Isolation of fungi using the diffusion chamber device FIND technology

• Benjamin Libor,
• Henrik Harms,
• Stefan Kehraus,
• Ekaterina Egereva,
• Max Crüsemann and
• Gabriele M. König

Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216

• antibiotics (e.g., cephalosporins), immunosuppressants (e.g., mycophenolic acid) and immunomodulators (e.g., fingolimod), as well as cholesterol lowering agents (statins). Generally, fungal metabolites were shown to have antiviral, cytotoxic, antineoplastic, cardiovascular, anti-inflammatory, immune

• -stimulating, and anticancer activities [2]. Since the World Health Organization (WHO) declared antibiotic resistance a global threat and urged the search for new antibiotics, the interest in fungal metabolites increased recently. In order to find new structural types, novel source organisms have to be

• with 15 mL agar solution. In summary, the diluted sample from experiment 1, the undiluted solutions from experiments 2 and 3, and the concentrated, resuspended sea water solution from experiment 4 were each mixed with a warm agar preparation, containing a minimal nutrient medium and antibiotics

Cyclopropanation–ring expansion of 3-chloroindoles with α-halodiazoacetates: novel synthesis of 4-quinolone-3-carboxylic acid and norfloxacin

• Sara Peeters,
• Linn Neerbye Berntsen,
• Pål Rongved and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2019, 15, 2156–2160, doi:10.3762/bjoc.15.212

• ethyl group and yields quinolone (6) after tautomerization. Standard hydrolysis (LiOH, H2O/THF) of ester 6 gave the 4-quinolone-3-carboxylic acid (7) in 87% yield (not shown). Quinolones, and fluoroquinolones (FQs) in particular, are among the most commonly prescribed antibiotics in the world [34

• ]. Norfloxacin (1) is considered to be the first broad band antibiotic and its structurally related cousin ciprofloxacin (2) is one of the most prescribed antibiotics even after 20 years of clinical use. We elected 1 as a synthetic target for our novel approach towards FQs (Scheme 4). Chlorination of

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• as tert-butyldiphenylsilyl ethers, individually transformed into 2-(3-hydroxypropyl)pyrrolidines by LiAlH4 reduction and deprotected. Diamines PF-00951966 (Scheme 18) belongs to a fluoroquinolone family of antibiotics which is substituted at C7 with a (3R)-3-[(1S)-2-cyano-1-(methylamino)ethyl

• )-105 (Scheme 27) [78]. Application of other organometallics paved the way to synthesis of a variety of 3-substituted 2-amino-1,3-propanodiols. 1,3-Diamino-2-hydroxy derivatives Linezolid ((S)-107) represents a new class of 1,3-oxazolidin-2-one antibiotics and contains the (2S)-1,3-diamino-2

Synthesis and biological evaluation of truncated derivatives of abyssomicin C as antibacterial agents

• Leticia Monjas,
• Peter Fodran,
• Johanna Kollback,
• Carlo Cassani,
• Thomas Olsson,
• Maja Genheden,
• D. G. Joakim Larsson and
• Carl-Johan Wallentin

Beilstein J. Org. Chem. 2019, 15, 1468–1474, doi:10.3762/bjoc.15.147

• structure–activity relationship studies towards novel antibiotics targeting 4-amino-4-deoxychorismate (ADC) synthase. Specifically, it is demonstrated that the synthetically challenging bicyclic motif is essential for activity towards methicillin-resistant Staphylococcus aureus (MRSA). Keywords

• develop new antibiotics, but the reevaluation of known natural products (NP) and the identification of new NPs and derivatives thereof is considered an especially important pathway in the search for more robust antibiotics [1][2]. The main reasons are the inherent high selectivity and appropriate

Robust perfluorophenylboronic acid-catalyzed stereoselective synthesis of 2,3-unsaturated O-, C-, N- and S-linked glycosides

• Madhu Babu Tatina,
• Xia Mengxin,
• Rao Peilin and
• Zaher M. A. Judeh

Beilstein J. Org. Chem. 2019, 15, 1275–1280, doi:10.3762/bjoc.15.125

• molecular recognition, cell–cell interaction, immunological recognition and transmission of biological information [4][5][6]. They are easily transformed into important bioactive compounds such as oligosaccharides, glycopeptides, nucleosides, antibiotics, uronic acids and other natural products [1][2][3

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• the natural cationic peptide antibiotics [60] or as a way to constrain peptide sequences in protein epitope conformations [61]. In this regard, the groups of Rivera and Wessjohann have pioneered the utilization of MCRs for the conjugation of oligosaccharides [62] and peptides [63][64] to steroids

Phylogenomic analyses and distribution of terpene synthases among Streptomyces

• Lara Martín-Sánchez,
• Kumar Saurabh Singh,
• Mariana Avalos,
• Gilles P. van Wezel,
• Jeroen S. Dickschat and
• Paolina Garbeva

Beilstein J. Org. Chem. 2019, 15, 1181–1193, doi:10.3762/bjoc.15.115

• remarkable genetic potential to produce a large variety of secondary metabolites with different functions including antibiotics, antifungals, pigments or immunosuppressants [1][2][3]. These are compounds of diverse chemical nature such as polyketides, peptides, aminoglycosides or terpenoids [4][5

Catalytic asymmetric oxo-Diels–Alder reactions with chiral atropisomeric biphenyl diols

• Chi-Tung Yeung,
• Wesley Ting Kwok Chan,
• Wai-Sum Lo,
• Ga-Lai Law and
• Wing-Tak Wong

Beilstein J. Org. Chem. 2019, 15, 955–962, doi:10.3762/bjoc.15.92

• stereogenic centers in a one-step [4 + 2] cycloaddition or cyclization reaction [6][7][8] and it has become hugely popular in preparing vital intermediates for the syntheses of key structural subunits of natural products with biological activities (e.g., carbohydrates, antibiotics, toxins etc.) [9][10

Solid-phase synthesis of biaryl bicyclic peptides containing a 3-aryltyrosine or a 4-arylphenylalanine moiety

• Iteng Ng-Choi,
• Àngel Oliveras,
• Lidia Feliu and
• Marta Planas

Beilstein J. Org. Chem. 2019, 15, 761–768, doi:10.3762/bjoc.15.72

• amino acids [11]. Cyclic peptides containing biaryl linkages constitute attractive targets. On the one hand, a wide range of biaryl natural products have been reported to display interesting biological properties, such as biphenomycins, arylomycins and glycopeptide antibiotics [4]. On the other hand

Dirhodium(II)-catalyzed [3 + 2] cycloaddition of N-arylaminocyclopropane with alkyne derivatives

• Wentong Liu,
• Yi Kuang,
• Zhifan Wang,
• Jin Zhu and
• Yuanhua Wang

Beilstein J. Org. Chem. 2019, 15, 542–550, doi:10.3762/bjoc.15.48

• cycloaddition protocol. Keywords: [3 + 2]; alkyne; cycloaddition; cyclopropanes; dirhodium catalysis; N-arylaminocyclopropanes; Introduction N-Arylaminocyclopropanes 1 are important structural motifs for pharmaceuticals and are found especially in marketed fluoroquinolone antibiotics [1], such as

Synthesis and SAR of the antistaphylococcal natural product nematophin from Xenorhabdus nematophila

• Frank Wesche,
• Hélène Adihou,
• Thomas A. Wichelhaus and
• Helge B. Bode

Beilstein J. Org. Chem. 2019, 15, 535–541, doi:10.3762/bjoc.15.47

• Frankfurt, Max-von-Laue-Str. 15, D-60438 Frankfurt am Main, Germany 10.3762/bjoc.15.47 Abstract The repeated and improper use of antibiotics had led to an increased number of multiresistant bacteria. Therefore, new lead structures are needed. Here, the synthesis and an expanded structure–activity

Study on the regioselectivity of the N-ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide

• Pedro N. Batalha,
• Luana da S. M. Forezi,
• Maria Clara R. Freitas,
• Nathalia M. de C. Tolentino,
• Ednilsom Orestes,
• José Walkimar de M. Carneiro,
• Fernanda da C. S. Boechat and
• Maria Cecília B. V. de Souza

Beilstein J. Org. Chem. 2019, 15, 388–400, doi:10.3762/bjoc.15.35

• ; regioselectivity; Introduction Since the discovery of the antibacterial agent nalidixic acid, as a byproduct from the synthesis of chloroquine, the medicinal interest in 4-oxoquinolines as bioactive substances has exponentially grown over the years. Nowadays, some of the most important antibiotics used in the

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• More than 135 years after the discovery of Mycobacterium tuberculosis (Mtb) by Robert Koch [1], tuberculosis (TB) is still one of the world’s deadliest communicable diseases [2]. TB is theoretically curable and preventable, especially since effective antibiotics have been available since the 1940s [3

• connected to colonization of the kidney [64][65]. Inhibition of carbohydrate–lectin interactions by antiadhesive drugs is an emerging anti-infective therapeutic approach, particularly in light of increasing rates of bacterial resistance to traditional antibiotics. α-D-Mannosides containing aromatic aglycons

Repurposing the anticancer drug cisplatin with the aim of developing novel Pseudomonas aeruginosa infection control agents

• Mingjun Yuan,
• Song Lin Chua,
• Yang Liu,
• Daniela I. Drautz-Moses,
• Joey Kuok Hoong Yam,
• Thet Tun Aung,
• Roger W. Beuerman,
• May Margarette Santillan Salido,
• Stephan C. Schuster,
• Choon-Hong Tan,
• Michael Givskov,
• Liang Yang and
• Thomas E. Nielsen

Beilstein J. Org. Chem. 2018, 14, 3059–3069, doi:10.3762/bjoc.14.284

• antibiotics. Although cisplatin is highly toxic for humans upon systemic exposure, a low toxicity was demonstrated with topical treatment. This indicated that higher-than-minimal inhibitory concentration (MIC) doses of cisplatin could be topically applied to treat persistent and recalcitrant P. aeruginosa

• are notoriously difficult to be cleared by conventional antibiotics, cisplatin possesses the additional advantage of killing biofilms. This makes cisplatin a more attractive antimicrobial for treating biofilm infections clinically. Even though cisplatin is known for its toxic side effects on cancer

• distinct from other conventional antibiotics, which may offer alternative therapeutic approaches towards persistent infections. In recent years, metal-containing compounds have been identified as antimicrobial agents. Gallium was shown to disrupt the iron metabolism of P. aeruginosa and efficiently kill

Stereodivergent approach in the protected glycal synthesis of L-vancosamine, L-saccharosamine, L-daunosamine and L-ristosamine involving a ring-closing metathesis step

• Pierre-Antoine Nocquet,
• Aurélie Macé,
• Frédéric Legros,
• Jacques Lebreton,
• Gilles Dujardin,
• Sylvain Collet,
• Arnaud Martel,
• Bertrand Carboni and
• François Carreaux

Beilstein J. Org. Chem. 2018, 14, 2949–2955, doi:10.3762/bjoc.14.274

• structures 3-amino-2-deoxy sugars [1]. For instance, N,N-dimethyl-L-vancosamine is an essential component of pluramycin antibiotics such as kidamycin and pluramycin A via a C-glycosidic linkage (Figure 1). For constructing aryl C-glycoside bonds, glycal derivatives are versatile synthetic intermediates

• aminoglycals. The use of these synthons in the synthesis of glycosylated antibiotics as kidamycin is underway in our laboratory. N,N-Dimethyl-L-vancosamine as substructure of kidamycin and pluramycin. Glycals as relevant scaffolds for constructing aryl C-glycosidic linkage. Strategy including a ring-closing

Protein–protein interactions in bacteria: a promising and challenging avenue towards the discovery of new antibiotics

• Laura Carro

Beilstein J. Org. Chem. 2018, 14, 2881–2896, doi:10.3762/bjoc.14.267

• Laura Carro School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK 10.3762/bjoc.14.267 Abstract Antibiotics are potent pharmacological weapons against bacterial infections; however, the growing antibiotic resistance of microorganisms is compromising the efficacy

• represent an alternative lead discovery strategy to obtain new anti-infective molecules. Keywords: new antibiotics; protein–protein interactions; resistance; Introduction Bacterial infections are not only one of the most frequent diseases in humans and livestock, but also one of the top ten causes of

• death according to the World Health Organization [1]. The serendipitous discovery of penicillin and its introduction into the clinic in the first half of the 20th century gave rise to the “Golden Age” of antibiotics discovery and have unquestionably represented one of the most important achievements in

Synthesis of pyrrolidine-based hamamelitannin analogues as quorum sensing inhibitors in Staphylococcus aureus

• Jakob Bouton,
• Kristof Van Hecke,
• Reuven Rasooly and
• Serge Van Calenbergh

Beilstein J. Org. Chem. 2018, 14, 2822–2828, doi:10.3762/bjoc.14.260

• resistance problem need to be multifactorial. Next to disease prevention and the development of new antibiotics, it is essential to investigate innovative strategies to combat bacterial infections [3][4]. Recently, targeting bacterial virulence has gained a lot of attention [5][6][7]. It has been

• system and antibiotics. The Centers for Disease Control and Prevention (CDC) have listed a number of bacteria that present serious, urgent and concerning threats [8]. One of these problematic bacteria is methicillin-resistant Staphylococcus aureus (MRSA), a human pathogen that causes a wide range of

• ), an inhibitor of the RAP/TRAP (RNAIII-activating protein/target of RAP) quorum sensing system in S. aureus (Figure 1) [12][13][14]. Furthermore, hamamelitannin has been shown to inhibit biofilm formation and to potentiate the activity of antibiotics against staphylococcal biofilms in vitro and in vivo

Synthesis and biological evaluation of 1,2-disubstituted 4-quinolone analogues of Pseudonocardia sp. natural products

• Stephen M. Geddis,
• Teodora Coroama,
• Suzanne Forrest,
• James T. Hodgkinson,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2018, 14, 2680–2688, doi:10.3762/bjoc.14.245

• PQS analogues, which has been hitherto underexplored. Keywords: antibiotics; cross-coupling; heterocycles; quorum-sensing; structure–activity relationships; Introduction The quinolone core has long been implemented in structures possessing formidable activity in a broad range of fields, including

• antibiotics, bacterial signalling and iron metabolism [1]. Structural optimisation of quinolones possessing intriguing properties can lead to the discovery of important drug classes, as demonstrated by the fluoroquinolone antibiotics, which were inspired by the observation of an antibacterial quinolone side

Non-native autoinducer analogs capable of modulating the SdiA quorum sensing receptor in Salmonella enterica serovar Typhimurium

• Matthew J. Styles and
• Helen E. Blackwell

Beilstein J. Org. Chem. 2018, 14, 2651–2664, doi:10.3762/bjoc.14.243

• to complement antibiotics, and the interception of quorum sensing (QS) in bacteria has attracted considerable attention in this regard [7][8][9]. QS, a type of intra- and interspecies chemical communication, has been found to occur in many common bacterial pathogens [10][11]. These pathogens use QS

The design and synthesis of an antibacterial phenothiazine–siderophore conjugate

• Abed Tarapdar,
• James K. S. Norris,
• Oliver Sampson,
• Galina Mukamolova and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2018, 14, 2646–2650, doi:10.3762/bjoc.14.242

• antibacterial agents. Keywords: NDH-2; phenothiazine; siderophore; siderophore–antibiotic; siderophore conjugate; Introduction One of the biggest challenges facing the modern society is antibiotic resistance and the prospect of current antibiotics becoming near redundant against previously treatable

• infections [1]. To meet this challenge there is a desperate need for new antibiotics, antibiotic targets and strategies to enhance the efficacy of current antibiotics [2]. One novel strategy which is receiving significant interest is the manipulation of bacterial iron transport pathways to deliver

• antibiotics to the bacterial cell [3]. Iron is essential for bacterial survival and bacteria secrete high affinity iron chelating molecules to scavenge and solubilise Fe3+ from the extracellular environment [3]. The siderophore–Fe complex is recognised by specific receptor proteins on the outer membrane of

Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• resist antibiotic treatment via several mechanisms. First and foremost, it possesses an intrinsic resistance to many antibiotics because of the low permeability of its cell wall and due to the action of a number of efflux pumps as well as β-lactamases. Efflux pumps in particular are nifty molecular

• machineries consisting of several protein components, which in total span from the inner to the outer side of the cell membrane. Their function is to expel a wide range of xenobiotics, among them antibiotics from the cephalosporin, carbapenem, fluroquinolone and aminoglycoside classes [13]. Through this

• strains. Hence, these antibiotic-inactivating enzymes provide resistance against penicillins and cephalosporins [14]. In addition to these intrinsic capabilities, P. aeruginosa is able to acquire resistances toward antibiotics it has come in contact with. These acquired resistances can be the result of

Pathoblockers or antivirulence drugs as a new option for the treatment of bacterial infections

• Matthew B. Calvert,
• Varsha R. Jumde and
• Alexander Titz

Beilstein J. Org. Chem. 2018, 14, 2607–2617, doi:10.3762/bjoc.14.239

• current trends continue. To avoid this scenario, new classes of anti-infectives must urgently be developed. Antibiotics with new modes of action are needed, but other concepts are also currently being pursued. Targeting bacterial virulence as a means of blocking pathogenicity is a promising new strategy

• . Keywords: antimicrobial resistance; bacterial adhesins; bacterial toxins; pathoblockers; quorum sensing; Review 1. Antimicrobial resistance crisis for bacterial infections The current crisis caused by antimicrobial resistance [1][2] demands new strategies to fight infections. Antibiotics have served as

• life-saving drugs during the last 100 years and rescued the world from a situation where practically untreatable infections with high mortality rates were the norm. However, starting in the 1960s, the delusive belief that the available antibiotics were sufficiently effective to treat all infections led

Impact of Pseudomonas aeruginosa quorum sensing signaling molecules on adhesion and inflammatory markers in endothelial cells

• Carmen Curutiu,
• Florin Iordache,
• Veronica Lazar,
• Aurelia Magdalena Pisoschi,
• Aneta Pop,
• Mariana Carmen Chifiriuc and
• Alina Maria Hoban

Beilstein J. Org. Chem. 2018, 14, 2580–2588, doi:10.3762/bjoc.14.235

• compromised individuals and in patients with bronchiectasis or cystic fibrosis. The infections become chronic, as P. aeruginosa develops resistance to conventional antibiotics due to its ability to produce virulence factors and modulate immune defenses by quorum sensing (QS) and biofilm production

• containing 5% CO2 and 21% O2. To maintain optimal culture conditions, the medium was changed twice a week. Prior the infection with P. aeruginosa and adding QSSMs the endothelial cells were cultured in a medium without antibiotics. Endothelial cells were stimulated with P. aeruginosa PAO1 strain (control

• were washed with PBS (phosphate buffered saline) and 1 mL of fresh medium without antibiotics was added to each well. Suspensions of P. aeruginosa were obtained from bacterial mid-logarithmic phase cultures grown in nutrient broth adjusted to 107 CFU/mL and 1 mL were used for the inoculation of each

Synthesis of a leopolic acid-inspired tetramic acid with antimicrobial activity against multidrug-resistant bacteria

• Luce Mattio,
• Loana Musso,
• Leonardo Scaglioni,
• Andrea Pinto,
• Piera Anna Martino and
• Sabrina Dallavalle

Beilstein J. Org. Chem. 2018, 14, 2482–2487, doi:10.3762/bjoc.14.224

• class of antibacterial agents active also against resistant strains. Keywords: antimicrobial activity; multidrug-resistant bacteria; natural products; synthesis; tetramic acid; Introduction The treatment of bacterial infections by antibiotics is widely regarded as one of the major achievements of the

• -resistant phenotype (average MIC 32 µg/mL on 30 strains tested). Conclusion The development of novel strategies to fight bacterial infections is an imperative goal, mainly due to the increasing number of bacterial strains resistant to a wide spectrum of antibiotics. Aim of this work was the development of a

Defining the hydrophobic interactions that drive competence stimulating peptide (CSP)-ComD binding in Streptococcus pneumoniae

• Bimal Koirala,
• Robert A. Hillman,
• Erin K. Tiwold,
• Michael A. Bertucci and
• Yftah Tal-Gan

Beilstein J. Org. Chem. 2018, 14, 1769–1777, doi:10.3762/bjoc.14.151

• significant attention as a potential antivirulence alternative to traditional antibiotics. Streptococcus pneumoniae, a notorious human pathogen responsible for a variety of acute and chronic infections, utilizes the competence regulon and its associated signaling peptide, the competence stimulating peptide