Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole

• Martina Tireli,
• Silvija Maračić,
• Stipe Lukin,
• Marina Juribašić Kulcsár,
• Dijana Žilić,
• Mario Cetina,
• Ivan Halasz,
• Silvana Raić-Malić and
• Krunoslav Užarević

Beilstein J. Org. Chem. 2017, 13, 2352–2363, doi:10.3762/bjoc.13.232

• solution, but these reactions are usually much slower [31]. Also, click polymerization was applied using a ball-milling process with no significant influence on the integrity of the polymer chain [27][32]. Herein we have studied the efficiency of copper catalysts with Cu(0), Cu(I) and Cu(II) oxidation

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• of nucleophiles is complicated by side reactions, such as polymerization. Successful coupling of nitrosoalkenes with nucleophiles is highly challenging and depends on many factors such as temperature, concentration, solvent and, especially, the nature of the α-nitrosoalkene precursor. Nevertheless

• elimination upon treatment with a base [13] (Scheme 1, reaction (1)). A disadvantage of this method is that NSA are generated fast and high stationary concentrations are achieved facilitating polymerization. Furthermore, an excess of nucleophile is needed since it also serves as a base. A milder method was

• and acetylacetone, providing adducts 5 in high to quantitative yields. Six-membered cyclic oxime 1a afforded the corresponding products only in moderate yields owing to the formation of undesired side products and polymerization of the α,β-unsaturated nitroso compound. This early example demonstrates

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• 114 [224] or chitosan 115 [225]. The functionalization of polyacrylamide obtained by reversible addition-fragmentation chain transfer (RAFT) polymerization was also recently reported to produce 116 (Figure 31). However, the conditions of the Moedritzer–Irani reaction induced the hydrolysis of the

Superstructures with cyclodextrins: Chemistry and applications IV

• Gerhard Wenz

Beilstein J. Org. Chem. 2017, 13, 2157–2159, doi:10.3762/bjoc.13.215

• -dienes and bulky stoppers in the presence of CDs (so-called rotaxa-polymerization) was further applied for the syntheses of water-soluble polyisoprene polyrotaxanes [25]. Furthermore, ABA-type block-copolyrotaxanes could be synthesized using this polymerization technique controlled by RAFT chain transfer

Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A

• Tao Wang,
• Yan-Chao Zhao,
• Li-Min Zhang,
• Yi Cui,
• Chang-Shan Zhang and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 2131–2137, doi:10.3762/bjoc.13.211

• area. As for PPOP-3, using M3 as a monomer may induce a depression of polymerization degree owing to its stereo-hindrance effect, which might be responsible for its lower BET surface area value (880 m2 g−1) and micropore volume (0.20 cm3 g−1) than that of PPOP-2 using M2 as the monomer. However, it is

Solid-state mechanochemical ω-functionalization of poly(ethylene glycol)

• Michael Y. Malca,
• Pierre-Olivier Ferko,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2017, 13, 1963–1968, doi:10.3762/bjoc.13.191

• chelation or ligand-exchange reactions at metal-based nanomaterials with ω-functionalized PEG polymers [16][17][18]. The two most common methods for accessing ω-functionalized PEG derivatives are solution-based through either ring-opening polymerization of ethylene oxide unites or modification of

• pharmaceutical ingredients (APIs) is an emergent area that was recently reviewed [25]. In particular, solvent-free polymerization methods have been recently developed to access polyimines [26], polylactides [27], poly(phenylene vinylene) [28] and polyolefins [29]. There has been, however, limited effort towards

• . CEA·HCl was milled with NaOH briefly for only 5 min to avoid polymerization of the free base before reaction with mPEG. The milled products were then mixed and milled for 45 minutes, leading to a yield of 42% and 63% (for Mn = 750 and 2000 Da, respectively), according to 1H NMR spectroscopy (Table 2

An efficient Pd–NHC catalyst system in situ generated from Na₂PdCl₄ and PEG-functionalized imidazolium salts for Mizoroki–Heck reactions in water

• Nan Sun,
• Meng Chen,
• Liqun Jin,
• Wei Zhao,
• Baoxiang Hu,
• Zhenlu Shen and
• Xinquan Hu

Beilstein J. Org. Chem. 2017, 13, 1735–1744, doi:10.3762/bjoc.13.168

• polymers from the polymerization of ethylene oxide [67]. Owing to their significant advantages, including widely commercial availability, biocompatibility, chemical and thermal stability and ease to be derived, PEGs have been widely used as phase-transfer catalysts (PTC) or in the preparation of water

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

• Sadaf Hanif,
• Bernd Oschmann,
• Dmitri Spetter,
• Muhammad Nawaz Tahir,
• Wolfgang Tremel and
• Rudolf Zentel

Beilstein J. Org. Chem. 2017, 13, 1693–1701, doi:10.3762/bjoc.13.163

• Sadaf Hanif Bernd Oschmann Dmitri Spetter Muhammad Nawaz Tahir Wolfgang Tremel Rudolf Zentel Institute for Organic Chemistry, University of Mainz, Duesbergweg 10-14, 55128 Mainz, Germany 10.3762/bjoc.13.163 Abstract This paper describes the controlled radical polymerization of an ionic-liquid

• monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO2 nanoparticles

• ; ionic liquid; polymeric ionic liquid; RAFT polymerization; Introduction Ionic liquids (ILs) are organic salts. Most of them have a melting point below 100 °C [1][2]. These organic salts do not have the same structure like inorganic salts. This is due to the structure of the ion pairs. They are built of

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• domain to bind to and activate the cytoskeletal organizing complex ARP2/3, which in turn stimulates actin polymerization. Mycolactone A/B was found to bind to the CR1 domain of N-WASP and the CR7 domain of WASP about 100 times more tightly (Kd = 20–70 nM in both cases) than the natural ligand CDC42, thus

Chemical systems, chemical contiguity and the emergence of life

• Terrence P. Kee and
• Pierre-Alain Monnard

Beilstein J. Org. Chem. 2017, 13, 1551–1563, doi:10.3762/bjoc.13.155

• characteristics of various biomolecules, e.g., the catalytic activity of RNAs and their evolution potential [9][10][11], as well as processes that were essential for their syntheses, such as Fischer–Tropsch-like reactions [12], non-enzymatic RNA [13] or peptide polymerization [14]. Moreover, it has also allowed

• effect self-assembly [51]. Thus, mineral surfaces and porous formations could have been excellent media to foster the emergence of “self-contained”, dispersed chemical systems. Furthermore, mineral surfaces can serve as supports for chemical systems to undergo organization. The polymerization of nucleic

• systems (stacks of alternating amphiphile bilayers and monomer layers). In stark contrast to the polymerization of RNA on montmorillonite, the absence of strong direct interactions between the mineral surfaces and the molecular species does neither reduce the chemical availability of the reaction products

2-Methyl-2,4-pentanediol (MPD) boosts as detergent-substitute the performance of ß-barrel hybrid catalyst for phenylacetylene polymerization

• Julia Kinzel,
• Daniel F. Sauer,
• Marco Bocola,
• Marcus Arlt,
• Tayebeh Mirzaei Garakani,
• Andreas Thiel,
• Klaus Beckerle,
• Tino Polen,
• Jun Okuda and
• Ulrich Schwaneberg

Beilstein J. Org. Chem. 2017, 13, 1498–1506, doi:10.3762/bjoc.13.148

• over micelle-forming detergents is demonstrated in the polymerization of phenylacetylene, showing a ten-fold increase in yield and increased molecular weights. Keywords: amphiphilic molecule 2-methyl-2,4-pentanediol; hybrid catalyst; phenylacetylene polymerization; refolding agents; transmembrane

• can destroy the three dimensional structure and cause protein precipitation [19][20][21]. To avoid precipitation when using nonpolar substrates, the protein concentration usually is decreased leading to a loss in activity. As an example, the polymerization of phenylacetylene was achieved in water by

• using the robust β-barrel protein nitrobindin. The selectivity in the polymerization of phenylacetylene was influenced with the protein as second ligand sphere [12][13]. The catalyst achieved a cis/trans ratio of 91:9 in the organic solvent tetrahydrofuran (THF) or being bound on a protein surface

Mechanochemistry-assisted synthesis of hierarchical porous carbons applied as supercapacitors

• Desirée Leistenschneider,
• Nicolas Jäckel,
• Felix Hippauf,
• Volker Presser and
• Lars Borchardt

Beilstein J. Org. Chem. 2017, 13, 1332–1341, doi:10.3762/bjoc.13.130

• polymerization of the educts induced by mechanochemical forces by IR spectroscopy (Figure 2). Two bands at 1703 cm−1 and 1136 cm−1 appear, indicating the formation of the polyester (EG-CA). Likewise, the characteristic bands of the educts (CA: 1210 cm−1; EG: 1418 cm−1) become less pronounced and much broader as

• they are gradually consumed by the mechanically-induced polymerization. The spectrum of the Ti-containing polymer (Polymer-SF-3) displays the appearance of a band at 1558 cm−1, which corresponds to titanium, bidentate to a carboxylic group [50]. Additionally, the blue-shift of the vibration at 1703 cm

• , resulting in a well-connected pore system of the carbon material (Figure 3A,B). To display the complete removal of the porogenous TiO2, we compared the XRD pattern (Figure 4) of the material at different synthesis steps: after mechanochemical polymerization (Polymer-SF-3), after temperature treatment but

Detection of therapeutic radiation in three-dimensions

• John A. Adamovics

Beilstein J. Org. Chem. 2017, 13, 1325–1331, doi:10.3762/bjoc.13.129

• the polymerization of acrylamide with N,N’-methylenebisacrylamide and various monomers to yield a cloud like precipitate in the aqueous gel [13]. Due to the nature of their radical chemistry, polymer gel dosimeters have several limitations. They are susceptible to atmospheric oxygen inhibiting the

• polymerization processes. Irradiated dosimeters scatter light during optical scanning. The solutions are toxic, require 24 hours to equilibrate, and require a container to maintain the dosimeter shape [13]. Interest in a 3D dosimeter made of a transparent plastic was initially reported in 1961 [14]. The ideal

• their effective atomic number is not tissue equivalent. Acrylates, polyesters, polystyrenes and polycarbonates were also eliminated due to the relatively high exotherms created (>100 °C) during polymerization which prematurely oxidize the leuco dyes and rendered the dosimeter product unusable due to

One-pot synthesis of block-copolyrotaxanes through controlled rotaxa-polymerization

• Jessica Hilschmann,
• Gerhard Wenz and
• Gergely Kali

Beilstein J. Org. Chem. 2017, 13, 1310–1315, doi:10.3762/bjoc.13.127

• act as stoppers for the cyclodextrin rings threaded onto the inner polyisoprene block. Statistical copolyrotaxanes were synthesized by RAFT polymerization as well. RAFT polymerization conditions allow control of the composition as well as the sequence of the constituents of the polymer backbone which

• further effects the CD content and the aqueous solubility of the polyrotaxane. Keywords: block copolymer; cyclodextrin; polyisoprene; polyrotaxane; RAFT polymerization; Introduction Polymer necklaces, i.e., polyrotaxanes and pseudopolyrotaxanes, are supramolecular assemblies comprising polymeric axes

• dethreading already takes place. This multistep reaction methodology hinders the large-scale production and broad application of these materials. Recently our group has developed a method for a simple and environmentally friendly synthesis of polyrotaxanes. This, so called rotaxa-polymerization, is an aqueous

Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction

• Qing Yin,
• Qi Chen,
• Li-Can Lu and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 1212–1221, doi:10.3762/bjoc.13.120

• -linker, the Friedel–Crafts cross-linking polymerization is promoted smoothly by anhydrous FeCl3 in dry 1,2-dichloroethane (DCE). The monomers were either commercially available (Sug-1) or prepared (Sug-2 and Sug-3) by benzylation of free sugars with benzyl bromide and sodium hydride. The chemical

Kinetic analysis of mechanoradical formation during the mechanolysis of dextran and glycogen

• Naoki Doi,
• Yasushi Sasai,
• Yukinori Yamauchi,
• Tetsuo Adachi,
• Masayuki Kuzuya and
• Shin-ichi Kondo

Beilstein J. Org. Chem. 2017, 13, 1174–1183, doi:10.3762/bjoc.13.116

• radicals. Great attention has been paid to graft polymerization of synthetic polymers onto polysaccharides, because this method easily produces a polymer combining the advantages of both natural and synthetic macromolecules [6]. A polysaccharide possessing functional group on its backbone that allows to

• initiate the polymerization is frequently used to synthesize such a graft polymer [7]. Dextran (Dx), a biodegradable polysaccharide, has been utilized as a graft copolymer backbone. The glycosidic linkages between the α-glucose units of Dx synthesized from Leuconostoc mesenteroides are composed of

• initiation, γ-irradiation) from hydroxy groups [11][12][13][14]. However, as the polysaccharide backbone is unstable under these harsh and high temperature conditions, these compounds are not suitable for condensation polymerizations to synthesize graft copolymers [15]. In general a radical polymerization

From chemical metabolism to life: the origin of the genetic coding process

• Antoine Danchin

Beilstein J. Org. Chem. 2017, 13, 1119–1135, doi:10.3762/bjoc.13.111

• together, associating proteins and nucleic acids. What we discussed above can be summarised with the words of Monnard: “(1) The synthesis of RNA monomers is difficult; (2) efficient pathways for monomer polymerization into functional RNAs and their subsequent, sequence-specific replication remain elusive

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• [45][56][57][58]. Prosperi and co-workers coated dodecanthiol AuNPs with manno-calixarenes exploiting hydrophobic interactions, obtaining an efficient targeting against cancer cells [56]. Similarly, a reversible addition−fragmentation chain transfer (RAFT) polymerization approach has been exploited

• of mucin glycoprotein on the surface of cancer cells, which are characterized by a dense presentation of glycans attached to a protein backbone. So, multicopy–multivalent polymeric versions of the tumor-associated α-GalNAc (Tn) antigen, obtained through RAFT polymerization, were prepared and used to

Interactions between shape-persistent macromolecules as probed by AFM

• Johanna Blass,
• Jessica Brunke,
• Franziska Emmerich,
• Cédric Przybylski,
• Vasil M. Garamus,
• Artem Feoktystov,
• Roland Bennewitz,
• Gerhard Wenz and
• Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

• phenyl moieties and β-CD rings leading to daisy chains [54]. The polymerization of 7 was performed through Glaser coupling in pyridine catalyzed by Cu(I)/Cu(II). After removal of low molecular weight material by ultrafiltration polymer 8 was isolated as a light orange solid in 91% yield. Polyrotaxane

Cyclodextrins tethered with oligolactides – green synthesis and structural assessment

• Cristian Peptu,
• Mihaela Balan-Porcarasu,
• Alena Šišková,
• Ľudovít Škultéty and
• Jaroslav Mosnáček

Beilstein J. Org. Chem. 2017, 13, 779–792, doi:10.3762/bjoc.13.77

• available as commercial products, the modification with polymers is still under development [4][5]. So far, several polymerization reactions were used for CD modification, including free radical polymerization, reversible-deactivation radical polymerizations [5] as well as ring opening polymerizations (ROP

• ) of cyclic esters [6], oxiranes [7] and oxazolines [8]. However, the ROP of cyclic esters should also be considered as a method of producing polymer-modified CDs with some particular features, such as possibility of employing green polymerization procedures and availability of renewable monomers like

• cyclic esters. The methods published so far for polymerization of cyclic esters initiated by cyclodextrins employed catalysts commonly used in ROP, such as Sn-octoate [9][10][11] or amine-based organic catalysts [12], resulting in star polymers with a more or less well defined structure. CD functional

Conjecture and hypothesis: The importance of reality checks

• David Deamer

Beilstein J. Org. Chem. 2017, 13, 620–624, doi:10.3762/bjoc.13.60

• hydrothermal fields associated with volcanic landmasses. These are considered as alternative hypotheses and the accumulating weight of evidence for each site is described and analyzed. Keywords: hydrothermal fields; hydrothermal vents; origin of life; polymerization by condensation; protocells; Introduction

• fluctuations of wetting and drying. The fluctuating hydrothermal field hypothesis has been used as a model for polymerization reactions in which monomers like amino acids and mononucleotides form peptide and ester bonds of biologically relevant polymers. The idea that evaporation and heat can drive

• polymerization is obvious and was first proposed years ago [19]. Lahav and White [20] adopted the approach and demonstrated that peptide bonds could be produced using clay as a catalyst. The approach was largely abandoned with the advent of the RNA World scenario that suggested a way for life to begin in

Decarboxylative and dehydrative coupling of dienoic acids and pentadienyl alcohols to form 1,3,6,8-tetraenes

• Ghina’a I. Abu Deiab,
• Mohammed H. Al-Huniti,
• I. F. Dempsey Hyatt,
• Emma E. Nagy,
• Kristen E. Gettys,
• Sommayah S. Sayed,
• Christine M. Joliat,
• Paige E. Daniel,
• Rupa M. Vummalaneni,
• Andrew T. Morehead Jr,
• Andrew L. Sargent and
• Mitchell P. Croatt

Beilstein J. Org. Chem. 2017, 13, 384–392, doi:10.3762/bjoc.13.41

• -component reaction using a dienoic acid and bis-allylic acetate might be possible, however, the presence of both water and a carboxylic acid would increase the possibility for isomerization of the 1,3,6,8-tetraenes into the fully conjugated 1,3,5,7-tetraenes, or possibly polymerization. Despite the low

Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

• Maximilian Maier,
• Magnus S. Schmidt,
• Markus Ringwald and
• Christoph P. Fik

Beilstein J. Org. Chem. 2017, 13, 372–383, doi:10.3762/bjoc.13.40

• elucidated the underlying polymerization mechanism. Mechanical testing of the obtained polymers exhibited gradual differences in network densities, depending on the intramolecular arrangement and number of functional groups. Overall, a general building principle for highly reactive, liquid diacrylamides via

• ; Introduction The selection of suitable monomers is a critical step for any free-radical polymerization approach. Particularly for (in situ) photo-induced polymerizations, monomers should comprise sufficient solubility in a given matrix, moderate viscosity, matching refractive indices as well as an optimized

• reactivity – the proper design of these features ensures continuous light transmittance, adequate propagation rates and, ultimately, thorough polymerization [1][2]. The number of applications for UV–vis curable monomer systems has greatly increased over the last decades [3]. At the same time, the selection

Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions

• Andreas C. Boukis,
• Baptiste Monney and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2017, 13, 54–62, doi:10.3762/bjoc.13.7

• Biginelli compounds and reacted them with the respective Ugi components under reflux in methanol to yield 30 different DHMP amides in 5–51% yield [36]. Furthermore, the Biginelli reaction has been used in a polymerization process combined with the Hantzsch reaction to from copolycondensates [37]. It is

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

• Pavel Nagorny and
• Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

• [50][51]. In 2013 Bibal and co-workers investigated the use of methylated amines, pyridines and guanidines (L11) as hydrogen bond-donor catalysts for the activation of cyclic esters toward ring-opening polymerization (ROP) [53]. Ionic catalysts L11 (5 mol %) were successfully employed in combination

• with DBU and initiator (Ph2CHOH) to accomplish C=O activation and to promote the polymerization reactions (Scheme 6). Highly charged tetraalkylbisammonium salts (i.e., DABCO-Me2·2X) were found to be particularly active catalysts. Based on computational studies, the authors proposed that substrate