruker AV 300 NMR spectrometer with a single contact time of 1 ms and a spinning rate of 5 kHz. Chemical shifts were compared to an external adamantane standard. Gel

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

• complementary and non-complementary strands modified with guest molecules and the investigation of their complexation behavior towards each other by isothermal titration calorimetry (ITC). As complementary binding motifs n-butyl and α-CD and adamantane and β-CD were selected. It was found that it is possible to

• realize sequence-specific molecular recognition by the use of host–guest chemistry, but the recognition motifs as well as the linkages have to be chosen very carefully. In the case of trivalent systems one adamantane moiety must be included to induce preferred formation of 1:1 adducts. Due to the too weak

• interaction between n-butyl and α-CD these systems have a negative chelate cooperativity and open adducts are preferentially formed. As soon as two adamantane moieties are present, the complementary systems have a positive chelate cooperativity and double-stranded structures are favored over open adducts. In

(CF₃CO)₂O/CF₃SO₃H-mediated synthesis of 1,3-diketones from carboxylic acids and aromatic ketones

• JungKeun Kim,
• Elvira Shokova,
• Victor Tafeenko and
• Vladimir Kovalev

Beilstein J. Org. Chem. 2014, 10, 2270–2278, doi:10.3762/bjoc.10.236

• hydroxydiketone 3x, which could be hydrolyzed to the corresponding alcohol 3y (reaction 3 in Scheme 2). The acylation of 1-indanone (2а) with 2,2’-(adamantane-1,3-diyl)diacetic acid (1l) gave the tetraketone 3z. Finally, we used our method in a two-stage one-pot syntheses of pyrazoles, which find extensive use in

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• methyl 2-(4-methoxy-4-(triethylsilylperoxy)cyclohexyl)acetate (108) with 2-methyleneadamantane (109) produced adamantane-2-spiro-3’,8’-methoxycarbonylmethyl-1’,2’-dioxaspiro[4.5]decane (110) in 40% yield (Scheme 28) [258]. The use of easily accessible triethylsilylperoxyacetals 111 as the starting

•  48) [300]. 2.5. Structural modifications, in which 1,2,4-trioxolane ring remains intact Scheme 49 shows possible modifications of substituents at the ozonide ring by the reduction of the ester group in cis-adamantane-2-spiro-3’-8’-ethoxycarbonyl-1’,2’,4’-trioxa-spiro[4.5]decane 182 to form the

• alcohol cis-adamantane-2-spiro-3’-8’-hydroxymethyl-1’,2’,4’-trioxaspiro[4.5]decane 183. The latter was mesylated to 184 (cis-adamantane-2-spiro-3’-8’-methanesulfonylmethyl-1’,2’,4’-trioxa-spiro[4.5]decane), and used in the reaction with sodium 1-methyl-1H-tetrazole-5-thiolate 185 for the synthesis of cis

Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones – First evidence for the 1,3-oxathiole–thiocarbonyl ylide interconversion

• Valerij A. Nikolaev,
• Alexey V. Ivanov,
• Ludmila L. Rodina and
• Grzegorz Mlostoń

Beilstein J. Org. Chem. 2013, 9, 2751–2761, doi:10.3762/bjoc.9.309

• . Results and Discussion Two cycloaliphatic thioketones that were previously studied in similar reactions with diazo compounds [14], were selected as dipolarophiles for the present study, namely 2,2,4,4-tetramethyl-3-thioxocyclobutanе-1-one (1a) [15] and adamantane-2-thione (1b) [16] (Figure 1). As for the

• ; arbitrary numbering of atoms). Energy profile for the transformation of 1,3-oxathiole 3e to alkene 5e. Relative free energies (kcal·mol−1, 298 K) computed at the DFT PBE1PBE/6-31G(d) level. Reaction of diazocarbonyl compounds 2a,c,e with adamantane-2-thione (1b). Three possible pathways A, B and C for the

Flow Giese reaction using cyanoborohydride as a radical mediator

• Takahide Fukuyama,
• Takuji Kawamoto,
• Mikako Kobayashi and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2013, 9, 1791–1796, doi:10.3762/bjoc.9.208

• ) these two flow Giese reactions worked well to give the corresponding addition products 3b and 3c in 88 and 81% yield, respectively (Scheme 5). It should be noted that for these secondary and tertiary substrates, simple reduction to give octane (2b) or adamantane (2c) was hardly observed. Conclusion The

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

• including oxygen [1]. Sometimes, however, the merit turns out to be a drawback by limiting its properties and reactivity. For example, 1 is inefficient in the oxidation of sterically hindered secondary alcohols. The AZADO radical (2) [2] is an intriguing nitroxide radical with adamantane-like structure and

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• proceeded under 1 atmosphere of O2 alone, without any additional initiator being required. Radical initiation by redox processes Nitrogen oxides and nitric acid The PINO activation by means of nitric oxide was first reported by Ishii et al. in 1997 [22]. By reacting adamantane in a mixed solvent of

• hydroxamic acid and O2. NHPI-catalyzed reaction of adamantane under NO atmosphere. Nitration of alkanes and alkyl side-chains of aromatics. Radical mechanism for the nitration of alkanes catalyzed by NHPI. Benzyl alcohols from alkylbenzenes. Catalytic cycle of laccase-NHDs mediator oxidizing system. DADCAQ

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

• Helmut Ritter,
• Berit Knudsen and
• Valerij Durnev

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

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

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

• 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

• )-interactions. The supramolecular structures were characterized by 1H NMR-ROESY spectroscopy, dynamic light scattering, UV–vis spectroscopy, fluorescence spectroscopy, and asymmetric flow field-flow fractionation. By adding potassium adamantane-1-carboxylate, the thiazol dye is displaced from the CD-cavity and

• spectroscopy and fluorescence spectroscopy. Figure 2 shows the UV–vis absorption spectra of 3 in water with the characteristic band at λmax= 340 nm. The addition of a 10-fold excess of potassium adamantane-1-carboxylate, as competitive guest for CD leads to a hypsochromic shift with λmax = 336 nm, through the

• exclusion of the fluorophore moiety from the hydrophobic cavity of CD. This exchange causes a change in the HOMO–LUMO gap [14][15]. Figure 3 shows the fluorescence spectra of 3 in aqueous solution. Upon addition of potassium adamantane-1-carboxylate the maximum wavelength changes from 417 to 442 nm and the