naphthoquinones has been researched along with lactonamycin* in 20 studies
20 other study(ies) available for naphthoquinones and lactonamycin
Article | Year |
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Lactomycins A-C, Dephosphorylated Phoslactomycin Derivatives that Inhibit Cathepsin B, from the Marine-derived Streptomyces sp. ACT232.
Topics: Antifungal Agents; Cathepsin B; Indoles; Magnetic Resonance Spectroscopy; Naphthoquinones; Polyketides; Streptomyces | 2018 |
Total syntheses of lactonamycin and lactonamycin Z with late-stage A-ring formation and glycosylation.
Topics: Anti-Bacterial Agents; Carbamates; Catalysis; Coordination Complexes; Cyclization; Glycosylation; Indoles; Naphthoquinones; Polyketides | 2013 |
Acinetobacter baumannii virulence is enhanced in Galleria mellonella following biofilm adaptation.
The opportunistic nosocomial pathogen Acinetobacter baumannii is responsible for a growing number of infections; however, few of its potential virulence factors have been identified, and how this organism causes infection remains largely unknown. Bacterial biofilms are often an important component in infection and persistence but there is no conclusive evidence to link biofilm formation with virulence and severity of infection in Acinetobacter. To investigate this link, several clinical isolates were assessed in biofilm culture models and were tested for virulence in the insect model Galleria mellonella. In both systems, the profiles showed significant differences between strains, but no correlation was observed between virulence and the ability to form biofilms. In contrast, A. baumannii cells from a biofilm produced higher mortality rates than an equivalent number of planktonic cells. Relative to planktonic cells, A. baumannii biofilm cultures also showed reduced sensitivity to antibiotics normally used in the treatment of A. baumannii, especially colistin. This model, therefore, provides a suitable system to investigate the link between biofilm growth and various factors influencing virulence during A. baumannii infection. Topics: Acinetobacter baumannii; Animals; Anti-Bacterial Agents; Bacterial Proteins; Biofilms; Drug Resistance, Bacterial; Gene Expression Regulation, Bacterial; Indoles; Microbial Sensitivity Tests; Moths; Naphthoquinones; Quorum Sensing; Virulence | 2012 |
Dramatic influence of the substitution of alkylidene-5H-furan-2-ones in Diels-Alder cycloadditions with o-quinonedimethide as diene partner: en route to the CDEF polycyclic ring system of lactonamycin.
An efficient and rapid synthesis of the CDEF ring system of lactonamycinone is reported via a highly chemo- and diastereoselective intermolecular Diels-Alder cycloaddition between trans-1,2-disilyloxybenzocyclobutene and the appropriate γ-alkylidenebutenolide. The feasibility and the total chemoselectivity of the [4 + 2] cycloaddition for the construction of a spirolactone moiety via an intramolecular approach (IMDA) using both partners is also described demonstrating the versatility of the γ-alkylidenebutenolide building block. Topics: Alkylation; Cyclization; Furans; Indoles; Molecular Structure; Naphthoquinones; Quinones; Spironolactone; Stereoisomerism | 2012 |
Synthetic studies on lactonamycins: synthesis of the model BCDEF aglycon.
The lactonamycin model aglycon 4 was synthesized from the trihalogenated benzene derivative 10. Ethynyltetraol 6 was prepared from 10 via carbon elongations, oxidative demethylation, a cycloaddition reaction with the diene derived from homophthalic anhydride, and dihydroxylation. Final E- and F-ring constructions from 6 were realized via a palladium-catalyzed cyclization-methoxycarbonylation, a stereoselective methanol addition, and lactonization, leading to the production of 4. Topics: Cyclization; Indoles; Molecular Structure; Naphthoquinones; Stereoisomerism | 2010 |
Biosynthetic investigations of lactonamycin and lactonamycin z: cloning of the biosynthetic gene clusters and discovery of an unusual starter unit.
The antibiotics lactonamycin and lactonamycin Z provide attractive leads for antibacterial drug development. Both antibiotics contain a novel aglycone core called lactonamycinone. To gain insight into lactonamycinone biosynthesis, cloning and precursor incorporation experiments were undertaken. The lactonamycin gene cluster was initially cloned from Streptomyces rishiriensis. Sequencing of ca. 61 kb of S. rishiriensis DNA revealed the presence of 57 open reading frames. These included genes coding for the biosynthesis of l-rhodinose, the sugar found in lactonamycin, and genes similar to those in the tetracenomycin biosynthetic gene cluster. Since lactonamycin production by S. rishiriensis could not be sustained, additional proof for the identity of the S. rishiriensis cluster was obtained by cloning the lactonamycin Z gene cluster from Streptomyces sanglieri. Partial sequencing of the S. sanglieri cluster revealed 15 genes that exhibited a very high degree of similarity to genes within the lactonamycin cluster, as well as an identical organization. Double-crossover disruption of one gene in the S. sanglieri cluster abolished lactonamycin Z production, and production was restored by complementation. These results confirm the identity of the genetic locus cloned from S. sanglieri and indicate that the highly similar locus in S. rishiriensis encodes lactonamycin biosynthetic genes. Precursor incorporation experiments with S. sanglieri revealed that lactonamycinone is biosynthesized in an unusual manner whereby glycine or a glycine derivative serves as a starter unit that is extended by nine acetate units. Analysis of the gene clusters and of the precursor incorporation data suggested a hypothetical scheme for lactonamycinone biosynthesis. Topics: Bacterial Proteins; Cloning, Molecular; DNA, Bacterial; Glycine; Indoles; Molecular Sequence Data; Multigene Family; Naphthoquinones; Sequence Analysis, DNA; Streptomyces | 2008 |
Studies on the total synthesis of lactonamycin: construction of model ABCD ring systems.
Model studies on the synthesis of the tetracyclic ABCD ring system of lactonamycin (1) are described. The key step involved the double Michael addition reaction of alcohol 8 to propynoate esters to produce the BCD units 13 and 14 of the target 1. Alternatively, double Michael addition of alcohol 8 to di-tert-butyl acetylenedcarboxylate gave the corresponding BCD ring systems 36 and 37. Acid-mediated hydrolysis of the dihydroquinone monoketal units of 13 and 14 and 36 and 37 in the presence of air gave the corresponding quinones 7 and 39. These were converted into the tetracyclic ABCD units 6, 26a, 40, and 42 of lactonamycin (1) by either dihydroxylation or epoxidation and acid-catalyzed lactonization. Topics: Cyclization; Indoles; Molecular Structure; Naphthoquinones; Stereoisomerism | 2006 |
Studies on the total synthesis of lactonamycin: synthesis of the CDEF ring system.
A concise and efficient synthesis of the tetracyclic CDEF ring system of lactonamycin (1) is described. The key step involved the Lewis acid mediated, intramolecular Friedel-Crafts acylation of carboxylic acid 6 to produce the tetracyclic CDEF core structure of target 1. The synthesis of 6 was carried out using a high-yielding Negishi coupling of benzyl bromide 7 with triflate 8, which was accessible in 11 steps and 31% overall yield on a multigram scale starting from trihydroxy acid 9. Topics: Indoles; Naphthoquinones | 2006 |
Asymmetric synthesis of the AB ring system of lactonamycin.
[reaction: see text] An enantiospecific synthesis of the AB fragment of lactonamycin (5) is achieved in eight steps from dimethyl D-tartrate. Ester enolate chemistry features prominently in the sequence. Topics: Indoles; Molecular Conformation; Naphthoquinones; Stereoisomerism | 2004 |
Studies directed toward the total synthesis of lactonamycin: control of the sense of cycloaddition of a quinone through directed intramolecular catalysis.
Topics: Anthracenes; Anti-Bacterial Agents; Benzoquinones; Catalysis; Indoles; Magnetic Resonance Spectroscopy; Molecular Structure; Naphthoquinones | 2003 |
Total synthesis of lactonamycinone.
Topics: Benzoquinones; Crystallography, X-Ray; Indoles; Magnetic Resonance Spectroscopy; Molecular Conformation; Molecular Structure; Naphthoquinones | 2003 |
Lactonamycin Z, an antibiotic and antitumor compound produced by Streptomyces sanglieri strain AK 623.
Topics: Anti-Bacterial Agents; Antineoplastic Agents; Cell Line, Tumor; Drug Screening Assays, Antitumor; Humans; Indoles; Molecular Structure; Naphthoquinones; Streptomyces | 2003 |
Tandem conjugate cyanide addition-Dieckmann condensation in the synthesis of the ABCD-ring system of lactonamycin.
An efficient synthesis of the ABCD-ring system of lactonamycin (1) is reported in this Letter. The key step is the tandem cyanide conjugate addition-Dieckmann condensation of alkyne 17 to afford a fully functionalized anthracene. Selective reduction of the cyano group with subsequent lactam formation affords the tetracyclic core of lactonamycin 19. [reaction: see text] Topics: Anti-Bacterial Agents; Cyanides; Indicators and Reagents; Indoles; Models, Biological; Naphthoquinones; Streptomyces | 2002 |
Short synthesis of the CDEF ring system of lactonamycin.
[reaction: see text]. A synthesis of the CDEF fragment of lactonamycin is achieved in eight steps (six pots) from the known and readily available anhydride 4 via a Diels-Alder reaction between tricycle 13 and 2,3-dimethylbenzoquinone. Topics: Anti-Bacterial Agents; Indicators and Reagents; Indoles; Magnetic Resonance Spectroscopy; Naphthoquinones; Silicon Compounds | 2002 |
Concise synthesis of a lactonamycin model system by diastereoselective dihydroxylation of a highly functionalized naphthoquinone.
[reaction: see text]. In this Letter, we describe an approach to the highly functionalized tetracycle 6, a model compound corresponding to the CDEF ring system contained in the recently discovered antibiotic lactonamycin. Our approach features an unprecedented, highly stereoselective dihydroxylation of quinone 13a, which leads directly to spirocyclic lactone 15, following acid-promoted deprotection/cyclization. The methodology described herein paves the way for a concise, highly diastereo- and enantioselective synthesis of the natural product. Topics: Anti-Bacterial Agents; Hydroxylation; Indoles; Molecular Conformation; Naphthoquinones | 2001 |
Synthesis of the functionalized tricyclic core of lactonamycin by oxidative dearomatization.
[reaction: see text] We report in this Letter a synthesis of the densely oxygenated CDEF ring system (27) corresponding to that found in the recently discovered antibiotic lactonamycin. The key steps in the synthesis consist of an intramolecular Wessely oxidative lactonization of acid 18, followed by a hydroxyl-directed epoxidation of enol ether 21. Topics: Anti-Bacterial Agents; Drug Design; Indicators and Reagents; Indoles; Molecular Conformation; Naphthoquinones; Structure-Activity Relationship | 2000 |
Lactonamycin, a new antimicrobial antibiotic produced by Streptomyces rishiriensis MJ773-88K4. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.
Lactonamycin (1) was isolated from a culture broth of Streptomyces rishiriensis MJ773-88K4. Antibiotic 1 exhibited antimicrobial activities against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). Topics: Animals; Anti-Bacterial Agents; Antibiotics, Antineoplastic; Antineoplastic Agents; Fermentation; Gram-Positive Bacteria; Humans; Indoles; Methicillin Resistance; Mice; Mice, Inbred ICR; Microbial Sensitivity Tests; Naphthoquinones; Streptomyces; Tumor Cells, Cultured; Vancomycin | 1999 |
Gilvusmycin, a new antitumor antibiotic related to CC-1065.
A new antitumor antibiotic gilvusmycin was isolated from the culture broth of Streptomyces sp. QM16. The structure of gilvusmycin was related to CC-1065 and determined by NMR spectral analysis. Gilvusmycin exhibited antitumor activity against murine leukemia P388 in vivo. Topics: Animals; Antibiotics, Antineoplastic; Culture Media; Drug Screening Assays, Antitumor; Fermentation; Humans; Indoles; Leukemia P388; Magnetic Resonance Spectroscopy; Mice; Naphthoquinones; Spectrophotometry, Ultraviolet; Streptomyces; Tumor Cells, Cultured | 1999 |
Lactonamycin, a new antimicrobial antibiotic produced by Streptomyces rishiriensis MJ773-88K4. II. Structure determination.
The absolute structure of a new antibiotic lactonamycin is described. The NMR studies deduced one of four possible structures for the aglycon attached by a rhodinose through glycosidic bond. The stereochemistry of the sugar obtained by an acid hydrolysis was determined to be L-form by measuring optical rotation. The stereochemistry of the aglycon was determined by X-ray crystallographic analysis. Topics: Anti-Bacterial Agents; Crystallography, X-Ray; Hydrolysis; Indoles; Magnetic Resonance Spectroscopy; Molecular Conformation; Naphthoquinones; Optical Rotation; Spectrometry, Mass, Fast Atom Bombardment | 1999 |
Lactonamycin, a new antimicrobial antibiotic produced by Streptomyces rishiriensis.
Topics: Animals; Anti-Bacterial Agents; Female; Fermentation; Gram-Positive Bacteria; Indoles; Magnetic Resonance Spectroscopy; Methicillin Resistance; Mice; Mice, Inbred ICR; Molecular Structure; Naphthoquinones; Spectrometry, Mass, Fast Atom Bombardment; Staphylococcus aureus; Streptomyces | 1996 |