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Isolation and characterization of compounds

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https://www.readbyqxmd.com/read/28941807/gas-chromatographic-mass-spectrometric-determination-of-glycosides-without-prior-hydrolysis
#1
Valery A Isidorov, Jolanta Nazaruk
The article presents for the first time the linear temperature programmed retention indices on a column with stationary phases of 5% phenylpolydimethyl silicone and the mass spectra of trimethylsilyl (TMS) derivatives of 71 glycosides (both commercial preparations and compounds extracted from plant tissues) which were not characterized earlier by these parameters. Converted to their TMS derivatives, the glycosides were thermally stable: they exhibited single peaks on their chromatograms without products of thermal decomposition...
September 18, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28941699/synthesis-of-whey-peptide-iron-complexes-influence-of-using-different-iron-precursor-compounds
#2
Maria Elisa Caetano-Silva, Renata Carolina Alves, Guilherme Nunes Lucena, Regina Célia Galvão Frem, Maria Teresa Bertoldo-Pacheco, Juliana Azevedo Lima-Pallone, Flavia Maria Netto
Iron-binding peptides are an alternative for increasing the bioavailability of iron and to decreasing its pro-oxidant effect. This study aimed to synthesize and characterize peptide-iron complexes using FeCl2 or FeSO4 as the iron precursor compounds. Whey protein isolate (WPI), WPI hydrolyzed with pancreatin, and its fractions obtained via ultrafiltration (cut-off 5kDa) were used as ligands. The fluorescence intensity of the ligands significantly decreased as the iron concentration increased as a result of metal coordination with the iron-binding sites, which may have led to changes in the microenvironment of tryptophan...
November 2017: Food Research International
https://www.readbyqxmd.com/read/28938642/facile-total-synthesis-of-lysicamine-and-the-anticancer-activities-of-the-ru-ii-rh-iii-mn-ii-and-zn-ii-complexes-of-lysicamine
#3
Jiao-Lan Qin, Ting Meng, Zhen-Feng Chen, Xiao-Li Xie, Qi-Pin Qin, Xiao-Ju He, Ke-Bin Huang, Hong Liang
Lysicamine is a natural oxoaporphine alkaloid, which isolated from traditional Chinese medicine (TCM) herbs and has been shown to possess cytotoxicity to hepatocarcinoma cell lines. Reports on its antitumor activity are scarce because lysicamine occurs in plants at a low content. In this work, we demonstrate a facile concise total synthesis of lysicamine from simple raw materials under mild reaction conditions, and the preparation of the Ru(II), Rh(III), Mn(II) and Zn(II) complexes 1-4 of lysicamine (LY). All the compounds were fully characterized by elemental analysis, IR, ESI-MS, (1)H and (13)C NMR, as well as single-crystal X-ray diffraction analysis...
August 29, 2017: Oncotarget
https://www.readbyqxmd.com/read/28937749/heterooctamolybdate-based-clusters-h3-cp-rh-4pmo8o32-and-h5-na2-cp-ir-4pmo8o34-and-derived-hybrid-nanomaterials-with-efficient-electrocatalytic-hydrogen-evolution-reaction-activity
#4
Vikram Singh, Pengtao Ma, Michael G B Drew, Jingyang Niu, Jingping Wang, Guo-Xin Jin
Polyoxometalates (POMs), emerging as a new class of porous molecular materials, play a promising role in homo- and heterogeneous catalysis. Among them, noble-metal-decorated POMs have a profound impact as catalytic materials. Thus, it is imperative to design and structurally explore new catalysts including noble metals. Herein, two new clusters, H3[(Cp*Rh)4PMo8O32]·14H2O (1) and H5[Na2(Cp*Ir)4PMo8O34]·13H2O (2) (Cp* = pentamethylcyclopentadienyl), based on a heterooctamolybdate anionic core were successfully obtained via a one-pot reaction using [Cp*MCl2]2 [M = Rh (1) and Ir (2)] and Na2MoO4 in acidic conditions...
September 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28937585/phytochemicals-extraction-isolation-and-identification-of-bioactive-compounds-from-plant-extracts
#5
REVIEW
Ammar Altemimi, Naoufal Lakhssassi, Azam Baharlouei, Dennis G Watson, David A Lightfoot
There are concerns about using synthetic phenolic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) as food additives because of the reported negative effects on human health. Thus, a replacement of these synthetics by antioxidant extractions from various foods has been proposed. More than 8000 different phenolic compounds have been characterized; fruits and vegetables are the prime sources of natural antioxidants. In order to extract, measure, and identify bioactive compounds from a wide variety of fruits and vegetables, researchers use multiple techniques and methods...
September 22, 2017: Plants (Basel, Switzerland)
https://www.readbyqxmd.com/read/28937158/bioactivity-guided-isolation-of-neuritogenic-triterpenoids-from-the-leaves-of-ilex-latifolia-thunb
#6
Xueli Cao, Yu Liu, Jing Li, Lan Xiang, Hiroyuki Osada, Jianhua Qi
Ilex latifolia Thunb is a traditional Chinese tea and herbal medicine. In this study, one new triterpene saponin (1) and six known triterpenoids (2-7) were isolated from the methanol extract of I. latifolia using a PC12 cell bioassay system. The structures and stereochemistry of these compounds were elucidated using spectroscopic methods and chemical derivatization. This new triterpene saponin (1) was characterized as an ursolic type acid with a 19α-hydroxyl and a trisaccharide moiety at C-3. Compound 1 significantly promoted the neurite outgrowth in PC12 cells by 52% at 10 μM, whereas compounds 2-7 showed less neuritogenic activity...
September 22, 2017: Food & Function
https://www.readbyqxmd.com/read/28936533/small-iron-carbonyl-clusters-bearing-imidazolium-2-trithioperoxycarboxylate-ligands
#7
Tomás F Beltrán, Guillermo Zaragoza, Lionel Delaude
The reaction of [Fe2(CO)9] with two representative imidazolium-2-dithiocarboxylate zwitterions derived from common N-heterocyclic carbenes (NHCs) bearing mesityl (IMes) or 2,6-diisopropylphenyl substituents on their nitrogen atoms (IDip) unexpectedly afforded two small bimetallic iron-carbonyl clusters with the generic formula [Fe2(CO)6(μ-κ(2)-S,S'-κ(2)-S,S'-S3C·NHC)]. After a brief optimization of the reaction conditions, these two "sulfur-enriched" products were isolated in low yields. They were fully characterized by IR, NMR, UV/Visible, and ESI-MS techniques, and their molecular structures were determined by single crystal X-ray diffraction analysis...
September 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28936331/double-c-h-bond-activation-of-acetylene-by-atomic-boron-in-forming-aromatic-cyclic-hbc2bh-in-solid-neon
#8
Jiwen Jian, Wei Li, Xuan Wu, Mingfei Zhou
The organo-boron species formed from the reactions of boron atoms with acetylene in solid neon are investigated using matrix isolation infrared spectroscopy with isotopic substitutions as well as quantum chemical calculations. Besides the previously reported single C-H bond activation species, a cyclic-HBC2BH diboron species is formed via double C-H bond activation of acetylene. It is characterized to have a closed-shell singlet ground state with planar D2h symmetry. Bonding analysis indicates that it is a doubly aromatic species involving two delocalized σ electrons and two delocalized π electrons...
June 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28935203/hr-lc-ms-based-analysis-of-two-antibacterial-metabolites-from-a-marine-sponge-symbiont-streptomyces-pharmamarensis-icn40
#9
Francis-Joseph Rosemary Sharmila Joseph, Appadurai Muthamil Iniyan, Samuel Gnana Prakash Vincent
On the effort to screen antibiotics against Methicillin resistant Staphylococcus aureus (MRSA), an actinomycete strain which can produce bactericidal compound was isolated from a marine sponge of Kanyakumari Coast, India. Two anti-MRSA compounds (PVI401 and PVI402) were isolated from the fermentation plates of Streptomyces pharmamarensis ICN40. TLC bioautography analysis yielded two active spots with Rf value of 0.75 (PVI401) and 0.8 (PVI402) from the crude extract. Both the compounds were characterized by HR-LC-MS analysis...
September 18, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28933865/organocopper-iii-spiro-complexes-synthesis-structural-characterization-and-redox-transformation
#10
Liang Liu, Miaomiao Zhu, Hai-Tao Yu, Wen-Xiong Zhang, Zhenfeng Xi
Reductive elimination of Cu(III) intermediates is often proposed as a key step in many copper-catalyzed or -mediated formation of C‒C or C‒heteroatom bonds. However, there still lacks concrete evidence on this key step, mainly because Cu(III) complexes are usually too unstable to be isolated and structurally characterized. In this work, novel organocopper(III) spiro complexes and their analogous organocopper(I) spiro complexes were synthesized and structurally characterized. Single-crystal X-ray structural analysis revealed that the spiro Cu(III) atom adopted a distorted square-planar geometry while its corresponding spiro Cu(I) atom was tetrahedrally coordinated...
September 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28933494/catalyst-free-room-temperature-iclick-reaction-of-molybdenum-ii-and-tungsten-ii-azide-complexes-with-electron-poor-alkynes-structural-preferences-and-kinetic-studies
#11
Paul Schmid, Matthias Maier, Hendrik Pfeiffer, Anja Belz, Lucas Henry, Alexandra Friedrich, Fabian Schönfeld, Katharina Edkins, Ulrich Schatzschneider
Two isostructural and isoelectronic group VI azide complexes of the general formula [M(η(3)-allyl)(N3)(bpy)(CO)2] with M = Mo, W and bpy = 2,2'-bipyridine were prepared and fully characterized, including X-ray structure analysis. Both reacted smoothly with electron-poor alkynes such as dimethyl acetylenedicarboxylate (DMAD) and 4,4,4-trifluoro-2-butynoic acid ethyl ester in a catalyst-free room-temperature iClick [3 + 2] cycloaddition reaction. Reaction with phenyl(trifluoromethyl)acetylene, on the other hand, did not lead to any product formation...
September 21, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28932951/structure-elucidation-and-in-silico-docking-studies-of-a-novel-furopyrimidine-antibiotics-synthesized-by-endolithic-bacterium-actinomadura-sp-al2
#12
Kaushik Bhattacharjee, Shakti Kumar, Narasinga Rao Palepu, Pradeep Kumar Patra, Kollipara Mohan Rao, Santa Ram Joshi
On screening of endolithic actinobacteria from a granite rock sample of Meghalaya for antibacterial compound, a novel antibacterial compound CCp1 was isolated from the fermentation broth of Actinomadura sp. AL2. On purification of the compound based on chromatographic techniques followed by characterization with FT-IR, UV-visible, (1)H NMR, (13)C NMR and mass spectrometry, the molecular formula of the compound was generated as C20H17N3O2, a furopyrimidine derivative. In vitro antibacterial activity of the compound was evaluated against both Gram positive and negative bacteria by agar well diffusion assay...
September 20, 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28927792/heliotropiumides-a-and-b-new-phenolamides-with-n-carbamoyl-putrescine-moiety-from-heliotropium-foertherianum-collected-in-hawaii-and-their-biological-activities
#13
You-Sheng Cai, Ariel M Sarotti, Daniela Gündisch, Tamara P Kondratyuk, John M Pezzuto, James Turkson, Shugeng Cao
Two new compounds heliotropiumides A (1) and B (2), phenolamides each with an uncommon carbamoyl putrescine moiety, were isolated from the seeds of a naturalized Hawaiian higher plant, Heliotropium foertherianum Diane & Hilger in the borage family, which is widely used for the treatment of ciguatera fish poisoning. The structures of compounds 1 and 2 were characterized based on MS spectroscopic and NMR analysis, and DP4+ calculations. The absolute configuration (AC) of compound 1 was determined by comparison of its optical rotation with those reported in literature...
September 9, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28925024/complete-characterization-of-new-isolates-of-neptunomonas-phycophila-leads-to-emend-its-description-and-opens-possibilities-of-biotechnological-applications
#14
Ana L Diéguez, Phillip Pichon, Sabela Balboa, Thorolf Magnesen, Jesús L Romalde
Five strains were isolated from gonad of Great scallop (Pecten maximus) broodstock in a Norwegian hatchery. The study of 16S rRNA gene sequences showed that these isolates belong to Neptunomonas phycophila, a bacterium originally isolated from a symbiont of the anemone Aiptasia tagetes from Puerto Rico. The gyrB and rpoB genes sequences confirmed the affiliation of the scallop isolates to this species. Phenotypic characterization was performed and some differences between the Norwegian isolates and the type strain of N...
September 18, 2017: MicrobiologyOpen
https://www.readbyqxmd.com/read/28921964/versatile-synthetic-route-for-%C3%AE-functionalized-chlorins-and-porphyrins-by-varying-the-size-of-michael-donors-syntheses-photophysical-and-electrochemical-redox-properties
#15
Nivedita Chaudhri, Nitika Grover, Muniappan Sankar
One-pot facile synthesis and characterization of novel β-substituted meso-tetraphenylporphyrins and/or chlorins were described. The high regioselective reactivity of active methylene compounds in Michael addition reaction was reported to access β-substituted trans-chlorins. Size-dependent approach was applied for the fine-tuning of product formation from porphyrins to chlorins. Notably, we were able to isolate mono/trisubstituted porphyrin and/or di/tetra-substituted chlorin from one-pot synthesis for the first time in porphyrin chemistry...
September 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28921494/solid-phase-synthesis-of-rna-analogs-containing-phosphorodithioate-linkages
#16
Xianbin Yang
The oligoribonucleotide phosphorodithioate (PS2-RNA) modification uses two sulfur atoms to replace two non-bridging oxygen atoms at an internucleotide phosphorodiester backbone linkage. Like a natural phosphodiester RNA backbone linkage, a PS2-modified backbone linkage is achiral at phosphorus. PS2-RNAs are highly stable to nucleases and several in vitro assays have demonstrated their biological activity. For example, PS2-RNAs silenced mRNA in vitro and bound to protein targets in the form of PS2-aptamers (thioaptamers)...
September 18, 2017: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/28920630/experimental-and-ab-initio-studies-of-cd5-bo3-3cl-the-first-cadmium-borate-chlorine-nlo-material-with-isolated-bo3-groups
#17
Yunxia Song, Min Luo, Fei Liang, Chensheng Lin, Ning Ye, Guiyang Yan, Zheshuai Lin
A nonlinear optical crystal cadmium borate chlorine (Cd5(BO3)3Cl) has been successfully grown through a spontaneous crystallization method. Cd5(BO3)3Cl crystallizes in the noncentrosymmetric space group Cm with isolated BO3 and distorted CdOnClm (n = 4, 5, 7; m = 0, 1, 2) polyhedra. Powder second harmonic generation (SHG) measurements on polycrystalline Cd5(BO3)3Cl indicated that the title compound is phase-matchable in the visible region and exhibits a large SHG response of about 5 × KH2PO4 (KDP). Further optical characterization suggested that the compound has a wide transparent region ranging from UV to near IR with a UV cutoff edge at about 295 nm...
September 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28920626/mononuclear-salen-gallium-complexes-for-iso-selective-ring-opening-polymerization-rop-of-rac-lactide
#18
David Specklin, Christophe Fliedel, Frédéric Hild, Samir Mameri, Lydia Karmazin, Corinne Bailly, Samuel Dagorne
A series of mononuclear salen-supported gallium amido/alkoxide derivatives were prepared and structurally characterized and subsequently used as initiators in rac-lactide ring-opening polymerisation (ROP). The reaction of variously substituted salen ligands (1a-1f) with 0.5 equiv. of Ga2(NMe2)6 allowed the isolation of the corresponding (salen)Ga-NMe2 chelates (2b-2d, 2f) via an amine elimination route, as poorly soluble compounds in common solvents. The (salen)Ga-OBn derivatives (3a-3e) may be readily accessed by an amine-elimination/alcoholysis sequence and the molecular structures of 3a, 3d and 3e were confirmed through X-ray crystallography diffraction analysis...
September 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28920124/a-family-of-one-dimensional-lanthanide-complexes-bridged-by-two-distinct-carboxylate-ligands-with-the-dy-analogue-displaying-magnetic-relaxation-behaviour
#19
Wen-Hua Zhu, Xia Xiong, Chen Gao, Shan Li, Yan Zhang, Juan Wang, Chi Zhang, Annie K Powell, Song Gao
A series of isostructural lanthanide one-dimensional (1D) chain complexes, [Ln(INNO)(Bza)2(H2O)2]·(H2O) {INNO = isonicotinate N-oxide, Bza = benzoic acid; Nd(1), Eu(2), Gd(3), Tb(4), Dy(5), Er(6) and Y(7)}, have been successfully isolated by hydrothermal reactions utilizing two distinct carboxylates as co-ligands. Due to the similar steric hindrance of the two carboxylic ligands, the neighboring lanthanide ions are bridged simultaneously by their carboxyl groups from the opposite sides to form a 1D chain structure...
September 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28914496/silver-thiolate-nano-sized-molecular-clusters-and-their-supramolecular-covalent-frameworks-an-approach-toward-pre-templated-synthesis
#20
Zi-Yi Chen, Dennis Y S Tam, Leon Li-Min Zhang, Thomas Chung Wai Mak
A series of seven new complexes including silver-thiolate molecular clusters and their covalent supramolecular frameworks have been assembled from the silver carbide precursor Ag2C2 using a C22- pre-templated approach. Herein, two prototype clusters Ag14(SR)6 and CO3@Agm(SR)10 (R = isopropyl, cyclohexyl or tert-butyl; m = 18 or 20) are employed to construct cluster-based metal-organic frameworks of different dimensions. In particular, both new ellipsoidal tetradecanuclear molecular cluster compounds, namely Ag14(S-iPr)6(CF3CO2)8·DMSO6 (two polymorphic forms 1, 2) and [Ag14(S-Cy)6(CO2CF3)8(DMSO)4] · DMSO3 (3), and a cluster-based metal-organic framework {Ag3[Ag14(S-iPr)6(CF3CO2)11(H2O)3CH3OH] · (H2O)2...
September 15, 2017: Chemistry, An Asian Journal
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