Postsynthetic functionalization of glycodendrons at the focal point

• Thisbe K. Lindhorst and
• Katharina Elsner

Beilstein J. Org. Chem. 2014, 10, 1482–1487, doi:10.3762/bjoc.10.152

• frequently applied for the synthesis of multivalent glycoconjugates [6]. Dendrons resemble a branched fragment of a whole dendrimer with an orthogonal functional group (FG) at the focal point of the molecular fragment (Figure 1a). This molecular architecture comprises the possibility to anchor a multivalent

Carbohydrate PEGylation, an approach to improve pharmacological potency

• M. Eugenia Giorgi,
• Rosalía Agusti and
• Rosa M. de Lederkremer

Beilstein J. Org. Chem. 2014, 10, 1433–1444, doi:10.3762/bjoc.10.147

• units of mannose, fucose or lactose, have been incorporated into the surface of PEGylated dendritic polymers by means of click chemistry. The larger dendrimer generations have demonstrated an increased capacity to aggregate lectins [47]. Analogs of lactose have been reported as inhibitors of the enzyme

Bis(benzylamine) monomers: One-pot preparation and application in dendrimer scaffolds for removing pyrene from aqueous environments

• Olivia N. Monaco,
• Sarah C. Tomas,
• Meghan K. Kirrane and
• Amy M. Balija

Beilstein J. Org. Chem. 2013, 9, 2320–2327, doi:10.3762/bjoc.9.266

• , novel first-generation dendrimers and hybrid second-generation dendrimers have been synthesized. Using fluorescence spectroscopy, pyrene was shown to be removed from an aqueous environment upon exposure to thin dendrimer films, with the first-generation dendrimer removing 70% of the pyrene within 30 min

• composition. Keywords: amines; dendrimer; fluorescence studies; imines; pyrene; Introduction Highly-branched polymeric systems provide an attractive route for removing pollutants from water due to their interior cavities and their ease of formation [1]. While several promising approaches have been reported

• objective of the research disclosed is the development of a straightforward synthesis for novel dendrimers that can effectively remove small organic molecule pollutants from water. Furthermore, the ability to fine-tune the dendrimer easily is desired. The focus of this report is on three areas of progress

Aqueous reductive amination using a dendritic metal catalyst in a dialysis bag

• Jorgen S. Willemsen,
• Jan C. M. van Hest and
• Floris P. J. T. Rutjes

Beilstein J. Org. Chem. 2013, 9, 960–965, doi:10.3762/bjoc.9.110

• unfriendly solvents. As part of a research program, in which we focus on conducting cascade reactions catalyzed by the joint action of organometallic catalysts and enzymes, we studied possibilities to compartmentalize metal catalysts in an aqueous environment. Inspired by the aforementioned dendrimer

• applying a dendritic analogue in a dialysis device we were able to successfully drive the aqueous reductive amination of an unprotected amino acid to completion, despite the unfavorable equilibria for iminium ion formation in water. Since the dendrimer remains inside the dialysis bag due to its size, the

• readily coordinates to bipyridine 1 to form iridium complex 2. Subsequent abstraction of the chloride ion in the presence of Ag2SO4 afforded the active species 3 in excellent yield. To attach catalyst 3 to a dendrimer, an amine functionality was introduced on the bipyridine ligand in three steps (Scheme 2

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

• Amaresh Mishra,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2013, 9, 866–876, doi:10.3762/bjoc.9.100

• that arise from the population of a triplet luminescent level as the lowest excited-state after photoexcitation [14][15][16], and their derived multinuclear complexes are topologically interesting species including rods, wires, helicates, and dendrimer scaffolds [16][17][18][19][20][21][22]. In the

• )2]2+ complex (Δλem = 41 nm) compared to the parent [Ru(tpy)2]2+ (see Table 1) [48]. Recently, Andvincula et al. also reported a large red-shift (Δλem = 165 nm) of the 3MLCT emission for the ruthenium(II)-cored phenanthroline-oligothiophene dendrimer compared to the parent phenanthroline complex [51

Low-generation dendrimers with a calixarene core and based on a chiral C₂-symmetric pyrrolidine as iminosugar mimics

• Marco Marradi,
• Stefano Cicchi,
• Francesco Sansone,
• Alessandro Casnati and
• Andrea Goti

Beilstein J. Org. Chem. 2012, 8, 951–957, doi:10.3762/bjoc.8.107

• rigidification of the dendrimer structure and the iminosugar presentation in the clusters. The combination of the supramolecular properties of calixarenes with the advantage of a dendrimeric presentation of repetitive units opens up the possibility of generating well-defined multivalent and multifaceted systems

• dendrimers, based on the C2-symmetric (3S,4S)-3,4-dihydoxypyrrolidine (1) unit, to a simple calix[4]arene scaffold (Figure 1). This allows a rapid increase of the valency of the iminosugar dendrimer in a reduced volume. The C2 symmetry of pyrrolidine 1, its ready accessibility from the “chiral pool” (L

• 3, respectively. The synthesis of (3S,4S)-3,4-bis(tert-butyldimethylsilyloxy)pyrrolidine (4) was achieved by following a reported procedure [31], via the key intermediate 6 (Scheme 1 and Supporting Information File 1). Tripyrrolidine 5 required for the second generation calixarene-dendrimer 3 was

Synthetic glycopeptides and glycoproteins with applications in biological research

• Ulrika Westerlind

Beilstein J. Org. Chem. 2012, 8, 804–818, doi:10.3762/bjoc.8.90

• , tripalmitoyl-(S)-glyceryl lipopeptide Pam3-Cys-Ser-(Lys)4 (Pam3CSK4) and carrier proteins, such as tetanus toxoid (T.Tox.), have been successfully applied in MUC1 anti-tumor vaccines [28][29][30]. TH-cell peptides included in two- or three-component vaccines and multivalent glycopeptide dendrimer vaccines have

• airways [106][143]. Previously, it was found that the LecB protein was important for biofilm formation [144][145][146]. In the screening for LecB inhibitors, one glycopeptide dendrimer, FD2 49 (C-FucLysProLeu)4(LysPheLysIle)2LysHisIleNH2, showed particularly strong LecB inhibition (FD2 IC50 = 0.14 μM and

• L-fucose IC50 = 11 μM) [106]. The glycopeptide dendrimer was able to completely inhibit P. aeruginosa biofilm formation at a concentration of 50 μM and established biofilms from wild-type strain and clinical isolates could be completely dispersed. In a later study, analogues of FD2 49 were prepared

Liquid-crystalline nanoparticles: Hybrid design and mesophase structures

• Gareth L. Nealon,
• Romain Greget,
• Cristina Dominguez,
• Zsuzsanna T. Nagy,
• Daniel Guillon,
• Jean-Louis Gallani and
• Bertrand Donnio

Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39

• mesomorphic phases upon their combination into one hybrid system has also been reported [82]. This publication was the first to report on dendrimer-functionalised gold NPs that exhibited a thermotropic cubic phase and 2-D hexagonal arrangement on a surface. Dodecanethiol coated Au NPs of diameter 2.1 ± 0.5 nm

Synthesis of dye/fluorescent functionalized dendrons based on cyclotriphosphazene

• Aurélien Hameau,
• Sabine Fuchs,
• Régis Laurent,
• Jean-Pierre Majoral and
• Anne-Marie Caminade

Beilstein J. Org. Chem. 2011, 7, 1577–1583, doi:10.3762/bjoc.7.186

• aldehyde or an amine. The characterization of these dendrons is reported. An unexpected behaviour of a fluorescent and water-soluble dendron based on dansyl groups in mixtures of dioxane/water was observed. Keywords: dabsyl; dansyl; dendrimer; dendron; fluorescence; Introduction Dendrimers constitute an

Olefin metathesis in nano-sized systems

• Didier Astruc,
• Abdou K. Diallo,
• Sylvain Gatard,
• Liyuan Liang,
• Cátia Ornelas,
• Victor Martinez,
• Denise Méry and
• Jaime Ruiz

Beilstein J. Org. Chem. 2011, 7, 94–103, doi:10.3762/bjoc.7.13

• ) or, more usefully, dendrimer encapsulation – ring closing metathesis (RCM), cross metathesis (CM), enyne metathesis reactions (EYM) – for reactions in water without a co-solvent and (ii) construction and functionalization of dendrimers by CM reactions. Keywords: dendrimer; green chemistry

• in which dendrimer chemistry can be useful in this direction, and this short review article will indicate the various connections between metathesis reactions and dendrimer chemistry. Review Covalent attachment of the olefin metathesis catalyst to the tethers of the dendrimer periphery The attachment

• still remained a challenge. The difficulty resided in the need to sustain both metathesis activity and stability of the metallodendrimer. Thus, we selected the ruthenium family of catalysts and designed metallodendrimers containing ruthenium-benzylidene fragments located at the dendrimer periphery and

Conjugated polymers containing diketopyrrolopyrrole units in the main chain

• Bernd Tieke,
• A. Raman Rabindranath,
• Kai Zhang and
• Yu Zhu

Beilstein J. Org. Chem. 2010, 6, 830–845, doi:10.3762/bjoc.6.92

• observed a red emission with maximum at about 640 nm. A relevant plot of current density and light intensity vs. voltage is reproduced in Figure 2. DeSchryver et al. synthesized dendrimer macromolecules with a DPP core [29]. Embedded in a spin-coated polystyrene film, single dendrimer molecules could be

• imaged via a confocal microscope by utilizing the strong fluorescence of the DPP core. It could be shown that the orientation of the absorption transition dipole of single dendrimer molecules in the film changed in a time window of seconds. Recent work on diphenylDPP-based polymers In recent years a

Synthesis, spectral characterization, electron microscopic study and thermogravimetric analysis of a phosphorus containing dendrimer with diphenylsilanediol as core unit

• E. Dadapeer,
• B. Hari Babu,
• C. Suresh Reddy and
• Naga Raju Charmarthi

Beilstein J. Org. Chem. 2010, 6, 726–731, doi:10.3762/bjoc.6.85

• E. Dadapeer B. Hari Babu C. Suresh Reddy Naga Raju Charmarthi Department of Chemistry, Sri Venkateswara University, Tirupati, Andhra Pradesh, India -517 502 Department of Chemistry, National Cheng Kung University, Tainan -701, Taiwan 10.3762/bjoc.6.85 Abstract A phosphorus containing dendrimer

• on the final dendritic molecule. Keywords: diphenyl silanediol; divergent method; phosphorus containing dendrimer; scanning electron microscopy; Schiff’s base; thermogravimetric analysis; Introduction Dendrimers constitute a new class of macromolecules that can offer a potentially defect-free

• linear polymer typically consists of an entangled mixture of individual molecular chains, each having only two terminal groups. But a dendrimer, by contrast, has many branches, each with its own end groups, so that each molecule contains a very high number of terminal functional groups. This gives a

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32