Design and synthesis of multivalent neoglycoconjugates by click conjugations

• Feiqing Ding,
• Li Ji,
• Ronny William,
• Hua Chai and
• Xue-Wei Liu

Beilstein J. Org. Chem. 2014, 10, 1325–1332, doi:10.3762/bjoc.10.134

• ][27][28][29][30][31]. The α-GalNAc-linked glycopeptides, α-N-glycosidically linked to the polypeptide chain through the amido nitrogen of an asparagine residue at the N-terminal [32], were found to be the most important semi-synthetic glycoconjugates, usually modified from their naturally occurring

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

• ]. The principle of peptide synthesis in homogenous solution is based on the reversible blocking of the carboxylic acid function of the C-terminal amino acid and the amino group of the N-terminal amino acid. In addition, activation of the free carboxy group of the N-terminal amino acid is necessary to

• coupling step, whereas the side-chain protecting groups and the resin ensure a permanent protection against unwanted side reactions [20]. Moreover, the relatively inert carboxy group has to be activated by a special auxiliary to increase the electrophilicity [23]. After loading of the resin, the N-terminal

• protecting group of the first amino acid can be removed and the next activated building block can be coupled. These alternating steps of Nα-deprotection, activation and coupling are repeated until the desired peptide chain is obtained. Following, the Nα-protecting group of the N-terminal amino acid has to be

Amino acid motifs in natural products: synthesis of O-acylated derivatives of (2S,3S)-3-hydroxyleucine

• Oliver Ries,
• Martin Büschleb,
• Markus Granitzka,
• Dietmar Stalke and
• Christian Ducho

Beilstein J. Org. Chem. 2014, 10, 1135–1142, doi:10.3762/bjoc.10.113

• . Within the context of our work regarding the total synthesis of muraymycin nucleoside antibiotics, we have developed a synthetic approach towards (2S,3S)-3-hydroxyleucine building blocks. Application of different protecting group patterns led to building blocks suitable for C- or N-terminal

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

• nucleophile preferentially attacks from the re-face as shown in TS 1 (Figure 4) to give 10b [48][55]. In the next step, ester saponification of 10a using lithium hydroxide afforded D-glucose derived β-amino acid 11a in 84% yield. Finally, N-terminal fluorenylmethoxycarbonyl (Fmoc) protection of the β-amino

Polyglycerol-functionalized nanodiamond as a platform for gene delivery: Derivatization, characterization, and hybridization with DNA

• Li Zhao,
• Yuki Nakae,
• Hongmei Qin,
• Tadamasa Ito,
• Takahide Kimura,
• Hideto Kojima,
• Lawrence Chan and
• Naoki Komatsu

Beilstein J. Org. Chem. 2014, 10, 707–713, doi:10.3762/bjoc.10.64

• Diamond Co., Ltd. (Lot. No. 66093). Glycidol was purchased from Kanto Chemical Co., Ltd. p-Toluenesulfonyl chloride and sodium azide were purchased from Nacalai Tesque, Co. Basic polypeptides binding propargyl glycine (G*) at an N terminal (G*BPP) were obtained from two sources; G*Lys8 and G*His8 were

Synthesis of (2S,3R)-3-amino-2-hydroxydecanoic acid and its enantiomer: a non-proteinogenic amino acid segment of the linear pentapeptide microginin

• Rajendra S. Rohokale and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2014, 10, 667–671, doi:10.3762/bjoc.10.59

• -hydroxy-β-aminodecanoic acid (AHDA, 2a) and its enantiomer 2b. The enantiomer of 2a is the N-terminal part of the natural linear pentapeptide microginin, which is used as an antihypertensive agent. Keywords: AHDA; carbohydrate; chiron approach; enantioselective; natural products; non-proteinogenic amino

• activity against angiotensin converting enzyme, which is responsible for the vasoconstriction of blood vessels [2][3][4]. Amongst different amino acids present in microginin, (2S,3R)-AHDA (2a) is a non-proteinogenic natural amino acid attached at the N-terminal part of the peptide chain. The α-hydroxy-β

Conformation of dehydropentapeptides containing four achiral amino acid residues – controlling the role of L-valine

• Michał Jewgiński,
• Joanna Krzciuk-Gula,
• Maciej Makowski,
• Rafał Latajka and
• Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 660–666, doi:10.3762/bjoc.10.58

• type II, which is localized on the N-terminal part of the peptide. The values of the dihedral angles indicate that peptide 1 could display two types of a bent conformation in DMSO solution with an opposite orientation of turns (see Figure 2). As in the case of the peptide 1, our analysis of the

• torsion angles of the main chain of the obtained conformational cluster indicates that peptide 3 exhibits a right-handed helix [28]. Only such a bent structure with a flexible N-terminal part could explain the strong NOE signals between the methyl residue of the Boc group and the side chain of both the

• increase in solvent polarity promotes more ordered conformations of hexapeptides containing two dehydrophenylalanine residues [38]. On the other hand, Inai and co-workers showed that in the case of dehydropeptides containing only one chiral L-residue in the N-terminal position of the peptide a left-handed

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

• an identical ester section composed of dolaproine and (2S)-3-phenylpropan-1,2-diol. On the N-terminal side, the isopropyl and two sec-butyl side chains of isodolastatin H (2) are replaced by one sec-butyl and two isopropyl side chains, respectively, in the case of malevamide D (1). The total

• possible. The occurrence of conformers has been mentioned by Scheuer and co-workers and is also known for dolastatin 10 [12] and symplostatin 1 [13]. As an alternative route to the N-terminal tripeptide 11, we also investigated the coupling of the N-terminal dipeptide 15 with MMMAH tert-butyl ester (16

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

New tridecapeptides of the theonellapeptolide family from the Indonesian sponge Theonella swinhoei

• Annamaria Sinisi,
• Barbara Calcinai,
• Carlo Cerrano,
• Henny A. Dien,
• Angela Zampella,
• Claudio D’Amore,
• Barbara Renga,
• Stefano Fiorucci and
• Orazio Taglialatela-Scafati

Beilstein J. Org. Chem. 2013, 9, 1643–1651, doi:10.3762/bjoc.9.188

• inferring the configurations of the two isoleucine residues. Similarly, it appeared reasonable to assume that, as in the co-occurring theonellapeptolide Id (and in all the theonellapeptolide found to date), the L-Val could be the N-terminal amino acid and thus, the D-Val should be the amino acid at

Recent progress in the discovery of small molecules for the treatment of amyotrophic lateral sclerosis (ALS)

• Allison S. Limpert,
• Margrith E. Mattmann and
• Nicholas D. P. Cosford

Beilstein J. Org. Chem. 2013, 9, 717–732, doi:10.3762/bjoc.9.82

• induce cellular stress through mitochondrial inhibition led to the formation of TDP-43 aggregates in the cytoplasm. The formation of TDP-43-containing cellular inclusions was dependent on the activation of stress-induced kinases such as c-Jun N-terminal kinase (JNK). Treatment of cells with bis

Synthesis and evaluation of cell-permeable biotinylated PU-H71 derivatives as tumor Hsp90 probes

• Tony Taldone,
• Anna Rodina,
• Erica M. DaGama Gomes,
• Matthew Riolo,
• Hardik J. Patel,
• Raul Alonso-Sabadell,
• Danuta Zatorska,
• Maulik R. Patel,
• Sarah Kishinevsky and
• Gabriela Chiosis

Beilstein J. Org. Chem. 2013, 9, 544–556, doi:10.3762/bjoc.9.60

• clinical trials, has been the ATP-competitive inhibitors that bind to the N-terminal nucleotide binding pocket [4][5]. Hsp90 belongs to the family of GHKL (G = DNA gyrase subunit B; H = Hsp90; K = histidine kinases; L = MutL) ATPases, which is distinguished by a unique bent shape of its nucleotide binding

• interest is the purine scaffold, including its representative PU-H71 (1a). This agent, currently in clinical investigation for cancer, binds to the N-terminal nucleotide binding pocket of Hsp90 [12]. We have shown that PU-H71 selects for tumor Hsp90 species, and therefore labeled derivatives of PU-H71 may

Thioester derivatives of the natural product psammaplin A as potent histone deacetylase inhibitors

• Matthias G. J. Baud,
• Thomas Leiser,
• Vanessa Petrucci,
• Mekala Gunaratnam,
• Stephen Neidle,
• Franz-Josef Meyer-Almes and
• Matthew J. Fuchter

Beilstein J. Org. Chem. 2013, 9, 81–88, doi:10.3762/bjoc.9.11

• epigenetic modifications, their biological outcomes, and how their misregulation is involved in diseases such as cancer [1][2]. The dynamic post-translational acetylation/deacetylation of histone proteins is one of the most commonly studied epigenetic events, and occurs at specific lysine residues on the N

• -terminal histone tails, which project out from the nucleosome (the fundamental repeating unit of chromatin). Acetylation/deacetylation of such lysine residues is achieved by the action of histone acetyltransferases (HATs) and histone deacetylases (HDACs), respectively. Histone deacetylation by HDACs causes

Asymmetric synthesis of γ-chloro-α,β-diamino- and β,γ-aziridino-α-aminoacylpyrrolidines and -piperidines via stereoselective Mannich-type additions of N-(diphenylmethylene)glycinamides across α-chloro-N-sulfinylimines

• Gert Callebaut,
• Sven Mangelinckx,
• Pieter Van der Veken,
• Karl W. Törnroos,
• Koen Augustyns and
• Norbert De Kimpe

Beilstein J. Org. Chem. 2012, 8, 2124–2131, doi:10.3762/bjoc.8.239

• specifically cleave off N-terminal dipeptides and are involved in the degradation of incretin hormones, including glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). GLP-1 is involved in the regulation of glucose homeostasis through stimulation of insulin secretion

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

• synthesis of the N-terminal dipeptide 3, amino acid 9 was coupled with benzyl glycinate in the presence of ethyl chloroformate to give 10 in 88% yield. This intermediate was hydrogenated to afford the dipeptide acid 3 quantitatively. An alternative multicomponent approach to dipeptide 3 requires the use of

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

• dimethylformamide. After cleavage of the N-terminal Fmoc group, the peptide was removed from the resin under simultaneous cleavage of the amino-side-chain protecting groups by incubation for 3 h in a mixture of trifluoroacetic acid (TFA) (12 mL), ethanedithiol (0.6 mL), anisole (0.3 mL), water (0.3 mL), and

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

• compensation for the loss of R59 by R58. Finally, we probed the stereoselectivity of the peptide–gp120 interaction by replacing F43 in CD4-M5 by D-phenylalanine (CD4-M7). All peptides were equipped with an N-terminal hexahistidine tag for directed attachment to Ni-NTA assay plates. The tag, as well as the

• capping step using a mixture of acetic anhydride/pyridine/DMF (1:2:3; 30 min). The Fmoc group was removed by using 20% piperidine/DMF (20 min). After completing the sequence, the N-terminal amino group was acetylated. Peptides were cleaved from the resin by using Reagent K (TFA/water/phenol/thioanisole

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

• introduction of N-terminal modifications. To test the hypothesis of improved internalization behavior of the dimer, we conducted flow-cytometric cellular uptake studies with sC18 versus (sC18)2 in various cell lines after N-terminal labeling with carboxyfluorescein (labeling of the dimer occurred at the N

• /DIC. Synthesis of branched (sC18)2 was achieved by N-terminal coupling of Dde-Lys(Fmoc)-OH to sC18(5-16) and subsequent automated elongation of the peptide chain at the lysine side chain by using Nα-Boc protected glycine at the terminal position. Cleavage of the Dde group was achieved by treatment

• with a 3% solution of hydrazine in DMF for 12 × 10 min. Subsequently, the peptide was elongated to its final length by automated SPPS. N-terminal coupling of Cym2 or 5(6)-carboxyfluorescein was carried out by using 2 equiv of the substance to be coupled and activation with 2 equiv of HATU/DIPEA in DMF

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

• of small synthetic arginine and tryptophan containing peptides was prepared and analyzed for their antibacterial activity. The effect of N-terminal substitution with metallocenoyl groups such as ferrocene (FcCO) and ruthenocene (RcCO) was investigated. Antibacterial activity in different media

• , growth inhibition, and killing kinetics of the most active peptides were determined. The toxicity of selected derivatives was determined against erythrocytes and three human cancer cell lines. It was shown that the replacement of an N-terminal arginine residue with a metallocenoyl moiety modulates the

• of the N-terminal arginine residue in non-toxic and non-hemolytic (RW)3 peptides can modulate the kinetics of the peptide’s antibacterial activity. Acetylation completely suppresses this activity. In comparison, replacement of the N-terminal arginine residue with the organometallic ferrocenoyl moiety

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

• N-terminal amino group at the activated carbonyl group provided cleavage of the cyclized β-tripeptide from the resin. Purification did not require any chromatography since organization by intermolecular hydrogen bonding resulted in decreased solubility and precipitation of the β-tripeptide template

• (N3)-β3-HLys(Cbz)) (4). The peptide sequence H-β3-HLys(Fmoc)-β3-HLys(N3)-β3-HLys(Cbz)-OH was synthesized on 4-Fmoc-hydrazinobenzoyl AM NovaGel resin (0.700 mmol/g, 1.00 g, 7.00 mmol, 1.00 equiv). After N-terminal Fmoc deprotection (20% piperidine in DMF, 3.50 mL, 20 min), standard Boc protocols were

• used for coupling (β-amino acid 5.00 equiv, HBTU 4.50 equiv, HOBt 5.00 equiv, DIEA 10.0 equiv, 2.80 mL DMF, 18 h) and Boc cleavage (3.00 mL TFA/m-cresole–95/5 v/v, 2 × 2 min) of β-amino acids Boc-β3-HLys(Fmoc)-OH, Boc-β3-HLys(Cbz)-OH and Boc-β3-HLys(N3)-OH. After N-terminal deprotection of the last

A macrolactonization approach to the total synthesis of the antimicrobial cyclic depsipeptide LI-F04a and diastereoisomeric analogues

• James R. Cochrane,
• Dong Hee Yoon,
• Christopher S. P. McErlean and
• Katrina A. Jolliffe

Beilstein J. Org. Chem. 2012, 8, 1344–1351, doi:10.3762/bjoc.8.154

• the synthesis of 2 by a macrolactonization approach is 4 (Scheme 1), in which the N-terminal amino group of the L-Thr residue is protected while the side-chain hydroxy group is free. The Cbz group was chosen as a suitable protecting group for the N-terminus. The D-Asn and D-allo-Thr residues were the

Design of a novel tryptophan-rich membrane-active antimicrobial peptide from the membrane-proximal region of the HIV glycoprotein, gp41

• Evan F. Haney,
• Leonard T. Nguyen,
• David J. Schibli and
• Hans J. Vogel

Beilstein J. Org. Chem. 2012, 8, 1172–1184, doi:10.3762/bjoc.8.130

• peptide with a backbone root-mean-square deviation (RMSD) of 0.630 Å (Figure 7). It appears that the structure is slightly bent, especially in the N-terminal region, which lies well below the plane of the helix formed by residues 7–19. The side-chain distribution of gp41w-4R in the cosolvent solution

• backbone RMSD of 0.389 Å (Figure 7). In agreement with the structure of gp41w-4R, the N-terminal region of gp41w-KA is not aligned with the C-terminal helix formed across residues 7–19 and these first six residues appear to form a slightly extended conformation. This may be an important structural feature

• this model, the N-terminal region of gp41w-KA would then be oriented into the bilayer, which would bring the Lys residues at positions 1, 4 and 5 into the hydrophobic core of the bilayer. This may be related to the membrane-destabilizing properties of the gp41w-KA peptide. The gp41w-FKA peptide has a

Building photoswitchable 3,4'-AMPB peptides: Probing chemical ligation methods with reducible azobenzene thioesters

• Gehad Zeyat and
• Karola Rück-Braun

Beilstein J. Org. Chem. 2012, 8, 890–896, doi:10.3762/bjoc.8.101

• -terminal thioester peptide and either an N-terminal cysteine peptide or Nα-auxiliary-capped peptides. However, for elucidating the complex redox chemistry of the two azobenzene building blocks under the reducing conditions of ligation methods, we solely applied the Boc-protected azobenzene ω-amino acid

• chromatography are summarized in Table 1. In ligation reactions employing the N-terminal Cys-peptide 3, nearly complete conversion was determined after five hours, but stirring was nevertheless continued overnight (Table 1, entries 1 and 4). For peptide 5 containing the 4,5,6-trimethoxy-2-mercaptobenzyl

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

• synthetic glycoproteins. Since the discovery of native chemical ligation (NCL) by Kent and co-workers, numerous efforts have been made to prepare challenging protein targets [39][40][41][42][43][44]. In the NCL method, a native amide bond is formed by coupling of a C-terminal thioester with the N-terminal

• expressed protein fragment 40–124 (18) containing a N-terminal cysteine, employing thiophenol and tris(2-carboxyethyl)phosphine (TCEP). The obtained RNase fragment 26–124 (19) was then treated with N-methoxyamine (0.2 M, pH 3–4, 4 h) to remove the protecting group on the N-terminal cysteine. Ligation of the

• fragment, (β-FSH 28–111) was obtained by ligation of two shorter synthetically prepared peptides followed by sequential coupling of two N-terminal glycopeptide fragments (β-FSH 1–19 and 20–27) employing standard NCL conditions. Binding of the hFSH glycoprotein to its receptor stimulates the maturation of

Natural product biosyntheses in cyanobacteria: A treasure trove of unique enzymes

• Jan-Christoph Kehr,
• Douglas Gatte Picchi and
• Elke Dittmann

Beilstein J. Org. Chem. 2011, 7, 1622–1635, doi:10.3762/bjoc.7.191

• through imino bond formation between the N-terminal and C-terminal amino acids. The responsible enzyme NcpB contains a C-terminal reductase domain that has been shown to catalyze the reductive release of the peptide from the synthetase as an aldehyde followed by spontaneous formation of the imino head-to

• /MvdD) and one ω-amide linkage between lysine and aspartate (MdnB/MvdC) (Figure 10) [64][65]. Microviridins can be heterologously produced in E. coli [65]. Cyclizations occur in a strictly defined order. Ring size and composition of the microviridin core peptide is invariant [66], whereas N-terminal and