Investigation on the reactivity of α-azidochalcones with carboxylic acids: Formation of α-amido-1,3-diketones and highly substituted 2-(trifluoromethyl)oxazoles

• Kandasamy Rajaguru,
• Arumugam Mariappan,
• Rajendran Suresh,
• Periasamy Manivannan and
• Shanmugam Muthusubramanian

Beilstein J. Org. Chem. 2015, 11, 2021–2028, doi:10.3762/bjoc.11.219

• construction of other heterocyclic systems. Experimental General A CEM Discover microwave synthesizer (Model No: 908010) operating at 180/264 V and 50/60 Hz with microwave power maximum level of 300 W and microwave frequency of 2455 MHz was employed for the microwave-assisted experiments. Nuclear Magnetic

New palladium–oxazoline complexes: Synthesis and evaluation of the optical properties and the catalytic power during the oxidation of textile dyes

• Rym Hassani,
• Mahjoub Jabli,
• Yakdhane Kacem,
• Jérôme Marrot,
• Damien Prim and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2015, 11, 1175–1186, doi:10.3762/bjoc.11.132

• Microwave Synthesizer, producing continuous irradiation with IR temperature control. An ultraviolet–visible spectrophotometer (U-2000 Hitachi), wavelengths of range 200–800 nm and a quartz cell were employed for the absorbance measurements. Synthesis of the ligands The amino acids and (R)-2-aminobutan-1-ol

Automated solid-phase synthesis of oligosaccharides containing sialic acids

• Chian-Hui Lai,
• Heung Sik Hahm,
• Chien-Fu Liang and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2015, 11, 617–621, doi:10.3762/bjoc.11.69

• [19][20]. Rather than slowly warming a reaction mixture as is done in solution phase, on the automated synthesizer, the building block will be delivered at the optimal temperature and reacted for a predetermined time. For sialic acid building block 4, the activation temperature was determined to be

• automated method for chemical sialylation. Monosaccharide building blocks 4, 5 [14], 6, 7 [21], 8, 9 [21], and 10 [5] were employed for these syntheses. Merrifield polystyrene resin equipped with a photocleavable linker, 11, was placed in the reaction chamber of the automated synthesizer and the coupling

• . Mattan Hurevich and Mr. Frank Schuhmacher for assistance in operating the synthesizer, HPLC and fruitful discussions.

Potential of acylated peptides to target the influenza A virus

• Daniel Lauster,
• Damian Pawolski,
• Julian Storm,
• Kai Ludwig,
• Rudolf Volkmer,
• Henry Memczak,
• Andreas Herrmann and
• Sumati Bhatia

Beilstein J. Org. Chem. 2015, 11, 589–595, doi:10.3762/bjoc.11.65

• . Results and Discussion Peptide synthesis and characterization Peptide synthesis was performed using a rink amide resin on an automatic synthesizer by the Fmoc/tert-butyl strategy [17][18]. The N-terminus of the N-terminal free resin bound peptide was acylated with stearic acid using O-(benzotriazol-1-yl

NAA-modified DNA oligonucleotides with zwitterionic backbones: stereoselective synthesis of A–T phosphoramidite building blocks

• Boris Schmidtgall,
• Claudia Höbartner and
• Christian Ducho

Beilstein J. Org. Chem. 2015, 11, 50–60, doi:10.3762/bjoc.11.8

• synthesizer and base-mediated cleavage from the solid support, the desired full-length products were purified, isolated and identified by ESI mass spectrometry. The sequence of 30 and 31 resembled the sequence of model oligonucleotides 32 and 33 prepared for our initial studies on the NAA-modification [38

Reversibly locked thionucleobase pairs in DNA to study base flipping enzymes

• Christine Beuck and
• Elmar Weinhold

Beilstein J. Org. Chem. 2014, 10, 2293–2306, doi:10.3762/bjoc.10.239

• stable under the conditions of the binding experiment, the linker should be short to avoid steric interference with protein binding, and, preferentially, the oligodeoxynucleotides (ODN) should be easily obtained on a DNA synthesizer without the need for synthesizing special building blocks. In fact, a

• extrahelical side and thus has an important contribution to the overall DNA-binding energy of M.TaqI. Experimental Solid-phase DNA synthesis was performed on an ABI DNA Synthesizer 392 in 1 µmol scale following the standard cycles recommended by Applied Biosystems with a coupling time of 30 s for the natural

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

• Supporting Information File 1. The RNA GUC AGC CGU CAG GAU CCG UG used as model for studying 3'-terminal conjugation of 1 was synthesized on an Applied Biosystems 394 DNA/RNA Synthesizer following the standard protocol for oligoribonucleotide chain assembly. The synthesized RNA was deprotected using aqueous

Structure/affinity studies in the bicyclo-DNA series: Synthesis and properties of oligonucleotides containing bc^en-T and iso-tricyclo-T nucleosides

• Branislav Dugovic,
• Michael Wagner and
• Christian J. Leumann

Beilstein J. Org. Chem. 2014, 10, 1840–1847, doi:10.3762/bjoc.10.194

• affinity. ON5–7, containing the known tc-T residues in the respective positions, were synthesized for comparison. ON1–3 were assembled on the 1.3 μmol scale on a DNA synthesizer utilizing standard phosphoramidite chemistry protocols first. The trityl assay after incorporation of 13 and the subsequent

Orthogonal dual thiol–chloroacetyl and thiol–ene couplings for the sequential one-pot assembly of heteroglycoclusters

• Michele Fiore,
• Gour Chand Daskhan,
• Baptiste Thomas and
• Olivier Renaudet

Beilstein J. Org. Chem. 2014, 10, 1557–1563, doi:10.3762/bjoc.10.160

• 3000+ Bruker Daltonics in positive mode. General procedure for solid-phase peptide synthesis. Assembly of all protected peptides was carried out on a synthesizer (Syro II, Biotage) using the Fmoc/t-Bu strategy and the Fmoc-Gly-SasrinTM resin. Coupling reactions were performed using, relative to the

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

• a batch-wise or a continuous-flow modus. The decision for a peptide synthesizer has to be made according to the intended application and thus, the scale (necessary amounts), the type of chemistry (Fmoc or Boc-strategy) and the number of reaction tubes (plates or vessels). The decision should also be

• generated more potent and stable peptidomimetics as compared to the wild types. Most steps within the synthesis of those analogs can be performed automatically by a peptide synthesizer, providing a fast and straightforward access to the peptides. SPPS can also be used to introduce specific tools into the

One-step synthesis of pyridines and dihydropyridines in a continuous flow microwave reactor

• Mark C. Bagley,
• Vincenzo Fusillo,
• Robert L. Jenkins,
• M. Caterina Lubinu and
• Christopher Mason

Beilstein J. Org. Chem. 2013, 9, 1957–1968, doi:10.3762/bjoc.9.232

• -(trimethylsilyl)propynal (14d, 50 mg, 0.53 mmol) and ethyl β-aminocrotonate (11, 0.14 g, 1.1 mmol) in PhMe–glacial acetic acid (5:1, 2 mL) was irradiated at 100 °C for 1 min in a sealed tube using a CEM Discover microwave synthesizer at an initial power of 70 W. The reaction mixture was cooled in a stream of

• EtOH–glacial acetic acid (5:1, 2 mL) was irradiated at 120 °C for 7 min in a sealed tube using a CEM Discover microwave synthesizer at an initial power of 90 W. The reaction mixture was cooled in a stream of compressed air and evaporated in vacuo. The residue was partitioned between saturated aqueous

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• agent in a modified PET-MF-2V-IT-1 synthesizer and by purifying using plus C18 Sep-Pak cartridges [41]. In the preparation of [11C]44d, the [11C]-methylation of 4-amino-4'-hydroxystilbene was carried out using the “LOOP” method, in which trapping and reaction of [11C]CH3OTf with the appropriate stilbene

Glycosylation efficiencies on different solid supports using a hydrogenolysis-labile linker

• Mayeul Collot,
• Steffen Eller,
• Markus Weishaupt and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2013, 9, 97–105, doi:10.3762/bjoc.9.13

• blocks 34 or 35 was performed by using an automated oligosaccharide synthesizer (Scheme 5, Supporting Information File 1). This synthesizer is an improved version of a recently disclosed synthesizer prototype [20] whereby a separate unit to accommodate aqueous chemistry was added. To avoid cross

• automated oligosaccharide synthesizer, and subsequent linker cleavage with sodium methoxide afforded the crude products, which were analyzed by LC–MS. These analyses clearly showed lower glycosylation efficiencies for all water-compatible resins when compared to PS resins 23 and 24. To prevent the basic

• ; 5. p-TsOH·H2O, MeOH, DCM, rt. Model glycosylation by using an automated oligosaccharide synthesizer. Reactions and conditions: (a) 34, TMSOTf, DCM, −15 °C (30 min); (b) 35, NIS, TfOH, DCM, dioxane, different temperatures and reaction times; (c) Pd(OAc)2, HCOONH4, H2O; (d) NaOMe, MeOH, DCM, rt

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

• carried out on a fully automated Syro II peptide synthesizer (MultiSynTech). Manual peptide synthesis was performed in polypropylene syringes fitted with a polyethylene porous disk. Solvents and soluble reagents were removed by suction. Chemicals were purchased from commercial suppliers Sigma–Aldrich

• min, the slurry was transferred to the resin. The reaction mixture was heated in a microwave instrument to 60 °C for 2 × 10 min, and then the resin was washed with DMF (3 × 1 min), CH2Cl2 (3 × 1 min) and DMF (3 × 1 min). Peptide elongation was performed on the fully automatic synthesizer MultiSynTech

Chemical modification allows phallotoxins and amatoxins to be used as tools in cell biology

• Jan Anderl,
• Hartmut Echner and
• Heinz Faulstich

Beilstein J. Org. Chem. 2012, 8, 2072–2084, doi:10.3762/bjoc.8.233

• phalloidin esters. Linear peptides linked to aminophalloidin Linear peptides such as Ac-Cys-Gly-Tyr-Gly-Arg-Lys-Lys-Arg-Arg-Gln-Arg-Arg-Arg-OH (Tat peptide), and Ac-Cys-Gly-Arg8-OH (Arg8) were synthesized on an Eppendorf Ecosyn P solid-phase synthesizer by using 9-fluorenylmethoxycarbonyl (Fmoc)-Arg(Pbf)SPHB

Acylsulfonamide safety-catch linker: promise and limitations for solid–phase oligosaccharide synthesis

• Jian Yin,
• Steffen Eller,
• Mayeul Collot and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2012, 8, 2067–2071, doi:10.3762/bjoc.8.232

• Abstract Safety-catch linkers are useful for solid-phase oligosaccharide synthesis as they are orthogonal to many common protective groups. A new acylsulfonamide safety-catch linker was designed, synthesized and employed during glycosylations using an automated carbohydrate synthesizer. The analysis of the

• reaction conditions on solid support since cleavage only occurs following preactivation. Thus, different modification reactions, such as Staudinger reduction, ester saponification or sulfation, necessary for the synthesis of GAGs, can be performed on solid support in an automated carbohydrate synthesizer

• acylsulfonamide safety-catch linker 10 plus the Zemplén cleavage site, were employed in glycosylation reactions on a solid phase using an automated synthesizer [13], subsequently cleaved with NaOMe, and the products were analyzed by HPLC (Scheme 3, see Supporting Information File 1). Glycosylations were performed

Peptides presenting the binding site of human CD4 for the HIV-1 envelope glycoprotein gp120

• Julia Meier,
• Kristin Kassler,
• Heinrich Sticht and
• Jutta Eichler

Beilstein J. Org. Chem. 2012, 8, 1858–1866, doi:10.3762/bjoc.8.214

• RAM resin (0.23 mmol/g) by using an automated multiple peptide synthesizer (SYRO from MultiSynTech), as previously described [25]. In a standard coupling cycle, five equiv of Fmoc-amino acid/N,N’-diisopropylcarbodiimide/N-hydroxybenzotrialzole in DMF were coupled twice for 60 min, followed by a

Automated three-component synthesis of a library of γ-lactams

• Erik Fenster,
• David Hill,
• Oliver Reiser and
• Jeffrey Aubé

Beilstein J. Org. Chem. 2012, 8, 1804–1813, doi:10.3762/bjoc.8.206

• synthesis The combined sequence was next attempted as a rehearsal 2 × 3 × 3 validation library by using a Chemspeed Accelerator SLT-100 synthesizer (Table 3). In general, substrates which varied in their steric and electronic nature were chosen (alkyl and aryl groups). By using the three-step single-pot

• plates. All library syntheses using automated technology were performed by using a Chemspeed Accelerator SLT-100 Automated Synthesizer under an argon atmosphere in vacuum dried (50 °C, 9 mmHg) 13 mL reactor vessels. Parallel evaporations were performed by using a GeneVac EZ-2 plus evaporator. Automated

• using an automated synthesizer (Scheme 5) Using a Chemspeed Accelerator SLT-100 automated synthesizer with 64 individual 13 mL reactor vessels, 0.400 M solutions of the maleimides 1 in chloroform (1.00 mL, 0.400 mmol, 1.0 equiv) were added to the appropriate reactor vessels, and the reactors were cooled

Dimerization of a cell-penetrating peptide leads to enhanced cellular uptake and drug delivery

• Jan Hoyer,
• Ulrich Schatzschneider,
• Michaela Schulz-Siegmund and
• Ines Neundorf

Beilstein J. Org. Chem. 2012, 8, 1788–1797, doi:10.3762/bjoc.8.204

• . Peptide synthesis The peptides used were synthesized as described previously [30] by automated solid-phase peptide synthesis (SPPS) on a multiple Syro II peptide synthesizer (MultiSynTech, Witten, Germany) following Fmoc/t-Bu-strategy utilizing a double-coupling procedure and in situ activation with Oxyma

Antifreeze glycopeptide diastereomers

• Lilly Nagel,
• Carsten Budke,
• Axel Dreyer,
• Thomas Koop and
• Norbert Sewald

Beilstein J. Org. Chem. 2012, 8, 1657–1667, doi:10.3762/bjoc.8.190

• purchased from Iris Biotech (Marktredwitz, Germany), Orpegen (Heidelberg, Germany) and Molekula (Gillingham, Dorset, UK). Peptide synthesis was executed on a Liberty Automated Microwave Peptide Synthesizer (CEM, Kamp-Lintfort, Germany). For preparative RP-HPLC a Thermo Separation Products system equipped

• vessel of the peptide synthesizer. Subsequently, HOAt (0.25 mmol, 2.25 equiv) dissolved in DMF (1 mL) and DIPEA (0.28 mmol, 2.75 equiv) were transferred manually. Unreacted amino groups were capped by an acetylation reaction after coupling of the glycosylated building block using acetic anhydride (0.5

Automated synthesis of sialylated oligosaccharides

• Davide Esposito,
• Mattan Hurevich,
• Bastien Castagner,
• Cheng-Chung Wang and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2012, 8, 1601–1609, doi:10.3762/bjoc.8.183

• diverse set of glycans rapidly and efficiently. The automated synthesizer proved capable of performing iterative glycosylation–deprotection cycles under conditions commonly employed for solution-phase oligosaccharide synthesis. The synthetic strategy relies on the solid support-bound linker 17 (Scheme 3

• accessible starting materials. In combination with a fully automated synthesizer, the disaccharide building blocks have been exploited for the solid-phase synthesis of several oligosaccharides ready for biological evaluation. This work represents the first full account of an automated solid-phase synthesis

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

• (Trt)R(Pbf)R(Pbf)MK(Boc)W(Boc) K(Boc)K(Boc)-OH (8). The fully protected penetratin 8 was synthesized on H-Lys(Boc)-2-ClTrt resin (0.61 mmol/g, 163.9 mg, 0.100 mmol, 1.00 equiv) using a Liberty peptide synthesizer (CEM, Kamp-Lintfort, Germany) equipped with a Discover microwave reaction cavity (CEM

• (39.4 mg, 36.0 μmol, 1.00 equiv) was dissolved in a solution of 20% piperidine in DMF (500 μL) and stirred for 3 min at 50 °C (25 W) by using a manual discover SPS ultrasound peptide synthesizer. Afterwards, the crude peptide was precipitated with ice-cold MTBE (1 × 15 mL) and the title compound was

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

• molecules (Figure 2). To begin, an 8 × 16 library (coumarin C1–8 × amine A1–16) of aminomethylcoumarins was devised for preparation by using a Chemspeed SLT100 automated synthesizer. For automated synthesis, the procedure and workflow was modified somewhat for optimal yield. Specifically, the loading of Pd

• coumarin (C) coupling partners. Results for the synthesis of a 128-member library of aminated coumarins by using the Chemspeed SLT100 automated synthesizer. Purified by an automated preparative reverse-phase HPLC (Waters 2767 Mass Directed Fractionation) detected by UV (270 nm). Purity was determined by

Diarylethene-modified nucleotides for switching optical properties in DNA

• Sebastian Barrois and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103

• . MS–FAB m/z (%): 883.4 (25) [M + Na]+; HRMS–ESI (m/z): [M + H]+ calcd for C45H41N4O10S2, 861.2264; found, 861.2282. DNA synthesis: Oligonucleotides were prepared with an Expedite 8909 Synthesizer from ABI by using standard phosphoramidite chemistry. Reagents and CPGs were purchased from ABi and Glen

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

• 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

• solid-phase synthesis (0.05 mM scale) using a SyroXP-I peptide synthesizer (MultiSyn Tech GmbH, Witten, Germany) and HOBT/TBTU activation. Manual coupling of β- and γ-amino acids was carried out by HOAT/DIC activation. The molar excess of amino acid and coupling reagents was reduced for β- and γ