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

• -methoxyhydnocarpin has been described to enhance the antimicrobial activity of berberine [19]. In the light of steadily growing antibiotic resistance any potent and nontoxic MDR inhibitor is of utmost importance. Hydnocarpin has also antineoplastic activity due to sensitizing multidrug-resistant cancer cell lines

Biosynthesis of α-pyrones

• Till F. Schäberle

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

• (29) showed antifungal activity against Rhizoctonia cerealis, Gaeumannomyces graminis and Botrytis cinerea (Figure 6) [34]. The structural related trichopyrone (30) instead showed no antimicrobial activity [35]. For compound 29 it was further revealed that it represents the prominent headspace

Synthesis of bi- and bis-1,2,3-triazoles by copper-catalyzed Huisgen cycloaddition: A family of valuable products by click chemistry

• Zhan-Jiang Zheng,
• Ding Wang,
• Zheng Xu and
• Li-Wen Xu

Beilstein J. Org. Chem. 2015, 11, 2557–2576, doi:10.3762/bjoc.11.276

• series of ester-linked dialkynes from the acid dichloride and propargyl alcohol in the presence of DMAP [34]. Here, the CuAAC reaction between the dialkynes 42 and the azides provided the desired bistriazoles 43 in good yield (70–92%, Scheme 16). Interestingly, the antimicrobial activity studies revealed

Bromotyrosine-derived alkaloids from the Caribbean sponge Aplysina lacunosa

• Qun Göthel,
• Thanchanok Sirirak and
• Matthias Köck

Beilstein J. Org. Chem. 2015, 11, 2334–2342, doi:10.3762/bjoc.11.254

• comparison with 21, compound 3 showed one extra aliphatic carbon and was named aplysinin B. The new compounds 14-debromo-11-deoxyfistularin-3 (1) and aplysinin A (2) were tested for their antimicrobial activity against different Gram-positive and Gram-negative bacteria, fungi, and for their antiproliferative

• showed mild toxicity against the breast cancer cell line MCF-7 and to FS4-LTM conditional immortalization human fibroblasts (IC50 = 78 and 32 µM, respectively). The cytotoxicities of the known compounds (4–17) are also listed in Table 5. None of the isolated compounds showed any antimicrobial activity

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

• IR spectroscopic techniques. Chalcone conjugate 6c showed the best antimicrobial activity, while the lactoside conjugate 27 showed the best cytotoxic effect in vitro. Keywords: antimicrobial; chalcone; cholesterol; cytotoxicity; glycoside; triazole; Introduction Cholest-5-en-3β-ol (cholesterol, 1

• this mechanism, synthetic polycarbonates arising from organocatalytic ring-opening polymerization of cholesterol monomers were reported to create self-assemblies possessing high interior charge density and wide spectrum antimicrobial activity [6]. Interestingly, the causative vector of human gastritis

• line and it showed an activity close to that of the positive control doxorubicin. Structure of ceragenin (CSA-8) and selected cholesterol conjugates. In vitro antimicrobial activity of some new cholesterol derivatives against E.coli, S. aureus. A. flavus and C. albicans. Ampicillin was used as positive

SmI₂-mediated dimerization of indolylbutenones and synthesis of the myxobacterial natural product indiacen B

• Nils Marsch,
• Peter G. Jones and
• Thomas Lindel

Beilstein J. Org. Chem. 2015, 11, 1700–1706, doi:10.3762/bjoc.11.184

• , confirming its antimicrobial activity. The E-configuration of the chloroalkene moiety of indiacen B was confirmed by X-ray analysis. Keywords: biological evaluation; heterocycles; indoles; natural products; total synthesis; Introduction Indole alkaloids prenylated at the benzene ring are found in tropical

• violaceum (67 µg/mL), and Pseudomonas stutzeri (no inhibition), and also against the fungus Mucor hiemalis (8.3 µg/mL). The antimicrobial activity of indiacen B (2) against M. diernhoferi, which was described by Müller et al. [5] in course of the isolation from the myxobacterium Sandaracinus amylolyticus

• , was confirmed. Against N. simplex and M. hiemalis the activity was twofold and against E. coli TOL C fourfold higher than observed for the isolated sample. Against C. violaceum a slightly weaker activity was observed. Overall, the antimicrobial activity of indiacen B (2) can be regarded as confirmed

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• -quinone somehow showed cytotoxic activitiy although the lack of a pyridine E ring or the presence of a thiazole and a thiazinone ring diminished the activity. A similar loss of potency is also observed when the pyridine E ring contains substituents like MeO and OH groups. Antimicrobial activity An

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• . Nostocyclyne A (21) is an acetylenic cyclophane derivative isolated from a terrestrial Nostoc species, with antimicrobial activity (Figure 4). The turriane family of natural products 22–24 were isolated from the stem wood of the Australian tree Grevillea striata. Turrianes 22–24 are effective DNA-cleaving

N-Alkyl derivatives of diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside; synthesis and antimicrobial activity

• Agata Walczewska,
• Daria Grzywacz,
• Dorota Bednarczyk,
• Małgorzata Dawgul,
• Andrzej Nowacki,
• Wojciech Kamysz,
• Beata Liberek and
• Henryk Myszka

Beilstein J. Org. Chem. 2015, 11, 869–874, doi:10.3762/bjoc.11.97

• thiocarbonyl group. Such analogues are much more lipophilic, but also less basic than the parent saponin 7. In this paper, for the first time, the synthesis and antimicrobial activity of the N-alkyl derivatives of diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside (7) are presented. From the chemical point of view

• glycoside (7), adopt the 4C1 conformation, as demonstrated by the J1,2 ≈ 8 Hz, J2,3 ≈ J3,4 ≈ J4,5 ≈ 9–10 Hz coupling constants. Evaluation of antimicrobial activity The N-alkyl derivatives of diosgenyl 2-amino-2-deoxy-β-D-glucopyranosides 8–15 and 17 were tested for their antibacterial and antifungal in

• antimicrobial activity indicate that N-ethyl and N-propyl derivatives exhibit stronger activity against Gram-positive bacteria than the parent diosgenyl 2-deoxy-2-amino-β-D-glucopyranoside hydrochloride. Reagents used for the synthesis of diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside (7). N-Alkylation of

Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view

• Qiu Sun,
• Jörg Heilmann and
• Burkhard König

Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28

• of alkyl groups instead of acyl groups enhanced the antimicrobial activity and stability at pH 7.4. Xanthohumol Xanthohumol (XN, 58), a naturally occurring prenylated chalcone in hop plants (Humulus lupulus L., Cannabaceae), has been suggested to have potential to suppress the development and

A novel 4-aminoantipyrine-Pd(II) complex catalyzes Suzuki–Miyaura cross-coupling reactions of aryl halides

• Claudia A. Contreras-Celedón,
• Darío Mendoza-Rayo,
• José A. Rincón-Medina and
• Luis Chacón-García

Beilstein J. Org. Chem. 2014, 10, 2821–2826, doi:10.3762/bjoc.10.299

• complexes of 4-AAP have shown anti-inflammatory, analgesic, antiviral, antipyretic, antirheumatic and antimicrobial activity [20][21]. Despite the potential biological importance of 4-AAP, the catalytic activity of its transition metal complexes for C–C bond formation have not yet been investigated. Herein

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

• antifungal effect of p-hydroxybenzoic acid esters against C. albicans is directly linked to their hydrophobicity: the minimal inhibition concentrations were directly correlated to the nature of the residue. Table 3 also highlights that the antimicrobial activity of the preservatives is reduced in the

• pronounced with α- than β-CD [44]. Indeed, interactions between a series of p-hydroxybenzoic acid esters (from methyl to dodecyl residues) with α-CD than with β-CD have been investigated by Uekama and coworkers [44]. In the presence of both types of CD, the antimicrobial activity against C. albicans was

• -hydroxybenzoate, benzyl alcohol, 2-phenoxyethanol) [45]. The authors established a clear relationship between the binding constants and the antimicrobial activity of the preservatives on various strains: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and C. albicans. Indeed, highly water-soluble

Sacrolide A, a new antimicrobial and cytotoxic oxylipin macrolide from the edible cyanobacterium Aphanothece sacrum

• Naoya Oku,
• Miyako Matsumoto,
• Kohsuke Yonejima,
• Keijiroh Tansei and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2014, 10, 1808–1816, doi:10.3762/bjoc.10.190

• . However, to date, only two substances have been reported: pseudovitamin B12 [10] and sulfated polysaccharide sacran [11]. We evaluated the antimicrobial activity of this alga and found that a lipophilic fraction of an ethanolic extract showed inhibitory activity against several microbes. Activity-guided

• . Initial derivatization strategy for the stereochemical analysis of sacrolide A (1). Determination of the stereochemistry of sacrolide A (1). Plausible biosynthesis of sacrolide A (1). 1H (500 MHz) and 13C (125 MHz) NMR data for sacrolide A (1) in CDCl3 (δ in ppm). Antimicrobial activity of sacrolide A (1

New sesquiterpene hydroquinones from the Caribbean sponge Aka coralliphagum

• Qun Göthel and
• Matthias Köck

Beilstein J. Org. Chem. 2014, 10, 613–621, doi:10.3762/bjoc.10.52

• two sulfate ester groups. Compound 5 could be the precursor of bis(sulfato)cyclosiphonodictyol A. Another possibility is that bis(sulfato)cyclosiphonodictyol A lost its sulfate ester group during the isolation procedure. The new compounds were tested for antimicrobial activity against different Gram

An oxidative amidation and heterocyclization approach for the synthesis of β-carbolines and dihydroeudistomin Y

• Suresh Babu Meruva,
• Akula Raghunadh,
• Raghavendra Rao Kamaraju,
• U. K. Syam Kumar and
• P. K. Dubey

Beilstein J. Org. Chem. 2014, 10, 471–480, doi:10.3762/bjoc.10.45

• from the active Caribbean colonial tunicate Eudistoma olivaceum. β-Carboline alkaloids bearing a substituted phenylacetyl group at C-1 position such as eudistomin T (1) [4], eudistomin R (2a) and eudistomin S (2b) [5] were isolated by Cardellina et al. [6], and these compounds exhibit antimicrobial

• activity. Xestomanzamine A (3) [5] is a β-carboline alkaloid with an 1-methyl-1H-imidazole-5-acyl group at the C-1 position and was isolated from the Okinawan marine sponge Xestopongia sp. The other β-carboline alkaloids reported in the literature are fascaplysin (4) [7], eudistomin A (5a) [3], harmine (5b

Tanzawaic acids I–L: Four new polyketides from Penicillium sp. IBWF104-06

• Louis P. Sandjo,
• Eckhard Thines,
• Till Opatz and
• Anja Schüffler

Beilstein J. Org. Chem. 2014, 10, 251–258, doi:10.3762/bjoc.10.20

• oryzae was not reported to date. The structurally related hynapenes B and C showed antimicrobial activity against Pyricularia oryzae [8] whereas arohynapenes A, B, and D [3][9] were not active in agar diffusion assays. However, arohynapenes A and B inhibited the spore germination at 25 µg/mL (IC90). In

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

Total synthesis of the endogenous inflammation resolving lipid resolvin D2 using a common lynchpin

• John Li,
• May May Leong,
• Alastair Stewart and
• Mark A. Rizzacasa

Beilstein J. Org. Chem. 2013, 9, 2762–2766, doi:10.3762/bjoc.9.310

• evaluation of the resolvin series in preclinical models of bacterial sepsis has stimulated strong interest in their therapeutic potential, as RvD2 appears to express the unusual combination of anti-inflammatory and antimicrobial activity. Further interest in inflammation-resolving lipids is stimulated by

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• antimicrobial activity against fungi and yeast of 26 was simultaneously reported with its isolation [16]. Moreover, with IC50 values in the low nanomolar range (1–20 nM), staurosporine (26) is one of the most potent protein kinase inhibitors to date [18]. It took nine years to identify the crucial protein

Simple synthesis of pyrrolo[3,2-e]indole-1-carbonitriles

• Adam Trawczyński,
• Robert Bujok,
• Zbigniew Wróbel and
• Krzysztof Wojciechowski

Beilstein J. Org. Chem. 2013, 9, 934–941, doi:10.3762/bjoc.9.107

• -dihydropyrrolo[3,2-e]indole fragment is present in anticancer agents, such as CC-1065 [1], duocarmycin [1], and yatakemycin [2]. Some pyrrolo[3,2-e]indole derivatives show antimicrobial activity [3]. One method of synthesis of the 1,2-dihydropyrrolo[2,3-e]indoles is reduction of pyrrolo[3,2-e]indoles with sodium

Chemoenzymatic synthesis and biological evaluation of enantiomerically enriched 1-(β-hydroxypropyl)imidazolium- and triazolium-based ionic liquids

• Paweł Borowiecki,
• Małgorzata Milner-Krawczyk and
• Jan Plenkiewicz

Beilstein J. Org. Chem. 2013, 9, 516–525, doi:10.3762/bjoc.9.56

• liquids to exhibit excellent antimicrobial activity, raising the possibility that ionic liquids could find application as biocidal agents in the control of microorganism growth [42][43][44][45]. Herein, we report the results of our investigation on the chemoenzymatic synthesis of new chiral ionic liquids

• ionization mass spectrometry (HRMS–ESI). Their structures were found to be spectroscopically well–defined, which was further confirmed by elemental analyses. For the purpose of biological tests, the racemic mixtures all of salts presented in Table 3 were synthesized. Antimicrobial activity of racemic ionic

Multivalent display of the antimicrobial peptides BP100 and BP143

• Imma Güell,
• Rafael Ferre,
• Kasper K. Sørensen,
• Esther Badosa,
• Iteng Ng-Choi,
• Emilio Montesinos,
• Eduard Bardají,
• Lidia Feliu,
• Knud J. Jensen and
• Marta Planas

Beilstein J. Org. Chem. 2012, 8, 2106–2117, doi:10.3762/bjoc.8.237

• active against human red blood cells pointing out that peptide preassembly is critical for the hemolytic activity. Notably, peptide preassembly resulted in an enhanced bactericidal effect. Keywords: antimicrobial activity; carbopeptides; multimeric structures; oxime ligation; phytopathogenic bacteria

• occasionally been reported that an improved binding to microbial membranes and thus an improved antimicrobial activity can be achieved if several copies of an antimicrobial peptide are linked together to form multimeric species [9][10][11][12][13][14][15]. The hypothesis of the assembly model is based on

• ]. In this study we used carbohydrate templates for the design of multivalent antimicrobial peptides targeted to control plant and human pathogenic bacteria and explored whether multivalency enhances the antimicrobial activity. These multivalent constructs were obtained by preassembling the

Modulating the activity of short arginine-tryptophan containing antibacterial peptides with N-terminal metallocenoyl groups

• H. Bauke Albada,
• Alina-Iulia Chiriac,
• Michaela Wenzel,
• Maya Penkova,
• Julia E. Bandow,
• Hans-Georg Sahl and
• Nils Metzler-Nolte

Beilstein J. Org. Chem. 2012, 8, 1753–1764, doi:10.3762/bjoc.8.200

• prevented widespread systemic administration in the clinic. However, during the past couple of decades a large number of peptides with very potent antimicrobial activity and lower general toxicity were discovered [7]. Inspired by these antimicrobial peptides, many synthetic derivatives of naturally

• synthesized and tested for antimicrobial activity. In this paper we add another metal to the spectrum of existing organometallic synAMPs and we provide a detailed assessment of the kinetic parameters of this peptide. Specifically, we describe the effect of the introduction of ruthenocenoyl (ruthenocene

A macrolactonization approach to the total synthesis of the antimicrobial cyclic depsipeptide LI-F04a and diastereoisomeric analogues

• James R. Cochrane,
• Dong Hee Yoon,
• Christopher S. P. McErlean and
• Katrina A. Jolliffe

Beilstein J. Org. Chem. 2012, 8, 1344–1351, doi:10.3762/bjoc.8.154

• -chain analogue 12 for attachment to the cyclic peptide core (Scheme 3). Notably, a previously synthesised LI-F04a analogue with a twelve-carbon side chain lacking the hydroxy group has been observed to have antimicrobial activity [9]. Thus, hydrolysis of pentadecanolide 13 [26] was followed by

Antibiotic and cytotoxic peptides

• Norbert Sewald

Beilstein J. Org. Chem. 2012, 8, 1144–1145, doi:10.3762/bjoc.8.127

• : chemical compounds that provide the producing species with specific protective mechanisms or other advantages. Among these, there are, e.g., peptides that display antibiotic/antimicrobial activity. These have been isolated from plants, invertebrates, vertebrates, and humans, but also from microorganisms