NMR reaction monitoring in flow synthesis

• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31

• and Sons. Flowsheet of the experimental setup used to study the reaction kinetics of the oligomer formation in mixtures of acetaldehyde (AA) and water (A) (Flow rates VAA 254 μL min−1 and VW 748 μL min−1). Reproduced with permission from reference [46]. Copyright 2014 The American Chemical Society

Extrusion – back to the future: Using an established technique to reform automated chemical synthesis

• Deborah E. Crawford

Beilstein J. Org. Chem. 2017, 13, 65–75, doi:10.3762/bjoc.13.9

• by initially forming a dimer from multifunctional monomers, which then forms a trimer, then oligomer and finally a polymer (Figure 4) [24]. Kim and Hyun report the synthesis of polyurethane, discussing the associated numerical simulation they conducted to determine the dependency of shear rate on

• segments. Representative diagram explaining the process involved in step growth polymerisation, which involves the formation of a dimer, then trimer followed by oligomer synthesis. Taken from [24]. Comparison of choline chloride/D-fructose DES prepared via twin screw extrusion (left) and conventional

A versatile route to polythiophenes with functional pendant groups using alkyne chemistry

• Xiao Huang,
• Li Yang,
• Rikard Emanuelsson,
• Jonas Bergquist,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 2682–2688, doi:10.3762/bjoc.12.265

• starting points for future new functionalized EDOT monomers and following polymer or oligomer research. CVs of electrochemical polymerization of (a) pyEDOT 3 and (b) EDOT in MeCN solution with 0.1 M TEAPF6, glassy carbon electrode, 0.1 V s−1. Insets show the structure and voltammograms for the monomers

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

• Loïc Leclercq

Beilstein J. Org. Chem. 2016, 12, 2644–2662, doi:10.3762/bjoc.12.261

• -CD to exposed groups on insulin monomers after dissociation. Therefore, the α-CD facilitates the oligomer dissociation. In contrast, the dissociation is observed to be more endothermic in the presence of HP-β- and ME-β-CD although oligomer dissociation is induced. The authors suggest that the binding

Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells

• Hideaki Komiyama,
• Chihaya Adachi and
• Takuma Yasuda

Beilstein J. Org. Chem. 2016, 12, 1459–1466, doi:10.3762/bjoc.12.142

• functionality has not been fully characterized because of the small variation in the central core units researched so far. Herein, we report the design and synthesis of a new star-shaped π-conjugated oligomer composed of an electron-donating tetrathienoanthracene (TTA) core coupled with multiple electron

From N-vinylpyrrolidone anions to modified paraffin-like oligomers via double alkylation with 1,8-dibromooctane: access to covalent networks and oligomeric amines for dye attachment

• Daniela Obels,
• Melanie Lievenbrück and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 1395–1400, doi:10.3762/bjoc.12.133

• poly(ethylene glycol) side chains. Keywords: double alkylation; modified N-vinylpyrrolidone; oligomeric anthraquinone dye; paraffin-like oligomer; radical thiol-ene click reaction; Introduction Poly(N-vinylpyrrolidone) (PVP) is established in daily life due to its high water solubility and

• bonds of 2a were subjected to further modification through a thiol–ene [40][41][42] click reaction with 2-aminoethanethiol hydrochloride yielding oligomer 4 (Scheme 2). Subsequently, the reactivity of the primary amino groups in 4 was proven by the attachment of 1,4-difluoro-9,10-anthraquinone (DFA

• Jeffamine® M 600 leads to blue-colored branched oligomer 6 with poly(ethylene glycol) side chains. The conducted reaction sequence is shown in Scheme 2. The quantitative conversion of the double bonds of oligomer 2a was verified by 1H NMR spectroscopy. As described above, the corresponding product 4 bears

Creating molecular macrocycles for anion recognition

• Amar H. Flood

Beilstein J. Org. Chem. 2016, 12, 611–627, doi:10.3762/bjoc.12.60

• triazolophane’s rigidity and that preorganization may be crucial for the large binding affinity. To test this idea, we examined the macrocyclic effect using an oligomer (Figure 8a) that folds up around chloride [17]. The affinity decreased by four orders of magnitude to ≈100 M−1, perfectly consistent with

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

• -threaded supramolecular dimer in water, the 3-Cio-α-CD formed a soluble supramolecular oligomer in the same solvent. The mixture of both regioisomers led to the formation of a self-sorting oligomeric system, where only the heterosupramolecular interactions between the two isomers were present but the

Assembly of synthetic Aβ miniamyloids on polyol templates

• Sebastian Nils Fischer and
• Armin Geyer

Beilstein J. Org. Chem. 2015, 11, 2646–2653, doi:10.3762/bjoc.11.284

• reversible dynamic chemistry of specific oligomers are suitable for oligopeptides. Disulfide bonds seem to be the natural choice for the reversible covalent chemistry of peptides, but it appeared to us impossible to prevent both the template and the peptide from homo-oligomer formation. Self-aggregation is

• the Hot=Tap oligomer. The mixture of azide 9, 2-formylphenylboronic acid (14) and LVFFA shows a single signal set for the esterified product (Figure 8). Another advantage of this system is the cooperativity of imine formation and esterification, because the imino nitrogen coordinates the boron atom

Supramolecular chemistry: from aromatic foldamers to solution-phase supramolecular organic frameworks

• Zhan-Ting Li

Beilstein J. Org. Chem. 2015, 11, 2057–2071, doi:10.3762/bjoc.11.222

• of a better acceptor” [47][48]. We conjectured that fluorine might work as an acceptor for intramolecular five- and six-membered F···H–N hydrogen bonding for aromatic amides because of their co-planarity. Chuang Li thus prepared oligomer 24 and shorter analogues [9]. Systematic 1H NMR experiments in

Polythiophene and oligothiophene systems modified by TTF electroactive units for organic electronics

• Alexander L. Kanibolotsky,
• Neil J. Findlay and
• Peter J. Skabara

Beilstein J. Org. Chem. 2015, 11, 1749–1766, doi:10.3762/bjoc.11.191

• the aforementioned synthetic pathway B, the strategy for the synthesis of 29 involves construction of the thiophene ring by cyclisation of diketone 30 (synthetic pathway C). The diketone 31 is constructed through the cycloaddition reaction of diacylethene 33 with oligomer 32, readily available by

Preparation of a disulfide-linked precipitative soluble support for solution-phase synthesis of trimeric oligodeoxyribonucleotide 3´-(2-chlorophenylphosphate) building blocks

• Amit M. Jabgunde,
• Alejandro Gimenez Molina,
• Pasi Virta and
• Harri Lönnberg

Beilstein J. Org. Chem. 2015, 11, 1553–1560, doi:10.3762/bjoc.11.171

• , the disulfide linkage may be reductively cleaved and the phosphate bound 2-mercaptoethyl group is removed. Accordingly, the oligomer expectedly is released in a fully protected form. We now report on the synthesis of such a soluble support, 3, and show that it allows efficient coupling by the 1

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F₄TCNQ

• Raúl García,
• M. Ángeles Herranz,
• Edmund Leary,
• M. Teresa González,
• Gabino Rubio Bollinger,
• Marius Bürkle,
• Linda A. Zotti,
• Yoshihiro Asai,
• Fabian Pauly,
• Juan Carlos Cuevas,
• Nicolás Agraït and
• Nazario Martín

Beilstein J. Org. Chem. 2015, 11, 1068–1078, doi:10.3762/bjoc.11.120

• upon oxidation has been skillfully used in a variety of D–π–A systems, namely exTTF–π-bridge–C60 derivatives, for determining the attenuation factor of the molecular wire (oligomer) acting as the π-bridge [20][21][22]. In this paper, we describe the synthesis of a new exTTF derivative, suitably

Quarternization of 3-azido-1-propyne oligomers obtained by copper(I)-catalyzed azide–alkyne cycloaddition polymerization

• Shun Nakano,
• Akihito Hashidzume and
• Takahiro Sato

Beilstein J. Org. Chem. 2015, 11, 1037–1042, doi:10.3762/bjoc.11.116

• Shun Nakano Akihito Hashidzume Takahiro Sato Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan 10.3762/bjoc.11.116 Abstract 3-Azido-1-propyne oligomer (oligoAP) samples, prepared by copper(I)-catalyzed azide

• . Keywords: 3-azido-1-propyne oligomer; CuAAC polymerization; hydrodynamic radius; methyl iodide; pulse-field-gradient spin-echo NMR; quarternization; Introduction The copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) efficiently yields 1,4-disubstituted-1,2,3-triazole from rather stable azides and

• monomer precursor, and obtained its oligomer, whose backbone is composed of 1,2,3-triazole and methylene moieties (Scheme 1a) [37]. The oligomer obtained was crystalline and adsorbed strongly copper ions. Since the oligomer was soluble only in strong acids and insoluble in water and organic solvents, it

Terminal lipophilization of a unique DNA dodecamer by various nucleolipid headgroups: Their incorporation into artificial lipid bilayers and hydrodynamic properties

• Emma Werz and
• Helmut Rosemeyer

Beilstein J. Org. Chem. 2015, 11, 913–929, doi:10.3762/bjoc.11.103

• the cis channel followed by cycles of incubation and perfusion leads to the binding of the corresponding oligomer on the membrane, as detected by microscopy and single molecule fluorescence spectroscopy. The kinetics of the binding of the different bilayer-bound oligonucleotides were studied as well

• events (perfusion and incubation time) for the lipo-oligomer 10. As can be seen, the incorporation of the lipo-oligomer 10 carrying an O-2’,3’-undecylidene-modified uridine head group into the artificial lipid bilayer occurs spontaneously after 25 min, corresponding to the maximum brightness. However

• lipid bilayer against perfusion. Figure 7 presents the bilayer brightness as a function of the perfusion/incubation events for the oligomer 12. This oligomer is 5’-terminated with a nucleolipid head group which carries a double-chained lipid with a clickable group at N(3) of thymidine (6a). Among all

DNA display of glycoconjugates to emulate oligomeric interactions of glycans

• Alexandre Novoa and
• Nicolas Winssinger

Beilstein J. Org. Chem. 2015, 11, 707–719, doi:10.3762/bjoc.11.81

• ][42]. Since these methods are compatible with the powerful scheme of mix and split combinatorial chemistry the synthesis of libraries is easily performed wherein each library member is tagged with a unique sequence. Conjugation of glycans at different positions within a PNA oligomer has been achieved

• . aeruginosa, a focused library displaying two galactose mono- or disaccharides with different linkers was synthesized in order to optimize affinity of a conjugate interacting with one face of the lectin [42]. LecA is a tetrameric protein with two binding sites on each face of the oligomer. An important

Sequence-specific RNA cleavage by PNA conjugates of the metal-free artificial ribonuclease tris(2-aminobenzimidazole)

• Friederike Danneberg,
• Alice Ghidini,
• Plamena Dogandzhiyski,
• Elisabeth Kalden,
• Roger Strömberg and
• Michael W. Göbel

Beilstein J. Org. Chem. 2015, 11, 493–498, doi:10.3762/bjoc.11.55

• , optimization of the PNA oligomer length is necessary, especially for strands rich in G/C base pairs. Reduced activity of long PNA conjugates caused by aggregation can be a minor disadvantage in comparison to DNA conjugates. However, the higher affinity of PNA towards RNA allows using shorter PNA oligomers. In

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

• acid 4 was observed and the starting material was recovered almost quantitatively which indicates that no oligomer formation took place (see Supporting Information File 2). Screening of different anode materials and reaction parameters allowed an optimization of the electrochemical process. Ni foam

Synthesis and chemosensing properties of cinnoline-containing poly(arylene ethynylene)s

• Natalia A. Danilkina,
• Petr S. Vlasov,
• Semen M. Vodianik,
• Andrey A. Kruchinin,
• Yuri G. Vlasov and
• Irina A. Balova

Beilstein J. Org. Chem. 2015, 11, 373–384, doi:10.3762/bjoc.11.43

• oligomer structures possessing alkylated iodohydroquinone units as the end groups. The presence of iodine in oligomers was also confirmed by the Beilstein test [62]. Regarding the NMR data, the chemical shift values of H and C atoms in both PAEs synthesized do not significantly differ from the chemical

• ). Moreover, all signals in 1H and 13C NMR spectra are rather sharp that corresponds to the oligomer structure of both PAEs 10a,b. In 1H NMR spectra of both compounds 10a,b the ratio of integral intensities within signals of H atoms from cinnoline (aromatic and alkyl chain hydrogen atoms) and aromatic and

• the oligomer chain while in the 13C NMR spectrum of PAE 10b two additional Csp signals (E, F) of ethynyl pendant group are observed (Figure 4). The splitting of H atoms (2', a') and C atoms (1'–3', a') signals of hydroquinone structural units of PAEs 10a,b in NMR spectra confirmed that the orientation

Anion effect controlling the selectivity in the zinc-catalysed copolymerisation of CO₂ and cyclohexene oxide

• Sait Elmas,
• Muhammad Afzal Subhani,
• Walter Leitner and
• Thomas E. Müller

Beilstein J. Org. Chem. 2015, 11, 42–49, doi:10.3762/bjoc.11.7

• many of the physicochemical properties of the polymer, such as the glass-transition temperature (Tg). With incorporated ether linkages, a molecular weight in the oligomer range and at least two terminal OH groups, polyethercarbonates are interesting polyol building blocks in polyurethane chemistry [8

• the results are collected in Table 2 (entries 1–4). Under the applied conditions (100 °C, 20 bar), both 1 and 2 afforded high conversion of CHO. A polymer with the expected molecular weight in the oligomer range and a narrow molecular weight distribution was obtained (Table 2, entries 1 and 2). Closer

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

• purchased from Wako Pure Chemical Ind. (Japan) and used as received. In this MeCD, two methoxy groups per glucopyranose unit were introduced in β-CD. PLLA (LACEA, Mitsui Chemicals Inc.; Mn = 1.3 × 105, Mw = 2.6 × 105) was used after removing the oligomer and polymerization catalyst by dissolution in

Come-back of phenanthridine and phenanthridinium derivatives in the 21st century

• Lidija-Marija Tumir,
• Marijana Radić Stojković and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2930–2954, doi:10.3762/bjoc.10.312

• -nucleobase was incorporated close to the centre of the DNA oligomer in combination with two different charge acceptors (7-deazaguanine as an electron hole acceptor and a 5-nitroindole as a suitable electron acceptor) [94], showed similar rates and distance dependencies for both, electron and hole transfer

Galactan synthesis in a single step via oligomerization of monosaccharides

• Marius Dräger and
• Amit Basu

Beilstein J. Org. Chem. 2014, 10, 2658–2663, doi:10.3762/bjoc.10.279

• by HF followed by chromatographic separation afforded chito-oligosaccharides as long as hexasaccharides in reasonable yields [13]. In most of these oligomerizations the reducing end of the oligomer is a hemi-acetal, or a reduced or protected derivative thereof, and both anomers are present [14]. An

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

• ; enzyme; oxidative coupling; phenol oligomer; Introduction Lignin consists of mechanical stabilizing polyphenols and thus plays an important role in many plants [1][2]. For the in vitro synthesis of polyphenols via oxidative coupling reactions, laccases and peroxidases are suitable enzymes to catalyze

• reaction mixture. After addition of 510 µL of hydrogen peroxide (30%) in aliquots of 51 µL in 15 minutes intervals, the mixture was stirred for 2 h at room temperature. The precipitated product was isolated by filtration, washed with 0.5 M HCl, water and dried. Then the oligomer was dissolved in dioxan

• oligomer was dissolved in dioxan, acidified with HCl (37%) and stirred for 24 h. The product was precipitated in 0.5 M HCl and dried under vacuum. Yield depending on use of racemic or (S)-, (R)-enantiomer of N-(4-hydroxyphenyl)mandelamide (1): (RS)-2 = 0.51 g (42%), (S)-2 = 0.45 (37%), (R)-2 = 0.49 g (41