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https://www.readbyqxmd.com/read/28326640/catalytic-enantioselective-synthesis-of-protecting-group-free-1-5-benzothiazepines
#1
Sara Meninno, Chiara Volpe, Alessandra Lattanzi
A one-pot enantioselective route to N-unprotected 2,3-dihydro-1,5-benzothiazepinones, by an organocatalyzed sulfa-Michael reaction of readily available α,β-unsaturated N-acyl pyrazoles with 2-aminothiophenols followed by silica-gel-catalyzed lactamization, has been developed. The method proceeds under mild conditions at room temperature and it requires only 1 mol % catalyst loading, to give 2-aryl/alkyl-substituted 1,5-benzothiazepines in generally good to excellent yields and enantioselectivities. The process, used for a short synthesis of antidepressant drug (R)-(-)-thiazesim, represents the first method to access enantioenriched unprotected 1,5-benzotiazepines, which are useful for rapid derivatization in drug discovery...
March 22, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28326135/regiochemistry-of-cyclocondensation-reactions-in-the-synthesis-of-polyazaheterocycles
#2
Patrick T Campos, Leticia V Rodrigues, Andrei L Belladona, Caroline R Bender, Juliana S Bitencurt, Fernanda A Rosa, Davi F Back, Helio G Bonacorso, Nilo Zanatta, Clarissa P Frizzo, Marcos A P Martins
The syntheses of several polyazaheterocycles are demonstrated. The cyclocondensation reactions between β-enaminodiketones [CCl3C(O)C(=CNMe2)C(O)-CO2Et] and aromatic amidines resulted in glyoxalate-substituted pyrido[1,2-a]pyrimidinone, thiazolo[3,2-a]pyrimidinone and pyrimido[1,2-a]benzimidazole. Pyrazinones and quinoxalinones were obtained through the reaction of these glyoxalates with ethylenediamine and 1,2-phenylenediamine derivatives. On the other hand, the reaction of glyoxalates with amidines did not lead to the formation of imidazolones, but rather N-acylated products were obtained...
2017: Beilstein Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28323149/the-effect-of-tobramycin-incorporated-with-bismuth-ethanedithiol-loaded-on-niosomes-on-the-quorum-sensing-and-biofilm-formation-of-pseudomonas-aeruginosa
#3
Faeze Mahdiun, Shahla Mansouri, Payam Khazaeli, Rasoul Mirzaei
Pseudomonas aeruginosa is an opportunistic pathogen, enable of causing infections especially in immunocompromised patients. Recently many isolates developed multiple drug resistance, resulting in treatment failure in serious infections. In this study, the effect of tobramycin incorporated with bismuth-ethanedithiol loaded on niosomes on the quorum sensing and biofilm production by P. aeruginosa was evaluated. Thin layer hydration method with cholesterol (30%), Span 40 and Tween 40 were used to make niosomes...
March 18, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28320885/identification-of-the-lyso-form-n-acyl-intramolecular-transferase-in-low-gc-firmicutes
#4
Krista M Armbruster, Timothy C Meredith
Bacterial lipoproteins are embedded in the cell membrane of both Gram-positive and Gram-negative bacteria where they serve numerous functions central to cell envelope physiology. Lipoproteins are tethered to the membrane by an N-acyl-S-(mono/di)-acyl-glyceryl-cysteine anchor that is variably acylated depending on genera. In several low-GC Gram-positive Firmicutes, a monoacyl-glyceryl-cysteine with an N-terminal fatty acid (known as the lyso form) has been reported, though how it is formed is unknown. Here, through an intergenic complementation rescue assay in Escherichia coli, we report the identification of a common orthologous transmembrane protein in both Enterococcus faecalis and Bacillus cereus capable of forming lyso-form lipoproteins...
March 20, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28319297/tandem-coupling-of-azide-with-isonitrile-and-boronic-acid-facile-access-to-functionalized-amidines
#5
Zhen Zhang, Baoliang Huang, Guanyu Qiao, Liu Zhu, Fan Xiao, Feng Chen, Bin Fu, Zhenhua Zhang
Amidine is a notable nitrogen-containing structural motif found in bioactive natural products and pharmaceuticals. Herein, a novel rhodium(I)-catalyzed tandem reaction of readily accessible azides with isonitriles and boronic acids via a carbodiimide intermediate is achieved. This protocol offers an alternative approach toward N-sulfonyl-, N-acyl-, and N- phosphoryl-functionalized, as well as general N-aryl and N-alkyl amidines with broad substrate scope. In addition, functionalized guanidines can also been synthesized when amines are used instead...
March 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28297656/the-long-chain-sphingoid-base-of-ceramides-determines-their-propensity-for-lateral-segregation
#6
Md Abdullah Al Sazzad, Tomokazu Yasuda, Michio Murata, J Peter Slotte
We examined how the length of the long-chain base or the N-linked acyl chain of ceramides affected their lateral segregation in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayers. Lateral segregation and ceramide-rich phase formation was ascertained by a lifetime analysis of trans-parinaric acid (tPA) fluorescence. The longer the length of the long-chain base (d16:1, d17:1, d18:1, d19:1, and d20:1 in N-palmitoyl ceramide), the less ceramide was needed for the onset of lateral segregation and ceramide-rich phase formation...
March 14, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28284052/high-yield-production-of-rhizobium-nodb-chitin-deacetylase-and-its-use-for-in%C3%A2-vitro-synthesis-of-lipo-chitinoligosaccharide-precursors
#7
Rémi Chambon, Stéphanie Pradeau, Sébastien Fort, Sylvain Cottaz, Sylvie Armand
Lipo-chitinoligosaccharides (LCOs) are key molecules for the establishment of plant-microorganisms symbiosis. Interactions of leguminous crops with nitrogen-fixing rhizobial bacteria involve Nod factors, while Myc-LCOs improve the association of most plants with arbuscular mycorrhizal fungi. Both Nod factors and Myc-LCOs are composed of a chitinoligosaccharide fatty acylated at the non-reducing end accompanied with various substituting groups. One straightforward way to access LCOs is starting from chitin hydrolysate, an abundant polysaccharide found in crustacean shells, followed by regioselective enzymatic cleavage of an acetyl group from the non-reducing end of chitin tetra- or pentaose, and subsequent chemical introduction of N-acyl group...
February 27, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28281272/quorum-sensing-of-microalgae-associated-marine-ponticoccus-sp-pd-2-and-its-algicidal-function-regulation
#8
Wendan Chi, Li Zheng, Changfei He, Bin Han, Minggang Zheng, Wei Gao, Chengjun Sun, Gefei Zhou, Xiangxing Gao
Quorum sensing (QS) systems play important roles in regulating many physiological functions of microorganisms, such as biofilm formation, bioluminescence, and antibiotic production. One marine algicidal bacterium, Ponticoccus sp. PD-2, was isolated from the microalga Prorocentrum donghaiense, and its N-acyl-homoserine lactone (AHL)-mediated QS system was verified. In this study, we analyzed the AHLs profile of strain PD-2. Two AHLs, 3-oxo-C8-HSL and 3-oxo-C10-HSL, were detected using a biosensor overlay assay and GC-MS methods...
December 2017: AMB Express
https://www.readbyqxmd.com/read/28248527/accessing-n-acyl-azoles-via-oxoammonium-salt-mediated-oxidative-amidation
#9
John M Ovian, Christopher B Kelly, Vincent A Pistritto, Nicholas E Leadbeater
An operationally simple, robust, metal-free approach to the synthesis of N-acyl azoles from both alcohols and aldehydes is described. Oxidative amidation is facilitated by a commercially available organic oxidant (4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate) and proceeds under very mild conditions for an array of structurally diverse substrates. Tandem reactions of these activated amides, such as transamidation and esterification, enable further elaboration. Also, the spent oxidant can be recovered and used to regenerate the oxoammonium salt...
March 1, 2017: Organic Letters
https://www.readbyqxmd.com/read/28241461/quorum-sensing-inhibitors-from-the-sea-discovered-using-bacterial-n-acyl-homoserine-lactone-based-biosensors
#10
REVIEW
Kumar Saurav, Valeria Costantino, Vittorio Venturi, Laura Steindler
Marine natural products with antibiotic activity have been a rich source of drug discovery; however, the emergence of antibiotic-resistant bacterial strains has turned attention towards the discovery of alternative innovative strategies to combat pathogens. In many pathogenic bacteria, the expression of virulence factors is under the regulation of quorum sensing (QS). QS inhibitors (QSIs) present a promising alternative or potential synergistic treatment since they disrupt the signaling pathway used for intra- and interspecies coordination of expression of virulence factors...
February 23, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28239068/complete-genome-sequence-of-pseudomonas-chlororaphis-subsp-aurantiaca-reveals-a-triplicate-quorum-sensing-mechanism-for-regulation-of-phenazine-production
#11
Tomohiro Morohoshi, Takahito Yamaguchi, Xiaonan Xie, Wen-Zhao Wang, Kasumi Takeuchi, Nobutaka Someya
Pseudomonas chlororaphis subsp. aurantiaca StFRB508 regulates phenazine production through N-acyl-l-homoserine lactone (AHL)-mediated quorum sensing. Two sets of AHL-synthase and AHL-receptor genes, phzI/phzR and aurI/aurR, have been identified from the incomplete draft genome of StFRB508. In the present study, the complete genome of StFRB508, comprising a single chromosome of 6,997,933 bp, was sequenced. The complete genome sequence revealed the presence of a third quorum-sensing gene set, designated as csaI/csaR...
February 25, 2017: Microbes and Environments
https://www.readbyqxmd.com/read/28225111/cubr-tbhp-mediated-synthesis-of-n-acyl-sulfonimidamides-via-the-oxidative-cross-coupling-of-sulfonimidamides-and-aldehydes
#12
Ganesh Chandra Nandi, Cijil Raju
N-Acyl sulfonimidamides were synthesized via a Cu-catalyzed double C-H/N-H activation protocol. The imino end of sulfonimidamides was acylated using aldehyde as the acylating agent and t-butyl hydrogen peroxide (TBHP) as the oxidant in acetonitrile (MeCN) at 82 °C. The mild reaction conditions afforded low-to-moderate yields of N-acyl sulfonimidamides with high structural diversity.
February 22, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28225085/aidp-a-novel-n-acyl-homoserine-lactonase-gene-from-antarctic-planococcus-sp
#13
Wah Seng See-Too, Robson Ee, Yan-Lue Lim, Peter Convey, David A Pearce, Wai-Fong Yin, Kok-Gan Chan
Planococcus is a Gram-positive halotolerant bacterial genus in the phylum Firmicutes, commonly found in various habitats in Antarctica. Quorum quenching (QQ) is the disruption of bacterial cell-to-cell communication (known as quorum sensing), which has previously been described in mesophilic bacteria. This study demonstrated the QQ activity of a psychrotolerant strain, Planococcus versutus strain L10.15(T), isolated from a soil sample obtained near an elephant seal wallow in Antarctica. Whole genome analysis of this bacterial strain revealed the presence of an N-acyl homoserine lactonase, an enzyme that hydrolyzes the ester bond of the homoserine lactone of N-acyl homoserine lactone (AHLs)...
February 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28223925/effects-of-intermittent-alcohol-exposure-on-emotion-and-cognition-a-potential-role-for-the-endogenous-cannabinoid-system-and-neuroinflammation
#14
Laura Sanchez-Marin, Francisco J Pavon, Juan Decara, Juan Suarez, Ana Gavito, Estela Castilla-Ortega, Fernando Rodriguez de Fonseca, Antonia Serrano
Intermittent alcohol exposure is a common pattern of adolescent alcohol use that can lead to binge drinking episodes. Alcohol use is known to modulate the endocannabinoid system (ECS), which is involved in neuronal communication, neuroplasticity, neuroinflammation and behavior. Adolescent male Wistar rats were exposed to 4-week intermittent alcohol intoxication (3 g/kg injections for 4 days/week) or saline (N = 12 per group). After alcohol deprivation, adult rats were assessed for emotionality and cognition and the gene expression of the ECS and other factors related to behavior and neuroinflammation was examined in the brain...
2017: Frontiers in Behavioral Neuroscience
https://www.readbyqxmd.com/read/28197135/cloning-and-characterization-of-the-autoinducer-synthase-gene-from-lipid-degrading-bacterium-cedecea-neteri
#15
Kian-Hin Tan, Kah-Yan How, Jia-Yi Tan, Wai-Fong Yin, Kok-Gan Chan
The process of intercellular communication among bacteria, termed quorum sensing (QS), is mediated by small diffusible molecules known as the autoinducers. QS allows the population to react to the change of cell density in unison, in processes such as biofilm formation, plasmid conjugation, virulence, motility and root nodulation. In Gram-negative proteobacteria, N-acyl homoserine lactone (AHL) is the common "language" to coordinate gene expression. This signaling molecule is usually synthesized by LuxI-type proteins...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28173026/p780-3-oxo-c12-2-hsl-a-new-n-acyl-homoserine-lactone-identified-in-gut-ecosystem-exerts-an-anti-inflammatory-effect-and-does-not-modify-paracellular-permeability
#16
E Le Balc'h, C Landman, E Tauziet, L Brot, E Quevrain, D Rainteau, J-P Grill, S Thenet, P Seksik
No abstract text is available yet for this article.
February 1, 2017: Journal of Crohn's & Colitis
https://www.readbyqxmd.com/read/28164039/quorum-sensing-n-acyl-homoserine-lactones-sdia-suppresses-escherichia-coli-pseudomonas-aeruginosa-conjugation-through-inhibiting-trai-expression
#17
Yang Lu, Jianming Zeng, Binning Wu, Shunmei E, Lina Wang, Renxin Cai, Ni Zhang, Youqiang Li, Xianzhang Huang, Bin Huang, Cha Chen
Conjugation is a key mechanism for horizontal gene transfer and plays an important role in bacterial evolution, especially with respect to antibiotic resistance. However, little is known about the role of donor and recipient cells in regulation of conjugation. Here, using an Escherichia coli (SM10λπ)-Pseudomonas aeruginosa (PAO1) conjugation model, we demonstrated that deficiency of lasI/rhlI, genes associated with generation of the quorum sensing signals N-acyl homoserine lactones (AHLs) in PAO1, or deletion of the AHLs receptor SdiA in the donor SM10λπ both facilitated conjugation...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28154204/linear-ion-trap-msn-with-high-resolution-mass-spectrometry-reveals-structural-diversity-of-epidermal-1-o-acyl-ceramide-family-in-mouse-epidermis
#18
Meei-Hua Lin, Jeffery Miner, John Turk, Fong-Fu Hsu
1-O-acylceramide is a new class of epidermal ceramide found in humans and mice. Here, we report ESI linear ion-trap (LIT) multiple stage mass spectrometric (MSn) approach with high resolution towards structural characterization of this lipid family isolated from mice. Molecular species desorbed as the [M + H]+ ions was subjected to LIT MS2 to yield predominately the [M + H - H2O]+ ions, followed by MS3 to cleave the 1-O-acyl residue to yield the [M + H - H2O - (1-O-fatty acid)]+ ions. The structures of the N-acyl chain and long-chain base (LCB) of the molecule were determined by MS4 on ([M + H - H2O - (1-O-fatty acid)]+) ions that yielded multiple sets of specific ions...
February 2, 2017: Journal of Lipid Research
https://www.readbyqxmd.com/read/28152429/synthesis-and-biological-evaluation-of-fluorinated-n-benzoyl-and-n-phenylacetoyl-derivatives-of-3-4-aminophenyl-coumarin-7-o-sulfamate-as-steroid-sulfatase-inhibitors
#19
Mateusz Daśko, Maja Przybyłowska, Janusz Rachon, Maciej Masłyk, Konrad Kubiński, Majus Misiak, Andrzej Składanowski, Sebastian Demkowicz
In the present work, we report convenient methods for the synthesis of 3-(4-aminophenyl)-coumarin-7-O-sulfamate derivatives N-acylated with fluorinated analogues of benzoic or phenylacetic acid as steroid sulfatase (STS) inhibitors. The design of these potential STS inhibitors was supported by molecular modeling techniques. Additionally, computational docking methods were used to determine the binding modes of the synthesized inhibitors and to identify potential interactions between inhibitors and amino acid residues located in the active site of STS...
January 22, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28138687/serum-endocannabinoids-and-n-acyl-ethanolamines-and-the-influence-of-simulated-solar-uvr-exposure-in-humans-in-vivo
#20
Sarah J Felton, Alexandra C Kendall, Abdalla F M Almaedani, Paula Urquhart, Ann R Webb, Richard Kift, Andy Vail, Anna Nicolaou, Lesley E Rhodes
Solar ultraviolet radiation (UVR) exposure of human skin has beneficial and harmful effects on health, including impact on immune function, inflammation and reportedly mood, but these are not fully elucidated. Since the endocannabinoid system is implicated in many activities including mood alteration, our objective was to (i) determine and quantify circulating levels of a wide range of endocannabinoid and N-acyl ethanolamine (NAE) species (ii) evaluate whether these are modulated by cutaneous UVR exposures, as attained through repeated low level summer sunlight exposure...
January 31, 2017: Photochemical & Photobiological Sciences
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