Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• should undergo a wide range of addition reactions. Ozonolysis, on the other hand, should generate a carbonyl functionality. Radical additions towards the double unsaturated side chain of the Cyl-1 derivative might also allow cyclizations. To get access to the desired double unsaturated cyclopeptide, we

• ozonide formed during the reaction [57]. Consequently, no PPh3 or Me2S was required to obtain the crude aldehyde. Subsequent addition of a Wittig ylide gave access to a cyclopeptide with an α,β-unsaturated ester side chain as a (E/Z) mixture. Unfortunately, this compound contained triphenylphosphine oxide

• as impurity, which could not be separated from the product. Subsequent hydrogenation proceeded readily and afforded the saturated cyclopeptide 13. However, the impurity could also not be removed on this stage. Apparently, the Cyl derivatives with a short side chain are not good candidates for further

Unsaturated fatty acids and a prenylated tryptophan derivative from a rare actinomycete of the genus Couchioplanes

• Shun Saito,
• Kanji Indo,
• Naoya Oku,
• Hisayuki Komaki,
• Masashi Kawasaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2939–2949, doi:10.3762/bjoc.17.203

• metabolites of Pseudosporangium sp. RD062863, a strain available at the culture collection of the Biological Resource Center, National Institute of Technology and Evaluation (NBRC) [20], and discovered a novel cyclopeptide pseudosporamide along with three new oligomycin-class polyketide [21]. In addition, the

Optical detection of di- and triphosphate anions with mixed monolayer-protected gold nanoparticles containing zinc(II)–dipicolylamine complexes

• Lena Reinke,
• Julia Bartl,
• Marcus Koch and
• Stefan Kubik

Beilstein J. Org. Chem. 2020, 16, 2687–2700, doi:10.3762/bjoc.16.219

• residues and cyclopeptides selectively precipitated from water in the presence of sulfate [18]. The anion sensing in this case relied on the sulfate affinity of the cyclopeptide and on the propensity of this receptor to bind a sulfate ion in the form of a sandwich-type 2:1 complexes, rendering the presence

• solution, potentially giving rise to highly selective receptors if the two binding sites are arranged at a distance that allows for binding a diphosphate, but not a larger triphosphate anion. The peptide and cyclopeptide-derived receptors introduced by Jolliffe are examples [26] along with a range of

• the cyclopeptide-derived ligand used in our previous work had also failed, and we therefore had to use a two-step immobilization procedure to obtain the respective mixed monolayer-protected AuNPs [18]. Here, we tested whether performing the immobilization at a lower pH value at which 2 was partially

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• and subjected to metabolite analysis, which resulted in the discovery of a novel cyclopeptide, pseudosporamide (1), along with three new oligomycin-class polyketides, pseudosporamicins A–C (2–4). The unusual structure of compound 1, featured by a biaryl-bond bridging across a tripeptide scaffold, N

An azobenzene container showing a definite folding – synthesis and structural investigation

• Abdulselam Adam,
• Saber Mehrparvar and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2019, 15, 1534–1544, doi:10.3762/bjoc.15.156

• for such rigid systems are macrocycles which stem from Lissoclinum cyclopeptide alkaloids (Figure 1) [2][3]. Here, the required recognition units can be introduced via the amino acid side chains or via the side chains of the azole rings. The orientation and the distance between the recognition units

• are determined by the type and size of the macrocyclic platform, e.g., if all of the amino acid side chains are of the same configuration, they are presented on one face of the macrocycle in a convergent manner. The artificial Lissoclinum cyclopeptide platforms feature C2, C3 and C4 symmetry [3]. So

• protective group, the resulting amino acid was cyclodimerized to the benzyl-protected macrocycle. The yield for the cyclization amounts to about 50%. The last step was the removal of the benzyl group by hydrogenolysis to yield the desired macrocycle 3a. The cyclopeptide 2a [52] is commercially available

Synthesis and photophysical studies of a multivalent photoreactive Ru^II-calix[4]arene complex bearing RGD-containing cyclopentapeptides

• Sofia Kajouj,
• Lionel Marcelis,
• Alice Mattiuzzi,
• Adrien Grassin,
• Damien Dufour,
• Pierre Van Antwerpen,
• Didier Boturyn,
• Eric Defrancq,
• Mathieu Surin,
• Julien De Winter,
• Pascal Gerbaux,
• Ivan Jabin and
• Cécile Moucheron

Beilstein J. Org. Chem. 2018, 14, 1758–1768, doi:10.3762/bjoc.14.150

• ), as these nanomaterials are known to catalyze efficiently a wide range of organic reactions and notably the azide–alkyne cycloaddition [79]. Calixarene 7 was reacted with a slight excess (5 equiv) of cyclopeptide 8 in the presence of CuNPs and the mixture was heated by microwave (100 W) at 50 °C for 1

Synthesis of the heterocyclic core of the D-series GE2270

• Christophe Berini,
• Thibaut Martin,
• Pierrik Lassalas,
• Francis Marsais,
• Christine Baudequin and
• Christophe Hoarau

Beilstein J. Org. Chem. 2017, 13, 1407–1412, doi:10.3762/bjoc.13.137

• organized into 32 families and 5 series [1][2][3][4][5][6][7][8][9]. The particularity of these molecules is the interruption of the modified cyclopeptide chain by a more complex nitrogen-containing heterocycle found at different oxidation states (from series a to e) and bearing many azole units. They

Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex

• Chompoonut Rungnim,
• Sarunya Phunpee,
• Manaschai Kunaseth,
• Supawadee Namuangruk,
• Kanin Rungsardthong,
• Thanyada Rungrotmongkol and
• Uracha Ruktanonchai

Beilstein J. Org. Chem. 2015, 11, 2306–2317, doi:10.3762/bjoc.11.251

• anion affinity and selectivity of a neutral anion receptor, bis(cyclopeptide) [17]. Molecular dynamics (MD) simulations can give important insights into the energetics of structural interactions. The hydrated structure of β-CD in aqueous solution [18] and those showing host–guest interactions between

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

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

• Abstract We describe the first one-pot orthogonal strategy to prepare well-defined cyclopeptide-based heteroglycoclusters (hGCs) from glycosyl thiols. Both thiol–chloroactetyl coupling (TCC) and thiol–ene coupling (TEC) have been used to decorate cyclopeptides regioselectively with diverse combination of

• ]. Herein we report a new strategy based on both thiol–chloroactetyl coupling (TCC) and thiol–ene coupling (TEC) to prepare hGCs from glycosyl thiols and cyclopeptide scaffolds displaying chloroacetyl (ClAc) and allyloxycarbonyl (Alloc) groups and vice versa. We demonstrate that cyclopeptides

• α-D-ManSH 1 and β-D-GlcNAcSH 2 were prepared from the corresponding bromo peracetyl and chloro peracetyl sugars by treatment with potassium thioacetate followed by de-O-acetylation under standard conditions [24]. Cyclopeptide 3 displaying two orthogonal functionalities, i.e., four lysine residues

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

• , stability to enzymatic degradation, and ability to form intermolecular stacked tubular structures. To validate the applicability of cyclic β-tripeptides within the TASP concept, an efficient synthesis of the cyclopeptide with orthogonal functionalization of the side chains is desired. A solid-phase

Synthesis of heteroglycoclusters by using orthogonal chemoselective ligations

• Baptiste Thomas,
• Michele Fiore,
• Isabelle Bossu,
• Pascal Dumy and
• Olivier Renaudet

Beilstein J. Org. Chem. 2012, 8, 421–427, doi:10.3762/bjoc.8.47

• : chemoselective ligation; click chemistry; cyclopeptide; heteroglycocluster; oxime; Introduction Multivalent interactions between carbohydrates and proteins play key roles in diverse biological events, including fertilization, cell–cell communication, host–pathogen interactions, immune response and cancer

• acids at randomized positions on a topological cyclopeptide scaffold [26]. Deconvolution of the resulting libraries by affinity chromatography allowed the selection of heteroglycoclusters that were proved to be useful for exploring the surrounding regions of the binding pocket in a model lectin

• tetravalent cyclopeptide sequence, whereas the second series (heteroglycocluster 3:1) contains one of a given sugar and three of another. Results and Discussion Glycoclusters are classically constructed from a molecular scaffold containing multiple anchoring sites that can be functionalized with sugars by

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

The first preparative solution phase synthesis of melanotan II

• Vladimir V. Ryakhovsky,
• Georgy A. Khachiyan,
• Nina F. Kosovova,
• Elena F. Isamiddinova and
• Andrey S. Ivanov

Beilstein J. Org. Chem. 2008, 4, No. 39, doi:10.3762/bjoc.4.39

• added. The mixture was stirred under a hydrogen atmosphere for 20 h at r.t., then 4 h at 50 °C, filtered, and evaporated to dryness under vacuum at 40 °C to produce cyclopeptide 13 (7.0 g) as bis-trifluoracetate salt. Yield 96%. Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 (2) The salt 13 (7.0 g, 6.38