Building complex carbon skeletons with ethynyl[2.2]paracyclophanes

• Ina Dix,
• Lidija Bondarenko,
• Peter G. Jones,
• Thomas Oeser and
• Henning Hopf

Beilstein J. Org. Chem. 2014, 10, 2013–2020, doi:10.3762/bjoc.10.209

• extensive column chromatography/recrystallization. Isomer 11 is chiral and could be separated on a column impregnated with cellulose tris(3,5-dimethylphenyl)carbamate. The bridge-extended cyclophane precursor 18 furnished the ring-enlarged cyclophanes 19 and 20 on Glaser–Hay coupling. Cross-coupling of 4

• chiral compound, was resolved into its enantiomers on a OD-column impregnated with cellulose tris(3,5-dimethylphenyl) carbamate using hexane/propan-2-ol (9:1) as an eluent and a UV-detector set at 254 nm. A baseline separation was achieved and the two enantiomers had [α]D25 = −44 ° (c 0.375, hexane

Supercritical carbon dioxide: a solvent like no other

• Jocelyn Peach and
• Julian Eastoe

Beilstein J. Org. Chem. 2014, 10, 1878–1895, doi:10.3762/bjoc.10.196

• ]. There is also promise being seen with organic hydroxylated and oxygenated compounds such as cellulose triacetate [87], cyclodextrins [88], amorphous poly(lactic acid) and glucopyranoside [89] (Table 2, compounds 25–28) as well as polymers with incorporated ether linkages [87]. Beckman and Enick et al

The chemoenzymatic synthesis of clofarabine and related 2′-deoxyfluoroarabinosyl nucleosides: the electronic and stereochemical factors determining substrate recognition by E. coli nucleoside phosphorylases

• Ilja V. Fateev,
• Konstantin V. Antonov,
• Irina D. Konstantinova,
• Tatyana I. Muravyova,
• Frank Seela,
• Roman S. Esipov,
• Anatoly I. Miroshnikov and
• Igor A. Mikhailopulo

Beilstein J. Org. Chem. 2014, 10, 1657–1669, doi:10.3762/bjoc.10.173

• residue of FMAU was realized by the concerted action of E. coli thymidine phosphorylase (TP) absorbed on DEAE cellulose for the intermediary generation of the phosphate 12a and E. coli purine nucleoside phosphorylase (PNP) for the condensation of the latter with bases. The two most challenging features of

A promising cellulose-based polyzwitterion with pH-sensitive charges

• Thomas Elschner and
• Thomas Heinze

Beilstein J. Org. Chem. 2014, 10, 1549–1556, doi:10.3762/bjoc.10.159

• groups could be efficiently synthesized from cellulose phenyl carbonate. Polyanion, polycation, and polyzwitterion are accessible by orthogonal removal of protecting groups. The molecular structure was proofed by FTIR- and NMR spectroscopy. Characteristic properties of the cellulose derivatives, e.g

• . Keywords: carbonate; cellulose; complexation; multivalent glycosystems; NMR; polyzwitterion; Introduction Ionic polymers are important naturally occurring macromolecules and various synthetic polyelectrolytes play an important role in commercial applications [1]. Naturally occurring biopolymers are for

• . While polyzwitterions based on N-functionalized chitosan [14][15] or 6-desoxy-6-aminocelluloses [16] are composed like synthetic polybetaines, a few cellulose-based zwitterions are described where the isoelectric point and the properties in solution could be tuned by varying the substitution pattern [17

Bis(β-lactosyl)-[60]fullerene as novel class of glycolipids useful for the detection and the decontamination of biological toxins of the Ricinus communis family

• Hirofumi Dohi,
• Takeru Kanazawa,
• Akihiro Saito,
• Keita Sato,
• Hirotaka Uzawa,
• Yasuo Seto and
• Yoshihiro Nishida

Beilstein J. Org. Chem. 2014, 10, 1504–1512, doi:10.3762/bjoc.10.155

• dimethyl sulfoxide (2 mL), and the solution was poured into a dialysis tube (Cellulose Dialyzer Tubing VT351, molecular weight cut-off: 3500, Nacalai Tesque, Inc., Japan) suffused with distilled water (20 mL). After 2 days of dialysis, the solution was subjected to ultrafiltration at 3,000g for 15 min by

Multichromophoric sugar for fluorescence photoswitching

• Stéphane Maisonneuve,
• Rémi Métivier,
• Pei Yu,
• Keitaro Nakatani and
• Juan Xie

Beilstein J. Org. Chem. 2014, 10, 1471–1481, doi:10.3762/bjoc.10.151

• (700 rpm, monitoring by TLC), and poured into distilled water after cooling to room temperature. The precipitate was then filtred through a cellulose acetate filter (porosity 2 µm) under vacuum and washed with water, then purified by column chromatography using pure EtOAc, then EtOAc/acetone (gradient

• stirred at 110 °C during 15 min under microwave irradiation (700 rpm, monitoring by TLC). After cooling to room temperature, the reaction mixture was poured into 20 to 25 mL of distilled water. The precipitate was then filtred through cellulose acetate filter (porosity 2 µm) under vacuum and washed with

• . The precipitate was then filtred through a cellulose acetate filter (porosity 2 µm) under vacuum and washed with water, then purified by column chromatogrphy using EtOAc:ethanol (9:1) to give 66% of the desired compound (45.8 mg, 0.022 mmol) as a red solid; mp 181–183 °C; Rf = 0.53 (EtOAc/acetone = 4

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

• addition, SPPS can be carried out on cellulose papers, in which reagents are spotted onto porous membranes [65]. The typical reactions proceed only in the volume that has been infused into the solid pores. Again, coupling and deprotection reactions as well as washing steps take place simultaneously. The

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

• modification of fibers or polymers (e.g., plasma technique). Without a polymerizable group, phosphoramidates can be used as an additive in polymers. Gaan et al. [113] have studied the thermal decomposition of cotton cellulose treated with different phosphoramidates. More specifically, they have shown that a

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

• of applications of cellulose, a glucose-based polysaccharide, is limited by its inherently poor mechanical properties. The grafting of synthetic polymer chains by, for example, a “grafting from” process may provide the means to broaden the range of applications. The nitroxide-mediated polymerization

• (NMP) method is a technique of choice to control the length, the composition and the architecture of the grafted copolymers. Nevertheless, cellulose is difficult to solubilize in organic media because of inter- and intramolecular hydrogen bonds. One possibility to circumvent this limitation is to

• solubilize cellulose in N,N-dimethylformamide (DMF) or N,N-dimethylacetamide (DMA) with 5 to 10 wt % of lithium salts (LiCl or LiBr), and carry out grafted polymerization in this medium. The stability of nitroxides such as SG1 has not been studied under these conditions yet, even though these parameters are

A³-Coupling catalyzed by robust Au nanoparticles covalently bonded to HS-functionalized cellulose nanocrystalline films

• Jian-Lin Huang,
• Derek G. Gray and
• Chao-Jun Li

Beilstein J. Org. Chem. 2013, 9, 1388–1396, doi:10.3762/bjoc.9.155

• Jian-Lin Huang Derek G. Gray Chao-Jun Li Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A0B8, Canada 10.3762/bjoc.9.155 Abstract We decorated HS-functionalized cellulose nanocrystallite (CNC) films with monodisperse Au nanoparticles (AuNPs) to form a

• ) either in water or without solvent. Most importantly, the catalyst could be used repetitively more than 11 times without significant deactivation. Our strategy also promotes the use of naturally renewable cellulose to prepare reusable nanocomposite catalysts for organic synthesis. Keywords: A3-coupling

• reaction; cellulose nanocrystallites (CNCs) films; gold catalysis; water or without solvent; Introduction Organic synthesis is usually performed in organic solvents; however, from a green chemistry perspective, evaporation and discharge of organic solvents not only generates chemical waste but also causes

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• cellulose fibers promoted by the NaClO/NaBr system (Scheme 16). According to the proposed mechanism PINO radical is oxidized to the corresponding N-oxammonium cation, which in turn is responsible for the oxidation of the C6 alcoholic function. The surface modification of cellulose fibers by selectively

• catalytic system allowed higher conversion of hydroxyl groups. A comparison study on the effect of TEMPO and PINO radicals on the oxidation efficiency toward cellulose led to the conclusion that the NHPI/AQ oxidation mediator affords the highest content of carboxylic groups and better preserves the

• /NHPI-mediated aerobic oxidation mechanism. DADCAQ/TCNHPI mediated aerobic oxidation of ethylbenzene. NHPI/xanthone/TMAC mediated aerobic oxidation of ethylbenzene. NHPI/AQ-mediated aerobic oxidation of α-isophorone. NHPI/AQ-mediated oxidation of cellulose fibers by NaClO/NaBr system. NHPI/AQ mediated

C–C Bond formation catalyzed by natural gelatin and collagen proteins

• Dennis Kühbeck,
• Basab Bijayi Dhar,
• Eva-Maria Schön,
• Carlos Cativiela,
• Vicente Gotor-Fernández and
• David Díaz Díaz

Beilstein J. Org. Chem. 2013, 9, 1111–1118, doi:10.3762/bjoc.9.123

• Bruker Avance 300 spectrometer. Chemical shifts are denoted in δ (ppm) relative to tetramethylsilane (TMS δ = 0) as an internal standard or relative to residual solvent peaks. Samples were analyzed by chiral-phase HPLC using a Varian 920-LC Liquid Chromatograph and a column Phenomenex Lux Cellulose-1

Polymerization of novel methacrylated anthraquinone dyes

• Christian Dollendorf,
• Susanne Katharina Kreth,
• Soo Whan Choi and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 453–459, doi:10.3762/bjoc.9.48

• ][4][5][6] and are used for the coloration of cotton and cellulose fibers as well as for synthetic materials such as polyamides [7]. Besides azo dyes, they represent the second largest class of textile pigments [8], and unlike these dyes, anthraquinone derivatives are resistant against degradation due

The β-cyclodextrin/benzene complex and its hydrogen bonds – a theoretical study using molecular dynamics, quantum mechanics and COSMO-RS

• Jutta Erika Helga Köhler and
• Nicole Grczelschak-Mick

Beilstein J. Org. Chem. 2013, 9, 118–134, doi:10.3762/bjoc.9.15

• solvation-free-energy differences was used to distinguish amylose helices from cellulose sheets by analysing the different reactivity of oxygen atoms O2, O3 and O6 of the sugar units with and without methylation, in line with experimental data [13]. Cyclodextrin-complex formation with substituted benzenes

Polysiloxane ionic liquids as good solvents for β-cyclodextrin-polydimethylsiloxane polyrotaxane structures

• Narcisa Marangoci,
• Rodinel Ardeleanu,
• Laura Ursu,
• Constanta Ibanescu,
• Maricel Danu,
• Mariana Pinteala and
• Bogdan C. Simionescu

Beilstein J. Org. Chem. 2012, 8, 1610–1618, doi:10.3762/bjoc.8.184

• supermolecules formed by ILs with different host molecules), leading to interesting phenomena, properties and applications [7][8][9][10][11][12]. This includes the dissolution of cellulose and cyclodextrins (CDs) with ILs [12], synthesis of ILs containing slide-ring gels [7], synthesis of IL-CD inclusion

Combined bead polymerization and Cinchona organocatalyst immobilization by thiol–ene addition

• Kim A. Fredriksen,
• Tor E. Kristensen and
• Tore Hansen

Beilstein J. Org. Chem. 2012, 8, 1126–1133, doi:10.3762/bjoc.8.125

• cellulose paper thimble and purified by Soxhlet extraction with CH2Cl2 (70 mL) for 12 h, and then the purified beads were left to dry at room temperature for 24 h (67% yield for 10a, 67% yield for 10b, 63% yield for 10c, 64% yield for 10d). Catalyst loadings were determined by CHN analysis. Preparation of

• :1), MeOH (200 mL) and CH2Cl2 (50 mL). The polymer beads were then transferred to a cellulose paper thimble and purified by Soxhlet extraction with CH2Cl2 (70 mL) for 12 h, and then the purified beads were left to dry at room temperature for 24 h (75% yield for 11a, 85% yield for 11b). Catalyst

• (1–2 repetitions). CH2Cl2 (50 mL) was added, the suspension was filtered by vacuum, and the polymer beads washed with water (1000 mL), THF–H2O (200 mL, 1:1), MeOH (200 mL) and CH2Cl2 (50 mL). The polymer beads were then transferred to a cellulose paper thimble and purified by Soxhlet extraction with

Investigation of the network of preferred interactions in an artificial coiled-coil association using the peptide array technique

• Raheleh Rezaei Araghi,
• Carsten C. Mahrenholz,
• Rudolf Volkmer and
• Beate Koksch

Beilstein J. Org. Chem. 2012, 8, 640–649, doi:10.3762/bjoc.8.71

• investigate the Acid-pp–chimera interaction, a peptide array (1764 spots), featuring multiple substitutions at positions a/d/e/g of the central heptad of the wt Acid-pp sequence (Figure 2a), was created on cellulose membrane and probed for binding to the αβγ-chimera. The chimeric sequence B3β2γ, containing

• is an excellent and reliable technique for generating natural sequences that suitably interact with unknown patterns forming artificial coiled-coils. Experimental SPOT-synthesis (analogous to a procedure from [26]): Cellulose-bound peptide arrays were prepared according to standard SPOT synthesis

• protocols by using a SPOT synthesizer (Intavis, Köln, Germany) as described in detail in [15]. The peptides were synthesized on amino-functionalized cellulose membranes (Whatman, Maidstone, Great Britain) of the ester type prepared by modifying cellulose paper with Fmoc-β-alanine as the first spacer residue

Cyanoethylation of the glucans dextran and pullulan: Substitution pattern and formation of nanostructures and entrapment of magnetic nanoparticles

• Kathrin Fiege,
• Heinrich Lünsdorf,
• Sevil Atarijabarzadeh and
• Petra Mischnick

Beilstein J. Org. Chem. 2012, 8, 551–566, doi:10.3762/bjoc.8.63

• spectroscopy (PEELS). Keywords: cyanoethyldextran; cyanoethylpullulan; ferromagnetic nanoparticles; glycan nanostructures; substitution pattern; Introduction Cyanoethylation has been widely applied to polysaccharides, e.g., to cellulose [1], inulin [2], and starch [3]. Onda reported on cyanoethylation of

• nanoparticles is usually mediated by carboxylate groups [19]. The interaction of magnetic nanoparticles, coated with glucans (cellulose, pullulan and dextran), with human cells was reported by Heinze et al. [17][20]. A prerequisite for any application in pharmaceutical as well as technological fields is the

• ]. Verraest described the substituent distribution in O-cyanoethylinulin by HPLC analysis and 13C NMR spectroscopy [7]. The structure and the solution properties of cyanoethylcellulose were investigated by FT–IR and 13C NMR spectroscopy, as well as by light scattering [21][22]. Cellulose and starch

Synthesis of szentiamide, a depsipeptide from entomopathogenic Xenorhabdus szentirmaii with activity against Plasmodium falciparum

• Friederike I. Nollmann,
• Andrea Dowling,
• Marcel Kaiser,
• Klaus Deckmann,
• Sabine Grösch,
• Richard ffrench-Constant and
• Helge B. Bode

Beilstein J. Org. Chem. 2012, 8, 528–533, doi:10.3762/bjoc.8.60

• an inoculum (turbidity equivalent to the optical density of 0.5 measured at 600 nm) of the different strains. Cellulose disks (100% cotton linter; Carl Roth, Karlsruhe, Germany) were loaded with 100 µg of the peptide. The dried disks were applied to the prepared agar plates and incubated for 24 h

Conserved and species-specific oxylipin pathways in the wound-activated chemical defense of the noninvasive red alga Gracilaria chilensis and the invasive Gracilaria vermiculophylla

• Martin Rempt,
• Florian Weinberger,
• Katharina Grosser and
• Georg Pohnert

Beilstein J. Org. Chem. 2012, 8, 283–289, doi:10.3762/bjoc.8.30

• mechanically simulated by grinding of algae (10 g) in a mortar and subsequent incubation for 5 min at rt before extraction with MeOH (2 mL). After filtration through cellulose, the extracts were mixed in a glass Petri dish with hot (60 °C) seawater (10 mL) containing 1.5% agar (Sigma Aldrich, Deisenhofen

Air-stable, recyclable, and time-efficient diphenylphosphinite cellulose-supported palladium nanoparticles as a catalyst for Suzuki–Miyaura reactions

• Qingwei Du and
• Yiqun Li

Beilstein J. Org. Chem. 2011, 7, 378–385, doi:10.3762/bjoc.7.48

• Qingwei Du Yiqun Li Department of Chemistry, Jinan University, 510632 Guangzhou, China 10.3762/bjoc.7.48 Abstract A diphenylphosphinite cellulose palladium complex (Cell–OPPh2–Pd0) was found to be a highly efficient heterogeneous catalyst for the Suzuki–Miyaura reaction. The products were

• obtained in good to excellent yield under mild reaction conditions. Moreover, the catalyst could be easily recovered by simple filtration and reused for at least 6 cycles without losing its activity. Keywords: diphenylphosphinite cellulose; heterogeneous catalysis; nanopalladium; polymer-supported

• ligands [23][24][25] or palladium(0) nanoparticles on various solid supports [26][27][28][29][30][31] (polystyrene [26], silica [27], cellulose [28], corn starch [29], polymethyl methacrylate [30] and others [31]). In addition, cellulose as efficient support for Pd nanoparticles in other cross-coupling

Functionalized copolyimide membranes for the separation of gaseous and liquid mixtures

• Nadine Schmeling,
• Roman Konietzny,
• Daniel Sieffert,
• Patrick Rölling and
• Claudia Staudt

Beilstein J. Org. Chem. 2010, 6, 789–800, doi:10.3762/bjoc.6.86

• separations are currently not possible because suitable membrane materials are not commercially available. It has been found that polymeric membranes, e.g., silicone rubber, polysulfone, cellulose acetate, PDMS, 1,2-polybutadiene and polyethylene are not suitable for this kind of separation because the

• . For economic reasons more and more membrane based processes in natural gas treatments are operated with polyimides as the membrane material instead of cellulose derivatives, since the intrinsic transport properties for the polyimides are much better. However, strong plasticization effects occur with

• between the single components in the feed mixture as previously discussed. However, the modified polymer structure shows good selectivity for CO2 over methane between 30 and 40, which indeed is attractive for commercial applications because it is much higher than the separation factors of the cellulose

Functionalized polymers: synthesis and properties

• Helmut Ritter

Beilstein J. Org. Chem. 2010, 6, No. 55, doi:10.3762/bjoc.6.55

• , naturally occurring polymers as cellulose or polyisoprene were simply modified, for example by esterification or cross-linking to obtain the desired properties. Hermann Staudinger, for instance, chemically modified starch to prove the existence of high molecular weight substances. Nowadays, the development