Linear-g-hyperbranched and cyclodextrin-based amphiphilic block copolymer as a multifunctional nanocarrier

• Yamei Zhao,
• Wei Tian,
• Guang Yang and
• Xiaodong Fan

Beilstein J. Org. Chem. 2014, 10, 2696–2703, doi:10.3762/bjoc.10.284

• exhibit controlled drug release based on the diffusion release mechanism. The novel multifunctional nanocarrier may be applicable to produce highly efficient and specialized delivery systems for drugs, genes, and diagnostic agents. Keywords: amphiphilic block copolymer; cyclodextrin polymer

• agent [21]. Subsequently, the triblock copolymer (denoted as PHEMA-b-PDMAEMA-b-PHEMA) was easily obtained by using PHEMA-macroCTA. Finally, P1 was synthesized by the reaction of acryloyl chloride with the pendent hydroxy groups of PHEMA blocks. The introduction of double bonds further provides the

• values of micelles are dependent on the composition of the copolymers [26], the length of the hydrophobic blocks [27], the feed ratio of the drug to copolymer, and the preparation methods, as well as the process conditions of micelles [28]. For DLMP3, the higher EE and LC values may be mainly attributed

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

• form an inclusion complex with α-CD, indicating that the PCL chains at the ends of PEG cannot prevent the dethreading of the CDs. We demonstrated the complexation between α-CD and PCL-PEG-PCL triblock copolymers. The triblock copolymer was synthesized by the ring-opening polymerization of ε

• -caprolactone from the same PEG-amine (Mn = 18,400), and each PCL block had Mn of ca. 3,000. When an aqueous solution of the copolymer is mixed with that of α-CD, the solution gradually became turbid until the white precipitate of pseudo-polyrotaxane (pPR) was obtained. Accordingly, the grafting of a single

Host–guest-driven color change in water: influence of cyclodextrin on the structure of a copper complex of poly((4-hydroxy-3-(pyridin-3-yldiazenyl)phenethyl)methacrylamide-co-dimethylacrylamide)

• Nils Retzmann,
• Gero Maatz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2480–2483, doi:10.3762/bjoc.10.259

• experiments. Keywords: cyclodextrin; copolymer; copper(II) sulfate; supramolecular; water complex; Introduction In recent years, the interest in stimuli-responsive polymers increased exponentially [1]. Many polymers have been described, showing sensitivity towards e.g. light, pH and heat [2][3][4

• with N,N-dimethylacrylamide (6) using 2,2’-azobis(2,4-dimethyl)valeronitril (V-65) as an initiator (Scheme 1). The resulting copolymer 7 is orange colored. The color-changing effects of 7 upon addition of CuSO4 alone and in the presence of γ-CD were investigated and representative images are shown in

• )phenethyl)methacrylamide-co-dimethylacrylamide) copolymer leads to reversible color changes and further to aggregation processes in the diluted state. The described phenomena are easy to observe with the naked eye. Color-changing effects of polymer 7 upon addition of A) CuSO4 and B) CuSO4 and γ-CD in a 50

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

• Tao Kong Lin Ye Ai-ying Zhang Zeng-guo Feng School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China 10.3762/bjoc.10.257 Abstract A pentablock copolymer was prepared via the atom transfer radical polymerization of 2-hydroxyethyl methacrylate (HEMA

• ) initiated by 2-bromoisobutyryl end-capped PPO-PEO-PPO as a macroinitiator in DMF. Attaching PHEMA blocks altered the self-assembly process of the pentablock copolymer with γ-CDs in aqueous solution. Before attaching the PHEMA, the macroinitiator was preferentially bent to pass through the inner cavity of γ

• -CDs to give rise to tight-fit double-chain stranded polypseudorotaxanes (PPRs). After attaching the PHEMA, the resulting pentablock copolymer was single-chain stranded into the interior of γ-CDs to form more stable, loose-fit PPRs. The results of 1H NMR, WXRD, DSC, TGA, 13C CP/MAS NMR and FTIR

Molecular ordering at electrified interfaces: Template and potential effects

• Thanh Hai Phan and
• Klaus Wandelt

Beilstein J. Org. Chem. 2014, 10, 2243–2254, doi:10.3762/bjoc.10.233

• through a hot melt glue film (ethylen–vinylacetat copolymer). The Cu(111) single crystal used was manufactured by MaTeck, Jülich, Germany. Prior to each series of STM measurements the copper sample was electropolished by immersing it into 50% orthophosphoric acid at an anodic potential of 2 V for about 20

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

• native γ-CD decrease [13]. Nevertheless, they are in good agreement with the reported stability constants of CDs with different molecules in organic solvents [36]. 4a and 4b polyrotaxanes and 4 non-rotaxane copolymer were obtained by firstly carrying out the well-known paladium-catalyzed Suzuki coupling

• 4b polyrotaxanes and the 4 non-rotaxane copolymer. The encapsulation into permodified CDs cavities compared to those previously reported [13], i.e., the use of toluene as a solvent medium instead of a 1:1 v/v toluene/DMF mixture, led to copolymers soluble in toluene, THF, CH2Cl2 (DCM), and CHCl3. In

• , respectively. Figure 3 displays the 1H NMR spectrum of the 4a polyrotaxane copolymer with the assignments of the resonance peaks. The 1H NMR spectra of 4b and non-rotaxane 4 are shown in Figures S4 and S5 in Supporting Information File 1. The resonance peaks of l, m and n protons from monomer 1 are shifted

Influence of cyclodextrin on the UCST- and LCST-behavior of poly(2-methacrylamido-caprolactam)-co-(N,N-dimethylacrylamide)

• Alexander Burkhart and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1951–1958, doi:10.3762/bjoc.10.203

•  3), respectively. According to 1H NMR spectroscopy, the monomer conversions were nearly quantitative. Therefore it is assumed, that the copolymer compositions are exactly identical with the monomer feed ratios. To investigate the solubility behavior of polymers 6 in water, turbidity measurements

• were performed. As shown in Figure 1, copolymer 6a has a typical LCST-behavior in water. The cloud point upon heating is 34 °C and upon cooling 37 °C, respectively. The hysteresis effect is a result of insoluble to soluble transition which depends on the shape and size distribution of dispersed polymer

• particles [16][17]. The more hydrophilic copolymer 6b has a higher cloud point at 67 °C whereas copolymer 6c is completely soluble in water up to >95 °C. Complexation of copolymer 6a with a 1.5 molar excess of CD, based on monomer 4, was carried out to yield the complexed copolymer 6aCD. Due to that

Supercritical carbon dioxide: a solvent like no other

• Jocelyn Peach and
• Julian Eastoe

Beilstein J. Org. Chem. 2014, 10, 1878–1895, doi:10.3762/bjoc.10.196

• copolymer and fluorinated Teflon analogue Teflon AF have also been solubilised in CO2 (Table 2, compound 17) [11][12]. Non fluorinated polymers: There has also been a large amount of research around non-fluorinated polymer analogues, for the same reasons as surfactants, to reduce fluorocarbon use. The

Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salen)Co(III) complex tethering four quaternary ammonium salts

• Jong Yeob Jeon,
• Seong Chan Eo,
• Jobi Kodiyan Varghese and
• Bun Yeoul Lee

Beilstein J. Org. Chem. 2014, 10, 1787–1795, doi:10.3762/bjoc.10.187

• -transition temperature (48 °C) than the CO2/PO alternating copolymer (40 °C). Keywords: carbon dioxide; CO2 chemistry; cobalt complex; phthalic anhydride; propylene oxide; terpolymerization; Introduction Carbon dioxide (CO2) can be utilized to prepare aliphatic polycarbonates through coupling reactions

• CO2/PO or CO2/EO copolymer itself shows some advantageous properties such as biodegradability, good adhesiveness, good barrier properties, and clean burning properties, the incorporation of a third monomer has also been pursued to improve the properties and hence facilitate its use in more widespread

• alternating PO/PA copolymer. Three aromatic signals were observed in the 1H NMR spectra at 7.71, 7.68, and 7.50 ppm in 1:1:2 ratios (Figure 1(A)). The OCH(Me) signal was observed at 5.35 ppm, while the CH2O signal was observed at 4.3–4.5 ppm. When a larger amount of PA (2.0 g) was added, the conversion of PA

Carbohydrate PEGylation, an approach to improve pharmacological potency

• M. Eugenia Giorgi,
• Rosalía Agusti and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 1433–1444, doi:10.3762/bjoc.10.147

• mannose to PEI via a PEG chain spacer (Figure 3B). This system was used to deliver small interfering RNA (siRNA) into a murine macrophage cell line [44]. Mannose residues as their 2-aminoethyl glycosides were attached by reductive amination to the surface of copolymer micelles of PEG with poly-ε

Automated solid-phase peptide synthesis to obtain therapeutic peptides

• Veronika Mäde,
• Sylvia Els-Heindl and
• Annette G. Beck-Sickinger

Beilstein J. Org. Chem. 2014, 10, 1197–1212, doi:10.3762/bjoc.10.118

• resin beads can enlarge up to six times of their original volume in organic solvents. Moreover, the polymer needs to have a functional group for coupling the linker [20][21][24]. The first solid polymer for peptide synthesis was presented by the SPPS founder Merrifield in 1963, a copolymer consisting of

N-Alkylated dinitrones from isosorbide as cross-linkers for unsaturated bio-based polyesters

• Oliver Goerz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 902–909, doi:10.3762/bjoc.10.88

• used. A set of columns packed with porous styrene–divinylbenzene–copolymer beads was used for the separation of the analytes (MZ Analysentechnik GmbH, 1 × guard column 100 Å, 3 × columns with 10.000, 1000 und 100 Å). The system was calibrated with polystyrene standards with a molecular range from 575 g

Microflow photochemistry: UVC-induced [2 + 2]-photoadditions to furanone in a microcapillary reactor

• Sylvestre Bachollet,
• Kimitada Terao,
• Shin Aida,
• Yasuhiro Nishiyama,
• Kiyomi Kakiuchi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2013, 9, 2015–2021, doi:10.3762/bjoc.9.237

• characterization purposes and yield determination. The microcapillary reactor setup is shown in Figure 2. UV-transparent fluorinated ethylene propylene copolymer capillary (FEP; outer/inner diameter: 1.6/0.8 mm) was tightly wrapped around a Pyrex glass cylinder (λ ≥ 300 nm; outer diameter: 8.5 cm). A total of 10 m

Continuous flow photocyclization of stilbenes – scalable synthesis of functionalized phenanthrenes and helicenes

• Quentin Lefebvre,
• Marc Jentsch and
• Magnus Rueping

Beilstein J. Org. Chem. 2013, 9, 1883–1890, doi:10.3762/bjoc.9.221

• ) could be converted to phenanthrene (2a) in 95% NMR yield with a retention time of 83 min (Table 1, entry 5). The flow-reactor setup used for the optimization (Table 1) is shown in Figure 1. UV-transparent ethylene propylene copolymer capillary (FEP, outer/inner diameter 1/0.5 mm, total volume 5 mL) was

New core-pyrene π structure organophotocatalysts usable as highly efficient photoinitiators

• Sofia Telitel,
• Frédéric Dumur,
• Thomas Faury,
• Bernadette Graff,
• Mohamad-Ali Tehfe,
• Didier Gigmes,
• Jean-Pierre Fouassier and
• Jacques Lalevée

Beilstein J. Org. Chem. 2013, 9, 877–890, doi:10.3762/bjoc.9.101

• ) from Lamberti Spa. The (epoxycyclohexylethyl)methylsiloxane-dimethylsiloxane copolymer (EPOX-Si) was obtained from Bluestar Silicones-France (Silcolease UV POLY 200); trimethylolpropane triacrylate TMPTA and (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate (EPOX or UVACURE 1500) were

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

• ][25][26][27][28][29][30]. Results and Discussion 4-Ferrocenylphenol (2) was prepared according to the literature [31], in high purity (Scheme 1). It was then enzymatically copolymerized with 4-tert-butylphenol (3) in the presence of HRP and H2O2. The resulting copolymer 4 with a weight-average

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

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

• polysiloxanes with a pendant imidazolium bromide derivative (PDMS-Im/Br) through a multistep procedure (Scheme 1) as an ionic liquid, which serves as a good solvent for β-CD-polydimethylsiloxane polyrotaxane (PRot). The copolymer PDMS-Im is characterized by a (CH3)2SiO/Im(CH3)SiO molar ratio of 3/1, as

• -methyl)siloxane] copolymer (PDMS-H) (molar ratio: SiH(CH3)/Allyl-Im 1/1.01) was introduced dropwise at 90 °C. The mixture was stirred at 90 °C for 3 d. The reaction progress was monitored by 1H NMR and FTIR spectroscopy by the disappearing of peaks from 4.9 ppm and 2140 cm−1, respectively. Finally, 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

• 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

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

• ; cyclodextrins; graft copolymer; macromonomer; ring-opening free radical polymerization; 2-vinylcyclopropane; Introduction Macromonomers are polymers or oligomers with at least one functional end group that is capable of further polymerization. The molecular weight of macromonomers generally ranges between 1000

• product 6 was formed (Scheme 4). However, GPC of 6 shows only a preferred dimerization of macromonomer 5, which may result from the relative bulky poly(NiPAAm) side chains. Therefore, copolymerization of 5 and NiPAAm was carried out. In this case, as expected, a copolymer 8 was obtained with much higher

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

• morphology and thermal properties of the PDOF-BTc rotaxane copolymer compared to its noncomplexed PDOF-BT homologue. In contrast, the number-average molecular weight (Mn) of PDOF-BTc rotaxane copolymer indicated lower values suggesting that the condensation reaction is subjected to steric effects of 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

Restructuring polymers via nanoconfinement and subsequent release

• Alan E. Tonelli

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

• ICs are formed with block copolymers or with two or more different homopolymers, the resulting coalesced samples can exhibit intimate mixing between the copolymer blocks, or between entire homopolymer chains. Each of the distinct behaviors observed for polymers coalesced from their ICs is a

• -nucleated PET not only possesses improved properties, but contains no incompatible additives, and so may be readily recycled. Coalesced block copolymers The triblock copolymer PCL-PPG-PCL, with noncrystallizable central poly(propylene oxide blocks), was synthesized by coordinated ring-opening polymerization

• of ε-caprolactone with PPG-diol as the initiator [21]. In the IC of PCL-PPG-PCL formed with α-CD, only PCL blocks were included. In contrast, both PCL and PPG blocks were included in the IC of PCL-PPG-PCL formed with γ-CD, which has larger channels. Consequently, coalescence of the triblock copolymer

Synthesis and characterization of a novel carboxyl group containing (co)polyimide with sulfur in the polymer backbone

• Miroslav Mrsevic,
• David Düsselberg and
• Claudia Staudt

Beilstein J. Org. Chem. 2012, 8, 776–786, doi:10.3762/bjoc.8.88

• all synthesized (co)polyimides, as expected. Gibbs et al. already showed in 1958, that the glass-transition temperature is affected by the rigidity of the polymer backbone [30] and that the glass-transition temperature of a copolymer is a linear function of the composition of the copolymer [31

• results in higher Tg values for this copolymer series. Additionally, Figure 5 shows that the Tg values of both synthesized (co)polyimide series increase with increasing DABA content and follow the predicted linear trend. The reason for this increase is that the DABA monomer exhibits fewer freely rotatable

• of the postulated effects, the results obtained for the synthesized (co)polyimides were compared to those of the reference copolymer 6FDA-4MPD/6FDA-DABA m:n. The Tg values of this (co)polyimide correlate very well with the postulations from Gibbs et al. and Endrey [30][31][32]. The glass-transition

Mutational analysis of a phenazine biosynthetic gene cluster in Streptomyces anulatus 9663

• Orwah Saleh,
• Katrin Flinspach,
• Lucia Westrich,
• Andreas Kulik,
• Bertolt Gust,
• Hans-Peter Fiedler and
• Lutz Heide

Beilstein J. Org. Chem. 2012, 8, 501–513, doi:10.3762/bjoc.8.57

• used to inoculate individual wells of the deep-well plates, with each well containing 3 mL medium. In initial experiments, the medium was supplemented with 0.6% (w/v) of the siloxylated ethylene oxide/propylene oxide copolymer Q2-5247 (Dow Corning, USA), which acts as an oxygen carrier and has been

Azobenzene dye-coupled quadruply hydrogen-bonding modules as colorimetric indicators for supramolecular interactions

• Yagang Zhang and
• Steven C. Zimmerman

Beilstein J. Org. Chem. 2012, 8, 486–495, doi:10.3762/bjoc.8.55

• syntheses. With regard to applications, the DAN·UG (DeUG) heterodimer has been used to drive the formation of: (1) polymer blends [37], (2) a supramolecular multiblock copolymer with a high propensity for alteration [38], and (3) a supramolecular ABC triblock polymer [39]. Further, a structure–property