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Search for "antibiotics" in Full Text gives 215 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.

A novel and widespread class of ketosynthase is responsible for the head-to-head condensation of two acyl moieties in bacterial pyrone biosynthesis

  • Darko Kresovic,
  • Florence Schempp,
  • Zakaria Cheikh-Ali and
  • Helge B. Bode

Beilstein J. Org. Chem. 2015, 11, 1412–1417, doi:10.3762/bjoc.11.152

Graphical Abstract
  • including a novel derivative. Moreover this novel class of ketosynthases is only distantly related to other pyrone-forming enzymes identified in the biosynthesis of the potent antibiotics myxopyronin and corallopyronin. Keywords: cell–cell communication; ketosynthase; photopyrones; pseudopyronines; quorum
  • products have been shown to be potent antibiotics targeting the newly identified switch region of the bacterial RNA polymerase [24]. Furthermore the promiscuity of MxnB regarding its substrate specificity has been used in mutasynthesis experiments to produce novel myxopyronin derivatives [25]. Recently the
  • pyrone biosynthesis we analyzed the KS from Pseudomonas sp. GM30, as we knew that α-pyrone antibiotics pseudopyronine A (9) and B (10) have been isolated in two Pseudomonas strains but neither their biosynthesis nor the involved KS had been reported yet [28]. Both compounds have been described to show an
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Published 12 Aug 2015

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

  • Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

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  • reactions proceeded in good yields (71–84%) and high diastereoselectivities. This work has been useful because the syn-1,3-diol moiety is commonly observed in many natural products, most notably in polyol macrolide antibiotics [72][73][74]. Performing CA reactions on chiral lactams has been a common method
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Published 23 Apr 2015

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

Graphical Abstract
  • muraymycin antibiotics (e.g., muraymycin A1 (1)) [39][40][41][42][43][44][45][46] have led to our previously reported synthesis of 'nucleosyl amino acid' structures 2 [47][48] as simplified 5'-defunctionalized analogues of the muraymycin core motif. Formally merging the nucleosyl amino acid (NAA) structure
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Published 13 Jan 2015

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

  • Paweł Borowiecki,
  • Daniel Paprocki and
  • Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

Graphical Abstract
  • been reported. Only enantioselective analytical methods towards enantioresolution of promethazine employing various chiral selectors including proteins, cyclodextrines, modified crown ethers or macrocyclic antibiotics have been proposed [52][53][54][55][56]. Other two reports [57][58] containing
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Published 18 Dec 2014

Recent advances in the electrochemical construction of heterocycles

  • Robert Francke

Beilstein J. Org. Chem. 2014, 10, 2858–2873, doi:10.3762/bjoc.10.303

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  • . The large interest in this field is attributable to the occurrence of heterocyclic units in numerous natural products and biologically active compounds such as hormones, antibiotics and vitamins [1]. Considering the fact that more than 70% of all active ingredients in pharmaceutical and agrochemical
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Published 03 Dec 2014

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

  • Véronique Nardello-Rataj and
  • Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

Graphical Abstract
  • (Scheme 1) [16]. The emergence of resistance strains to biocides which, in some cases, can contribute to resistance to antibiotics becomes a major problem. Microorganisms are considered resistant to antibiotics or biocides when a strain is not killed or inhibited by: i) the biocidal concentration
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Published 07 Nov 2014

Indium-mediated allylation in carbohydrate synthesis: A short and efficient approach towards higher 2-acetamido-2-deoxy sugars

  • Christopher Albler,
  • Ralph Hollaus,
  • Hanspeter Kählig and
  • Walther Schmid

Beilstein J. Org. Chem. 2014, 10, 2230–2234, doi:10.3762/bjoc.10.231

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  • interested in developing a general route towards the synthesis of these higher aminosugars. Since the preparation of new potent aminoglycoside antibiotics remains an important topic in medicinal chemistry [22], our precursors used should be flexible in terms of stereochemical variety, thus potentially
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Published 19 Sep 2014

De novo macrolide–glycolipid macrolactone hybrids: Synthesis, structure and antibiotic activity of carbohydrate-fused macrocycles

  • Richard T. Desmond,
  • Anniefer N. Magpusao,
  • Chris Lorenc,
  • Jeremy B. Alverson,
  • Nigel Priestley and
  • Mark W. Peczuh

Beilstein J. Org. Chem. 2014, 10, 2215–2221, doi:10.3762/bjoc.10.229

Graphical Abstract
  • antibacterial activity [7][8]. Over time, antibiotic use has created a selection pressure that has led to bacterial resistance and a subsequent need for continuous development of new antibiotics. Despite cumbersome syntheses, erythromycin analogs continue to be used as front line antibiotics while the clinical
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Published 17 Sep 2014

Photo, thermal and chemical degradation of riboflavin

  • Muhammad Ali Sheraz,
  • Sadia Hafeez Kazi,
  • Sofia Ahmed,
  • Zubair Anwar and
  • Iqbal Ahmad

Beilstein J. Org. Chem. 2014, 10, 1999–2012, doi:10.3762/bjoc.10.208

Graphical Abstract
  • such as vehicles (ethanol, propylene glycol), buffers (phosphate and citrate) and tonicity modifiers (NaCl, MgCl2) [118]. RF is also known to form complexes with dendrimers [103][119], certain drugs including antibiotics like cloxacillin sodium [102] and doxorubicin [120], dopamine [121], agents like N
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Published 26 Aug 2014

Expeditive synthesis of trithiotriazine-cored glycoclusters and inhibition of Pseudomonas aeruginosa biofilm formation

  • Meriem Smadhi,
  • Sophie de Bentzmann,
  • Anne Imberty,
  • Marc Gingras,
  • Raoudha Abderrahim and
  • Peter G. Goekjian

Beilstein J. Org. Chem. 2014, 10, 1981–1990, doi:10.3762/bjoc.10.206

Graphical Abstract
  • ) is an opportunistic human pathogen known to cause a variety of hospital-borne infections. It poses a severe threat to immunocompromised patients, as well as to those suffering from cystic fibrosis or cancer [1][2][3]. Its virulence is largely associated with multi-resistance to antibiotics, in
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Published 25 Aug 2014

Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

  • Thilo Focken and
  • Stephen Hanessian

Beilstein J. Org. Chem. 2014, 10, 1848–1877, doi:10.3762/bjoc.10.195

Graphical Abstract
  • eight benzyl protecting groups was accomplished using Pearlman’s catalyst under mild acidic conditions to give fumonisin B2 (20) [45][46][47][84]. Tricylic β-lactams (1997) β-Lactam antibiotics are the most prescribed and successful class of antibiotics developed and used in clinical practice. This
  • broad class of antibiotics shares a highly reactive four-membered β-lactam ring and includes penicillin derivatives, cephalosporins, monobactams, carbapenems, and other related compounds [85][86][87]. Approved drugs such as imipenem (111) and meropenem (112) (Figure 6) belong to the subclass of
  • carbapenems, which are powerful antibiotics with a broad spectrum of activity against Gram-positive and Gram-negative bacteria and are often used as antibiotics for many hard-to-treat bacterial infections, such as Escherichia coli and Klebsiella pneumoniae [88][89]. Resistance of bacterial strains to
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Published 13 Aug 2014

Synthesis and bioactivity of analogues of the marine antibiotic tropodithietic acid

  • Patrick Rabe,
  • Tim A. Klapschinski,
  • Nelson L. Brock,
  • Christian A. Citron,
  • Paul D’Alvise,
  • Lone Gram and
  • Jeroen S. Dickschat

Beilstein J. Org. Chem. 2014, 10, 1796–1801, doi:10.3762/bjoc.10.188

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  • the bioactivity of the natural product. The synthesis of this compound and of several analogues is presented and the bioactivity of the synthetic compounds is discussed. Keywords: antibiotics; natural products; Roseobacter; SAR study; tropodithietic acid; tropone; Introduction Tropodithietic acid
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Published 06 Aug 2014

Multicomponent reactions in nucleoside chemistry

  • Mariola Koszytkowska-Stawińska and
  • Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

Graphical Abstract
  • . Biochemical properties of the novel nucleoside analogs are also presented (if provided by the authors). Keywords: multicomponent reaction; nucleoside analog; nucleoside antibiotics; nucleoside construction; nucleoside modification; Introduction Chemical modifications of natural ribose or 2'-deoxyribose
  • diseases [1]. Moreover, several novel nucleoside analogs (including those embedded in versatile conjugate or pronucleotide scaffolds) are under clinical or preclinical trials [1]. Recent studies have also revealed a potential of nucleoside analogs as radiopharmaceuticals [2][3][4][5][6], antibiotics [7][8
  • and 1H NMR analysis). Members of this library were claimed to show promising biological activity, however details were not given. Muraymycins (MRYs) are a class of naturally occurring nucleoside-lipopeptide antibiotics with excellent antibacterial activity. Matsuda and coworkers envisaged that MRYs
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Published 29 Jul 2014

Efficient routes toward the synthesis of the D-rhamno-trisaccharide related to the A-band polysaccharide of Pseudomonas aeruginosa

  • Aritra Chaudhury,
  • Sajal K. Maity and
  • Rina Ghosh

Beilstein J. Org. Chem. 2014, 10, 1488–1494, doi:10.3762/bjoc.10.153

Graphical Abstract
  • immunity with fatal consequences in a majority of cases. Its high persistence against a wide variety of antibiotics is also well documented. It has also been observed how the colonized form of this species in cystic fibrosis lungs, through non-expression of O-antigens, offer high persistence often
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Published 01 Jul 2014

Streptopyridines, volatile pyridine alkaloids produced by Streptomyces sp. FORM5

  • Ulrike Groenhagen,
  • Michael Maczka,
  • Jeroen S. Dickschat and
  • Stefan Schulz

Beilstein J. Org. Chem. 2014, 10, 1421–1432, doi:10.3762/bjoc.10.146

Graphical Abstract
  • polyketides, nonribosomal peptides, terpenoids, alkaloids, lipids and others. Such compounds became a major source of biologically active natural products as antibiotics, cytotoxic compounds, immunosuppressants etc. In addition, actinomycetes are also able to produce and release a wide variety of volatile
  • . Natural products of bacteria containing a pyridine ring are rare. As an example, 1-(2-pyridinyl)ethanone was identified as a volatile of Enterobacter agglomerans [20]. Highly substituted pyridine derivatives can be found in bacterial thiopeptide antibiotics [21]. The streptopyridines of Streptomyces sp
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Published 24 Jun 2014

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

Graphical Abstract
  • parent precursors [33][34][35][36][37][38][39]. Over the years, many structural analogues of this class of antibiotics have been synthesized. In addition, triazoles are considered as peptidic linkage surrogates. Surprisingly, despite the enormous research interests associated with their synthesis, only a
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Published 10 Jun 2014

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

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  • acids vary in their side-chain functionality and possess different polarities that are important for their biological function. Peptides can be biologically active hormones, neurotransmitters and neuropeptides, growth factors, signaling molecules and antibiotics. These diverse functions make peptides an
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Published 22 May 2014

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

Graphical Abstract
  • . 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
  • ], as monosulfuric acid ester [6] or as potential acylation site for fatty acid side chains such as in A- and B-series muraymycin nucleoside antibiotics (Figure 1) [7][8][9]. In the case of these muraymycin congeners, acylation of the 3-hydroxy position with fatty acid side chains, which are ω
  • -phase peptide synthesis (SPPS). Furthermore, we have employed such building blocks for the synthesis of protected analogues 15a,b of the tripeptide unit of naturally occurring muraymycin nucleoside antibiotics. We have also established unprecedented protocols for early- and late-stage derivatizations of
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Published 16 May 2014

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

Graphical Abstract
  • crucial for the biological activity of various peptide antibiotics [23], e.g., nisin (used as a food preservative [24]), epidermin (active against Gram positive bacteria [25]) and viomycin (used to fight infections of Mycobacterium tuberculosis [26]). As shown by Chauhan and co-workers, structure–activity
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Published 14 Mar 2014

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

Graphical Abstract
  • and triazines, whereas azepines form an important class of seven-membered cyclic peptidomimetics. Four membered ring constraints β-Lactams The smallest class of cyclic peptidomimetics is that of the β-lactams. β-lactams are effective antibiotics [30] but also show inhibitory activities against serine
  • moiety attached to the scaffold. These compounds could find application as potent antibiotics, protease inhibitors or as cholesterol absorption modifiers (Scheme 37) [18]. In this particular reaction, the scaffolds were obtained by reacting the complex isocyanide 118 with different aldehydes and β-amino
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Published 04 Mar 2014

Preparation of new alkyne-modified ansamitocins by mutasynthesis

  • Kirsten Harmrolfs,
  • Lena Mancuso,
  • Binia Drung,
  • Florenz Sasse and
  • Andreas Kirschning

Beilstein J. Org. Chem. 2014, 10, 535–543, doi:10.3762/bjoc.10.49

Graphical Abstract
  • introduce a thiol linker by Huisgen-type cycloaddition which can principally be utilized to create tumor targeting conjugates. In bioactivity tests, only those new ansamitocin derivatives showed strong antiproliferative activity that bear an ester side chain at C-3. Keywords: ansamitocins; antibiotics
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Published 03 Mar 2014

Intermediates in monensin biosynthesis: A late step in biosynthesis of the polyether ionophore monensin is crucial for the integrity of cation binding

  • Wolfgang Hüttel,
  • Jonathan B. Spencer and
  • Peter F. Leadlay

Beilstein J. Org. Chem. 2014, 10, 361–368, doi:10.3762/bjoc.10.34

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  • , University of Cambridge, Lensfield Road, Cambridge CB2 1QW, UK 10.3762/bjoc.10.34 Abstract Polyether antibiotics such as monensin are biosynthesised via a cascade of directed ring expansions operating on a putative polyepoxide precursor. The resulting structures containing fused cyclic ethers and a
  • tailoring step as well as polyether formation. Keywords: antibiotics; biosynthesis; natural products; polyketides; Streptomyces; synthetic biology; Introduction Monensin A (1) from Streptomyces cinnamonensis is one of the most prominent and best-studied of the polyether class of complex polyketides, an
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Published 10 Feb 2014

Boron-substituted 1,3-dienes and heterodienes as key elements in multicomponent processes

  • Ludovic Eberlin,
  • Fabien Tripoteau,
  • François Carreaux,
  • Andrew Whiting and
  • Bertrand Carboni

Beilstein J. Org. Chem. 2014, 10, 237–250, doi:10.3762/bjoc.10.19

Graphical Abstract
  • vinyl ether, this approach was successfully applied in the key steps of the total synthesis of a member of the thiomarinol class of marine antibiotics (Scheme 19) [66][67]. More recently, Hall and co-workers described the total synthesis of a complex 20-membered marine macrolide, palmerolide A, a potent
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Published 22 Jan 2014

Flow microreactor synthesis in organo-fluorine chemistry

  • Hideki Amii,
  • Aiichiro Nagaki and
  • Jun-ichi Yoshida

Beilstein J. Org. Chem. 2013, 9, 2793–2802, doi:10.3762/bjoc.9.314

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  • explored a flow microreactor system for sequential transformation towards fluoroquinolone antibiotics such as ciprofloxacin via both inter- and intramolecular SNAr reactions (Scheme 10) [70]. Starting from the acylation reaction of (N-dimethylamino)acrylate with 2,4,5-trifluorobenzoic acid chloride
  • [18F]-radiolabeled molecular imaging probes. Flow microreactor synthesis of dipeptides. Flow synthesis involving SNAr reactions. Flow synthesis of fluoroquinolone antibiotics. Highly controlled formation of PFPMgBr. Selective flow synthesis of photochromic diarylethenes. Flow microreactor system for
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Published 05 Dec 2013

Garner’s aldehyde as a versatile intermediate in the synthesis of enantiopure natural products

  • Mikko Passiniemi and
  • Ari M.P. Koskinen

Beilstein J. Org. Chem. 2013, 9, 2641–2659, doi:10.3762/bjoc.9.300

Graphical Abstract
  • substructures. This structural motif can be found in many natural products, such as iminosugars (7 and 9), peptide antibiotics (8), sphingosines and their derivatives (10 and 11, Figure 3). These naturally occurring polyhydroxylated compounds have attracted increasing interest from synthetic chemists, because
  • of Garner’s aldehyde. Structures of some iminosugars (7, 9), peptide antibiotics (8) and sphingosine (10) and pachastrissamine (11). (a) i) Boc2O, 1.0 N NaOH (pH >10), dioxane, +5 °C → rt; ii) MeI, K2CO3, DMF, 0 °C → rt (86% over two steps); (b) Me2C(OMe)2, cat. p-TsOH, benzene, reflux (70–89%); (c
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Published 26 Nov 2013
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