Synthesis of polyhydroxylated decalins via two consecutive one-pot reactions: 1,4-addition/aldol reaction followed by RCM/syn-dihydroxylation

• Michał Malik and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2016, 12, 2602–2608, doi:10.3762/bjoc.12.255

• possess strong and selective anti-glycosidase activity [16][17][18]. The polyoxygenated bicyclic motif is also found in some members of the nargenicin antibiotics family [19][20][21]. In our group, we have already proposed an approach to the synthesis of polyoxygenated bicyclic systems such as cis

Enduracididine, a rare amino acid component of peptide antibiotics: Natural products and synthesis

• Darcy J. Atkinson,
• Briar J. Naysmith,
• Daniel P. Furkert and
• Margaret A. Brimble

Beilstein J. Org. Chem. 2016, 12, 2325–2342, doi:10.3762/bjoc.12.226

• encountered to date in the development of efficient synthetic routes to facilitate drug discovery efforts inspired by the discovery of teixobactin. Keywords: amino acid; bacterial resistance; enduracididine; natural products; peptide antibiotics; Review Introduction The enduracididines The enduracididines

• (1–6) are a rare structural class of amino acids that contain a unique five-membered cyclic guanidine moiety (blue, Figure 1). L-Enduracididine (1) and D-allo-enduracididine (4) were the first identified as amino acid components of potent depsipeptide antibiotics [1][2]. Free enduracididine (1) was

• as components of the mannopeptimycin antibiotics, isolated from Streptomyces hygroscopicus LL-AC98 in 2002 [7] and to date, have not been isolated as the free amino acids or observed in any other natural products. Natural products containing enduracididine and hydroxyenduracididine Enduracidin A and

An effective one-pot access to polynuclear dispiroheterocyclic structures comprising pyrrolidinyloxindole and imidazothiazolotriazine moieties via a 1,3-dipolar cycloaddition strategy

• Alexei N. Izmest’ev,
• Galina A. Gazieva,
• Natalya V. Sigay,
• Sergei A. Serkov,
• Valentina A. Karnoukhova,
• Vadim V. Kachala,
• Alexander S. Shashkov,
• Igor E. Zanin,
• Angelina N. Kravchenko and
• Nina N. Makhova

Beilstein J. Org. Chem. 2016, 12, 2240–2249, doi:10.3762/bjoc.12.216

• of many natural and synthetic bioactive products [33][34][35][36][37][38][39][40]. The pyrimido[5,4-e]-1,2,4-triazine constitutes the core of the antibiotics fervenulin, xanthothricin, and reumycin [33][34]. Other hetero-annelated 1,2,4-triazines reveal antiviral effect against influenza A and B

Evidence for an iterative module in chain elongation on the azalomycin polyketide synthase

• Hui Hong,
• Yuhui Sun,
• Yongjun Zhou,
• Emily Stephens,
• Markiyan Samborskyy and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2016, 12, 2164–2172, doi:10.3762/bjoc.12.206

• ; marginolactone; natural products; polyketide synthase; Introduction Bacterial modular Type I polyketide synthases (PKSs) are multienzymes that govern the biosynthesis of diverse complex polyketide natural products, including clinically useful antibiotics, immunosuppressants, and antitumor compounds. They follow

Diastereoselective synthesis of 3,4-dihydro-2H-pyran-4-carboxamides through an unusual regiospecific quasi-hydrolysis of a cyano group

• Mikhail Yu. Ievlev,
• Oleg V. Ershov,
• Mikhail Yu. Belikov,
• Angelina G. Milovidova,
• Viktor A. Tafeenko and
• Oleg E. Nasakin

Beilstein J. Org. Chem. 2016, 12, 2093–2098, doi:10.3762/bjoc.12.198

• influenza caused by influenza A and B viruses contain a 3,4-dihydro-2H-pyran fragment [5]. Moreover, dihydropyrans have been proven to be particularly useful in the preparation of cyclic components of macrocyclic antibiotics [6][7] and as precursors in the synthesis of C-glycosides [8]. Modern and

Synthesis of the C8’-epimeric thymine pyranosyl amino acid core of amipurimycin

• Pramod R. Markad,
• Navanath Kumbhar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2016, 12, 1765–1771, doi:10.3762/bjoc.12.165

• ; carbohydrate; peptidyl nucleosides; Introduction Peptidyl nucleoside antibiotics are a class of complex molecules that encompass an extensive array of natural products [1]. The notable structural features of peptidyl nucleosides are responsible for their miscellaneous biological activities such as antitumor

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• chapter 1.1.1, furan rings can also be biosynthesised via oxa-Michael additions. Nonactin. Nonactin (70) is the smallest homolog of the macrotetrolides, a family of cyclic polyethers that commonly have activity as ionophore antibiotics (Scheme 11a). It is produced by Streptomyces griseus subsp. griseus

• the fact that four [4 + 2] cycloaddition events need to take place to assemble the four monomers into the highly symmetrical natural product [147]. Thiotetronates. Recently, Leadlay et al. presented their findings on the biosynthesis of thiotetronate antibiotics (Scheme 24) [148]. These small

Discovery of an inhibitor of the production of the Pseudomonas aeruginosa virulence factor pyocyanin in wild-type cells

• Bernardas Morkunas,
• Balint Gal,
• Warren R. J. D. Galloway,
• James T. Hodgkinson,
• Brett M. Ibbeson,
• Yaw Sing Tan,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2016, 12, 1428–1433, doi:10.3762/bjoc.12.137

• important opportunistic human pathogen [1]. This opportunistic pathogen is well known to be a challenging infection to completely eradicate in infected patients due to high levels of intrinsic resistance to a wide variety of antibiotics [1][2][3][4][5][6] and the tendency of P. aeruginosa cells to form

Cyclisation mechanisms in the biosynthesis of ribosomally synthesised and post-translationally modified peptides

• Andrew W. Truman

Beilstein J. Org. Chem. 2016, 12, 1250–1268, doi:10.3762/bjoc.12.120

• intrinsic requirement to be assembled from proteinogenic amino acids. The vast chemical space occupied by RiPPs means that they possess a wide variety of biological activities, and the class includes antibiotics, co-factors, signalling molecules, anticancer and anti-HIV compounds, and toxins. A considerable

• hydrolysis and disulphide bond formation through to the complex remodelling of almost every amino acid in a molecule. For example, thiopeptide antibiotics [15] and the marine toxin polytheonamide [16] were both believed to be non-ribosomal peptides for a number of years, while the bacterial cofactor

Synthesis of a deuterated probe for the confocal Raman microscopy imaging of squalenoyl nanomedicines

• Eric Buchy,
• Branko Vukosavljevic,
• Maike Windbergs,
• Dunja Sobot,
• Camille Dejean,
• Simona Mura,
• Patrick Couvreur and
• Didier Desmaële

Beilstein J. Org. Chem. 2016, 12, 1127–1135, doi:10.3762/bjoc.12.109

• induced focal cerebral ischemia and in rats undergoing spinal cord injury [16]. Interestingly, the “squalenisation platform” initially developed with highly hydrophilic therapeutics has been further extended to hydrophobic drugs such as beta-lactam antibiotics [17], paclitaxel [18], indolinone kinase

Antibacterial structure–activity relationship studies of several tricyclic sulfur-containing flavonoids

• Lucian G. Bahrin,
• Henning Hopf,
• Peter G. Jones,
• Laura G. Sarbu,
• Cornelia Babii,
• Alina C. Mihai,
• Marius Stefan and
• Lucian M. Birsa

Beilstein J. Org. Chem. 2016, 12, 1065–1071, doi:10.3762/bjoc.12.100

• . Fluorine-substituted flavonoids were found to be less active than those bearing other halogen atoms. Keywords: antibacterial activity; dithiocarbamates; dithiolium salts; flavonoids; SAR studies; Introduction The extensive use of antibiotics in human treatment and agriculture has led to the development

• [1][2]. Clearly, the development of new types of antibiotics is strongly needed [3]. Flavonoids are a diverse class of plant secondary metabolites that share the same C6–C3–C6 backbone. The great structural diversity of these compounds results in a wide range of biological activities. Flavonoids can

• values, suggesting once again that a smaller substituent leads to a lower antibacterial activity against Gram negative microorganisms. In order to perform a comparison with known antibiotics, both S. aureus and E. coli where exposed to ampicillin and kanamycin (Table 5, entries 15 and 16). The results

Marine-derived myxobacteria of the suborder Nannocystineae: An underexplored source of structurally intriguing and biologically active metabolites

• Antonio Dávila-Céspedes,
• Peter Hufendiek,
• Max Crüsemann,
• Till F. Schäberle and
• Gabriele M. König

Beilstein J. Org. Chem. 2016, 12, 969–984, doi:10.3762/bjoc.12.96

• ample amount of them was shown to work as antimicrobial agents, above all corallopyronin A. This is probably a reflection of their predatory habits [27][28]. A comprehensive description of antibiotics obtained from myxobacteria can be found in a previous review [21]. One outstanding example of a

Muraymycin nucleoside-peptide antibiotics: uridine-derived natural products as lead structures for the development of novel antibacterial agents

• Daniel Wiegmann,
• Stefan Koppermann,
• Marius Wirth,
• Giuliana Niro,
• Kristin Leyerer and
• Christian Ducho

Beilstein J. Org. Chem. 2016, 12, 769–795, doi:10.3762/bjoc.12.77

• natural products. These uridine-derived nucleoside-peptide antibiotics inhibit the bacterial membrane protein translocase I (MraY), a key enzyme in the intracellular part of peptidoglycan biosynthesis. This review describes the structures of naturally occurring muraymycins, their mode of action, synthetic

• access to muraymycins and their analogues, some structure–activity relationship (SAR) studies and first insights into muraymycin biosynthesis. It therefore provides an overview on the current state of research, as well as an outlook on possible future developments in this field. Keywords: antibiotics

• agents is of growing significance. The discovery of penicillin [1] and the proof of its in vivo efficacy [2] marked the starting point for the research on antibacterial drugs during the so-called "golden age" of antibiotics. Despite the early occurrence of first resistances [3][4][5], an innovation gap

Three new trixane glycosides obtained from the leaves of Jungia sellowii Less. using centrifugal partition chromatography

• Luíse Azevedo,
• Larissa Faqueti,
• Marina Kritsanida,
• Antonia Efstathiou,
• Despina Smirlis,
• Gilberto C. Franchi Jr,
• Grégory Genta-Jouve,
• Sylvie Michel,
• Louis P. Sandjo,
• Raphaël Grougnet and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2016, 12, 674–683, doi:10.3762/bjoc.12.68

• ) were cultured in RPMI 1640 (RPMI) medium, respectively, supplemented with 10% heat-inactivated fetal bovine serum, 10 mM HEPES and antibiotics (penicillin/streptomycin) as previously described at 26 C [43]. The inhibitory activity of compounds was determined with the use of an MTT-based assay, the

Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

• Guozheng Huang,
• Simon Schramm,
• Jörg Heilmann,
• David Biedermann,
• Vladimír Křen and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 662–669, doi:10.3762/bjoc.12.66

• (kernels) of H. wightiana, contains besides hydnocarpin mainly cyclopentenoic fatty acids [16], which show pronounced antibiotic activity and inhibit multiplication of mycobacteria [17]. Combination of these antibiotics together with hydnocarpin (MDR inhibitor) helped to treat such a persistent disease

Correction: Effective in silico prediction of new oxazolidinone antibiotics: force field simulations of the antibiotic–ribosome complex supervised by experiment and electronic structure methods

• Jörg Grunenberg and
• Giuseppe Licari

Beilstein J. Org. Chem. 2016, 12, 608–610, doi:10.3762/bjoc.12.59

Antibiotics from predatory bacteria

• Juliane Korp,
• María S. Vela Gurovic and
• Markus Nett

Beilstein J. Org. Chem. 2016, 12, 594–607, doi:10.3762/bjoc.12.58

• as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators

• : antibiotics; genome mining; Herpetosiphon; myxobacteria; predation; Introduction Microorganisms are major contributors to primary biomass production and nutrient cycling in nature. The composition of a microbial community shapes an ecosystem, but is also responsive to biotic and environmental cues. Predation

• closely related antibiotics featuring a distinctive 28-membered macrolide ring. First discovered by Rosenberg et al. in M. xanthus TA [74], the myxovirescins were later also reported from other myxobacterial isolates, including strain DK1622 [75][76][77][78][79]. Myxovirescins are excreted during late

Biosynthesis of α-pyrones

• Till F. Schäberle

Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56

• (2), tetraacetic acid lactone (3), and 6-pentyl-2-pyrone (29) also more complex systems, e.g., bufalin (31) [38], fusapyrones (32,33) [39], or the α-pyrone antibiotics corallopyronins (34,35) [40] and myxopyronins (36,37) [41], exist in the group of monocyclic α-pyrones (Figure 7). The bufadienolides

• A was also tested successfully using an in vivo mouse model for the treatment of infections with filarial nematodes [44]. Such antibiotics produced by heterotroph bacteria, e.g., marine and terrestrial myxobacteria which can feed on other bacteria, are suggested as predatory weapons to paralyze and

• paragraph the chain interconnecting mechanism will be described. For α-pyrone antibiotics, the corallopyronin and myxopyronin derivatives, free-standing KSs encoded in the respective cluster, i.e., CorB and MxnB, were suggested as the chain-interconnecting enzymes [84][87]. These enzymes have now been

Effective in silico prediction of new oxazolidinone antibiotics: force field simulations of the antibiotic–ribosome complex supervised by experiment and electronic structure methods

• Jörg Grunenberg and
• Giuseppe Licari

Beilstein J. Org. Chem. 2016, 12, 415–428, doi:10.3762/bjoc.12.45

• resistance phenomena as early as 1940 [4], in the 1970s the problem of bacterial infection seemed to be solved, because a wide range of potent antibiotics were available. During the last two decades the situation nevertheless changed dramatically: the logarithmic rise in the prevalence of penicillin

• injuries can kill, is a very real possibility for the 21st century” [6]. The need for a fast but effective, structure-based strategy for the development of new antibiotics is therefore more than evident [7]. From an experimental point of view, during the last years the amount of structural data describing

• (PRSP) [16]. Nevertheless, though oxazolidinones represent one of the few new chemical classes of antibiotics disclosed in the past 40 years, cases of oxazolidinone-resistant strains have been already reported [17][18][19], underscoring again the urgent demand for new linezolid analogues to overcome the

Natural products from microbes associated with insects

• Christine Beemelmanns,
• Huijuan Guo,
• Maja Rischer and
• Michael Poulsen

Beilstein J. Org. Chem. 2016, 12, 314–327, doi:10.3762/bjoc.12.34

• synthetic compound libraries to counteract a declining number of new antibiotic entities in the drug development pipeline has largely failed [3], and the current poor repertoire represents a ”ticking time bomb”. Societies face, as a consequence of the rapid globalization and intensive use of antibiotics, an

• identified as piericidin derivatives (e.g., piericidin A1 (1), Figure 3) and the chlorinated indole derivative streptochlorin (2). Imaging analysis based on a combination of laser desorption/ionization (LDI)–time of flight (TOF) mass spectrometry imaging visualized the spatial distribution of the antibiotics

• on the outer cocoon surface. Subsequent gas chromatography–mass spectrometry (GC–MS) analyses and expression studies revealed that the production of both antibiotics peaked within the first two weeks after cocoon spinning [45]. Although expression levels decreased shortly afterwards, the antibiotic

Synthesis of cyclic N¹-pentylinosine phosphate, a new structurally reduced cADPR analogue with calcium-mobilizing activity on PC12 cells

• Ahmed Mahal,
• Stefano D’Errico,
• Nicola Borbone,
• Brunella Pinto,
• Agnese Secondo,
• Valeria Costantino,
• Valentina Tedeschi,
• Giorgia Oliviero,
• Vincenzo Piccialli and
• Gennaro Piccialli

Beilstein J. Org. Chem. 2015, 11, 2689–2695, doi:10.3762/bjoc.11.289

• synthetic building blocks towards the synthesis of biologically relevant compounds such as antiviral and antineoplastic drugs [3][4][5][6][7][8], antibiotics and antifungal agents [9][10][11]. Furthermore, several NNs act as potent second messengers involved in the regulation of key metabolic pathways [12

Recent highlights in biosynthesis research using stable isotopes

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2015, 11, 2493–2508, doi:10.3762/bjoc.11.271

• are widely used as antibiotics in fish farming industry. All compounds from this class feature a nine-membered dilactone core and a 3-formamidosalicylic acid moiety [84]. The latter provides an interesting biosynthetic rearrangement starting from tryptophan, which was investigated both by isotopic

Synthesis, antimicrobial and cytotoxicity evaluation of new cholesterol congeners

• Mohamed Ramadan El Sayed Aly,
• Hosam Ali Saad and
• Shams Hashim Abdel-Hafez

Beilstein J. Org. Chem. 2015, 11, 1922–1932, doi:10.3762/bjoc.11.208

• incorporates it into its cytoplasmic membrane. In this way it boosts resistance to host immune defense and antibiotics as well [5][7]. In another case, eukaryotic cell membranes are supported by a membrane-associated cholesterol efflux regulatory protein (CERP). This protein, also known as ABCA1, is a major

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

• Ivan Bassanini,
• Karl Hult and
• Sergio Riva

Beilstein J. Org. Chem. 2015, 11, 1583–1595, doi:10.3762/bjoc.11.174

• in the esterification of the antineoplastic antibiotics mithramycin (5) catalyzed by Candida antarctica lipase A (CAL-A) and chromomycin A3 (6) catalyzed by Candida antarctica lipase B (CAL-B) [24]. In another report a series of mono-substituted troxerutin esters (7a) were synthesized by action of

Structure and conformational analysis of spiroketals from 6-O-methyl-9(E)-hydroxyiminoerythronolide A

• Ana Čikoš,
• Irena Ćaleta,
• Dinko Žiher,
• Mark B. Vine,
• Ivaylo J. Elenkov,
• Marko Dukši,
• Dubravka Gembarovski,
• Marina Ilijaš,
• Snježana Dragojević,
• Ivica Malnar and
• Sulejman Alihodžić

Beilstein J. Org. Chem. 2015, 11, 1447–1457, doi:10.3762/bjoc.11.157

• ; spiroketal; Introduction Macrolide antibiotics are natural or semi-synthetic products of polyketide origin, containing one or more desoxy sugars attached to a macrocyclic lactone aglycon. This large and structurally diverse category of compounds has traditionally been divided into classes based on the

• increasing its antibacterial spectrum, acid stability, masking the foul taste, improving the pharmacodynamic properties and reducing the associated side effects. The two most successful semisynthetic macrolide antibiotics derived from erythromycin A are azithromycin [2][3] and clarithromycin [4]. Recent