Sugar-derived oxazolone pseudotetrapeptide as γ-turn inducer and anion-selective transporter

• Sachin S. Burade,
• Sushil V. Pawar,
• Tanmoy Saha,
• Navanath Kumbhar,
• Amol S. Kotmale,
• Manzoor Ahmad,
• Pinaki Talukdar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2019, 15, 2419–2427, doi:10.3762/bjoc.15.234

• different types of cyclic peptides as anion transporters. Gale, Luis, and co-workers [41] have separately reported the linear pseudopeptides as receptors and transporters of chloride and nitrate anions. Inspired by our recent ion transport studies with fluorinated acyclic and cyclic sugar derived peptides

• tetrapeptides 8 and 9 led to the formation of the oxazolone ring at the C-terminal giving pseudopeptides 1 and 2a, respectively. The pseudotetrapeptide 2a showed a γ-turn conformation that is stabilized by a seven-membered intramolecular hydrogen bonding. The pseudotetrapeptide 2a was found to facilitate

• presence and absence of valinomycin (1 µM) across EYPC-LUVslucigenin (D). Synthesis of linear azido ester dipeptide 5 and tetrapeptide 7. Synthesis of oxazolone pseudopeptides 1, 2a and 2b. Supporting Information Supporting Information File 200: Experimental procedures, 1H and 13C NMR data, HRMS and 2D

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• allylamine structure exists in numerous natural products [60]. Moreover, allylamines are widely used in the synthesis of compounds such as β-aminohydroxylamines, β- and γ-amino acids, pseudopeptides, spermidine derivatives or five- and six-membered heterocyclic systems [56]. 2.3.2. In situ generation of α,β

Recent progress in the racemic and enantioselective synthesis of monofluoroalkene-based dipeptide isosteres

• Myriam Drouin and
• Jean-François Paquin

Beilstein J. Org. Chem. 2017, 13, 2637–2658, doi:10.3762/bjoc.13.262

• ). Similar results as above were obtained in the sense that the activity of the s-trans peptide bond isostere was superior and that the fluorinated pseudopeptides were not more active than the natural peptide or the alkene-containing pseudopeptides (Figure 5) [55]. Fujii and co-workers also prepared, without

• isomerization or epimerization, cyclic pseudopeptides using Fmoc SPPS [48][50]. Biological studies were conducted on monofluoroalkene-containing analogues of FC131, which is a known antagonist of the chemokine receptor CXCR4. The latter has implications in cancer metastasis and HIV 1 infection. Anti-HIV 1

Synthesis of acylhydrazino-peptomers, a new class of peptidomimetics, by consecutive Ugi and hydrazino-Ugi reactions

• Angélica de Fátima S. Barreto,
• Veronica Alves dos Santos and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2016, 12, 2865–2872, doi:10.3762/bjoc.12.285

• -hydrazino acid moiety, e.g., the vitamin B6 antagonist linatine and the antibiotic negamycin (Figure 3). In the early 1970s, the first attempts to peptide modifications by hydrazino acids generated bioactive pseudopeptides [39]. Analogously to azapeptides, these compounds possess a conformational constraint

Synthesis of antibacterial 1,3-diyne-linked peptoids from an Ugi-4CR/Glaser coupling approach

• Martin C. N. Brauer,
• Ricardo A. W. Neves Filho,
• Bernhard Westermann,
• Ramona Heinke and
• Ludger A. Wessjohann

Beilstein J. Org. Chem. 2015, 11, 25–30, doi:10.3762/bjoc.11.4

• , this reaction has been used in the synthesis of bioactive peptides and pseudopeptides, e.g., tubulysin mimetics [13], julocrotine derivatives [14], architecturally complex peptoid macrocycles [15][16], building blocks for diversity-oriented synthesis [17], and heterocyclic compounds [18]. Complex

A peptidic hydrogel that may behave as a “Trojan Horse”

• Nicola Castellucci,
• Giorgio Sartor,
• Natalia Calonghi,
• Carola Parolin,
• Giuseppe Falini and
• Claudia Tomasini

Beilstein J. Org. Chem. 2013, 9, 417–424, doi:10.3762/bjoc.9.44

• stimuli, such as changes in pH, ionic strength and temperature [16][17][18]. Results and Discussion We have recently described the synthesis and the application of a small library of stereoisomeric compounds made of azelaic acid (a long chain dicarboxylic acid) coupled with different pseudopeptides, all

• containing the L-Phe-D-Oxd (Oxd = 4-carboxy-5-methyloxazolidin-2-one) moiety [19][20][21]. This skeleton is the minimal framework of a class of foldamers, having the ability to self-organize. We have also shown that stable LMWGs are formed by stoichiometric mixtures of pseudopeptides and metal ions. The

Synthesis of chiral sulfoximine-based thioureas and their application in asymmetric organocatalysis

• Marcus Frings,
• Isabelle Thomé and
• Carsten Bolm

Beilstein J. Org. Chem. 2012, 8, 1443–1451, doi:10.3762/bjoc.8.164

• functionalization at the adjacent nitrogen and carbon atoms which allows a great structural diversity of the sulfoximine motif. Hence, optically active compounds based on 2 have been utilized in the synthesis of pseudopeptides [20][21][22][23][24], and they have found widespread application in auxiliary-assisted

• using closely related synthetic protocols. In the syntheses of (SS,SC)-18 and (RS,SC)-19 we benefited from our expertise in preparing sulfoximine-based pseudopeptides [20][21]. Hence, the reaction of (S)-2 with N-Boc protected L-valine, N,N'-dicyclohexylcarbodiimide (DCC) and hydroxybenzotriazole (HOBt

Novel synthesis of pseudopeptides bearing a difluoromethyl group by Ugi reaction and desulfanylation

• Jingjing Wu,
• Hui Li and
• Song Cao

Beilstein J. Org. Chem. 2011, 7, 1070–1074, doi:10.3762/bjoc.7.123

• Jingjing Wu Hui Li Song Cao Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China 10.3762/bjoc.7.123 Abstract Thirteen difluoromethyl-containing pseudopeptides were synthesized by Ugi reaction using the novel

• building block 2,2-difluoro-2-(phenylthio)acetic acid (2) as one component, followed by removal of the phenylsulfanyl protecting group in the presence of tributyltin hydride and azobisisobutyronitrile. Keywords: difluoromethyl functionality; gem-difluoromethylene-containing acid; pseudopeptides; reductive

• cleavage; Ugi reaction; Introduction Fluorinated amino acids and pseudopeptides have increasingly attracted attention in recent years [1][2][3][4][5]. The selective incorporation of fluorine-containing groups, such as trifluoromethyl, difluoromethyl and difluoromethylene, into peptides or peptidomimetics

The C–F bond as a conformational tool in organic and biological chemistry

• Luke Hunter

Beilstein J. Org. Chem. 2010, 6, No. 38, doi:10.3762/bjoc.6.38

• , governed by the conformational rules known to operate in multi-vicinal fluoroalkanes in addition to the α-fluoroamide effect and the fluorine-amide gauche effect. Progress has been made towards this goal with the synthesis of pseudopeptides containing a difluorosuccinate core (69 and 70, Figure 19) [58][59

• ]. In each of pseudopeptides 69 and 70, the two fluorine atoms align antiparallel to the adjacent C=O bonds and gauche to one another, leading to different backbone conformations in the two diastereoisomers. Building upon these promising results, a logical next step is to pursue the synthesis of non

• -symmetrical amino acids containing two or more vicinal fluorine atoms. Such fluorinated amino acids could be useful building blocks for the synthesis of shape-controlled bioactive pseudopeptides. Studies towards this goal are underway in the author’s laboratory, and details of these investigations will be

The use of chiral lithium amides in the desymmetrisation of N-trialkylsilyl dimethyl sulfoximines

• Matthew J. McGrath and
• Carsten Bolm

Beilstein J. Org. Chem. 2007, 3, No. 33, doi:10.1186/1860-5397-3-33

• dimethyl sulfoximines is possible. Introduction The preparation of enantioenriched sulfoximines is an important goal in synthesis as these S-chiral compounds make interesting ligands for asymmetric catalysis and have been used in the construction of pseudopeptides. [1][2][3][4] Enantiomerically enriched