Synthesis of 1,4-benzothiazinones from acylpyruvic acids or furan-2,3-diones and o-aminothiophenol

• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2020, 16, 2322–2331, doi:10.3762/bjoc.16.193

• (detailed data on biological assays is given in Supporting Information File 1). Unfortunately, we found that tested BTAs 3 did not show any significant antimicrobial activity (against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Candida

Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale

• Ken-ichi Nakashima,
• Junko Tomida,
• Tomoe Tsuboi,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 2100–2107, doi:10.3762/bjoc.16.177

• ,10R,11R) stereoisomer. Finally, since a number of azaphilones have been reported to exhibit antimicrobial activity [5][23], muyocopronones A (1) and B (2) were screened for their antibacterial activity against five strains of Gram-positive bacteria, namely Staphylococcus aureus (PAGU 273T

• Staphylococcus aureus (PAGU 273T), methicillin-resistant S. aureus (PAGU 841, MRSA), Staphylococcus epidermidis (PAGU 283T), Enterococcus faecalis (PAGU 102T), and vancomycin-resistant E. faecalis (PAGU 100, VRE). Piperacillin, vancomycin, and amikacin were used as positive controls. The isolated substances and

4-Hydroxy-3-methyl-2(1H)-quinolone, originally discovered from a Brassicaceae plant, produced by a soil bacterium of the genus Burkholderia sp.: determination of a preferred tautomer and antioxidant activity

• Dandan Li,
• Naoya Oku,
• Yukiko Shinozaki,
• Yoichi Kurokawa and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1489–1494, doi:10.3762/bjoc.16.124

• Alternaria alternata [36], staphyloxanthin from a firmicute Staphylococcus aureus [37], vitamin B6 from fungi Cercospora nicotianae, [38] and Rhizoctonia solani [39], and a melanin-like pigment from Burkholderia cenocepacia [40]. The antioxidant activity of 1 was evaluated using the luminol chemiluminescence

• tuberculosis H37Ra at IC90 6.8 μM while weakly cytotoxic to MRC-5 human lung-derived fibroblasts with GI50 84.7 μM [30]. It did not inhibit the production of nitric oxide in RAW 264.7 murine macrophage-like cells [31]. In our hands, 1 was inactive against any of the tested strains including Staphylococcus

• aureus FDA209P JC-1 (Gram-positive bacterium), Rhizobium radiobacter NBRC14554, Ralstonia solanacearum SUPP1541, Tenacibaculum maritimum NBRC16015 (Gram-negative bacteria), Candida albicans NBRC0197, and Saccharomyces cerevisiae S100 (yeasts). Oxidative burst, which is a transient production of massive

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

• inactive against Staphylococcus aureus, Escherichia coli, Rhizobium radiobacter, and Candida albicans. The antimicrobial potency of 2 and 3 were similar, implying that the acyl side chain at C13 of compound 2 had no influence on the activity. In addition, compounds 1–4 showed moderate cytotoxicity against

Fabclavine diversity in Xenorhabdus bacteria

• Sebastian L. Wenski,
• Harun Cimen,
• Natalie Berghaus,
• Sebastian W. Fuchs,
• Selcuk Hazir and
• Helge B. Bode

Beilstein J. Org. Chem. 2020, 16, 956–965, doi:10.3762/bjoc.16.84

• this work, the inhibitory activity of the wild type and the promoter-exchange mutants (induced and non-induced) were analyzed against the human pathogens Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Klebsiella pneumoniae by agar well-diffusion bioassays (Table 3). Briefly, cell

• : non-induced, ind: induced) in mm against the human pathogens Escherichia coli (a, ATCC 25922), Staphylococcus aureus (b, ATCC 29213), Enterococcus faecalis (c, ATCC 29212), and Klebsiella pneumoniae (d, ATCC 700603). The corresponding agar well-diffusion bioassays were performed three times, with ten

Towards the total synthesis of chondrochloren A: synthesis of the (Z)-enamide fragment

• Jan Geldsetzer and
• Markus Kalesse

Beilstein J. Org. Chem. 2020, 16, 670–673, doi:10.3762/bjoc.16.64

• (Cmc5) by the groups of Höfle and Reichenbach in 2003 [12]. This PKS/NRPS-derived natural product shows only weak antibiotic effects in agar diffusion tests against Micrococcus luteus, Schizosaccharomyces pombe, Bacillus subtilis and Staphylococcus aureus [12]. The relative and absolute stereochemistry

Two antibacterial and PPARα/γ-agonistic unsaturated keto fatty acids from a coral-associated actinomycete of the genus Micrococcus

• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku,
• Nobuyasu Matsuura,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 297–304, doi:10.3762/bjoc.16.29

• interesting contrast. No appreciable antimicrobial activity was observed for both compounds against bacterial strains of Micrococcus luteus ATCC9341, Staphylococcus aureus FDA209P JC-1, and Escherichia coli NIHJ JC-2 and yeast strains of Candida albicans NBRC0197 and Saccharomyces cerevisiae S100, nor

• bacteria, Micrococcus luteus ATCC9341, Staphylococcus aureus FDA209P JC-1, Rhizobium radiobacter NBRC14554, Escherichia coli NIHJ JC-2, Tenacibaculum maritimum NBRC16015, and two yeasts, Candida albicans NBRC0197 and Saccharomyces cerevisiae S100, as indication strains. Mueller–Hinton Broth (Difco

Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica

• Soleiman E. Helaly,
• Wilawan Kuephadungphan,
• Patima Phainuphong,
• Mahmoud A. A. Ibrahim,
• Kanoksri Tasanathai,
• Suchada Mongkolsamrit,
• Janet Jennifer Luangsa-ard,
• Souwalak Phongpaichit,
• Vatcharin Rukachaisirikul and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293

• formation of Staphylococcus aureus DSM1104. The lack of toxicity toward the studied microorganism and cell lines of pigmentosin B (2), as well as the antimicrobial effect of pigmentosin A (1), made them good candidates for further development for use in combination therapy of infections involving biofilm

• for their ability to interfere in the biofilm formation of Staphylococcus aureus DSM1104 and Pseudomonas aeruginosa PA14 [51]. The biofilm inhibition assay was performed in 96-well microtiter plates using the microtiter dish biofilm formation assay described by O’Toole [52], with minor modifications

Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• , compound 3 moderately inhibited the biofilm formation of Staphylococcus aureus (S. aureus), while compounds 3 and 4 performed moderately in the ʟ-leucine-7-amido-4-methylcoumarin (ʟ-Leu-AMC) inhibition assay. These compounds represent the first secondary metabolites reported to occur in the fruiting bodies

Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides

• José Brango-Vanegas,
• Luan A. Martinho,
• Lucinda J. Bessa,
• Andreanne G. Vasconcelos,
• Alexandra Plácido,
• Alex L. Pereira,
• José R. S. A. Leite and
• Angelo H. L. Machado

Beilstein J. Org. Chem. 2019, 15, 2544–2551, doi:10.3762/bjoc.15.247

• analogues were prepared in moderate overall yields and did not show toxic effects on Staphylococcus aureus growth and were not toxic to human fibroblasts. Two of them inhibited the hemolytic activity of S. aureus, suggesting an interfering action in the bacterial quorum sensing similar to the one already

• prevent the expression of Staphylococcus aureus virulence factors such as α-hemolysin and phenol-soluble modulins without affecting the bacterial growth [3]. Particularly, solonamide B and its analogues revealed no detectable toxicity against erythrocytes or human neutrophils [3][4]. Staphylococcus aureus

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• -dolabellatriene (12) possesses a mainly weak antibiotic activity against different types of Staphylococcus aureus strains (two epidemic MRSA strains, a macrolide-resistant variant and two multidrug-resistant efluxing strains) [72]. By contrast, 3,7,18-dolabellatriene (12, Scheme 3), only altered at C14 with a

Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

• Amit Raj Sharma,
• Enjuro Harunari,
• Tao Zhou,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

• and carbons from C3 to C18 are from palmitoyl-CoA. To the best of our knowledge, compound 1 is the first example of a simple fatty acid in which the carbonyl carbon of an acetate unit is methylated with SAM (Figure 3D). Compound 1 was not active against Staphylococcus aureus FDA209P JC-1, Micrococcus

• microtiter plates against six bacteria, Bacillus subtilis ATCC6633, Micrococcus luteus ATCC9341, Staphylococcus aureus FDA209P JC-1, Ralstonia solanacearum SUPP1541, Rhizobium radiobacter NBRC14554, Escherichia coli NIHJ JC-2, and two yeasts Candida albicans NBRC0197 and Saccharomyces cerevisiae S100 as

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

• methicillin- and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) with minimum inhibitory concentration (MIC) values of 4 and 13 µg/mL, respectively [4]. AbC belongs to a small family of NPs and two congeners of this family lacking the enone functionality, abyssomicins B and D, were discovered at

Doebner-type pyrazolopyridine carboxylic acids in an Ugi four-component reaction

• Maryna V. Murlykina,
• Oleksandr V. Kolomiets,
• Maryna M. Kornet,
• Yana I. Sakhno,
• Sergey M. Desenko,
• Victoriya V. Dyakonenko,
• Svetlana V. Shishkina,
• Oleksandr A. Brazhko,
• Vladimir I. Musatov,
• Alexander V. Tsygankov,
• Erik V. Van der Eycken and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2019, 15, 1281–1288, doi:10.3762/bjoc.15.126

• (strain 1211), Staphylococcus aureus (strain 2231) (gram-positive) and Escherichia coli (strain 1257), Pseudomonas aeruginosa (strain 1111) (gram-negative). Generally, the compounds were found to be less active than nitroxoline being the reference substance. The results obtained indicate that some

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

• ; nematophin; Staphylococcus aureus; Introduction Microorganisms present a rich source of bioactive natural products of pharmacological importance against an emerging number of multiresistant bacteria [1]. Such examples are Xenorhabdus sp., Gram-negative entomopathogenic bacteria which live in symbiosis with

• -oxopentanoic acid and tryptamine and showed good activities against different Gram-positive pathogens like Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) comparable with activities of vancomycin. Recently, the biosynthesis of 1 was elucidated by our group as well as the 2

Synthesis and biological activity of methylated derivatives of the Pseudomonas metabolites HHQ, HQNO and PQS

• Sven Thierbach,
• Max Wienhold,
• Susanne Fetzner and
• Ulrich Hennecke

Beilstein J. Org. Chem. 2019, 15, 187–193, doi:10.3762/bjoc.15.18

• from 3-iodinated quinolones by methylation and iodine–metal exchange/oxidation. The two N- and O-methylated derivatives of the PQS showed strong quorum sensing activity comparable to that of PQS itself. Staphylococcus aureus, another pathogenic bacterium often co-occurring with P. aeruginosa especially

• . aeruginosa and Staphylococcus aureus, which model interactions relevant to patients with cystic fibrosis, HQNO is a major factor for killing of S. aureus [15]. While HQNO seems to be generally toxic to Gram-positive bacteria, we could show that some bacteria are able to transform HQNO into less toxic

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

• among several other Pt(II)-based compounds to kill P. aeruginosa. It was previously reported that cisplatin had antimicrobial effects on nosocomial pathogens, such as Escherichia coli, Klebsiella pneumonia and Staphylococcus aureus [10] and persister cells [11]. Transcriptomic analysis was employed to

N-Acylated amino acid methyl esters from marine Roseobacter group bacteria

• Hilke Bruns,
• Lisa Ziesche,
• Nargis Khakin Taniwal,
• Laura Wolter,
• Thorsten Brinkhoff,
• Jennifer Herrmann,
• Rolf Müller and
• Stefan Schulz

Beilstein J. Org. Chem. 2018, 14, 2964–2973, doi:10.3762/bjoc.14.276

• program for their antimicrobial activity (Table 3). While the valine derivative 9 was virtually inactive, the other compounds showed some activity. Glycine compound 11 showed good activity against the Gram-positive bacteria Bacillus subtilis, Staphylococcus aureus, and Micrococcus luteus, and against the

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

• resistance: 1. Priority 1 – Critical: Acinetobacter baumannii, carbapenem-resistant Pseudomonas aeruginosa, carbapenem-resistant Enterobacteriaceae, carbapenem-resistant, 3rd generation cephalosporin-resistant 2. Priority 2 – High: Enterococcus faecium, vancomycin-resistant Staphylococcus aureus, methicillin

• and Gram-negative pathogens, namely Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Acinetobacter baylyi with MICs ranging from 39 to 78 μM [62]. A year later, further SAR investigations from the same research group led to the identification of another tetrahydrocarbazole derivative 12

• peptides for their ability to disrupt PPIs in the β-sliding clamp of Staphylococcus aureus. In this elegant study, from a library of 900,000 cyclic peptides, which was intracellularly generated using the split-intein circular ligation of peptides and proteins (SICLOPPS) technology [66], three hits

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

• ; quorum sensing; Staphylococcus aureus; Introduction Antimicrobial resistance is rapidly becoming a global threat [1][2]. It is estimated that worldwide, at least 700 000 people die every year from drug-resistant strains of common bacterial infections. Strategies to deal with the global antimicrobial

• 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

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

• potent antibacterial activity against Helicobacter pylori and induce growth defects in Escherichia coli and Staphylococcus aureus. Taking inspiration from a methodology used in our total synthesis of natural products, we applied this methodology to access analogues possessing bulky N-substituents

• Escherichia coli reporter system [9]), an intriguing effect upon the growth of E. coli and Staphylococcus aureus was noted, which showed an extended lag phase in response to the compounds (except 4, which was inactive towards E. coli. It should be noted that in this previous publication, the graphical data

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

• ]. Phenothiazines are a privileged scaffold in drug discovery most noted for their use as antipsychotic drugs including chlorpromazine, trifluoperazine, and thioridazine. However, such drugs have also long been noted for their significant antimicrobial activity particularly against Staphylococcus aureus and

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

• pathogens, [4] Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter species, were initially identified as the most problematic ones. In 2017, an extended list of twelve pathogens, currently considered as those with the highest

• factors playing crucial roles in acute virulence [55]. Staphylococcus aureus infections are characterized by the toxic action of bacterial α-hemolysin, a pore forming toxin leading to hemolysis. The antibody MEDI4893, which blocks S. aureus α-hemolysin, is currently in phase II clinical trials [56

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

• the plant Juniperus excelsa [3][4]. Leopolic acid A is endowed with antibacterial activity against Staphylococcus aureus and Staphylococcus pseudintermedius with a MIC of 16 μg/mL, and against Escherichia coli with a MIC of 128 µg/mL [3][4]. In terms of structural features, this compound contains a 4

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

• Staphylococcus aureus [11][12][13][14][15][16], Gram-positive QS systems are underrepresented in the literature. To address this issue, our research groups have been actively working to delineate the molecular mechanisms of several Gram-positive QS circuitries, including Enterococcus faecalis [17], Streptococcus