Macrocyclic bis(ureas) as ligands for anion complexation

• Claudia Kretschmer,
• Gertrud Dittmann and
• Johannes Beck

Beilstein J. Org. Chem. 2014, 10, 1834–1839, doi:10.3762/bjoc.10.193

• rather weak complexing agent, the large ring of 2 binds anions with association constants up to log K = 7.93 for chloride ions. Keywords: anion binding; macrocyclic compounds; NMR spectra; supramolecular chemistry; template; urea; Introduction Supramolecular chemistry – the “chemistry beyond the

Theoretical study of the adsorption of benzene on coinage metals

• Werner Reckien,
• Melanie Eggers and
• Thomas Bredow

Beilstein J. Org. Chem. 2014, 10, 1775–1784, doi:10.3762/bjoc.10.185

• ; dispersion correction; template; Introduction The adsorption of organic molecules on metals is of great interest since the formation of thin films and self-assembled monolayers opens the way toward a functionalization of surfaces [1][2][3][4][5][6][7][8]. The adsorbed molecules often contain an aromatic

Chemical templates

• Sigurd Höger

Beilstein J. Org. Chem. 2014, 10, 1670–1671, doi:10.3762/bjoc.10.174

• Sigurd Hoger Kekulé-Institut für Organische Chemie und Biochemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany 10.3762/bjoc.10.174 Keywords: template; When a single object is created from its constituents, a step-by-step assembly strategy is a modus

• or template can be used. All this holds true for the macroscopic as well as for the microscopic world. A chemical template controls a reaction in such a way that from a multitude of possible products a specific one is preferentially or even exclusively formed. The template can influence the reaction

• in a stoichiometric or a catalytic way, it can be reused or remain in the product as an integral part. Template effects in chemistry are commonly associated with the formation of (macro)cycles, or covalent bond formation in general. However, chemical templates can also exert a variety of other

Expedient synthesis of 1,6-anhydro-α-D-galactofuranose, a useful intermediate for glycobiological tools

• Luciana Baldoni and
• Carla Marino

Beilstein J. Org. Chem. 2014, 10, 1651–1656, doi:10.3762/bjoc.10.172

• starts from a galactofuranose (D-Galf) template conveniently derivatized. Pioneer procedures for the synthesis of 2 involved the pyrolysis of D-Gal under reduced pressure [11][12] and the acid treatment under heating [13], with the subsequent tedious separation from several byproducts, including the

• - and β-linked pyranosidic and furanosidic units [14]. On the other hand, when compound 2 was envisioned as a D-Galf template, the synthesis was devised starting from convenient derivatives of D-Galf in order to avoid the presence of 1. For example, compound 2 was synthesized in the past in six steps

Synthesis of isoprenoid bisphosphonate ethers through C–P bond formations: Potential inhibitors of geranylgeranyl diphosphate synthase

• Xiang Zhou,
• Jacqueline E. Reilly,
• Kathleen A. Loerch,
• Raymond J. Hohl and
• David F. Wiemer

Beilstein J. Org. Chem. 2014, 10, 1645–1650, doi:10.3762/bjoc.10.171

• physiological pH [12]. If an ether substituent on this template had a comparable impact, it could significantly increase the activity relative to DGBP itself [13]. Furthermore, one binding model suggests that the hydroxy group itself, so prominent in the clinically used bisphosphonates, contributes only

Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

• Andreas Gansäuer,
• Andreas Okkel,
• Lukas Schwach,
• Laura Wagner,
• Anja Selig and
• Aram Prokop

Beilstein J. Org. Chem. 2014, 10, 1630–1637, doi:10.3762/bjoc.10.169

• procedures and compound characterization, cytotoxicity studies. Acknowledgements We thank the DFG (SFB 624, ‘Template – Funktionale chemische Schablonen’, FOR 630, ‘Biologische Funktion von Organometallverbindungen’), Dr. Kleist Stiftung Berlin, Robert-Koch Stiftung Berlin.

The search for new amphiphiles: synthesis of a modular, high-throughput library

• George C. Feast,
• Thomas Lepitre,
• Xavier Mulet,
• Charlotte E. Conn,
• Oliver E. Hutt,
• G. Paul Savage and
• Calum J. Drummond

Beilstein J. Org. Chem. 2014, 10, 1578–1588, doi:10.3762/bjoc.10.163

• the Australian Synchrotron, we predict that amphiphiles will be found of various inverse phases, thus creating a template from which novel amphiphiles can be synthetically designed for a specific end application. Conclusion A library of double and triple-chained amphiphiles was synthesised using a

Synthesis and solvodynamic diameter measurements of closely related mannodendrimers for the study of multivalent carbohydrate–protein interactions

• Yoann M. Chabre,
• Alex Papadopoulos,
• Alexandre A. Arnold and
• René Roy

Beilstein J. Org. Chem. 2014, 10, 1524–1535, doi:10.3762/bjoc.10.157

• the benzene carbon, hence differing by a distance of only ~1.5 Å. Schemes 2–4 illustrate the syntheses of 9-mers 12 and 21 using the same trimesic acid core, together with a phloroglucinol template to initiate the synthesis of homologue 17, but incorporating 2-amino-2-hydroxymethylpropane-1,3-diol as

Substitution effect and effect of axle’s flexibility at (pseudo-)rotaxanes

• Friedrich Malberg,
• Jan Gerit Brandenburg,
• Werner Reckien,
• Oldamur Hollóczki,
• Stefan Grimme and
• Barbara Kirchner

Beilstein J. Org. Chem. 2014, 10, 1299–1307, doi:10.3762/bjoc.10.131

• binding is weakened by approximately 10 kcal/mol, and hydrogen bonds are slightly shortened (by up to 0.2 Å). Keywords: dispersion interaction; hydrogen bond; supramolecular chemistry; template; theoretical chemistry; Introduction Rotaxanes are prototypes for molecular machines and molecular switches [1

• rotaxanes are obtained from template synthesis [6][7]. Bulky stopper groups at the ends of the axle prevent the wheels from dethreading. Rotaxanes without their stopper groups are often referred to as pseudorotaxanes. It is implicitly assumed that these stopper functionalities have no further influence on

A new building block for DNA network formation by self-assembly and polymerase chain reaction

• Holger Bußkamp,
• Sascha Keller,
• Marta Robotta,
• Malte Drescher and
• Andreas Marx

Beilstein J. Org. Chem. 2014, 10, 1037–1046, doi:10.3762/bjoc.10.104

• suitable primers for DNA network formation by PCR. We used a 1062 nt open reading frame of human DNA polymerase β as template and Thermus aquaticus (Taq) DNA polymerase for amplification. In earlier studies [17] of flexible Y-motifs strong dependence of the network formation on the annealing temperature

• products were observed in the absence of template DNA under identical conditions (see Supporting Information File 1). Characterization of DNA networks. The formed DNA networks were studied by atomic force microscopy (AFM) using the tapping mode [43][44]. The original sample solutions were diluted to a

• high rotational mobility averaging the anisotropy of the hyperfine interaction to the 14N nucleus (Figure 5A) [54]. Using the same approach as described above, we generated a linear DNA construct as well as a DNA network using a 1062 bp long template in the presence of a 1:1 ratio of dT*TP to TTP and

Molecular architecture with carbohydrate functionalized β-peptides adopting 3₁₄-helical conformation

• Nitin J. Pawar,
• Navdeep S. Sidhu,
• George M. Sheldrick,
• Dilip D. Dhavale and
• Ulf Diederichsen

Beilstein J. Org. Chem. 2014, 10, 948–955, doi:10.3762/bjoc.10.93

• cooperative effects. To evaluate carbohydrate interaction and recognition, the structurally defined attachment of sugar units to a rigid template is highly desired. β-Peptide helices offer conformationally stable templates for the linear presentation of sugar units in defined distances. The synthesis and β

• potential of defined sugar presentation on a template. The β-glycopeptides are synthetically accessible by incorporation of sugar amino acids in β-peptide helical secondary structures, whereas sugar-β-amino acids were derived from a continuation of our efforts in synthesis of sugar-amino acids [51][52]. β3

The influence of intraannular templates on the liquid crystallinity of shape-persistent macrocycles

• Joscha Vollmeyer,
• Ute Baumeister and
• Sigurd Höger

Beilstein J. Org. Chem. 2014, 10, 910–920, doi:10.3762/bjoc.10.89

• appropriate guest molecules on this macrocycle template [7][8][9][10]. In solution, shape-persistent macrocycles aggregate into defined dimers or up to μm long fibers that can form gels (in solution) or can be casted to yield efficient sensor materials [11][12][13][14][15][16][17][18][19][20][21][22][23

• the literature. Here, we designed and synthesized macrocycles 1–4 with flexible extraannular alkyl groups and a fixed intraannular chain that crosses the ring interior (Figure 1) and acts during the synthesis as a template. We studied the influence of the extra- and intraannular substituents on the

• interior (1d). Results and Discussion Synthesis Template-based macrocycles The synthesis of the macrocycle 1 follows our often used strategy to dimerize appropriate rigid bisacetylenes oxidatively [48]. This coupling reaction can be performed statistically or template supported, where the latter is either

Molecular recognition of isomeric protonated amino acid esters monitored by ESI-mass spectrometry

• Andrea Liesenfeld and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 825–831, doi:10.3762/bjoc.10.78

• protonated amino acid esters. Keywords: amino acids; isomer labelled guest method (ILGM); mass spectrometry; molecular recognition; 9,9’-spirobifluorenes; template; Introduction The separation of constitutionally isomeric amino acids is of practical interest. This is particularly true for leucine (Leu

• achieve amino acid recognition by an artificial host [6][7][8][9][10][11] with regard to isomer separation upon isomer-selective molecular recognition by a concave template acting as a host, thereby avoiding the necessity to establish or break additional covalent chemical bonds. Hence, we have prepared

• a larger scale via supramolecular transport, for instance. However, these results are still promising with regard to the development of a template that allows the efficient separation of isoleucine and leucine which is obviously the most interesting challenge. The non-covalent isotope effects

From porphyrin benzylphosphoramidate conjugates to the catalytic hydrogenation of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin

• Marcos C. de Souza,
• Leandro F. Pedrosa,
• Géssica S. Cazagrande,
• Vitor F. Ferreira,
• Maria G. P. M. S. Neves and
• José A. S. Cavaleiro

Beilstein J. Org. Chem. 2014, 10, 628–633, doi:10.3762/bjoc.10.54

• reduction of the macrocycle, thereby affording chlorin and other derivatives (Scheme 1). Considering the importance of TPPF20 as a template for further functionalizations [7] and the better suitability of chlorins for PDT compared to porphyrins due to their enhanced red-shifted Q bands [2], we decided to

• the template TPPF20 to TPCF20 and TPIF20 is cleaner and also more straightforward than most of the methods employing chemicals other than H2 as hydrogen donors. So far, the results indicate that the reduction is facilitated in polar medium, such as mixtures of ethanol, DMF and triethylamine, and that

Self-assembly of metallosupramolecular rhombi from chiral concave 9,9’-spirobifluorene-derived bis(pyridine) ligands

• Rainer Hovorka,
• Sophie Hytteballe,
• Torsten Piehler,
• Georg Meyer-Eppler,
• Filip Topić,
• Kari Rissanen,
• Marianne Engeser and
• Arne Lützen

Beilstein J. Org. Chem. 2014, 10, 432–441, doi:10.3762/bjoc.10.40

• ] aggregates with different numbers of counter ions both from the enantiomerically pure (R)-3 and the racemic ligand (rac)-3 and the enantiomerically pure template (S)-6, and hence, proved the selectivity of the self-assembly processes in terms of aggregate stoichiometry (Figure 1 and Supporting Information

• further confirmed by 2D 1H DOSY NMR spectra (see Supporting Information File 1) of the aggregates as well as of the free ligands. In all cases the relative size of the aggregates was a little more than twice as large as that of the respective concave template. (Please note, that we could only determine

Plakilactones G and H from a marine sponge. Stereochemical determination of highly flexible systems by quantitative NMR-derived interproton distances combined with quantum mechanical calculations of ¹³C chemical shifts

• Simone Di Micco,
• Angela Zampella,
• Maria Valeria D’Auria,
• Carmen Festa,
• Simona De Marino,
• Raffaele Riccio,
• Craig P. Butts and
• Giuseppe Bifulco

Beilstein J. Org. Chem. 2013, 9, 2940–2949, doi:10.3762/bjoc.9.331

• sponge Plakinastrella mamillaris collected at Fiji Islands, is reported. The stereostructural studies began on plakilactone H by applying an integrated approach of the NOE-based protocol and quantum mechanical calculations of 13C chemical shifts. In particular, plakilactone H was used as a template to

• . Plakilactone H was used as a template to set up the potential application of a combined approach of quantitative NMR-derived interproton distances and QM calculations of 13C chemical shifts in defining the stereostructure of highly flexible chemical scaffolds. The two independent methodologies agree and

Synthetic scope and DFT analysis of the chiral binap–gold(I) complex-catalyzed 1,3-dipolar cycloaddition of azlactones with alkenes

• María Martín-Rodríguez,
• Luis M. Castelló,
• Carmen Nájera,
• José M. Sansano,
• Olatz Larrañaga,
• Abel de Cózar and
• Fernando P. Cossío

Beilstein J. Org. Chem. 2013, 9, 2422–2433, doi:10.3762/bjoc.9.280

• : asymmetric catalysis; DFT; 1,3-dipolar cycloaddition; gold catalysis; NICS; NTR; oxazolones; prolines; Introduction The synthesis of α-amino acids employing an α-amino carbonyl template constitutes the most straightforward route to introduce the α-side chain [1]. As a valid example, oxazol-5-(4H)-ones

Topochemical control of the photodimerization of aromatic compounds by γ-cyclodextrin thioethers in aqueous solution

• Hai Ming Wang and
• Gerhard Wenz

Beilstein J. Org. Chem. 2013, 9, 1858–1866, doi:10.3762/bjoc.9.217

• ][16] have already been employed in template controlled photoreactions. Among these hosts CDs offer the advantage of being soluble in water at neutral pH, which is the most favourable solvent for performing photoreactions because of its high transmittance and stability to UV light. Inclusion in CDs not

Self-assembly of 2,3-dihydroxycholestane steroids into supramolecular organogels as a soft template for the in-situ generation of silicate nanomaterials

• Valeria C. Edelsztein,
• Andrea S. Mac Cormack,
• Matías Ciarlantini and
• Pablo H. Di Chenna

Beilstein J. Org. Chem. 2013, 9, 1826–1836, doi:10.3762/bjoc.9.213

• conditions, the fibrillar superstructure of the organogel was successfully used as a template for the in-situ sol–gel polymerization of tetraethoxysilane and the further preparation of silica nanotubes. We propose that the driving forces for templating are hydrogen bonding and electrostatic interactions

• bridged pregnane skeleton and its use as template for the preparation of nanotubes and fluorescent nanospheres of silica via the in-situ sol-gel polymerization of tetraethyl orthosilicate (TEOS) [25][26]. In our search for new LMOGs analogues with structural variations in the steroidal nucleus and new

• . Although this simple steroid has been synthesized for the first time decades ago, its gelation property has never been described in the literature. In this paper, we report the broad scope and super-organogelating ability of steroid 1 and the use of their gels as template for the in situ polymerization of

True and masked three-coordinate T-shaped platinum(II) intermediates

• Manuel A. Ortuño,
• Salvador Conejero and
• Agustí Lledós

Beilstein J. Org. Chem. 2013, 9, 1352–1382, doi:10.3762/bjoc.9.153

• . No agostic interactions were detected, the shortest Pt–H and Pt–C distances being 2.542 Å and 3.117 Å, respectively. Inspired by this chemical template, the synthesis of Pt–boryl derivatives of the type trans-[Pt(BRR’)(PCy3)2]+ has been extended [21]. Even at extreme electronic conditions in

Cascade radical reaction of substrates with a carbon–carbon triple bond as a radical acceptor

• Hideto Miyabe,
• Ryuta Asada and
• Yoshiji Takemoto

Beilstein J. Org. Chem. 2013, 9, 1148–1155, doi:10.3762/bjoc.9.128

• 2002 that hydroxamic acid derivatives are useful achiral templates in enantioselective Diels–Alder reactions [69][70]. To study the effect of hydroxamate ester as an achiral template in the intermolecular radical reaction, our experiments began with the investigation of cascade radical addition

Design and synthesis of tag-free photoprobes for the identification of the molecular target for CCG-1423, a novel inhibitor of the Rho/MKL1/SRF signaling pathway

• Jessica L. Bell,
• Andrew J. Haak,
• Susan M. Wade,
• Yihan Sun,
• Richard R. Neubig and
• Scott D. Larsen

Beilstein J. Org. Chem. 2013, 9, 966–973, doi:10.3762/bjoc.9.111

• ), which was less potent (IC50 9.8 µM versus 1.5 µM), but maintained similar maximal efficacy to that of 1 with significantly less cytotoxicity [8]. We therefore selected 2 as a template for the design of affinity probes. The successful isolation/identification of molecular targets for low-affinity ligands

Multivalent display of the antimicrobial peptides BP100 and BP143

• Imma Güell,
• Rafael Ferre,
• Kasper K. Sørensen,
• Esther Badosa,
• Iteng Ng-Choi,
• Emilio Montesinos,
• Eduard Bardají,
• Lidia Feliu,
• Knud J. Jensen and
• Marta Planas

Beilstein J. Org. Chem. 2012, 8, 2106–2117, doi:10.3762/bjoc.8.237

• antimicrobial peptides. Herein, we describe the design and synthesis of chimeric structures containing two or four copies of the antimicrobial peptides KKLFKKILKYL-NH2 (BP100) and KKLfKKILKYL-NH2 (BP143) attached to the carbohydrate template cyclodithioerythritol (cDTE) or α-D-galactopyranoside (Galp). The

• synthesis involved the preparation of the corresponding peptide aldehyde followed by coupling to an aminooxy-functionalized carbohydrate template. After purification, the multivalent display systems were obtained in high purities (90–98%) and in good yields (42–64%). These compounds were tested against

• synthesis of carbopeptides and carboproteins bearing several copies of a peptide or a protein tethered in a carbohydrate template. They developed an efficient strategy for the synthesis of these carboproteins, in which C-terminal peptide aldehydes are ligated by oxime bond formation to aminooxyacetyl

Synthesis of trifunctional cyclo-β-tripeptide templates

• Frank Stein,
• Tahir Mehmood,
• Tilman Plass,
• Javid H. Zaidi and
• Ulf Diederichsen

Beilstein J. Org. Chem. 2012, 8, 1576–1583, doi:10.3762/bjoc.8.180

• The concept of template-assembled synthetic proteins (TASP) describes a central scaffold that predefines the three dimensional structure for diverse molecules linked to this platform. Cyclic β-tripeptides are interesting candidates for use as templates due to their conformationally defined structure

• ; cyclic β-tripeptide scaffold; orthogonal protection groups; peptide synthesis; template-assembled synthetic proteins (TASP); Introduction Cyclic β-tripeptides form structurally well-defined secondary structures with the potential for alignment of the rings to form intermolecular aggregates [1]. Due to

• cyclic β-tripeptides interesting candidates for the concept of template-assembled synthetic proteins (TASP) [5][6]. The TASP concept describes a central scaffolding molecule directing all further attached molecules into a spatially predefined structure. Cyclic β-tripeptides are suitable for use as a

Palladium-catalyzed substitution of (coumarinyl)methyl acetates with C-, N-, and S-nucleophiles

• Kalicharan Chattopadhyay,
• Erik Fenster,
• Alexander J. Grenning and
• Jon A. Tunge

Beilstein J. Org. Chem. 2012, 8, 1200–1207, doi:10.3762/bjoc.8.133

• chemical library synthesis. Thus, we chose to investigate the Pd-catalyzed benzylic substitution reaction of (coumarinyl)methyl acetates with various nucleophiles. In the forthcoming sections, the coupling of this coumarin template to arylboronic acids [56][57][58][59][60][61], amines [47] and