Investigations of thiol-modified phenol derivatives for the use in thiol–ene photopolymerizations

• Sebastian Reinelt,
• Monir Tabatabai,
• Urs Karl Fischer,
• Norbert Moszner,
• Andreas Utterodt and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1733–1740, doi:10.3762/bjoc.10.180

• inorganic fillers (40–90 wt %) [1]. Up to date, 2,2-bis(4-(2-hydroxy-3-methacryloxyprop-1-oxy)phenyl)propane (Bis-GMA), 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-(mixture of 2,2,4 and 2,4,4)-trimethylhexane (UDMA) and triethylene glycol dimethacrylate (TEGDMA) are still the dominating monomers of the

Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: new multivalent galectin-3 ligands

• Silvia Bernardi,
• Paola Fezzardi,
• Gabriele Rispoli,
• Stefania E. Sestito,
• Francesco Peri,
• Francesco Sansone and
• Alessandro Casnati

Beilstein J. Org. Chem. 2014, 10, 1672–1680, doi:10.3762/bjoc.10.175

• Milano-Bicocca, Piazza della Scienza 2, 20126 Milano, Italy 10.3762/bjoc.10.175 Abstract Four novel calix[4]arene-based glycoclusters were synthesized by conjugating the saccharide units to the macrocyclic scaffold using the CuAAC reaction and using long and hydrophilic ethylene glycol spacers

Photoswitchable precision glycooligomers and their lectin binding

• Daniela Ponader,
• Sinaida Igde,
• Marko Wehle,
• Katharina Märker,
• Mark Santer,
• David Bléger and
• Laura Hartmann

Beilstein J. Org. Chem. 2014, 10, 1603–1612, doi:10.3762/bjoc.10.166

• sugar ligands and the control of the backbone properties. Three different dimer building blocks were employed for the synthesis of the photoswitchable glycooligomers: the triple bond-functionalized building block TDS [7], an ethylene glycol spacer building block EDS [7], and the photoswitchable building

Design, automated synthesis and immunological evaluation of NOD2-ligand–antigen conjugates

• Marian M. J. H. P. Willems,
• Gijs G. Zom,
• Nico Meeuwenoord,
• Ferry A. Ossendorp,
• Herman S. Overkleeft,
• Gijsbert A. van der Marel,
• Jeroen D. C. Codée and
• Dmitri V. Filippov

Beilstein J. Org. Chem. 2014, 10, 1445–1453, doi:10.3762/bjoc.10.148

• neopentyl glycol at 60 °C and careful monitoring of the reaction progress led to compound 17 in 88% yield. Acetylation of 17 then afforded compound 18. Stabilization of the glycosidic linkage by the installment of electron-withdrawing groups proved to be successful, and the treatment of 18 with 20% TFA in

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

• polyethylene glycol (PEG), known as PEGylation, has been widely used to improve the bioavailability of proteins and low molecular weight drugs. The covalent conjugation of PEG to the carbohydrate moiety of a protein has been mainly used to enhance the pharmacokinetic properties of the attached protein while

• multiarm PEGs, with the aim to increase the loading of the active sugar. Multivalent glycomolecules have proven to mediate or inhibit a variety of biological or pathological processes [17][23]. Review Polyethylene glycol (PEG) derivatives Polyethyleneglycol is an amphiphilic polymer consisting of repeating

• protonable amines into neutral amide or carbamate linkers. Even though PEGylation of chitosan via the amino group is the most commonly used method a number of examples of polysaccharide derivatisation on the hydroxy groups have been reported. Chitosan-O-poly(ethylene glycol) graft copolymers were synthesized

A complete series of 6-deoxy-monosubstituted tetraalkylammonium derivatives of α-, β-, and γ-cyclodextrin with 1, 2, and 3 permanent positive charges

• Martin Popr,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2014, 10, 1390–1396, doi:10.3762/bjoc.10.142

• the preparation of 24 involved a 4-step protocol. In the first step, one hydroxy group of ethylene glycol was substituted by tosylate to yield 92% of 2-hydroxyethyl-4-methylbenzenesulfonate (21). Next, compound 22 was prepared by a nucleophilic substitution with sodium azide. The product of this

Biantennary oligoglycines and glyco-oligoglycines self-associating in aqueous medium

• Svetlana V. Tsygankova,
• Alexander A. Chinarev,
• Alexander B. Tuzikov,
• Nikolai Severin,
• Alexey A. Kalachev,
• Juergen P. Rabe,
• Alexandra S. Gambaryan and
• Nicolai V. Bovin

Beilstein J. Org. Chem. 2014, 10, 1372–1382, doi:10.3762/bjoc.10.140

• ’ principle, i.e., by their C-termini, so that the two amino groups are terminal. The obtained compounds differ threefold. Firstly, they differ by core X nature: hydrophilic oligoethylene glycol (OEG), hydrophobic flexible decamethylene (C10), or short ethylene (C2). Secondly, the length of oligoglycine

• glycol diamine was obtained from ditosylate as described in [7][8]. The synthesis of biantennary oligoglycines was carried out by means of the activated esters method (Scheme 1) [9]. The glycine chains were elongated stepwise by their N-terminus by using N-oxysuccinimidyl esters (BocGlyONSu or

• amino group the solution becomes neutral (рН 6.5), in the case of two Nа2CO3 equivalents the pH value is more than 8.5 (basic solution, denoted as pH > 8.5). At n < 4 peptides with an oligoethylene glycol core and the cores С2 and С10 did not form associates in aqueous medium in all the studied ranges

An economical and safe procedure to synthesize 2-hydroxy-4-pentynoic acid: A precursor towards ‘clickable’ biodegradable polylactide

• Quanxuan Zhang,
• Hong Ren and
• Gregory L. Baker

Beilstein J. Org. Chem. 2014, 10, 1365–1371, doi:10.3762/bjoc.10.139

• polymerization of functional lactide monomers, post-polymerization modification, or a combination of these two approaches. The appending hydroxy [9], carboxyl [10], poly(ethylene glycol) (PEG) [11][12][13][14], allyl [15], azido [16] and acetylene [17] functionalities on PLA backbones have been reported and

Molecular recognition of surface-immobilized carbohydrates by a synthetic lectin

• Melanie Rauschenberg,
• Eva-Corrina Fritz,
• Christian Schulz,
• Tobias Kaufmann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 1354–1364, doi:10.3762/bjoc.10.138

• previously [39]. Fluorescein-labeled FITC-HisHis was obtained by labeling of Cys-His-Cys with fluorescein isothiocyanate, which was achieved by using an Fmoc-protected oligo(ethylene glycol) spacer synthesized in four steps from commercially available ethylenediamine (see Supporting Information File 1). The

• ), respectively. In order to flexibly attach the carbohydrates on the substrate and to ensure unhindered carbohydrate–lectin interactions, oligo(ethylene glycol) spacers were introduced. Oligo(ethylene glycol) chains are flexible, water-soluble and do not interact with lectins [46]. A nucleophilic primary amine

• normal and that the printed layers exhibit a lower than maximal surface coverage. This is most likely due to a combination of factors, i.e., quality of the base epoxide SAM, reaction time with the amine inks, and steric bulk of the carbohydrates compared to the triethylene glycol linker. We note that

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

• (lipidation) or methoxy polyethylene glycol (PEG) polymers (PEGylation) [14]. These two strategies are based on substantially different mechanisms, which can lead to a remarkable increase of the potential utility of peptides as pharmaceuticals. Lipidation of peptides: In general, the half-life extension of

• be selectively modified with activated (mainly N-hydroxysuccinimidyl (NHS) esters) PEG. Small polyethylene glycol units up to 2 kDa can be introduced on the solid support [99]. The introduction of larger PEG units has to be carried out in solution. Therefore, side-chain protecting groups during the

A catalyst-free multicomponent domino sequence for the diastereoselective synthesis of (E)-3-[2-arylcarbonyl-3-(arylamino)allyl]chromen-4-ones

• Pitchaimani Prasanna,
• Pethaiah Gunasekaran,
• Subbu Perumal and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2014, 10, 459–465, doi:10.3762/bjoc.10.43

• , acetonitrile, dimethyl sulfoxide, ethanol, ethylene glycol) in the presence of one equivalent of HCl, but all these attempts failed, while the same conditions were successful in DMF. These results can be explained by assuming that the initial aldol-type reaction between 1 and 4 to give 6 is reversible and is

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• of different nitroarenes (e.g. nitroglycerin, ethylene glycol dinitrate, diethylene glycol dinitrate, cyclotrimethylenetrinitramine, pentaerythritol tetranitrate, nitrocellulose, etc.). Continuous processes were enforced as they allowed to retain the same scale of operation while keeping the plant

Carbenoid-mediated nucleophilic “hydrolysis” of 2-(dichloromethylidene)-1,1,3,3-tetramethylindane with DMSO participation, affording access to one-sidedly overcrowded ketone and bromoalkene descendants^§

• Rudolf Knorr,
• Thomas Menke,
• Johannes Freudenreich and
• Claudio Pires

Beilstein J. Org. Chem. 2014, 10, 307–315, doi:10.3762/bjoc.10.28

• disappeared with the aqueous phases. Without electron-withdrawing substituents in both 6 and the prospective ARE [12] intermediate 9, several strongly caustic methods of hydrolysis with KOH failed to consume 6 in diethylene glycol [18] (11 hours at 135 °C), in triglyme (six hours, 150 °C), in HMPA [tris

Substrate dependent reaction channels of the Wolff–Kishner reduction reaction: A theoretical study

• Shinichi Yamabe,
• Guixiang Zeng,
• Wei Guan and
• Shigeyoshi Sakaki

Beilstein J. Org. Chem. 2014, 10, 259–270, doi:10.3762/bjoc.10.21

• convenient method of the W-K reduction [4][5]. The method involves heating R1(R2)C=O, KOH and hydrazine hydrate (H2N–NH2·H2O) together in diethylene glycol (DEG in Scheme 1). This method gives the products from steroid ketones in a one-pot reaction and with a high yield. Scheme 2 shows the reaction mechanism

• reaction of acetone. In relation to issue 2, a base-free W-K reaction was examined. A model used for geometry optimizations is shown in Scheme 4a. The model of Scheme 4a is composed of acetone, hydrazine and (H2O)8 with the SCRF = PCM external field of ethylene glycol. Water dimers are linked to two lone

• -pair orbitals of the carbonyl oxygen and two N–H bonds. The model is based on Huang-Minglon conditions using H2N–NH2·H2O and diethylene glycol (DEG, bi-protic solvent). The DEG solvent was approximated by ethylene glycol. Figure 1 shows geometric changes of the neutral W-K reaction. In (i) of Figure 1

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

• activated double bond or a carbon atom of a keto or ester group). The desilylation of tert-butyldimethylsilylperoxy ketones 131a,b with HF followed by cyclization and subsequent reaction with monomethylethylene glycol afforded dioxolanes 132a,b in 75 and 88% yield, respectively. The intermediate

• used for the generation of the hydroperoxide group. The intramolecular cyclization afforded 3-methyl-5-pentyl-1,2-dioxolan-3-ol (134), which could be easily reacted with monomethylethylene glycol to form 3-(2-methoxyethoxy)-3-methyl-5-pentyl-1,2-dioxolane (135). Allylation of the latter produced 3

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

• Phei Li Lau,
• Ray W. K. Allen and
• Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

• biphasic mode using a mixture of solvents, such as ethylene glycol and toluene [8]. The drive to carry out reactions in environmentally benign media also led to studies being carried out in “green” (environmentally friendly) solvents, such as aqueous media, some supercritical fluids (SCFs), ionic liquids

Charge-transfer interaction mediated organogels from 18β-glycyrrhetinic acid appended pyrene

• Jun Hu,
• Jindan Wu,
• Qian Wang and
• Yong Ju

Beilstein J. Org. Chem. 2013, 9, 2877–2885, doi:10.3762/bjoc.9.324

• ]. Besides the mixed solvents, gelation and partial gelation also occurred in ethylene glycol (entry 12, Table 1) and acetonitrile (entry 13, Table 1). In aromatic solvents (entries 14 and 15, Table 1), chlorinated solvents (entries 16 and 17, Table 1) and low molecular weight alcohols (entries 18 and 19

• stronger gelation ability in ethylene glycol than in the other solvents. Stoichiometry study Studies on the thermal stability as a function of stoichiometry were also performed on these CT gels for different molar ratios of GA-pyrene (3) and TNF (4, 2:1, 3:2, 4:3, 1:1, 3:4, 2:3, 1:2, Figure 3

• /100 mL) with TNF (4) in varying ratios. Scanning electron micrographs of CT xerogels (3 and 4, 1:1, molar ratio, [3] = 9 mM) in DMSO/water (3:1, v/v) (a, b), ethylene glycol (c, d), and DMF/water (3:1, v/v) (e and f). Scale bars in are 20 μm for (a, c, e) and 10 μm for (b, d, f). Optical micrographs

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• substrate is bound to a hydrophilic tertiary amide-poly(ethylene glycol) based resin via a peptide linker [8]. With copper(I) salts as catalysts, the corresponding triazole is formed under mild conditions upon addition of the azide. This reaction proceeds in a variety of organic solvents at room temperature

Damage of polyesters by the atmospheric free radical oxidant NO₃^•: a product study involving model systems

• Catrin Goeschen and
• Uta Wille

Beilstein J. Org. Chem. 2013, 9, 1907–1916, doi:10.3762/bjoc.9.225

• neopentylates, where the latter provided a simplified model for diesters of neopentyl glycol, which is the commonly used diol component in such polyesters. All experiments were performed in solution, using two different methods to produce NO3• in situ in the presence of the respective substrate 1–3. In

Thermochemistry and photochemistry of spiroketals derived from indan-2-one: Stepwise processes versus coarctate fragmentations

• Götz Bucher,
• Gernot Heitmann and
• Rainer Herges

Beilstein J. Org. Chem. 2013, 9, 1668–1676, doi:10.3762/bjoc.9.191

• ) should be thermochemically activated (Scheme 2) [22]. To test the above hypothesis, we now investigate the thermochemistry and the photochemistry of the ketals 1 and 3, derived from indan-2-one and ethylene glycol, and cis-2-butene-1,4-diol (Scheme 3). The ketal 2, derived from 1,3-propanediol, was

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

• molecule (C32H61NO18P+, m/ztheo 778.3621) was accurately mass measured with a relative error of ±0.3 ppm by using two reference ions from a poly(propylene glycol) as internal standards. Nitroxide-mediated polymerization of styrene in N,N-dimethylacetamide After the addition of styrene (2.16 g, 20.7 mmol

Host–guest complexes of mixed glycol-bipyridine cryptands: prediction of ion selectivity by quantum chemical calculations, part V

• Svetlana Begel,
• Ralph Puchta and
• Rudi van Eldik

Beilstein J. Org. Chem. 2013, 9, 1252–1268, doi:10.3762/bjoc.9.142

• more stable cryptates with Na+ and Ca2+. Although the CH2-units containing molecular bars fixed at the bridgehead nitrogen atoms determine the flexibility of the cryptands, the twist angles associated with the bipyridine and glycol building blocks also contribute considerably. Keywords: cryptands; DFT

• .bpy]3+ are transition states for the movement of the metal ion inside the cavity of [2.2.bpy], as shown in Figure 5. This motion leads from one glycol molecular bar to the other, bringing the cation closer to the O donor atoms, hence supporting the coordination. The barrier for this movement lies at

• two glycol-containing molecular arms, which can wrap flexibly around the cation, allowing closer proximity between the metal center and bipyridine ligand. The increasing size of the guest ions is accompanied by a general enlargement of the metal–donor bond length, as can be concluded from the

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• the BBB in vivo. This disappointing result could be appointed to the excessively high lipophilicity of the compound. To improve the pharmacokinetic profile of 94, the [18F]-labeled analogue 96 was designed as an imaging probe [72]. Compound 96, which contains an [18F] end-capped polyethylene glycol

Aqueous reductive amination using a dendritic metal catalyst in a dialysis bag

• Jorgen S. Willemsen,
• Jan C. M. van Hest and
• Floris P. J. T. Rutjes

Beilstein J. Org. Chem. 2013, 9, 960–965, doi:10.3762/bjoc.9.110

• tetraethylene glycol azido mesylate 6 was reacted with diol 4, affording a mixture of the desired asymmetric bipyridine 7 and the two corresponding symmetric bipyridines. This mixture was separated by column chromatography resulting in 32% isolated yield of pure azide 7. Subsequent Staudinger reduction and

1-n-Butyl-3-methylimidazolium-2-carboxylate: a versatile precatalyst for the ring-opening polymerization of ε-caprolactone and rac-lactide under solvent-free conditions

• Astrid Hoppe,
• Faten Sadaka,
• Claire-Hélène Brachais,
• Gilles Boni,
• Jean-Pierre Couvercelle and
• Laurent Plasseraud

Beilstein J. Org. Chem. 2013, 9, 647–654, doi:10.3762/bjoc.9.73

• of ε-caprolactone (ε-CL) and rac-lactide (rac-LA) under solvent-free conditions and using 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) as precatalyst is described. Linear and star-branched polyesters were synthesized by successive use of benzyl alcohol, ethylene glycol, glycerol and

• precatalyst. Results and Discussion Two solvent-free polymerization procedures were developed in this study, named methods A and B (Scheme 1). Four initiator alcohols, with an increasing number of OH functions, were successively used: benzyl alcohol (1), ethylene glycol (2), glycerol (3) or pentaerythritol (4

• and form linear (benzyl alcohol, ethylene glycol) and star-branched (glycerol, pentaerythritol) polyesters. In comparison to their linear analogues, star-branched polymers feature lower crystallinity, lower melt viscosities and smaller hydrodynamic volume [56][57][58]. The crystallinity (defined