Modulating the activity of short arginine-tryptophan containing antibacterial peptides with N-terminal metallocenoyl groups

• H. Bauke Albada,
• Alina-Iulia Chiriac,
• Michaela Wenzel,
• Maya Penkova,
• Julia E. Bandow,
• Hans-Georg Sahl and
• Nils Metzler-Nolte

Beilstein J. Org. Chem. 2012, 8, 1753–1764, doi:10.3762/bjoc.8.200

• occurring antimicrobial peptides have been studied [5]. In addition, chemical syntheses of a large number of peptides that do not have natural counterparts have furnished promising synthetic antimicrobial peptides (synAMPs) [8]. For example, peptide-dendrimers [9][10][11][12][13], lipidated short peptides

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

• , Parco Area delle Scienze 17/A, I-43124 Parma, Italy 10.3762/bjoc.8.107 Abstract The preparation of low-generation dendrimers based on a simple calix[4]arene scaffold by insertion of the iminosugar-analogue C2-symmetric 3,4-dihydroxypyrrolidine is described. This methodology allows a rapid incorporation

• with more complex and/or biologically relevant iminosugars. Keywords: calixarenes; cation-responsive system; dendrimers; iminosugars; multivalency; Introduction Polyhydroxylated pyrrolidines are one of the main classes of naturally occurring sugar mimics [1][2] and belong to the so-called iminosugars

• calixarene core has only occasionally been explored. To the best of our knowledge, only one example in which a glycodendrimer was built on a calixarene core has been published [27], while no examples of iminosugar-based calixarene dendrimers have been reported so far. We report herein the synthesis of low

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

• and lectin binding [95][96][97][98][99][100][101][102][103][104][105]. The synthesis of glycoclusters/dendrimers is an area of research aimed at tackling the increasing problems with bacterial multi-antibiotic resistance. Microbe adherence to the glycans on the tissue cell surface is essential for an

• microbe and lectin binding studies, glycopeptide based glycoclusters/dendrimers were applied, employing linear peptide backbones, cyclic peptide scaffolds or multi-lysine scaffolds [106][107][108][109][110][111][112][113][114][115][116][117][118]. The pentavalent cholera toxin protein secreted by Vibrio

• monovalent derivative with the multivalent inhibitor [121]. The X-ray crystal structure of the cholera-toxin–GM1-ganglioside complex has shown that most of the protein contacts are given to the terminal galactose unit [122]. With this knowledge in hand, dendrimers based on readily available galactose

Thiophene-based donor–acceptor co-oligomers by copper-catalyzed 1,3-dipolar cycloaddition

• Stefanie Potratz,
• Amaresh Mishra and
• Peter Bäuerle

Beilstein J. Org. Chem. 2012, 8, 683–692, doi:10.3762/bjoc.8.76

• popular and reached high significance in materials synthesis, because high yields and easy to purify products are typically obtained [13][14]. The click chemistry approach was successfully employed to synthesize various oligomers [15][16][17], catenanes and rotaxanes [18], dendrimers [11][19][20], and

Azobenzene dye-coupled quadruply hydrogen-bonding modules as colorimetric indicators for supramolecular interactions

• Yagang Zhang and
• Steven C. Zimmerman

Beilstein J. Org. Chem. 2012, 8, 486–495, doi:10.3762/bjoc.8.55

• ]. Noncovalent hydrogen bonding, electrostatic interactions, π–π stacking and metal coordination have been used alone and in concert to assemble a broad range of building blocks, from small molecules [4][5][6][7] to polymers [8][9] including dendrimers [10][11]. Among these noncovalent interactions, hydrogen

• of lower molecular weight. The utility of these units is further demonstrated in the broad range of supramolecular architectures that have emerged and the materials to which these units have been attached, including dendrimers [15][16][17], polymer chain-ends [18][19][20] and polymer side-chains [21

Synthesis and mesomorphic properties of calamitic malonates and cyanoacetates tethered to 4-cyanobiphenyls

• Katharina C. Kress,
• Martin Kaller,
• Kirill V. Axenov,
• Stefan Tussetschläger and
• Sabine Laschat

Beilstein J. Org. Chem. 2012, 8, 371–378, doi:10.3762/bjoc.8.40

• malonates has been devoted to C60 fullerene dendrimers [27][28][29][30][31]. Only a few liquid crystalline cyanoacetates have been described so far. The first example, a dihydrazide, was reported by Schubert [32]. Furthermore some calamitic and bent-core mesogens derived from α-cyanocinnamic acid were

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

• finding success for example in the case of polymer-coated NP hybrids [38][39][40][41]. Dendrimers and dendrons offer some advantages in this context, due to the ability to exert a high degree of control over their structure and composition, with their size readily increased through additional generational

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

• important group of hyperbranched macromolecules, pertaining both to the field of molecular chemistry thanks to their perfectly defined structure due to their step-by-step synthesis, and to the field of polymers due to their repetitive structure. The numerous terminal groups of dendrimers are responsible for

• most of their properties for instance in catalysis, for the elaboration of materials, or in biology [1][2]. Dendrons are also branched macromolecules, reminiscent of dendrimers, but which possess one functional group at the level of the core, in addition to the terminal groups [3]. Several hundreds of

Efficient and selective chemical transformations under flow conditions: The combination of supported catalysts and supercritical fluids

• M. Isabel Burguete,
• Eduardo García-Verdugo and
• Santiago V. Luis

Beilstein J. Org. Chem. 2011, 7, 1347–1359, doi:10.3762/bjoc.7.159

• anchoring of the catalytic subunit on a solid support that was either organic (polymeric) [12] or inorganic (zeolites, clays, silicas, etc.) [13]. Nevertheless, other possibilities have been also assayed. These include the use of soluble supports such as dendrimers [14][15], nanoparticles [16], soluble

Novel carbazole–pyridine copolymers by an economical method: synthesis, spectroscopic and thermochemical studies

• Aamer Saeed,
• Madiha Irfan and
• Shahid Ameen Samra

Beilstein J. Org. Chem. 2011, 7, 638–647, doi:10.3762/bjoc.7.75

• has been focused on organic semiconductors, including polymers, oligomers, dendrimers, small molecules and heavy-metal complexes, after the discovery by Burroughes et al. in 1990 [1][2][3][4][5][6] that they can be used for fabricating organic light emitting diodes (OLEDs). A number of criteria exist

Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal

• Baoxiang Gao,
• Hongxia Li,
• Defang Xia,
• Sufang Sun and
• Xinwu Ba

Beilstein J. Org. Chem. 2011, 7, 198–203, doi:10.3762/bjoc.7.26

• dendrons or dendrimers are of great significance because of their similarity to proteins in composition and topology [9][10][11], as well as their architectural difference from currently prevalent linear model peptides. However, little attention has been paid to the self-assembly of natural amino acid

• based dendrimers, and especially to their gelation and liquid crystal properties [12][13]. Recently, a type of amphiphilic dendritic dipeptide was described by Percec et al. as self-assembling in helical pores [14]. In addition, Takashi Kato and co-workers have recently reported that dendritic

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

• olefin metathesis and dendrimers and other nano systems is addressed in this mini review mostly based on the authors’ own contributions over the last decade. Two subjects are presented and discussed: (i) The catalysis of olefin metathesis by dendritic nano-catalysts via either covalent attachment (ROMP

• ) 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

• as possible and that polluting classic organic solvents be replaced by “greener” solvents such as water or super-critical carbon dioxide. Therefore during the last decade, we have attempted to make progress in this field with dendrimers using nano-organometallic chemistry [10]. There are several ways

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

• 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

• molecule resembling a tree. Recently, dendrimers and dendrons have been defined in general terms for a class of hyper branched and poly functional macromolecules [4]. They are also called “cascade-type molecules”. Under ideal conditions, the molecular architecture is very uniform. A dendron is one of the

• major subdivisions of a dendrimer. Thus, one of the major differences between linear polymers and dendrimers is their branched architecture. They can be constructed by two fundamental approaches namely, the divergent and convergent methods. The divergent method, first reported by Vögtle is based on the

Poly(glycolide) multi-arm star polymers: Improved solubility via limited arm length

• Florian K. Wolf,
• Anna M. Fischer and
• Holger Frey

Beilstein J. Org. Chem. 2010, 6, No. 67, doi:10.3762/bjoc.6.67

• from dendrimers [17][18], well-defined hyperbranched polymers [19] fulfill this requirement and benefit from their accessibility via a facile one-step synthesis, which makes a tedious, generation-wise build-up ubiquitous. Besides poly(ethylene imine) (PEI) [20], hyperbranched polyglycerol [21][22][23

• contrast to dendrimers, where functional groups are exclusively located at the surface, poly(glycerol) scaffolds also contain hydroxy groups throughout the structure. At first glance this might be considered a disadvantage, however, this is in fact beneficial for the significantly hydrophilized core

Asymmetric reactions in continuous flow

• Xiao Yin Mak,
• Paola Laurino and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2009, 5, No. 19, doi:10.3762/bjoc.5.19

• heterogenized [18]. Soluble supported catalysts have also been developed, particularly in form of dendrimers that can be separated from the reaction mixture via membrane filtration, a process that is also applicable in continuous flow [19][20][21][22]. This following section summarizes some recent developments