Highly selective generation of vanillin by anodic degradation of lignin: a combined approach of electrochemistry and product isolation by adsorption

• Dominik Schmitt,
• Carolin Regenbrecht,
• Marius Hartmer,
• Florian Stecker and
• Siegfried R. Waldvogel

Beilstein J. Org. Chem. 2015, 11, 473–480, doi:10.3762/bjoc.11.53

• polymeric backbone has a very important influence on the adsorption behavior (Figure 7). The polystyrene backbones appear to be especially well suited for the adsorption of 1 from alkaline solutions. This can be explained by attractive π–π interactions between the backbone and the adsorptive phase. All

• experiments of non-modified polystyrene resin gave no adsorption at all. These batch experiments were optimized regarding the low vanillin (1) concentrations in the corresponding reaction solution after electrochemical degradation of lignin. Therefore, experiments were performed applying a high ratio of resin

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

• Tor E. Kristensen

Beilstein J. Org. Chem. 2015, 11, 446–468, doi:10.3762/bjoc.11.51

• acid containing an excess of sulfonic acid polystyrene resin [28]. The use of a polymeric resin also facilitated isolation of the reaction products, but it limited the scale of reaction because of the low capacity of the resin (but the reactions were nonetheless undertaken at gram-scale). Again

Properties of cationic monosubstituted tetraalkylammonium cyclodextrin derivatives – their stability, complexation ability in solution or when deposited on solid anionic surface

• Martin Popr,
• Sergey K. Filippov,
• Nikolai Matushkin,
• Juraj Dian and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2015, 11, 192–199, doi:10.3762/bjoc.11.20

• polystyrene. It showed high deposition of cationic PEMPDA-β-CD, but also of the native β-CD. The results indicated that undesired inclusion of the styrene moieties in the CD cavity takes place, which blocks the cavity from further complexation of guest molecules from solution. At this point we replaced Dowex

Redox active dendronized polystyrenes equipped with peripheral triarylamines

• Toshiki Nokami,
• Naoki Musya,
• Tatsuya Morofuji,
• Keiji Takeda,
• Masahiro Takumi,
• Akihiro Shimizu and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2014, 10, 3097–3103, doi:10.3762/bjoc.10.326

• polystyrene having peripheral bromo groups was prepared from the dendronization of unfunctionalized polystyrene with dendritic diarylcarbenium ions bearing peripheral bromo groups using the “cation pool” method. The palladium-catalyzed amination of the peripheral bromo groups with diarylamine gave dendronized

• polystyrene equipped with peripheral triarylamines, which exhibited two sets of reversible redox peaks in the cyclic voltammetry curves. Keywords: carbocation; cross-coupling; dendrimer; dendronized polymer; redox; Introduction Assembling small functional molecules using dendrimers [1] and dendronized

• dendronized polystyrenes: (a) the functionalization of dendronized polystyrene (the “graft from” approach, Figure 1a); and (b) dendronization of polystyrenes with the dendritic carbocation equipped with functional groups (the “graft to” approach, Figure 1b). Both approaches have advantages and disadvantages

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

• permeation chromatographic (GPC) measurements were carried out at 40 °C on a HLC-8320GPC (TOSOH, Japan) instrument using THF as eluent at a flow rate of 0.3 mL/min. All of the GPC data were calibrated using polystyrene (PS) standards. Fourier transform infrared spectroscopy (FTIR) spectra were measured using

Oligomerization of optically active N-(4-hydroxyphenyl)mandelamide in the presence of β-cyclodextrin and the minor role of chirality

• Helmut Ritter,
• Antonia Stöhr and
• Philippe Favresse

Beilstein J. Org. Chem. 2014, 10, 2361–2366, doi:10.3762/bjoc.10.246

• a Viscotek VE 3500 RI detector. The system was calibrated with polystyrene standards with a molecular range from 1,280 g/mol to 1,373,000 g/mol. Syntheses Synthesis of N-(4-hydroxyphenyl)mandelamide (1) 7.61 g (50 mmol) Mandelic acid and 5.75 g (50 mmol) N-hydroxysuccinimide were dissolved in 150 mL

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

• Vertex 70 spectrophotometer. The molecular weights of copolymers were determined by GPC in THF by using a Water Associates 440 instrument and polystyrene (Pst) calibrating standards. TGA analysis was performed under a constant flow of nitrogen (20 mL·min−1) with a heating rate of 10 °C·min−1 and using a

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

• using a Waters Millennium apparatus with polystyrene standards. The Tg data were determined from a second heating at a heating rate of 10 °C/min by differential scanning calorimetry (DSC) using a Thermal Analysis Q10 instrument. Typical procedure for PO/PA alternating copolymerizations. A bomb reactor

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• compounds 49 was obtained for antibacterial screening. In this report, 5'-azidothymidine or 5'-azido-2'-deoxyuridine was linked to a polystyrene butyldiethylsilane resin and subsequently reduced to the polymer-supported thymidinyl (R = CH3) or 2′-deoxyuridinyl (R = H) aminonucleoside 47. The library

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

• been PEGylated and introduced in the surface of polystyrene nanoparticles in order to increase the interaction with galactose receptors. p-Aminophenyl β-D-galactopyranoside was coupled with a bifunctional PEG activated on one end with NHS for the combination with the aniline and a FMOC-protected amino

• ]. PEGylation of a pentofuranose derivative, adapted from [41]. Galactosyl PEGylation of polystyrene nanoparticles, adapted from [42]. PEGylation of lactose analogs [53]. Conjugation of lactose analogs with dendritic PEGs [54]. Acknowledgements This work was supported by grants from Agencia Nacional de

Rasta resin–triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions

• Xuanshu Xia and
• Patrick H. Toy

Beilstein J. Org. Chem. 2014, 10, 1397–1405, doi:10.3762/bjoc.10.143

• ], and have reported the use of various polymer-supported phosphines as reagents, organocatalysts, and ligands in order to simplify product isolation [14][15][16][17][18]. Most recently we have studied the use of the rasta resin polystyrene architecture [19][20][21][22][23][24][25][26] as a platform for

• saturated aqueous solution of Na2CO3 in order to ensure that it was deprotonated and ready for use in the next reaction cycle. Note Added in Proof After the initial submission of our manuscript we became aware of a recent report by Denton and co-workers regarding similar work using polystyrene-supported

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

• styrene and cross-linked divinylbenzene [20]. At present, there are mainly three classes of solid carriers: traditional polystyrene (PS), polyethylene glycol (PEG)-functionalized PS (such as TentaGel-supports [47]) and pure PEG-based resins such as PEGA resin [48] and ChemMatrix [49]. Shelton et al

• . reported the parallel synthesis of different peptides, which was performed at polystyrene-based polymers welded in a polypropylene network [62]. Each so called 'tea bag' thereby reflects one independent peptide. In this method, collective deprotection and washing are carried out in a polyethylene (PE

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

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• additional scavenging of the unreacted amines with polystyrene-based isocyanate (PS-NCO) improved the purities of the final products (69–84%). It is noteworthy that the use of TMSN3 has several advantages, as it is less toxic and explosive than commercial derivatives and the byproduct (methoxytrimethylsilane

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• recently, silver–NHC complexes were found to be valuable catalysts for this MCR. Their first application was reported by Wang and co-workers in 2008 [12], who developed a polystyrene-supported NHC–Ag(I) complex as an efficient catalyst for the A3-coupling under solvent-free conditions, at room temperature

One-pot sequential synthesis of isocyanates and urea derivatives via a microwave-assisted Staudinger–aza-Wittig reaction

• Diego Carnaroglio,
• Katia Martina,
• Giovanni Palmisano,
• Andrea Penoni,
• Claudia Domini and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2013, 9, 2378–2386, doi:10.3762/bjoc.9.274

• preparation of triphenylphosphine-loaded cross-liked cyclodextrin complexes as recyclable green catalyst [39]. The reactivity of polystyrene-supported reagents strongly depends on the choice of solvent that can influence polymer swelling [40]. Solvent choice is therefore an important issue as it must allow

• . Experimental All chemicals were purchased from Sigma-Aldrich (solvents from Carlo Erba SpA) and used without further purification. Solid diphenylphosphino-polystyrene (PS-PPh2) was purchased from Novabiochem® (Cas-No: 39319-11-4, loading ca. 1.2 mmol/g). Reactions were monitored by TLC on Merck 60 F254 (0.25

Non-cross-linked polystyrene-supported 2-imidazolidinone chiral auxiliary: synthesis and application in asymmetric alkylation reactions

• Quynh Pham Bao Nguyen and
• Taek Hyeon Kim

Beilstein J. Org. Chem. 2013, 9, 2113–2119, doi:10.3762/bjoc.9.248

• Quynh Pham Bao Nguyen Taek Hyeon Kim School of Applied Chemistry and Center for Functional Nano Fine Chemicals, Chonnam National University, Gwangju 500-757, Republic of Korea 10.3762/bjoc.9.248 Abstract Asymmetric alkylation reactions using non-cross-linked polystyrene (NCPS)-supported 2

• auxiliaries; chiral carboxylic acids; 2-imidazolidinone; non-cross-linked polystyrene; Introduction Chiral auxiliaries have been proven as a powerful tool for the asymmetric synthesis of highly optical pure compounds used in pharmaceuticals or agrochemicals [1][2]. The recycling and reuse of expensive chiral

• polystyrene (NCPS)-supported 2-phenylimino-2-oxazolidine, which facilitated the synthesis of several chiral amides in excellent stereoselectivity (>96% ee). However, the sterically undemanding methylation has not been investigated [20]. Recently, we introduced 2-imidazolidinone [26][27], a versatile auxiliary

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

• Rajesh Munirathinam,
• Roberto Ricciardi,
• Richard J. M. Egberink,
• Jurriaan Huskens,
• Michael Holtkamp,
• Herbert Wormeester,
• Uwe Karst and
• Willem Verboom

Beilstein J. Org. Chem. 2013, 9, 1698–1704, doi:10.3762/bjoc.9.194

• Polystyrene sulfonate polymer brushes, grown on the interior of the microchannels in a microreactor, have been used for the anchoring of gallium as a Lewis acid catalyst. Initially, gallium-containing polymer brushes were grown on a flat silicon oxide surface and were characterized by FTIR, ellipsometry, and

• walls using polymer brushes. As a part of this program, herein, we report the anchoring of gallium as a Lewis acid catalyst making use of polystyrene sulfonate (PSS) polymer brushes. The choice for gallium was inspired by the successful application of solid supported gallium triflate to catalyze the

• a flat silicon oxide surface in order to optimize the reaction conditions before attempting the functionalization of a microreactor. Polystyrene sulfonate (PSS) polymer brushes [19] were synthesized according to the procedure summarized in Scheme 2. First, a monolayer of atom transfer radical

The rapid generation of isothiocyanates in flow

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 1613–1619, doi:10.3762/bjoc.9.184

• our study demonstrates that thiourea – either immobilised on a polystyrene-type support (QP-TU) or on silica gel (QS-MTU) – serves as an efficient source of a sulfur atom. Given the higher loading of QP-TU (~5.5 mmol/g) compared to QS-MTU (~1.5 mmol/g) as well as its lower cost, QP-TU might be

Organotellurium-mediated living radical polymerization under photoirradiation by a low-intensity light-emitting diode

• Yasuyuki Nakamura and
• Shigeru Yamago

Beilstein J. Org. Chem. 2013, 9, 1607–1612, doi:10.3762/bjoc.9.183

• , and easy availability of the low-cost light source. Structurally well-defined poly(methyl methacrylate), poly(methyl acrylate), and polystyrene, with narrow molecular weight distributions, were synthesized under LED irradiation with or without a neutral density filter. Keywords: free radical; light

• methacrylates. Polymerization in the absence of a filter quantitatively converted the monomer to the polymer within 6 h (96%), but the Mn(exp) of the resulting polystyrene (18100) was significantly different from the Mn(theo) (10100), and the MWD control was unsatisfactory (Mw/Mn = 1.36) (Table 2, run 4). On

• the other hand, when the polymerization was carried out through a 20% transmittance ND filter, although the monomer conversion was slower, the resulting polystyrene had a Mn(exp) close to Mn(theo), and a very narrow MWD (Mw/Mn = 1.09) (Table 2, run 5). High-molecular-weight polystyrene of Mn = 47400

Stability of SG1 nitroxide towards unprotected sugar and lithium salts: a preamble to cellulose modification by nitroxide-mediated graft polymerization

• Guillaume Moreira,
• Laurence Charles,
• Mohamed Major,
• Florence Vacandio,
• Yohann Guillaneuf,
• Catherine Lefay and
• Didier Gigmes

Beilstein J. Org. Chem. 2013, 9, 1589–1600, doi:10.3762/bjoc.9.181

• knowledge, only hydroxyisopropylcellulose (HPC) has been modified by NMP under homogeneous conditions with the 2,2,6,6-tetramethyl-1-piperidinyloxy radical (TEMPO) (Figure 1) as a control agent and by using Barton ester intermediates [17]. Several hydroxyisopropylcellulose-grafted polystyrene (HPC-g-PS

• porosity of 0.2 µm. The column oven was kept at 40 °C, and the injection volume was 20 µL. One ResiPore Pre-column (50 mm, 4.6 mm) and two ResiPore columns (250 mm, 4.9 mm) from Polymer Laboratories were used in series. The system was calibrated by using polystyrene standards in the range 100–400,000 g·mol

• bath to quench the polymerization. For all of them, the monomer conversion was determined by 1H NMR analysis of the raw polymerization medium in DMSO-d6 solution, whereas the Mn and the PDI of the polystyrene chains were measured by SEC/THF. Structure of the SG1, TEMPO and DBN nitroxides and the

Controlled synthesis of poly(3-hexylthiophene) in continuous flow

• Helga Seyler,
• Jegadesan Subbiah,
• David J. Jones,
• Andrew B. Holmes and
• Wallace W. H. Wong

Beilstein J. Org. Chem. 2013, 9, 1492–1500, doi:10.3762/bjoc.9.170

• reagent concentrations (Table 1). Gel-permeation chromatography (GPC) analysis in toluene (against polystyrene standards) revealed the formation of polymer with number-average molecular weights (Mn) ranging from 5 to 40 kg/mol. The Mn values increased linearly with nickel catalyst content, providing

• toluene as the eluent and calibrated against polystyrene reference standards. Materials: 2,5-Dibromo-3-hexylthiophene [27], 2-bromo-5-chloromagnesium-3-hexylthiophene [28], and cis-chloro(2-tolyl)(dppp)nickel(II) complex [8] were prepared according to procedures described in the literature. Commercial

A³-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

• Jian-Lin Huang,
• Derek G. Gray and
• Chao-Jun Li

Beilstein J. Org. Chem. 2013, 9, 1388–1396, doi:10.3762/bjoc.9.155

• about 4 h). This solution was cooled to room temperature, and then dried on a polystyrene Petri dish. After slow evaporation at room temperature, the nanocomposite films of the HS-CNC materials were dried at 120 °C for 2 h. Then, the films were successively soxhlet extracted with EtOH for 6 h and

Synthesis and testing of the first azobenzene mannobioside as photoswitchable ligand for the bacterial lectin FimH

• Vijayanand Chandrasekaran,
• Katharina Kolbe,
• Femke Beiroth and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2013, 9, 223–233, doi:10.3762/bjoc.9.26

• more stable (E)-form. Biological testing of azobenzene mannobioside 2 As a test system for mannose-specific bacterial adhesion, fluorescent GFP-transfected E. coli bacteria (pPKL1162) [23] were employed and tested on a mannan-coated polystyrene microtiter plate surface. In this setup the amount of

Glycosylation efficiencies on different solid supports using a hydrogenolysis-labile linker

• Mayeul Collot,
• Steffen Eller,
• Markus Weishaupt and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 97–105, doi:10.3762/bjoc.9.13

• different resins were briefly explored [26]. However, for automated solid-phase oligosaccharide synthesis, Merrifield polystyrene resin has almost exclusively been used as the solid support. Here, we describe the development of a new linker system that was tested in the context of different solid supports

• , different solid supports have been developed (Figure 1, [27][28]). The most commonly used solid support for organic synthesis is the Merrifield resin [1]. This polystyrene (PS) resin shows good swelling properties in organic media but is not compatible with the aqueous conditions that are often required for

• hydrolysis or enzymatic reactions. There are different variations of pure polystyrene resins. Jandajel resin for example features crosslinking of PS chains by tetrahydrofuran derivatives [29][30]. To improve the swelling behavior of PS resins in polar solvents, the PS core was grafted with polyethylene