From supramolecular chemistry to the nucleosome: studies in biomolecular recognition

• Marcey L. Waters

Beilstein J. Org. Chem. 2016, 12, 1863–1869, doi:10.3762/bjoc.12.175

• highly amenable to structure–function studies, since only a new monomer must be synthesized, rather than an entirely new receptor. With my interest in trimethyllysine provided a significant problem in which DCC seemed to be a promising solution. It turns out that the main tool for sensing protein post

Synthesis and characterization of benzodithiophene and benzotriazole-based polymers for photovoltaic applications

• Desta Gedefaw,
• Marta Tessarolo,
• Margherita Bolognesi,
• Mario Prosa,
• Renee Kroon,
• Wenliu Zhuang,
• Patrik Henriksson,
• Kim Bini,
• Ergang Wang,
• Michele Muccini,
• Mirko Seri and
• Mats R. Andersson

Beilstein J. Org. Chem. 2016, 12, 1629–1637, doi:10.3762/bjoc.12.160

• interchain π–π stacking, BDT is a widely used electron-rich monomer. Moreover, alkyl or aryl groups can easily be introduced to BDT basic units as side groups to finely tune the properties of the resulting polymers, not only in terms of solubility but also contributing, for example, to extend the π

• PTzBDT-2 (Scheme 1), based on Tz and BDT moieties. The Tz ring was substituted with an asymmetrically branched alkyl side chain and sandwiched between two thiophene rings. The chemical structure of the Tz based monomer was made to be the same in both polymers for the comparative study. On the other hand

Automated glycan assembly of a S. pneumoniae serotype 3 CPS antigen

• Markus W. Weishaupt,
• Stefan Matthies,
• Mattan Hurevich,
• Claney L. Pereira,
• Heung Sik Hahm and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2016, 12, 1440–1446, doi:10.3762/bjoc.12.139

• glucose building block. This monomer did not suffer from a loss of stereocontrol as was observed in the case of the similarly protected GlcA building block. The desired trisaccharide 5 was observed as the main product from the automated synthesis by HPLC analysis (Figure 5). The Lev protecting group had

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

• paraffin-like oligomeric chains bearing polymerizable vinyl moieties. These oligomers were radically crosslinked in bulk with N-VP as co-monomer yielding swellable polymer disks. The vinylic side groups of the N-VP oligomers allow thiol–ene click reactions with 2-aminoethanethiol hydrochloride to obtain

• . However, in contrast to the restricted monoalkylation of N-vinylcaprolactam [24], the five-membered ring of N-VP can be double alkylated in α-position. In this connection, 1-bromo-2-(2-bromoethoxy)ethane was used as alkylation reagent to allow the preparation of a spiro-type monomer [25] due to

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• interplay between ligand exchange and the ammonium salt (Scheme 19) [40]. Based on their findings they proposed a catalytic cycle in which the Brønsted basic dimeric palladium-μ-hydroxo complex 79 is broken up by the amine salt 74, liberating Lewis acidic palladium monomer 80 and free amine. Binding of the

Stimuli-responsive HBPS-g-PDMAEMA and its application as nanocarrier in loading hydrophobic molecules

• Yongsheng Chen,
• Li Wang,
• Haojie Yu,
• Zain-Ul-Abdin,
• Ruoli Sun,
• Guanghui Jing,
• Rongbai Tong and
• Zheng Deng

Beilstein J. Org. Chem. 2016, 12, 939–949, doi:10.3762/bjoc.12.92

• ) prepared through atom transfer radical self-condensing vinyl polymerization (AT-SCVP) was firstly reported in 1996 [26]. It used vinylbenzyl chloride (VBC), which is an important commercially available monomer and its industrial synthesis was started from 1957, as monomer with a self-initiation site [27

• (VBC), a commercially available monomer, as monomer and self-initiator. The feeding ratio of VBC/CuCl/2,2-bipyrene (bpy) was 10:1:2. The 1H NMR spectrum of HBPS showed peaks around 5.7 and 5.2 ppm attributed to double bonds [26][27] as shown in Figure 1B. For AT-SCVP, the polymerization was initiated

• by benzyl chloride of VBC. It was found that each polymer chain was tethered with a double bond and chloride groups. Each monomer inserted into the polymer chain has one initiate site to start propagation of the side chains, which leads to the formation of hyperbranched topology. The broad peak from

Amino-functionalized (meth)acryl polymers by use of a solvent-polarity sensitive protecting group (Br-t-BOC)

• Helmut Ritter,
• Monir Tabatabai and
• Markus Herrmann

Beilstein J. Org. Chem. 2016, 12, 245–252, doi:10.3762/bjoc.12.26

• product. This means that the amino-protecting group is extremely sensitive to decomposition. A third type of monomer was synthesized by reaction of 1a with 1-bromo-2-methylbut-3-en-2-ol (2c) yielding 2-((1-bromo-2-methylbut-3-en-2-yl)oxycarbonylamino)ethyl acrylate (3d, Scheme 3). Although monomer 3d is

• deprotection for 3a,b, 6a,b and 7a,b are summarized in Table 1. As assumed above the molecular dispersed monomer shows the highest reactivity followed by the copolymer. The solvolysis of the protecting group in the homopolymer is relatively slow because of neighboring group formed retarding hydrogen bonds

My maize and blue brick road to physical organic chemistry in materials

• Anne J. McNeil

Beilstein J. Org. Chem. 2016, 12, 229–238, doi:10.3762/bjoc.12.24

• : to evaluate the effect of through-space (rather than through-bond) interactions on a conjugated polymer’s properties. During this project I synthesized some of the most beautiful molecules I have ever seen, with one and two cofacial arenes surrounding the central arene of the monomer (Figure 1) [14

• by our surprising substituent effects on the Diels–Alder regioselectivity in our monomer synthesis. Together we designed a collaborative project to further evaluate these effects. These studies led us to conclude that the π system is relatively unimportant and that substituent effects can instead be

• students Cheryl Moy and Danielle Zurcher evaluated “disassembling” polymers wherein an analyte-mediated end-group cleavage triggers depolymerization, releasing many gelators for each analyte [32][45]. We investigated three different polymeric scaffolds but have not yet successfully polymerized any monomer

Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

• Julia Wappel,
• Roland C. Fischer,
• Luigi Cavallo,
• Christian Slugovc and
• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 154–165, doi:10.3762/bjoc.12.17

• nature [1][2], but exploiting similar strategies for synthetic catalysts is still in its infancy [3][4][5]. Prominent examples in catalytic polymerization [6][7] comprise the regulation of molecular weight by allosteric effects [8][9] or influencing the polymers’ microstructure upon changing the monomer

• years [24][25][26]. The latent initiators are ideal if they have the capacity of storage in combination with the monomer for a long period [27]. Then the reaction only initiates once an appropriate exogenous stimulus is exerted [28][29]. Amongst this important property, the latent initiator should be as

• observed upon heating at 80 °C for 48 h [43]. Catalytic activity The polymerization activity of the complexes was initially tested using dimethyl bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate (5) as the benchmark monomer. Monomer 5 was used because its polymers are not prone to backbiting. Therefore the

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

• electrophoresis as additives to the background electrolyte. These new monomer units with a potential to self-organize into supramolecular structures were synthesized via a straightforward one-step synthetic procedure and purified using preparative reversed-phase chromatography allowing a large scale separation of

• the regioisomers. The ability of the monomers to self-assemble was proved by various methods including NMR spectroscopy and dynamic light scattering (DLS). The light scattering experiments showed that the monomer units have distinguishable ability to form supramolecular structures in different

• that the position of the cinnamyl group plays an important role in the intermolecular complex formation. Keywords: capillary electrophoresis; cyclodextrin derivatives; mono-cinnamyl; regioisomers; supramolecular structures; Introduction Supramolecular polymers (SP) are aggregates of monomer units

Polydisperse methyl β-cyclodextrin–epichlorohydrin polymers: variable contact time ¹³C CP-MAS solid-state NMR characterization

• Isabelle Mallard,
• Davy Baudelet,
• Franca Castiglione,
• Monica Ferro,
• Walter Panzeri,
• Enzio Ragg and
• Andrea Mele

Beilstein J. Org. Chem. 2015, 11, 2785–2794, doi:10.3762/bjoc.11.299

• obtained and characterized by solid-state 13C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS) conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials

• paper, we described the synthesis of imprinted polymers. The imprinting technique is based on interactions between a template and a suitable functional monomer during the prepolymerization process. Once the template is removed, the resulting product is a cross-linked copolymer matrix with specific

• larger ratio of crosslinker to functional monomer to get insoluble polymers. The deprotonation was carried out in aqueous basic media and imprinting was performed in toluene for 20 min before the polymerization process. After the introduction of toluene, a clear solution was systematically observed. The

Recent advances in metathesis-derived polymers containing transition metals in the side chain

• Ileana Dragutan,
• Valerian Dragutan,
• Bogdan C. Simionescu,
• Albert Demonceau and
• Helmut Fischer

Beilstein J. Org. Chem. 2015, 11, 2747–2762, doi:10.3762/bjoc.11.296

• quite active and tolerant toward the monomer endowed with multiple functionalities (Scheme 1). By precisely controlling the living polymerization process, they succeeded in varying the number of amidoferrocenyl motifs in the polymers within pre-established limits. Such polymers and block copolymers were

• one block contains cobaltocenium units while the other block comprises an organic chain only [50] (Scheme 4). By the same technique, polymer 6 was further copolymerized with a cobaltocenium-BPh4 monomer and a cobaltocenium-Cl monomer affording, respectively, the new diblock copolymers 8 (X = PF6, Y

• application of metallopolymers as heterogeneous macromolecular catalysts for living radical polymerizations, Tang et al. [51] produced the cobalt-containing polymer 10 by ROMP of the norbornene monomer 9, derivatized with triazolyl and cyclopentadienylcobalt-1,3-cyclopentadiene moieties (Scheme 5). The

Enantioselective additions of copper acetylides to cyclic iminium and oxocarbenium ions

• Jixin Liu,
• Srimoyee Dasgupta and
• Mary P. Watson

Beilstein J. Org. Chem. 2015, 11, 2696–2706, doi:10.3762/bjoc.11.290

• high levels of enantioselectivity. This lack is likely due to the multiple possibilities for copper acetylide structures (monomer, dimer, dicopper acetylide, etc.) [18][59][60][61][62][63][64][65]. Careful mechanistic studies to elucidate the structures of chiral copper acetylides and to provide

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• was also synthesized by coupling 1 with 2 under similar reaction conditions (Scheme 1). TM-βCD and TM-γCD macrocyclic molecules were prepared according to previously reported procedures [47]. 1·TM-βCD and 1·TM-γCD were synthesized in water by using a 2:1 molar ratio of macrocycles and monomer 1. The

• polyrotaxane exhibits correlation peaks of both H3 and H5 protons of TM-βCD with those methylene protons (Hd) protons of monomer 2, and all the characteristic protons have been identified, Figure 1. Figures S4–S7 in Supporting Information File 1 show the 1H NMR and 13C NMR spectra of 3·TM-γCD and the reference

• 3. The resonance peak of the d proton from monomer 2 is upfield shifted by more than 0.06 ppm in the polyrotaxane 3·TM-βCD compared to those of the non-rotaxane 3 counterpart, as shown in Figure 1 and Figure S4 in Supporting Information File 1. The resonance peaks of a–c and a’–c’ protons of 3·TM

Exploring architectures displaying multimeric presentations of a trihydroxypiperidine iminosugar

• Camilla Matassini,
• Stefania Mirabella,
• Andrea Goti,
• Inmaculada Robina,
• Antonio J. Moreno-Vargas and
• Francesca Cardona

Beilstein J. Org. Chem. 2015, 11, 2631–2640, doi:10.3762/bjoc.11.282

• moiety, the CuAAC approach was investigated either on the protected and deprotected iminosugar, with different purification techniques employed in both cases. A monomer reference compound was also synthesized for comparison. Biological evaluation against a panel of eleven commercially available

Comparison of the catalytic activity for the Suzuki–Miyaura reaction of (η⁵-Cp)Pd(IPr)Cl with (η³-cinnamyl)Pd(IPr)(Cl) and (η³-1-t-Bu-indenyl)Pd(IPr)(Cl)

• Patrick R. Melvin,
• Nilay Hazari,
• Hannah M. C. Lant,
• Ian L. Peczak and
• Hemali P. Shah

Beilstein J. Org. Chem. 2015, 11, 2476–2486, doi:10.3762/bjoc.11.269

• literature method starting from the commercially available Pd(II) dimer (μ-Cl)2Pd2(η3-allyl)2 (Scheme 1) [18]. It is notable that in this synthesis dimeric {(IPr)Pd(Cl)}2(μ-Cl)2 is prepared as an intermediate, followed by treatment with two equivalents of NaCp to generate the monomer Cp. This synthesis makes

Convenient preparation of high molecular weight poly(dimethylsiloxane) using thermally latent NHC-catalysis: a structure-activity correlation

• Stefan Naumann,
• Johannes Klein,
• Dongren Wang and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2015, 11, 2261–2266, doi:10.3762/bjoc.11.246

• range of accessible monomer structures has grown impressively [6][7]. Nowadays, NHC-mediated polymerization can be applied to prepare polymers of high industrial and commercial importance, such as poly(amide)s [8][9], poly(ether)s [10], poly(urethane)s [11][12] or poly(acrylate)s [13][14][15][16][17][18

• the performance of NHCs in this area have been published. In 2006, Waymouth, Hedrick and co-workers showed that poly(carbosiloxane)s can be synthesized efficiently from the monomer 2,2,5,5-tetramethyl-1-oxa-2,5-disilacyclopentane in the presence of alcohols as initiators, using two different NHCs [22

• 000 g/mol was achieved at 94% monomer conversion. Interestingly, some degree of control over the molecular weight is possible by adjusting the initiator to monomer ratio (Table 1, entries 2–5). This way, up to a target degree of polymerization (DP) of 1000, considerable molecular weight can be built

Conformational equilibrium in supramolecular chemistry: Dibutyltriuret case

• Karina Mroczyńska,
• Małgorzata Kaczorowska,
• Erkki Kolehmainen,
• Ireneusz Grubecki,
• Marek Pietrzak and
• Borys Ośmiałowski

Beilstein J. Org. Chem. 2015, 11, 2105–2116, doi:10.3762/bjoc.11.227

• /methanol shown in Supporting Information File 1 (Figure S38) confirms that dibutyltriuret also self-associates and forms singly charged cations of monomer [1 + H+]+ (m/zcalc = 259.1770, m/zmeas = 259.17675), dimer [12 + H+]+ (m/zcalc = 517.3461, m/z = 517.34636), and trimer [13 + H+]+ (m/zcalc = 775.5153

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

• dimers [18]. The excimer exhibits an emission band at 500–600 nm, which is separated from that of the monomer. I thus determined the Kdim of 9 as 3.0 × 107 M−1 in chloroform saturated with water ([water] ≈ 0.45 M) and 8.5 × 107 M−1 in freshly opened chloroform ([water] ≈ 17 mM). Dimer 8·8 had another

Olefin metathesis in air

• Lorenzo Piola,
• Fady Nahra and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 2038–2056, doi:10.3762/bjoc.11.221

• the use of 81 in the living ROMP of a hydrophilic norbornene monomer in air, leading to the formation of hydrogels [71]. Despite the living character of this reaction, the propagating catalyst was found to be inactive after 1 hour. Indenylidene complexes The indenylidene-bearing family of complexes

Hexacoordinate Ru-based olefin metathesis catalysts with pH-responsive N-heterocyclic carbene (NHC) and N-donor ligands for ROMP reactions in non-aqueous, aqueous and emulsion conditions

• Shawna L. Balof,
• K. Owen Nix,
• Matthew S. Olliff,
• Sarah E. Roessler,
• Arpita Saha,
• Kevin B. Müller,
• Ulrich Behrens,
• Edward J. Valente and
• Hans-Jörg Schanz

Beilstein J. Org. Chem. 2015, 11, 1960–1972, doi:10.3762/bjoc.11.212

• -defined, hydrophilic Ru–alkylidene catalysts in combination with a hydrophobic monomer in emulsion. The first emulsion ROMP was reported in the early 2000’s when Claverie et al. used 1st generation Grubbs-type catalysts [24] 1 and 2 (Figure 1, approx. 400 ppm catalyst loading) to effectively polymerize

• accessibility of water-insoluble catalysts has resulted in an increased investigation of water-insoluble Ru–alkylidene complexes for emulsion ROMP in aqueous media. Slugovc et al. reported the ROMP of dicyclopentadiene (DCPD) in a “high internal phase emulsion” (HIPE) of the monomer in water [58]. Stable

• catalyst and monomer separately in significant amounts of an organic cosolvent. From a practical and environmental standpoint, the use of hydrophilic complexes for emulsion ROMP eliminating or reducing the need for high amounts of organic cosolvents seems advantageous. In this light it is desirable to

New aryloxybenzylidene ruthenium chelates – synthesis, reactivity and catalytic performance in ROMP

• Patrycja Żak,
• Szymon Rogalski,
• Mariusz Majchrzak,
• Maciej Kubicki and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2015, 11, 1910–1916, doi:10.3762/bjoc.11.206

• to the monomer). The reaction profiles for the catalysts 1a and 8–10, both in the dormant form and in the presence of an activator are shown in Figure 4. The results confirm the total lack of activity of complexes in their dormant forms and show a dramatic increase in catalytic activity in the

• reaction progress was monitored by 1H NMR spectroscopy. Inactivated catalyst 1a does not exhibit catalytic activity in ROMP of 15 performed at room temperature (23 °C). When HCl is added, the activity of complex 1a increases, but after 2 h of the reaction course only about 30% monomer conversion was

• observed. At 40 °C, complex 1a used without an activator remained inactive, but the addition of HCl led to complete monomer conversion within 2 h (Figure 6). In a separate experiment performed at room temperature the activated complex 1a gave 90% monomer conversion within 2 h, by using a monomer to

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• dimerized 16-membered ring product 101 in 57% yield, which was generated by a RRM–dimerization sequence and its monomer 100 in 14% yield along with 99 in 26% yield (Scheme 20). Bicyclo[2.2.1]heptene derivatives Holtsclaw and Koreeda [25] have explored a chemoselective RRM of the enone containing norbornene

Cross-metathesis of polynorbornene with polyoctenamer: a kinetic study

• Yulia I. Denisova,
• Maria L. Gringolts,
• Alexander S. Peregudov,
• Liya B. Krentsel,
• Ekaterina A. Litmanovich,
• Arkadiy D. Litmanovich,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2015, 11, 1796–1808, doi:10.3762/bjoc.11.195

• cis-cyclooctene because of their substantially different monomer reactivities. Keywords: cross-metathesis; 1st generation Grubbs’ catalyst; interchange reactions; kinetics; multiblock copolymer; Introduction A desired sequence of monomer units in a polymer chain can be achieved not only in the

• easily cleavable moieties in their backbone [4][5]. It aims at stimuli-responsive, intelligent polymeric materials, the structure and properties of which can be precisely controlled by adjusting temperature, pH or by introducing low molecular additives. Much less is known about the possibility of monomer

• scenario of the cross-metathesis of those polymers in the presence of the Gr-1 catalyst. Results and Discussion The initial homopolymers, PCOE and PNB, were synthesized by the ROMP of COE and NB, respectively, using Gr-1 under the conditions that prevent the formation of cyclooligomers (at a high monomer

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

• monomer are required. Both chemical [43] and electrochemical polymerisation [44] have been used to incorporate a TTF moiety within the polythiophene backbone. Yamamoto coupling of diiodo monomers 1a and 1b provided polymer 1c, albeit with a modest molecular weight (Mw = 5800 Da) compared to that of the

• TTF-PT hybrid polymer (4), now with an ester linkage between the tetrathio-TTF derivative and the PEDOT polymer backbone, has also been reported [47]. The TTF-functionalised EDOT monomer unit allowed the authors to manage the electropolymerisation in an acetonitrile:CH2Cl2 mixture using both

• potentiodynamic and potentiostatic electrodeposition. Nevertheless, the labile ester bond and its potential cleavage remain an issue due to formation of acid upon electropolymerisation. Roncali and co-workers used more reliable ether bonds to anchor a TTF moiety to a thiophene monomer via a long aliphatic spacer