Photoswitchable precision glycooligomers and their lectin binding

• Daniela Ponader,
• Sinaida Igde,
• Marko Wehle,
• Katharina Märker,
• Mark Santer,
• David Bléger and
• Laura Hartmann

Beilstein J. Org. Chem. 2014, 10, 1603–1612, doi:10.3762/bjoc.10.166

• building blocks contain a free carboxy- and an Fmoc-protected amino group and thus can be coupled via standard peptide coupling protocols giving a polyamide backbone. Additionally, dimer building blocks can carry functional groups as side groups or in the main chain, thereby allowing for the conjugation of

• ]. Five glycooligomers were synthesized – three photoswitchable glycooligomers containing the AZO building-block and two non-switchable control structures containing EDS instead of AZO (Table 1). The synthesis proceeded following standard peptide coupling protocols followed by introduction of the sugar

Molecular recognition of surface-immobilized carbohydrates by a synthetic lectin

• Melanie Rauschenberg,
• Eva-Corrina Fritz,
• Christian Schulz,
• Tobias Kaufmann and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2014, 10, 1354–1364, doi:10.3762/bjoc.10.138

• function was introduced on the terminus of the spacer in order to ensure reaction with the epoxide-functionalized substrate upon µCP. The NANA ink was prepared by solution phase peptide coupling using the DIPCDI/Oxyma pure® coupling protocol. The glucose (Glc), galactose (Gal) and mannose (Man) inks were

• functionalization of the polycarboxylate hydrogel with amine terminated NANA was performed by N-hydroxysuccinimide (NHS) activation and subsequent peptide coupling. Indeed, using the hydrogel sensor a small but significant SPR signal increase was observed upon the addition of HisHis (see Figure S5 in Supporting

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

• phosphorazidate (DPPA) and diethyl phosphorocyanidate (DEPC) are widely employed as peptide coupling reagents [59][60][61][62]. DPPA was also used in many organic reactions such as the Curtius rearrangement [59], the thiol ester synthesis [63], the azidation of alcohol and phenol [64], and the synthesis of

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• a subsequent Ugi 3-CR/oxidation protocoll to provide the final compound in a much shorter and more straightforward route compared to earlier described syntheses (11 vs. 24 steps). The bicyclic imine 57 was obtained via the MAO-N desymmetrizaton described above, whereas a peptide-coupling between L

Total synthesis and cytotoxicity of the marine natural product malevamide D and a photoreactive analog

• Werner Telle,
• Gerhard Kelter,
• Heinz-Herbert Fiebig,
• Peter G. Jones and
• Thomas Lindel

Beilstein J. Org. Chem. 2014, 10, 316–322, doi:10.3762/bjoc.10.29

• Analytical Chemistry, TU Braunschweig, Hagenring 30, 38106 Braunschweig, Germany 10.3762/bjoc.10.29 Abstract The marine natural product malevamide D from the cyanobacterium Symploca hydnoides was synthesized for the first time. The final peptide coupling linked the dolaisoleuine and dolaproine subunits. The

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

Asymmetric synthesis of host-directed inhibitors of myxoviruses

• Terry W. Moore,
• Kasinath Sana,
• Dan Yan,
• Pahk Thepchatri,
• John M. Ndungu,
• Manohar T. Saindane,
• Mark A. Lockwood,
• Michael G. Natchus,
• Dennis C. Liotta,
• Richard K. Plemper,
• James P. Snyder and
• Aiming Sun

Beilstein J. Org. Chem. 2013, 9, 197–203, doi:10.3762/bjoc.9.23

• known to limit racemization in peptide coupling reactions [16]. The enantiomeric excesses of the starting materials were ca. 95%. No erosion of stereochemistry in the products 12 was observed as determined by chiral HPLC. Recrystallization of 12 from ethanol did not increase the enantiomeric excess of

S-Fluorenylmethyl protection of the cysteine side chain upon N^α-Fmoc deprotection

• Johannes W. Wehner and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2012, 8, 2149–2155, doi:10.3762/bjoc.8.242

• described in this account together with a survey of the synthetic approaches to obtain 3 and 3-dimer. Results and Discussion Synthesis of 3-dimer was started from the known N,S-protected glycoamino acid derivative 1 [2], which can be obtained by peptide coupling of 2-aminoethyl α-D-mannopyranoside [11] and

The multicomponent approach to N-methyl peptides: total synthesis of antibacterial (–)-viridic acid and analogues

• Ricardo A. W. Neves Filho,
• Sebastian Stark,
• Bernhard Westermann and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2012, 8, 2085–2090, doi:10.3762/bjoc.8.234

• -University Halle-Wittenberg, Institute of Organic Chemistry, Kurt-Mothes-Str. 2, 06120 Halle (Saale), Germany 10.3762/bjoc.8.234 Abstract Two syntheses of natural viridic acid, an unusual triply N-methylated peptide with two anthranilate units, are presented. The first one is based on peptide-coupling

• readily available to provide first SAR insight. The biological activities of the natural product and its derivatives against the Gram-negative bacterium Aliivibrio fischeri were evaluated. Keywords: antibiotic; anticancer; Gram negative bacteria; natural product; peptide coupling; peptides; peptoid

• quantities and derivatives of viridic acid (1), required the development of a more efficient and milder approach. In this endeavor we envisioned two routes. The first one uses improved peptide-coupling protocols, leading to the natural enantiomer (Scheme 1) [11]. The blueprint of the synthesis was planned as

Synthetic studies towards bottromycin

• Stefanie Ackermann,
• Hans-Georg Lerchen,
• Dieter Häbich,
• Angelika Ullrich and
• Uli Kazmaier

Beilstein J. Org. Chem. 2012, 8, 1652–1656, doi:10.3762/bjoc.8.189

• we could even subsequently connect the side chain. Therefore, we prolonged the peptide chain 2 under standard peptide coupling conditions and tried to activate the linear peptide chain. We chose the pentafluorophenylester protocol developed by Schmidt et al. for cyclization [42]. But unfortunately

• subjected to a thio-Ugi reaction as described before, and the expected sterically highly demanding endothiopeptide 8 was obtained in high yield as a 1:1 diastereomeric mixture. In this case, the diastereomers could not be separated. Elongation of the peptide chain under standard peptide coupling conditions

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

• -bromobutyrate to give 2 in 72% yield [47]. Acid-catalyzed deprotection of 2 afforded carboxylic acid 3 in 85% yield [48]. The coupling of 3 with the mono-heptanamide of 2,7-diamino-1,8-naphthyridine (DAN 4) was effected by using a standard peptide-coupling method. Thus, 1-(3-dimethylaminopropyl)-3

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• the new 5-aminopyrazole acid ester 140. Reaction of 140 with the acid chloride of (9-fluoroenylmethyl)carbamate(Fmoc)-protected glycine led to peptide coupling and subsequent Fmoc deprotection with piperidine gave 141. A second coupling step can also be performed with Fmoc-protected glycine acid

En route to photoaffinity labeling of the bacterial lectin FimH

• Thisbe K. Lindhorst,
• Michaela Märten,
• Andreas Fuchs and
• Stefan D. Knight

Beilstein J. Org. Chem. 2010, 6, 810–822, doi:10.3762/bjoc.6.91

• scaffold molecule in two different ways in order to allow fine-tuning of the spacing between the mannoside ligand and the photoactive group. Thus, the amino acid derivatives Fmoc-Asp-OtBu and Fmoc-Asp(OtBu)-OH were employed in two analogous synthetic pathways, starting with peptide coupling to the known 2

• two steps gave the Fmoc-protected biotin-labeled glycoamino acids 9 and 10, respectively. Fmoc-cleavage and peptide coupling with the diazirine 11 led to the target molecules 12 and 13 in good yield. To test the prepared photoactive mannosides in crosslinking reactions, the model peptide angiotensin

A bivalent glycopeptide to target two putative carbohydrate binding sites on FimH

• Thisbe K. Lindhorst,
• Kathrin Bruegge,
• Andreas Fuchs and
• Oliver Sperling

Beilstein J. Org. Chem. 2010, 6, 801–809, doi:10.3762/bjoc.6.90

• molecules (3) and squaric acid diethyl ester (4, DES). The synthetic assembly relies on peptide coupling chemistry and the squaric acid diester to link two different amines in two subsequent steps. Results and Discussion Synthesis of the eastern part of target molecule 1 started from the known azidoethyl

• mannoside 5, which can be prepared from mannose pentaacetate in three simple steps [26]. Catalytic hydrogenation led to the amine 6 [27], which was subjected to peptide coupling with N-Boc-protected pentaglycine (Gly5Boc) under standard reaction conditions (Scheme 1). This led to the N-Boc-protected

•  2) [28][29]. Glycosylation of the acceptor diol 11 with the trichloroacetimidate 12 [30] led to mannotrioside 13 with the required azidoethyl aglycone. Reduction of the azido group gave amine 15 and subsequent peptide coupling reaction with Gly5Boc with inexpensive coupling reagents led to the

(Pseudo)amide-linked oligosaccharide mimetics: molecular recognition and supramolecular properties

• José L. Jiménez Blanco,
• Fernando Ortega-Caballero,
• Carmen Ortiz Mellet and
• José M. García Fernández

Beilstein J. Org. Chem. 2010, 6, No. 20, doi:10.3762/bjoc.6.20

• constrained building blocks for the formation of peptide and oligosaccharide mimetics using standard peptide coupling techniques in solution or in the solid phase. Exploitation of the rigidity and diversity of the sugar backbone should permit subtle modifications and the rational design of oligomeric

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides

• Ana Maria Castilla,
• M. Morgan Conn and
• Pablo Ballester

Beilstein J. Org. Chem. 2010, 6, No. 5, doi:10.3762/bjoc.6.5

• . Receptor 2 is anticipated to form an antiparallel sheet structure with the included peptide ligand. This change in connectivity does not involve any inversion of the stereogenic centers but only a modification in the sequence of peptide-coupling reactions that yield the cyclic structure, and will be

• differentiable functionality in a small molecule like 3. The sequential peptide coupling of two units of 4,4’-bis(alanyl)benzophenones 3a should lead to the construction of the designed macrocyclic bis-dipeptide receptor 1. Benzophenone 3a was converted into the carboxylic acid 8 by treatment with

• of SnCl2 and phenol in acid media and the Fmoc [30] in 3c using piperidine to obtain 10 and 11, respectively (Scheme 2). Next, we carried out intermolecular peptide-coupling reactions between 8 and 9, as well as between 10 and 11 to obtain the linear tetrapeptides 12 and 13, direct precursors of

Synthesis of rigidified flavin–guanidinium ion conjugates and investigation of their photocatalytic properties

• Harald Schmaderer,
• Mouchumi Bhuyan and
• Burkhard König

Beilstein J. Org. Chem. 2009, 5, No. 26, doi:10.3762/bjoc.5.26

• carboxyl group with Boc-protected guanidine was achieved using standard peptide coupling conditions. Boc-deprotection with hydrogen chloride in diethyl ether yielded the guanidinium chloride salts 1 and 2 (Scheme 2). The guanidinium salts are soluble in water and methanol, but also in chloroform and

A practical synthesis of the ¹³C/¹⁵N- labelled tripeptide N-formyl- Met-Leu-Phe, useful as a reference in solid- state NMR spectroscopy

• Sven T. Breitung,
• Jakob J. Lopez,
• Gerd Dürner,
• Clemens Glaubitz,
• Michael W. Göbel and
• Marcel Suhartono

Beilstein J. Org. Chem. 2008, 4, No. 35, doi:10.3762/bjoc.4.35

• were carried out at room temperature, we were able to obtain the per-13C/15N-labelled formylated Met-Leu-Phe tripeptide as carboxylic acid in acceptable yields [32.8 mg (23%) after HPLC purification]. Due to the selected reagents, i.e. MSNT for the esterification, DIC/HOBt for the peptide coupling and