Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

• Magdalena Ceborska,
• Magdalena Zimnicka,
• Aneta Aniela Kowalska,
• Kajetan Dąbrowa and
• Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

• complex with α-CD and pseudorotaxane inclusion-type complexes with β-, and γ-CDs. UV–vis titrations at pH 7.4 gave association constants for the obtained complexes. The stability of the complexes increases in the series: α-CD/PTX < γ-CD/PTX << β-CD/PTX. The association of PTX with a monomer cyclodextrin

• experiments in phosphate buffered saline (PBS, pH 7.4) were conducted for evaluation of association constants (Kas). Association of PTX with a monomer CD equivalent – methyl α-D-glucopyranoside – was investigated to fully understand the type of interactions between host and guest molecules. Additionally, the

• molecules. The experiments focused on association of PTX with monomer cyclodextrin equivalent – methyl α-D-glucopyranoside – were designed to provide additional information about the type of interactions between host and guest molecules. The second aim of this work is to demonstrate the importance of

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

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

• connecting phenolic molecules with formaldehyde or other aromatic aldehydes to form cross-linking structures through the simple Bakelite-type chemistry to obtain great number of polymers with different functionalities. Phloroglucinol has been utilized as a monomer by Kanatzidis and Katsoulidis [23][24] to

• produce a series of porous polymers. In this contribution, bisphenol A (BPA) was employed as a novel polyphenol monomer instead of phloroglucinol. BPA is a commercially available industrial raw material, which is much cheaper than phloroglucinol. In addition, BPA might be stored more easily, compared with

• t-plot method of PPOP-1 are smaller than those of PPOP-2 and PPOP-3. The difference between the pore volumes and BET specific surface area results of PPOPs may be related to the monomer strut length. With the shortest linker of M1, PPOP-1 possesses the lowest pore volume and BET specific surface

Spatial effects in polymer chemistry

• Helmut Ritter

Beilstein J. Org. Chem. 2017, 13, 2015–2016, doi:10.3762/bjoc.13.198

• tacticity of a polymeric chain is a result of spatial interactions between the active growing chain end and the free monomer or a monomer–metal complex. Moreover, the preferred head-to-tail chain growth of vinyl monomers can be a result of such spatial effects. The spatial arrangement of polymer chains in

1,3-Dibromo-5,5-dimethylhydantoin as promoter for glycosylations using thioglycosides

• Fei-Fei Xu,
• Claney L. Pereira and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2017, 13, 1994–1998, doi:10.3762/bjoc.13.195

• , including dichloromethane, is sold under the trade name Brom-55 and used as swimming pool sanitizer, as industrial brominating agent for ethylene propylene diene monomer rubber to improve ozone resistance, as additive in plastics to promote photodegradation and as a fungicide to preserve fresh fruits [27

18-Hydroxydolabella-3,7-diene synthase – a diterpene synthase from Chitinophaga pinensis

• Jeroen S. Dickschat,
• Jan Rinkel,
• Patrick Rabe,
• Arman Beyraghdar Kashkooli and
• Harro J. Bouwmeester

Beilstein J. Org. Chem. 2017, 13, 1770–1780, doi:10.3762/bjoc.13.171

• ], these findings point to the absolute configuration of (1R,3E,7E,11S,12S)-18-hydroxydolabella-3,7-diene. For the incubation experiments with (R)- and (S)-(1-13C,1-2H)GPP, the terpene monomer IPP, HdS and the GGPP synthase (GGPPS) from S. cyaneofuscatus [12] were added to the reaction mixtures for an

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

• 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

• . In a first step the PIL block is synthesized using 1-vinyl-3-cyanomethylimidazolium bromide (1) as an IL monomer, which was prepared following a literature procedure [16]. During this process the nitrogen atom in the imidazole ring in position 3 is quaternized. Monomer 1 was polymerized with 2

• polymerization is, we synthesized three block copolymers with different chain lengths for both the PIL block and the anchor block. For the PIL block we could synthesize short blocks, containing only 22 repeating units, as well as longer chain lengths consisting of 38 or 72 monomer units (as estimated by 1H NMR

Molecular recognition of N-acetyltryptophan enantiomers by β-cyclodextrin

• Spyros D. Chatziefthimiou,
• Mario Inclán,
• Petros Giastas,
• Athanasios Papakyriakou,
• Konstantina Yannakopoulou and
• Irene M. Mavridis

Beilstein J. Org. Chem. 2017, 13, 1572–1582, doi:10.3762/bjoc.13.157

• , exhibits more freedom: the carboxylic and acetylamino groups of guests D and F inside β-CD B are close and parallel, whereas in β-CD monomer A the acetylamino moiety of the major guest C is close to the carboxyl group of minor guest E, their respective carboxyl and acetylamino groups pointing to opposite

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

• 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

• , the polymerization of hydrophobic amino acids was enhanced (in terms of yield and product length in monomer units), whereas that of hydrophilic, charged amino acids depended on the types of lipid headgroups used, i.e., whether ionic interactions could occur between amphiphile and amino acid. The

• authors surmised that the product length (up 29 monomer units compared to 9 in aqueous set-ups) was possible due to solubilization of the products within the hydrophobic core of the vesicle bilayers. Recent investigations with potentially prebiotic fatty acid structures have confirmed these observations

Synthesis of oligonucleotides on a soluble support

• Harri Lönnberg

Beilstein J. Org. Chem. 2017, 13, 1368–1387, doi:10.3762/bjoc.13.134

• . Conventional ammonolysis was used for the release from support and removal of base and phosphate protections. By this approach, a 15-mer phosphorothioate ODN (sequence not given, one G coupled as a monomer) was synthesized in 58% overall yield. The development of new materials that allow nanofiltration in

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

• , free radical copolymerization of a hydrophobic monomer, complexed in a host, with a stopper comonomer [24][25]. This latter has to be large enough to prevent the dissociation of the growing axis and the host, as it happens in the case of aqueous CD assisted homopolymerizations of hydrophobic monomers

• description see Supporting Information File 1). The eventual content of free RAMEB in the product was checked by isothermal calorimetry (ITC) and was around 3 wt %. The conversion of the monomers was calculated from the yield of polyrotaxane minus the total RAMEB content. In both cases, the monomer

• Supporting Information File 1). The molar masses of polyrotaxanes 1 and 2 were determined after complete acetylation by GPC in THF (for results see Table 1). From the molar ratio i/st, the average molar mass per monomer repeat was derived Da for both polyrotaxanes 1 and 2, which allows to calculate the

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

• and potential treatments. Their initial work describes the direct synthesis of 1-O-phosphofuranosyl hexoses from the corresponding 1-thioimidoyl donor. The donor is available in good yield over five steps starting from the parent monomer unit using a methodology they previously developed (the

• anomeric center Davis and colleagues [51] developed a unique glycosylation strategy that employs a 4-bromobutanyl group as a self-activating aglycone on a mannose monomer (Scheme 13) which works even in the absence of any activating agent, such as TMSOTf. The synthesis of the self-activating donor proceeds

Aqueous semisynthesis of C-glycoside glycamines from agarose

• Juliana C. Cunico Dallagnol,
• Alexandre Orsato,
• Diogo R. B. Ducatti,
• Miguel D. Noseda,
• Maria Eugênia R. Duarte and
• Alan G. Gonçalves

Beilstein J. Org. Chem. 2017, 13, 1222–1229, doi:10.3762/bjoc.13.121

• available, these polysaccharides are far little explored as sources of chemical platforms for drug development. The rare monosaccharide 3,6-anhydro-α-L-galactopyranose (AnGal), naturally present in the agarose structure, is a valuable scaffold since it is a highly functionalized and a chiral-rich monomer

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

• derived from the monosaccharide has certain effects on the SSA and PSD of the prepared porous polymers, porosity tuning can be likely achieved with varying monomer molecular structures. Moreover, the aldehyde or ketone groups of the material provide the possibility for further modification and

• increase the affinity to carbon dioxide. Compared with the reported polymer Glc-3 [17] (prepared using the same monomer as for SugPOP-1 and with a similar method), the polymer SugPOP-1 also possesses a higher CO2 adsorption capacity due to its higher porosity. Compared with a class of microporous HCPs

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

Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates

• Tyler M. M. Stack,
• William H. Johnson Jr. and
• Christian P. Whitman

Beilstein J. Org. Chem. 2017, 13, 1022–1031, doi:10.3762/bjoc.13.101

• was eluted using a linear gradient [2–0 M (NH4)2SO4)]. Fractions (≈2 mL) were collected and pooled by their 4-OT activity. The protein sometimes appears as a series of bands (multiples of the monomer mass) by SDS-PAGE where no one band corresponds to the monomer mass (6915 Da). However, if the protein

• is exchanged into 20 mM HEPES buffer (pH 7.3), loaded onto a HiLoad 16/60 Superdex 75 prep grade column (120 mL resin), equilibrated, and eluted with the same buffer (at 0.5 mL/min), a single band of the correct size is observed. The enzyme elutes at 104 mL, which is consistent with the monomer mass

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

• -monoamino-6-deoxy-β-CD [52] using N,N’-dicyclohexyl-carbodiimide (DCC) and 1-hydroxybenzotriazole (HOBt) applying a procedure known for terephthalic acid [53]. The resulting product, monomer 7, was easily isolated due to its low solubility in water which was attributed to self-inclusion between hydrophobic

• backbone. Compared to monomer 7, peak broadening and the disappearance of the 1H NMR signals of the acetylene protons at 4.54 and 4.36 ppm indicate the formation of polymer 8. The presence of the conjugated backbone was confirmed by UV–vis and fluorescence measurements in water. Compared to 7, a

• of gyration Rg,app, and radius of gyration of a cylindrical cross-section Rg,CS are presented in Table 1. The ratio between I(0) and ICS(0) provides the apparent contour length of the polymer chain. SAXS and SANS indicate a contour length of 130–160 Å, i.e., 15 monomer units with the length of one

Expression, purification and structural analysis of functional GABA transporter 1 using the baculovirus expression system

• Jing Hu,
• Chris Weise,
• Christoph Böttcher,
• Hua Fan and
• Jian Yin

Beilstein J. Org. Chem. 2017, 13, 874–882, doi:10.3762/bjoc.13.88

• membrane. GAT1 dimers were expressed and examined as a distinct population of 9 nm freeze-fracture particles in the plasma membrane of Xenopuslaevis oocytes by freeze-fracture and electron microscopy [33]. The GAT1 protein monomer was determined to be the functional unit since each monomer functions

• independently [33][34]. A similar example is the bacteria homologue LeuT, which was also crystallized as a dimer [13], however, each monomer has its own binding pocket, indicating that the monomers are the functional units. Therefore, a GAT1/GFP fusion protein monomer could be suitable for further structural

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

• Vinila N. Viswanathan,
• Arun D. Rao,
• Upendra K. Pandey,
• Arul Varman Kesavan and
• Praveen C. Ramamurthy

Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87

• synthesis of monomer M1 started with the cyclization of o-phenylenediamine with thionyl chloride in the presence of triethylamine, a strong base and dichloromethane as the solvent at 0 °C. Compound 1 was then treated with bromine and HBr to obtain 4,7-dibromobenzo[c][1,2,5]thiadiazole (2). The latter

• impurities and subsequently brominated using N-bromosuccinimide to produce the desired monomer M1. The synthesis of fluorinated monomer M2 started from 1,2-difluorobenzene. However, the direct bromination of this compound in the 1,4-position is hindered due to the electronegative fluorine substituents. Hence

• nitric acid and acetic acid gave dinitro compound 6. The nitro groups in 6 were then reduced by treatment with iron powder and acetic acid. The cyclization of the diamino compound 7 (as described for compound 1) afforded the difluorinated benzothiadiazole 8. The monomer M2 was obtained by coupling 8 with

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

• polymers with different core and similar number of arms. The modification of CDs with a reduced amount of monomer units results in CD-oligomer materials which still keep an important property of the starting CDs, like their inclusion ability [16]. The CD-oligoester conjugate, compounds with a relatively

• molar ratio between L-LA and OH groups of CDs was kept to a value of 5 for all types of CDs (Table 1) and the reaction was stopped after 72 hours. Although the cyclodextrins were only dispersed in the molten monomer the magnetic stirring insured a good dispersion of the reactants. In previous studies

• [19], the molar ratio between CD and the total monomer amounts introduced in the reaction was about 1/5 which even, in conditions of melted monomer, would not ensure a good mixture of reactants and therefore the reaction would be considered as a heterogeneous system with all disadvantages resulting

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• , alginic acid has one carboxylic acid group per monomer unit, whereas chitosan is an amine-containing polysaccharide; analysis of the different CDs showed higher intensities for peaks attributed to carboxylic acid C=O bonds in both Alg-CDs and Chi-CDs. Similarly Chi-CDs showed an abundance of amine

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

• 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

• monomer structures [22]. In this sense, Bowman et al. demonstrated increased photo-polymerization rates for monoacrylates equipped with secondary functionalities, yet limiting discussion to oxygen-based (meth)acrylate derivatives [23]. In this study, we present the synthesis and characterization of tailor

• maximum rates of polymerization, Rp,max, were calculated according to Equation 1. With Q/s being the heat flow per second at the global minimum of the first deviation of the respective measurement (maximum Q/s), M the molar mass of the monomer, n the number of double bonds per monomer molecule, ∆Hp the

Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy

• Monica Ferro,
• Franca Castiglione,
• Nadia Pastori,
• Carlo Punta,
• Lucio Melone,
• Walter Panzeri,
• Barbara Rossi,
• Francesco Trotta and
• Andrea Mele

Beilstein J. Org. Chem. 2017, 13, 182–194, doi:10.3762/bjoc.13.21

• formation as the main mechanism of absorption [33]. We may conclude that the type of monomer and the cross-linker agent both play a key role in driving the absorption towards inclusion complexes or segregation in the polymer pores, although a sufficient number of data is still missing to formulate a general

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

• worthwhile noting the other various reaction types explored by extrusion: Grafting reactions – a grafted polymer is synthesised from the reaction of a polymer and a functionalised monomer [12]. Functionalisation – this takes place on already prepared polymers, when the polymer is either functionalised by the

• (Scheme 1). The s-BuLi reacts with the double bond of styrene, initiating a homopolymerisation process. Once all the monomer is consumed, the polymer has a stable anionic polymer chain, which allows for further functionalisation by reaction with electrophilic functional groups. The solution-based living

Stabilization of nanosized titanium dioxide by cyclodextrin polymers and its photocatalytic effect on the degradation of wastewater pollutants

• Tamás Zoltán Agócs,
• István Puskás,
• Erzsébet Varga,
• Mónika Molnár and
• Éva Fenyvesi

Beilstein J. Org. Chem. 2016, 12, 2873–2882, doi:10.3762/bjoc.12.286

• behavior and stability of nanoTiO2 in cyclodextrin solutions. On the other hand, we used various monomer and polymer cyclodextrin derivatives, and assessed the options for nanoTiO2 stabilization in the presence of various salts and tap water on the basis of turbidity tests. The physical stability of

• start to aggregate and form larger particles enhancing the turbidity of dispersion. The turbidity (the haziness of the dispersion caused by particles invisible for the naked eye) was measured to monitor the aggregation of the particles of nanoTiO2. Various monomer and polymer CD derivatives were studied

• how they influence the stability of nanoTiO2 in the presence of NaCl (0.1%) by recording the turbidity. We used neutral and charged CD derivatives, such as non-ionic 2-hydroxypropyl-β-cyclodextrin monomer (M) and polymer (P) (HPBCD-M/P), anionic carboxymethyl-β-cyclodextrin monomer and polymer (CMBCD