The preparation of new functionalized [2.2]paracyclophane derivatives with N-containing functional groups

• Henning Hopf,
• Swaminathan Vijay Narayanan and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 437–445, doi:10.3762/bjoc.11.50

• bridging and the strain of the desired 17 would be too high for a successful ring closure. Reacting 16 with tetraethylene glycol (TEG) under high dilution conditions (toluene, reflux, 7 d) provides the crownophane 18 in 68% yield (Scheme 2). Likewise, replacement of TEG by pentaethylene glycol (PEG

An unusually stable chlorophosphite: What makes BIFOP–Cl so robust against hydrolysis?

• Roberto Blanco Trillo,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2015, 11, 313–322, doi:10.3762/bjoc.11.36

• product (G2). Here, chloride is replaced at the phosphorus center with the hydroxide nucleophile (Table 2). The relatively high hydrolyzation barrier of BIFOP–Cl (1, 31.2 kcal/mol) in comparison to O–BIFOP–Cl (3, 22.5 kcal/mol) and the smaller, glycol-based, chlorophosphite [CH2O]2P–Cl (8, 18.3 kcal/mol

Synthesis of the furo[2,3-b]chromene ring system of hyperaspindols A and B

• Danielle L. Paterson and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 265–270, doi:10.3762/bjoc.11.29

• alkene 18 in 95% yield. Protection of the ketone in 18 as the cyclic ketal 19 was achieved in 44% yield using excess ethylene glycol and pTSA and despite attempting a variety of alternate conditions [20][21][22][23] this yield could not be improved without degradation of both the starting material 18 and

• h, 14%. Reagents and conditions: (i) H3C(CH3O)NH·HCl, n-BuLi, THF, −78 °C, 4 h, 81%; (ii) 1-bromo-3,4-methylenedioxybenzene, t-BuLi, THF, −78 °C, 3 h, 84%; (iii) NaH, allyl bromide, TBAI, THF, 65 °C, 20 h, 95%; (iv) ethylene glycol, pTSA, toluene, reflux, 16 h, 44%; (v) OsO4, NMO, t-BuOH, H2O, THF

Synthesis and biological evaluation of a novel MUC1 glycopeptide conjugate vaccine candidate comprising a 4’-deoxy-4’-fluoro-Thomsen–Friedenreich epitope

• Manuel Johannes,
• Maximilian Reindl,
• Bastian Gerlitzki,
• Edgar Schmitt and
• Anja Hoffmann-Röder

Beilstein J. Org. Chem. 2015, 11, 155–161, doi:10.3762/bjoc.11.15

• amino acids and the more reactive HATU/HOAt/NMM cocktail in NMP for attachment of building block 11 and a triethylene glycol spacer [52], the desired glycopeptide was assembled. Release from the resin using TFA/iPr3SiH/water (10:1:1) followed by careful de-O-acetylation with NaOMe/MeOH (pH 9.0) and

Synthesis of divalent ligands of β-thio- and β-N-galactopyranosides and related lactosides and their evaluation as substrates and inhibitors of Trypanosoma cruzi trans-sialidase

• María Emilia Cano,
• Rosalía Agusti,
• Alejandro J. Cagnoni,
• María Florencia Tesoriero,
• José Kovensky,
• María Laura Uhrig and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 3073–3086, doi:10.3762/bjoc.10.324

• -lactosyl residues showed to have trypanocidal activity [29]. On the other hand, a recent paper described the synthesis of 1,6-linked cyclic pseudo-galacto oligosaccharides and their in vitro sialylation by recombinant TcTS [30]. Conjugation of lactose analogs with multiarm poly(ethylene glycol) increases

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

• (α), seven (β), or eight (γ) glucose units. CDs have hydrophobic cavities that can contain guest molecules and form inclusion complexes (ICs). ICs with α-CD accelerate the nucleation and crystallization of poly(ε-caprolactone), poly(ethylene glycol), poly(butylene succinate), and poly(3

• around MeCD and PLLA may be caused by their high miscibility in each other. Therefore, MeCD acts as a plasticizer for PLLA. The plasticizing effects of triacetin and oligomeric poly(1,3-butylene glycol adipate) on PLLA have been reported [43][44][45][46]. Although these plasticizers are reported to be

Synthesis of uniform cyclodextrin thioethers to transport hydrophobic drugs

• Lisa F. Becker,
• Dennis H. Schwarz and
• Gerhard Wenz

Beilstein J. Org. Chem. 2014, 10, 2920–2927, doi:10.3762/bjoc.10.310

• displacement reactions starting from the corresponding per-(6-deoxy-6-bromo)cyclodextrins. Further modification of all 2-OH positions by etherification with iodo terminated triethylene glycol monomethyl ether (and tetraethylene glycol monomethyl ether, respectively) furnished water-soluble hosts. Especially

• hydrophobic β-CD derivatives [41][42]. Mazzaglia et al. reported on amphiphilic β-CD derivatives with alkyl chains (C2–C16) connected by the thioether linkages to the primary site and a statistical substitution with oligoethylene glycol at secondary sites [43]. Becker et al. describe similar hosts with 2,2,2

• -trifluoroethyl groups at all primary sites and also oligoethylene glycol at secondary sites [44]. In both latter cases statistical CD derivatives have been employed, where both the lengths of the oligoethylene oxide side chains and their locations were scattered. Herein, we report on the synthesis of water

Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer

• Florian Hamon,
• Claire Blaszkiewicz,
• Marie Buchotte,
• Estelle Banaszak-Léonard,
• Hervé Bricout,
• Sébastien Tilloy,
• Eric Monflier,
• Christine Cézard,
• Laurent Bouteiller,
• Christophe Len and
• Florence Djedaini-Pilard

Beilstein J. Org. Chem. 2014, 10, 2874–2885, doi:10.3762/bjoc.10.304

• over a typical range of 4000–100 Da. The mass spectra were collected as a continuum profile data. Accurate mass measurement was achieved using polyethylene glycol as the internal reference mass with a resolving power set to a minimum of 10,000 (10% valley). NMR experiments were performed at 300.13 and

Self-assembled monolayers of shape-persistent macrocycles on graphite: interior design and conformational polymorphism

• Joscha Vollmeyer,
• Friederike Eberhagen,
• Sigurd Höger and
• Stefan-S. Jester

Beilstein J. Org. Chem. 2014, 10, 2774–2782, doi:10.3762/bjoc.10.294

• respect to d1 is γ(a1,A,d1) = 3 ± 2°, γ(a2,A,d1) = 5 ± 2°, and γ(a3,A,d1) = 3 ± 2°, and the values do not vary within the experimental error. In other words, the packing of all three compounds is independent on whether the cavity is empty (1), filled by an undecyl diether (2), or a tetraethylene glycol

• (2), or a tetraethylene glycol strand (3). In the porous polymorphs (of each compound), the alkoxy side chains maximize their overlap, and both lattice constants are a direct effect of the side chain lengths. In the dense polymorphs, the packing along lattice vector an,B (n = 1, 2, 3) is similarly a

• (undecyl diether strand, 2), and a polar interior (tetraethylene glycol strand, 3). (a) Schematic structures. The bold lines represent the (identical) macrocycle backbones; the thin straight, dash-dotted, and dash-double-dotted lines indicate alkoxy side chains. (b) Chemical structures. (c) Molecular

Preparation and evaluation of cyclodextrin polypseudorotaxane with PEGylated liposome as a sustained release drug carrier

• Kayoko Hayashida,
• Taishi Higashi,
• Daichi Kono,
• Keiichi Motoyama,
• Koki Wada and
• Hidetoshi Arima

Beilstein J. Org. Chem. 2014, 10, 2756–2764, doi:10.3762/bjoc.10.292

• such as polyethylene glycol (PEG). On the other hand, PEGylated liposomes have been utilized as a representative anticancer drug carrier. However, little is known about the formation of CD PPRX with PEGylated liposome. In the present study, we first report the formation of CD PPRX with PEGylated

• et al. have reported that a number of α-CDs spontaneously thread onto polyethylene glycol (PEG) and form necklace-like supramolecular assemblies [6][7]. The latter are referred to as polypseudorotaxanes (PPRXs), since the release of α-CD from the polymer chain can be achieved upon dissolution in

• water. The assembly of PPRX complexes is a size-dependent process, whereby the small cavity of α-CD assembles with PEG, while the large cavity of β-CD forms the PPRX with polypropylene glycol (PPG) [6][7][8]. In addition, γ-CD forms PPRX with double strand PEG chains [9]. In this case, γ-CD not only

Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups

• Ji-Hun Seo,
• Shino Nakagawa,
• Koichiro Hirata and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2014, 10, 2623–2629, doi:10.3762/bjoc.10.274

• , e.g., α-cyclodextrin (α-CD), threaded on a linear guest molecule, e.g., poly(ethylene glycol) (PEG) [1]. The threaded α-CD molecules are known to be reversibly disassembled when a cleavable end-capping group was introduced in the PEGs, and the cleavable reaction was triggered by proper signals [2][3

Synthesis of graft polyrotaxane by simultaneous capping of backbone and grafting from rings of pseudo-polyrotaxane

• Kazuaki Kato,
• Katsunari Inoue,
• Masabumi Kudo and
• Kohzo Ito

Beilstein J. Org. Chem. 2014, 10, 2573–2579, doi:10.3762/bjoc.10.269

• , 277-0882, Japan 10.3762/bjoc.10.269 Abstract Graft polyrotaxanes, with poly(ε-caprolactone) (PCL) graft chains on the ring components were synthesized by the simultaneous ring-opening polymerization of ε-caprolactone from both ends of the backbone polymer, an end-functionalized polyethylene glycol

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• , numerous pilot scale processes have been demonstrated like the electrohydrodimerization of formaldehyde to ethylene glycol [36] or the production of glyoxylic acid [37]. The most important reasons for this raised interest are the higher energy efficiency compared to traditional thermochemical processes

Synthesis of aromatic glycoconjugates. Building blocks for the construction of combinatorial glycopeptide libraries

• Markus Nörrlinger and
• Thomas Ziegler

Beilstein J. Org. Chem. 2014, 10, 2453–2460, doi:10.3762/bjoc.10.256

• coupled with 1a (for 21) and 2a (for 23) under similar conditions as described for the non-glycosylated counterparts above to afford glycol-dipeptides 22 and 24 in 51% and 55% yield, respectively. As was observed for EDCI-promoted preparation of glycosylated derivatives 13 and 14 (see Table 2), the yields

Synthesis and immunological evaluation of protein conjugates of Neisseria meningitidis X capsular polysaccharide fragments

• Laura Morelli,
• Damiano Cancogni,
• Marta Tontini,
• Alberto Nilo,
• Sara Filippini,
• Paolo Costantino,
• Maria Rosaria Romano,
• Francesco Berti,
• Roberto Adamo and
• Luigi Lay

Beilstein J. Org. Chem. 2014, 10, 2367–2376, doi:10.3762/bjoc.10.247

• the sera from the three conjugated synthetic fragments were capable to recognize their own structures. To answer this question, conjugates with HSA were prepared with a similar protocol to that used for the formation of the CRM197 conjugates, except that a bis-succinimidyl ester penta-ethylene glycol

End group functionalization of poly(ethylene glycol) with phenolphthalein: towards star-shaped polymers based on supramolecular interactions

• Carolin Fleischmann,
• Hendrik Wöhlk and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2263–2269, doi:10.3762/bjoc.10.235

• easily utilized in polymer analogous reactions, is presented. The subsequent cycloaddition reaction with propargyl-functionalized methoxypoly(ethylene glycol) yielded polymers bearing phenolphthalein as the covalently attached end group. In presence of per-β-cyclodextrin-dipentaerythritol, the formation

• spectroscopy and even the naked eye. Keywords: cyclodextrin; phenolphthalein; poly(ethylene glycol); supramolecular assembly; UV–vis spectroscopy; Introduction Over the past decades, polymers with well-defined and complex architectures gained increasing attention due to a broad variety of applications

• in pure water. With the intention to enhance the guest molecule’s hydrophilicity in order to transfer it into the aqueous phase, poly(ethylene glycol) was chosen as the PP-bearing molecule. On the other hand, it was also of great importance to maintain the rather hydrophobic nature of the PP moiety

Second generation silver(I)-mediated imidazole base pairs

• Susanne Hensel,
• Nicole Megger,
• Kristina Schweizer and
• Jens Müller

Beilstein J. Org. Chem. 2014, 10, 2139–2144, doi:10.3762/bjoc.10.221

• + 1] type could be obtained [14][15]. While most examples focus on the use of DNA, other systems such as RNA [16], GNA [17][18] (glycol nucleic acid), PNA [19][20][21], and other nucleic acid derivatives [22] have been modified as well. It is interesting to note that metal-mediated base pairs do not

Photo, thermal and chemical degradation of riboflavin

• Muhammad Ali Sheraz,
• Sadia Hafeez Kazi,
• Sofia Ahmed,
• Zubair Anwar and
• Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

• such as vehicles (ethanol, propylene glycol), buffers (phosphate and citrate) and tonicity modifiers (NaCl, MgCl2) [118]. RF is also known to form complexes with dendrimers [103][119], certain drugs including antibiotics like cloxacillin sodium [102] and doxorubicin [120], dopamine [121], agents like N

Efficient CO₂ capture by tertiary amine-functionalized ionic liquids through Li⁺-stabilized zwitterionic adduct formation

• Zhen-Zhen Yang and
• Liang-Nian He

Beilstein J. Org. Chem. 2014, 10, 1959–1966, doi:10.3762/bjoc.10.204

• (mol CO2 absorbed per mol of base) through the formation of zwitterionic adducts being stabilized by Li+. Keywords: carbon capture and sequestration; CO2 chemistry; coordination effect; ionic liquid; polyethylene glycol; zwitterionic adducts; Introduction Carbon capture and sequestration (CCS) from

• ). Notably, equimolar CO2 absorption was obtained using task-specific ionic liquids (TSILs) with the phosphonium cation containing long alkyl chains and anions derived from AAs (prolinate and methioninate) [36], or AA salts with bulky N-substituents in polyethylene glycol (PEG) solution [37]. However

Synthesis of a bifunctional cytidine derivative and its conjugation to RNA for in vitro selection of a cytidine deaminase ribozyme

• Nico Rublack and
• Sabine Müller

Beilstein J. Org. Chem. 2014, 10, 1906–1913, doi:10.3762/bjoc.10.198

• support deamination of cytidine to uridine. For this purpose, a bifunctionalized cytidine derivative (Figure 1) was synthesized. Via its 5'-OH group, the cytidine derivative is linked to a hexaethylene glycol tether bearing a primary amino group. At the C4-position of the base, a short linker connected to

• bifunctionalized cytidine derivative and its successful conjugation to RNA. Results and Discussion Synthesis of the bifunctional cytidine derivative 1 started from uridine making use of four synthons: a protected hexaethylene glycol linker phosphoramidite 2 bearing a primary amine to be used later for RNA

• glycol with an overall yield of 52% over three steps following a standard literature protocol [41]. After introduction of a Boc group for protection of the linker amino function, the resulting compound 14 was reacted with (2-cyanoethyl-N,N-diisopropyl)chlorophosphoramidite to yield the phosphoramidite 2

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

• identification of Lewis acid–base interactions as a mechanism for solubility in CO2 has given rise to many potentially CO2 soluble polymers, including oxygenated and acylated species [26][71][79][80]. The first non-fluorous polymers to be effectively designed and solubilised were poly(propylene glycol)-diol

• , poly(propylene glycol) monobutyl ether, poly(propylene glycol) acetate and poly(ether carbonate), (Table 2, compounds 18–21) [13]. Beckman et al. developed a set of design rules for CO2-philic polymers based on both theoretical and experimental approaches [91]. These include (a) chain flexibility (for

• : Klostermann et al. has recently reported research around balanced supercritical CO2 microemulsions; systems where there are equal volumes of carbon dioxide and water [43]. These systems use a polyfluoroether surfactant (poly(ethylene glycol) perfluoroalkyl ether), along with commercially available ethoxylated

Synthesis and bioactivity of analogues of the marine antibiotic tropodithietic acid

• Patrick Rabe,
• Tim A. Klapschinski,
• Nelson L. Brock,
• Christian A. Citron,
• Paul D’Alvise,
• Lone Gram and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2014, 10, 1796–1801, doi:10.3762/bjoc.10.188

• . Oxidative cleavage of the glycol with NaIO4 resulted in a β-ketoester aldehyde that upon treatment with silica gel underwent an intramolecular aldol condensation to a mixture of 10a and 11a that were separable by column chromatography. Oxidation with DDQ gave tert-butyl tropone-2-carboxylate (12a) that was

Synthesis of rigid p-terphenyl-linked carbohydrate mimetics

• Maja Kandziora and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2014, 10, 1749–1758, doi:10.3762/bjoc.10.182

• chromatography. According to the protocol of Dondoni et al. [29] glycol cleavage of diol 8 afforded the corresponding aldehyde that was directly treated with N-benzylhydroxylamine to furnish the desired (Z)-nitrone 6. All compounds in this sequence of reactions are mixtures of the two diastereomers at the

Investigations of thiol-modified phenol derivatives for the use in thiol–ene photopolymerizations

• Sebastian Reinelt,
• Monir Tabatabai,
• Urs Karl Fischer,
• Norbert Moszner,
• Andreas Utterodt and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1733–1740, doi:10.3762/bjoc.10.180

• inorganic fillers (40–90 wt %) [1]. Up to date, 2,2-bis(4-(2-hydroxy-3-methacryloxyprop-1-oxy)phenyl)propane (Bis-GMA), 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-(mixture of 2,2,4 and 2,4,4)-trimethylhexane (UDMA) and triethylene glycol dimethacrylate (TEGDMA) are still the dominating monomers of the

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• glycol in the presence of tetrabutylammonium hydrogen sulfate as both an acid and a phase-transfer catalyst (Scheme 28) [100]. As the authors suggested, the formation of intermediate N-acyliminium ion from aldehyde 75 and (thio)urea was the key step of the reaction. Protonation of aldehyde 75 by

• reaction conditions: i. H3PW12O40 (2 mol %), EtOH, 50 °C, 2–15 h; ii. H3PW12O40 (2 mol %), EtOH, 50 °C, 8 h. General scheme of the Biginelli reaction. Reagents and reaction conditions: i. EtOH, reflux. Reagents and reaction conditions: i. Bu4N+HSO4−, diethylene glycol, 120 °C, 1.5–3 h. Reagents and

• , 25 °C, 5 d. Bu4N+HSO4−, diethylene glycol, 80 °C, 1–2 h. The three-component carbopalladation of dienes on the example of buta-1,3-diene. Reagents and reaction conditions: i. 5 mol % Pd(dba)2, Bu4NCl, ZnCl2, acetonitrile or DMSO, 80 °C or 100 °C, 1–2 days. Reagents and reaction conditions: i. 2.5 mol