Orthogonal dual-modification of proteins for the engineering of multivalent protein scaffolds

• Michaela Mühlberg,
• Michael G. Hoesl,
• Christian Kuehne,
• Jens Dernedde,
• Nediljko Budisa and
• Christian P. R. Hackenberger

Beilstein J. Org. Chem. 2015, 11, 784–791, doi:10.3762/bjoc.11.88

• application, since only biotinylated protein could bind to the chip for SPR studies (see below). Dual-labeling of TTL Oxime ligation and CuAAC have been reported previously to be orthogonal to each other in DNA model systems and proteins obtained from amber and ochre suppression [24][45][46]. Since glycol

• cleavage is needed to generate the N-terminal aldehyde [39][40], we initialized our synthetic route with NaIO4 treatment since the galactose units installed by CuAAC would be efficient targets for a glycol cleavage, as shown previously [47]. Based on optimization experiments for the periodate treatment of

• , to engineer precise protein models and study a variety of multivalent receptors. Experimental General protocol for glycol cleavage and oxime ligation on TTL. A solution of the TTL (12 µM; 100 mM phosphate buffer, 100 mM NaCl, pH 7) was mixed with NaIO4 (3 equiv) and shaken for 1 h at 15 °C. N-Acetyl

Multivalent polyglycerol supported imidazolidin-4-one organocatalysts for enantioselective Friedel–Crafts alkylations

• Tommaso Pecchioli,
• Manoj Kumar Muthyala,
• Rainer Haag and
• Mathias Christmann

Beilstein J. Org. Chem. 2015, 11, 730–738, doi:10.3762/bjoc.11.83

• and various families of branched polymers such as dendrimers, dendritic-hybrid and hyperbranched polymers are used as macromolecular support for catalysis [10][11][12]. Linear polymers such as poly(ethylene glycol) (PEG) [13] or non-cross-linked polystyrene (NCPS) [14] are readily available but suffer

Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

• Stephan Schmidt,
• Hanqing Wang,
• Daniel Pussak,
• Simone Mosca and
• Laura Hartmann

Beilstein J. Org. Chem. 2015, 11, 720–729, doi:10.3762/bjoc.11.82

• a concanavalin A (ConA) layer via poly(ethylene glycol)-(PEG)-based soft colloidal probes (SCPs). Special emphasis is on the dependence of multivalent presentation and density of carbohydrate units on specific adhesion. Consequently, we first present a synthetic strategy that allows for controlled

• interface presenting the sugar ligands has a pronounced effect on the resulting adhesion energy [8]. This was shown by varying the length of poly(ethylene glycol) chains that establish the soft hydrogel matrix of the SCPs and measuring the interactions between mannose SCPs and ConA surfaces. In this work

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

• . Keywords: bifunctional anchors; catecholates; multivalency; poly(ethylene glycol); ZnO nanoparticles; Introduction An elegant approach to generate tailored materials and nanoparticles is the formation of molecular monolayers by chemisorption of bifunctional anchor molecules (Figure 1A) [1]. The

• times. Synthesis of tripodal catecholates for surface immobilization. PEG-triscatecholate 3 was synthesized from 1 according to literature [31]. Abbreviations: PEG = poly(ethylene glycol) (5 kDa); EDC = 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; DMAP = 4-(dimethylamino)pyridine; HOBt

Design, synthesis and photochemical properties of the first examples of iminosugar clusters based on fluorescent cores

• Mathieu L. Lepage,
• Antoine Mirloup,
• Manon Ripoll,
• Fabien Stauffert,
• Anne Bodlenner,
• Raymond Ziessel and
• Philippe Compain

Beilstein J. Org. Chem. 2015, 11, 659–667, doi:10.3762/bjoc.11.74

• ethynyl tetra(ethylene glycol)methyl groups [58][59]. Synthesis of the BODIPY precursors The synthesis of the tris-iodo functionalized BODIPY dyes and their acetylenic derivatives is sketched in Scheme 1. The synthesis of derivatives 7 and 8 have previously been reported using a regioselective iodination

• glycol) chains at 4.16 ppm (protons a, integration 4H) and at 3.65 ppm for the methoxy groups (protons b, integration 6H) in addition to the presence of two TMS singlets at 0.20 and 0.28 ppm (respective integration 18 and 9H) confirmed the substitution. Finally, deprotection of the trimethylsilyl group

• bearing a tetraethylene glycol chain tethered to the boron center via an ethynyl bond proved difficult. The use of copper(I) bromide dimethyl sulfide complex [63] at room temperature led to a complex mixture of products. Better results were obtained with copper(II) sulfate and sodium ascorbate under

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

The preparation of new functionalized [2.2]paracyclophane derivatives with N-containing functional groups

• Henning Hopf,
• Swaminathan Vijay Narayanan and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 437–445, doi:10.3762/bjoc.11.50

• bridging and the strain of the desired 17 would be too high for a successful ring closure. Reacting 16 with tetraethylene glycol (TEG) under high dilution conditions (toluene, reflux, 7 d) provides the crownophane 18 in 68% yield (Scheme 2). Likewise, replacement of TEG by pentaethylene glycol (PEG

An unusually stable chlorophosphite: What makes BIFOP–Cl so robust against hydrolysis?

• Roberto Blanco Trillo,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2015, 11, 313–322, doi:10.3762/bjoc.11.36

• product (G2). Here, chloride is replaced at the phosphorus center with the hydroxide nucleophile (Table 2). The relatively high hydrolyzation barrier of BIFOP–Cl (1, 31.2 kcal/mol) in comparison to O–BIFOP–Cl (3, 22.5 kcal/mol) and the smaller, glycol-based, chlorophosphite [CH2O]2P–Cl (8, 18.3 kcal/mol

Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B

• Danielle L. Paterson and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 265–270, doi:10.3762/bjoc.11.29

• alkene 18 in 95% yield. Protection of the ketone in 18 as the cyclic ketal 19 was achieved in 44% yield using excess ethylene glycol and pTSA and despite attempting a variety of alternate conditions [20][21][22][23] this yield could not be improved without degradation of both the starting material 18 and

• h, 14%. Reagents and conditions: (i) H3C(CH3O)NH·HCl, n-BuLi, THF, −78 °C, 4 h, 81%; (ii) 1-bromo-3,4-methylenedioxybenzene, t-BuLi, THF, −78 °C, 3 h, 84%; (iii) NaH, allyl bromide, TBAI, THF, 65 °C, 20 h, 95%; (iv) ethylene glycol, pTSA, toluene, reflux, 16 h, 44%; (v) OsO4, NMO, t-BuOH, H2O, THF

Synthesis and biological evaluation of a novel MUC1 glycopeptide conjugate vaccine candidate comprising a 4’-deoxy-4’-fluoro-Thomsen–Friedenreich epitope

• Manuel Johannes,
• Maximilian Reindl,
• Bastian Gerlitzki,
• Edgar Schmitt and
• Anja Hoffmann-Röder

Beilstein J. Org. Chem. 2015, 11, 155–161, doi:10.3762/bjoc.11.15

• amino acids and the more reactive HATU/HOAt/NMM cocktail in NMP for attachment of building block 11 and a triethylene glycol spacer [52], the desired glycopeptide was assembled. Release from the resin using TFA/iPr3SiH/water (10:1:1) followed by careful de-O-acetylation with NaOMe/MeOH (pH 9.0) and

Synthesis of divalent ligands of β-thio- and β-N-galactopyranosides and related lactosides and their evaluation as substrates and inhibitors of Trypanosoma cruzi trans-sialidase

• María Emilia Cano,
• Rosalía Agusti,
• Alejandro J. Cagnoni,
• María Florencia Tesoriero,
• José Kovensky,
• María Laura Uhrig and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 3073–3086, doi:10.3762/bjoc.10.324

• -lactosyl residues showed to have trypanocidal activity [29]. On the other hand, a recent paper described the synthesis of 1,6-linked cyclic pseudo-galacto oligosaccharides and their in vitro sialylation by recombinant TcTS [30]. Conjugation of lactose analogs with multiarm poly(ethylene glycol) increases

Modification of physical properties of poly(L-lactic acid) by addition of methyl-β-cyclodextrin

• Toshiyuki Suzuki,
• Ayaka Ei,
• Yoshihisa Takada,
• Hiroki Uehara,
• Takeshi Yamanobe and
• Keiko Takahashi

Beilstein J. Org. Chem. 2014, 10, 2997–3006, doi:10.3762/bjoc.10.318

• (α), seven (β), or eight (γ) glucose units. CDs have hydrophobic cavities that can contain guest molecules and form inclusion complexes (ICs). ICs with α-CD accelerate the nucleation and crystallization of poly(ε-caprolactone), poly(ethylene glycol), poly(butylene succinate), and poly(3

• around MeCD and PLLA may be caused by their high miscibility in each other. Therefore, MeCD acts as a plasticizer for PLLA. The plasticizing effects of triacetin and oligomeric poly(1,3-butylene glycol adipate) on PLLA have been reported [43][44][45][46]. Although these plasticizers are reported to be

Synthesis of uniform cyclodextrin thioethers to transport hydrophobic drugs

• Lisa F. Becker,
• Dennis H. Schwarz and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 2920–2927, doi:10.3762/bjoc.10.310

• displacement reactions starting from the corresponding per-(6-deoxy-6-bromo)cyclodextrins. Further modification of all 2-OH positions by etherification with iodo terminated triethylene glycol monomethyl ether (and tetraethylene glycol monomethyl ether, respectively) furnished water-soluble hosts. Especially

• hydrophobic β-CD derivatives [41][42]. Mazzaglia et al. reported on amphiphilic β-CD derivatives with alkyl chains (C2–C16) connected by the thioether linkages to the primary site and a statistical substitution with oligoethylene glycol at secondary sites [43]. Becker et al. describe similar hosts with 2,2,2

• -trifluoroethyl groups at all primary sites and also oligoethylene glycol at secondary sites [44]. In both latter cases statistical CD derivatives have been employed, where both the lengths of the oligoethylene oxide side chains and their locations were scattered. Herein, we report on the synthesis of water

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

• over a typical range of 4000–100 Da. The mass spectra were collected as a continuum profile data. Accurate mass measurement was achieved using polyethylene glycol as the internal reference mass with a resolving power set to a minimum of 10,000 (10% valley). NMR experiments were performed at 300.13 and

Self-assembled monolayers of shape-persistent macrocycles on graphite: interior design and conformational polymorphism

• Joscha Vollmeyer,
• Friederike Eberhagen,
• Sigurd Höger and
• Stefan-S. Jester

Beilstein J. Org. Chem. 2014, 10, 2774–2782, doi:10.3762/bjoc.10.294

• respect to d1 is γ(a1,A,d1) = 3 ± 2°, γ(a2,A,d1) = 5 ± 2°, and γ(a3,A,d1) = 3 ± 2°, and the values do not vary within the experimental error. In other words, the packing of all three compounds is independent on whether the cavity is empty (1), filled by an undecyl diether (2), or a tetraethylene glycol

• (2), or a tetraethylene glycol strand (3). In the porous polymorphs (of each compound), the alkoxy side chains maximize their overlap, and both lattice constants are a direct effect of the side chain lengths. In the dense polymorphs, the packing along lattice vector an,B (n = 1, 2, 3) is similarly a

• (undecyl diether strand, 2), and a polar interior (tetraethylene glycol strand, 3). (a) Schematic structures. The bold lines represent the (identical) macrocycle backbones; the thin straight, dash-dotted, and dash-double-dotted lines indicate alkoxy side chains. (b) Chemical structures. (c) Molecular

Preparation and evaluation of cyclodextrin polypseudorotaxane with PEGylated liposome as a sustained release drug carrier

• Kayoko Hayashida,
• Taishi Higashi,
• Daichi Kono,
• Keiichi Motoyama,
• Koki Wada and
• Hidetoshi Arima

Beilstein J. Org. Chem. 2014, 10, 2756–2764, doi:10.3762/bjoc.10.292

• such as polyethylene glycol (PEG). On the other hand, PEGylated liposomes have been utilized as a representative anticancer drug carrier. However, little is known about the formation of CD PPRX with PEGylated liposome. In the present study, we first report the formation of CD PPRX with PEGylated

• et al. have reported that a number of α-CDs spontaneously thread onto polyethylene glycol (PEG) and form necklace-like supramolecular assemblies [6][7]. The latter are referred to as polypseudorotaxanes (PPRXs), since the release of α-CD from the polymer chain can be achieved upon dissolution in

• water. The assembly of PPRX complexes is a size-dependent process, whereby the small cavity of α-CD assembles with PEG, while the large cavity of β-CD forms the PPRX with polypropylene glycol (PPG) [6][7][8]. In addition, γ-CD forms PPRX with double strand PEG chains [9]. In this case, γ-CD not only

Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups

• Ji-Hun Seo,
• Shino Nakagawa,
• Koichiro Hirata and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2014, 10, 2623–2629, doi:10.3762/bjoc.10.274

• , e.g., α-cyclodextrin (α-CD), threaded on a linear guest molecule, e.g., poly(ethylene glycol) (PEG) [1]. The threaded α-CD molecules are known to be reversibly disassembled when a cleavable end-capping group was introduced in the PEGs, and the cleavable reaction was triggered by proper signals [2][3

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

• , 277-0882, Japan 10.3762/bjoc.10.269 Abstract Graft polyrotaxanes, with poly(ε-caprolactone) (PCL) graft chains on the ring components were synthesized by the simultaneous ring-opening polymerization of ε-caprolactone from both ends of the backbone polymer, an end-functionalized polyethylene glycol

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• , numerous pilot scale processes have been demonstrated like the electrohydrodimerization of formaldehyde to ethylene glycol [36] or the production of glyoxylic acid [37]. The most important reasons for this raised interest are the higher energy efficiency compared to traditional thermochemical processes

Synthesis of aromatic glycoconjugates. Building blocks for the construction of combinatorial glycopeptide libraries

• Markus Nörrlinger and
• Thomas Ziegler

Beilstein J. Org. Chem. 2014, 10, 2453–2460, doi:10.3762/bjoc.10.256

• coupled with 1a (for 21) and 2a (for 23) under similar conditions as described for the non-glycosylated counterparts above to afford glycol-dipeptides 22 and 24 in 51% and 55% yield, respectively. As was observed for EDCI-promoted preparation of glycosylated derivatives 13 and 14 (see Table 2), the yields

Synthesis and immunological evaluation of protein conjugates of Neisseria meningitidis X capsular polysaccharide fragments

• Laura Morelli,
• Damiano Cancogni,
• Marta Tontini,
• Alberto Nilo,
• Sara Filippini,
• Paolo Costantino,
• Maria Rosaria Romano,
• Francesco Berti,
• Roberto Adamo and
• Luigi Lay

Beilstein J. Org. Chem. 2014, 10, 2367–2376, doi:10.3762/bjoc.10.247

• the sera from the three conjugated synthetic fragments were capable to recognize their own structures. To answer this question, conjugates with HSA were prepared with a similar protocol to that used for the formation of the CRM197 conjugates, except that a bis-succinimidyl ester penta-ethylene glycol

End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

• Carolin Fleischmann,
• Hendrik Wöhlk and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2263–2269, doi:10.3762/bjoc.10.235

• easily utilized in polymer analogous reactions, is presented. The subsequent cycloaddition reaction with propargyl-functionalized methoxypoly(ethylene glycol) yielded polymers bearing phenolphthalein as the covalently attached end group. In presence of per-β-cyclodextrin-dipentaerythritol, the formation

• spectroscopy and even the naked eye. Keywords: cyclodextrin; phenolphthalein; poly(ethylene glycol); supramolecular assembly; UV–vis spectroscopy; Introduction Over the past decades, polymers with well-defined and complex architectures gained increasing attention due to a broad variety of applications

• in pure water. With the intention to enhance the guest molecule’s hydrophilicity in order to transfer it into the aqueous phase, poly(ethylene glycol) was chosen as the PP-bearing molecule. On the other hand, it was also of great importance to maintain the rather hydrophobic nature of the PP moiety

Second generation silver(I)-mediated imidazole base pairs

• Susanne Hensel,
• Nicole Megger,
• Kristina Schweizer and
• Jens Müller

Beilstein J. Org. Chem. 2014, 10, 2139–2144, doi:10.3762/bjoc.10.221

• + 1] type could be obtained [14][15]. While most examples focus on the use of DNA, other systems such as RNA [16], GNA [17][18] (glycol nucleic acid), PNA [19][20][21], and other nucleic acid derivatives [22] have been modified as well. It is interesting to note that metal-mediated base pairs do not

Photo, thermal and chemical degradation of riboflavin

• Muhammad Ali Sheraz,
• Sadia Hafeez Kazi,
• Sofia Ahmed,
• Zubair Anwar and
• Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

• such as vehicles (ethanol, propylene glycol), buffers (phosphate and citrate) and tonicity modifiers (NaCl, MgCl2) [118]. RF is also known to form complexes with dendrimers [103][119], certain drugs including antibiotics like cloxacillin sodium [102] and doxorubicin [120], dopamine [121], agents like N

Efficient CO₂ capture by tertiary amine-functionalized ionic liquids through Li⁺-stabilized zwitterionic adduct formation

• Zhen-Zhen Yang and
• Liang-Nian He

Beilstein J. Org. Chem. 2014, 10, 1959–1966, doi:10.3762/bjoc.10.204

• (mol CO2 absorbed per mol of base) through the formation of zwitterionic adducts being stabilized by Li+. Keywords: carbon capture and sequestration; CO2 chemistry; coordination effect; ionic liquid; polyethylene glycol; zwitterionic adducts; Introduction Carbon capture and sequestration (CCS) from

• ). Notably, equimolar CO2 absorption was obtained using task-specific ionic liquids (TSILs) with the phosphonium cation containing long alkyl chains and anions derived from AAs (prolinate and methioninate) [36], or AA salts with bulky N-substituents in polyethylene glycol (PEG) solution [37]. However