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61.
62.
Multiresidue method for the fast determination of pesticides in nutraceutical products (Camellia sinensis) by GC coupled to triple quadrupole MS 下载免费PDF全文
Gerardo Martínez‐Domínguez Patricia Plaza‐Bolaños Roberto Romero‐González Antonia Garrido Frenich 《Journal of separation science》2014,37(6):665-674
A method based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) has been developed and validated for the determination and quantification of more than 140 pesticides in nutraceutical products obtained from green tea (Camellia sinensis). Extraction was performed with acidified acetonitrile (acetic acid 1%, v/v) and a clean‐up step using primary secondary amine (50 mg), graphitized black carbon (100 mg) and magnesium sulfate (200 mg) was needed. Pesticide determination was achieved utilizing GC coupled to triple quadrupole MS/MS using the selective‐reaction monitoring mode. The total run time was 23 min. Pesticides were quantified using matrix‐matched calibration. Recoveries ranged from 70 to 120% and relative SD was lower than 25% at 10, 50, and 100 μg/kg. LOQs were lower than 10 μg/kg. 148 pesticides were validated. The validated method was applied to commercial nutraceutical products, detecting 4,4‐dichlorobenzophenone (28 μg/kg), o,p′‐dicofol (38 μg/kg) and p,p‐dicofol (44 μg/kg) in a few samples. 相似文献
63.
Juan Francisco Palacios-Espinosa Pablo No Núez-Aragn Erika Gomez-Chang Edelmira Linares Robert Bye Irma Romero 《Molecules (Basel, Switzerland)》2021,26(12)
Artemisia ludoviciana subsp. mexicana has been traditionally used for the treatment of digestive ailments such as gastritis, whose main etiological agent is Helicobacter pylori. In a previous screening study, the aqueous extract exhibited a good in vitro anti-H. pylori activity. With the aim of determining the efficacy of this species as a treatment for H. pylori related diseases and finding bioactive compounds, its aqueous extract was subjected to solvent partitioning and the fractions obtained were tested for their in vitro anti-H. pylori effect, as well as for their in vivo gastroprotective and anti-inflammatory activities. The aqueous extract showed a MIC = 250 µg/mL. No acute toxicity was induced in mice. A gastroprotection of 69.8 ± 3.8%, as well as anti-inflammatory effects of 47.6 ± 12.4% and 38.8 ± 10.2% (by oral and topical administration, respectively), were attained. Estafiatin and eupatilin were isolated and exhibited anti-H. pylori activity with MBCs of 15.6 and 31.2 µg/mL, respectively. The finding that A. ludoviciana aqueous extract has significant anti-H. pylori, gastroprotective and anti-inflammatory activities is a relevant contribution to the ethnopharmacological knowledge of this species. This work is the first report about the in vivo gastroprotective activity of A. ludoviciana and the anti-H. pylori activity of eupatilin and estafiatin. 相似文献
64.
Journal of Thermal Analysis and Calorimetry - We report data obtained from the spinodal decomposition in samples of two compositions of intermetallic Cu–Al–Mn shape memory alloys.... 相似文献
65.
Dr. Zhe Liu Dr. Isolda Romero‐Canelón Bushra Qamar Jessica M. Hearn Dr. Abraha Habtemariam Dr. Nicolas P. E. Barry Dr. Ana M. Pizarro Dr. Guy J. Clarkson Prof. Dr. Peter J. Sadler 《Angewandte Chemie (International ed. in English)》2014,53(15):3941-3946
Platinum complexes are the most widely used anticancer drugs; however, new generations of agents are needed. The organoiridium(III) complex [(η5‐Cpxbiph)Ir(phpy)(Cl)] ( 1‐Cl ), which contains π‐bonded biphenyltetramethylcyclopentadienyl (Cpxbiph) and C^N‐chelated phenylpyridine (phpy) ligands, undergoes rapid hydrolysis of the chlorido ligand. In contrast, the pyridine complex [(η5‐Cpxbiph)Ir(phpy)(py)]+ ( 1‐py ) aquates slowly, and is more potent (in nanomolar amounts) than both 1‐Cl and cisplatin towards a wide range of cancer cells. The pyridine ligand protects 1‐py from rapid reaction with intracellular glutathione. The high potency of 1‐py correlates with its ability to increase substantially the level of reactive oxygen species (ROS) in cancer cells. The unprecedented ability of these iridium complexes to generate H2O2 by catalytic hydride transfer from the coenzyme NADH to oxygen is demonstrated. Such organoiridium complexes are promising as a new generation of anticancer drugs for effective oxidant therapy. 相似文献
66.
Multifunctional Supramolecular Dendrimers with an s‐Triazine Ring as the Central Core: Liquid Crystalline,Fluorescence and Photoconductive Properties 下载免费PDF全文
Madalina Bucoş Dr. Teresa Sierra Dr. Attilio Golemme Dr. Roberto Termine Dr. Joaquín Barberá Dr. Raquel Giménez Prof. Dr. José Luis Serrano Dr. Pilar Romero Dr. Mercedes Marcos 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):10027-10037
Novel liquid crystal (LC) dendrimers have been synthesised by hydrogen bonding between an s‐triazine as the central core and three peripheral dendrons derived from bis(hydroxymethyl)propionic acid. Symmetric acid dendrons bearing achiral promesogenic units have been synthesised to obtain 3:1 complexes with triazine that exhibit LC properties. Asymmetric dendrons that combine the achiral promesogenic unit and an active moiety derived from coumarin or pyrene structures have been synthesised in order to obtain dendrimers with photophysical and electrochemical properties. The formation of the complexes was confirmed by IR and NMR spectroscopy data. The liquid crystalline properties were investigated by differential scanning calorimetry, polarising optical microscopy and X‐ray diffractometry. All complexes displayed mesogenic properties, which were smectic in the case of symmetric dendrons and their complexes and nematic in the case of asymmetric dendrons and their dendrimers. A supramolecular model for the lamellar mesophase, based mainly on X‐ray diffraction studies, is proposed. The electrochemical behaviour of dendritic complexes was investigated by cyclic voltammetry. The UV/Vis absorption and emission properties of the compounds and the photoconductive properties of the dendrons and dendrimers were also investigated 相似文献
67.
Dr. Albert Ferrer‐Ugalde Dr. Arántzazu González‐Campo Prof. Dr. Clara Viñas Dr. Jesús Rodríguez‐Romero Dr. Rosa Santillan Dr. Norberto Farfán Prof. Dr. Reijo Sillanpää Dr. Antonio Sousa‐Pedrares Dr. Rosario Núñez Prof. Dr. Francesc Teixidor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9940-9951
Two sets of o‐carborane derivatives incorporating fluorene and anthracene fragments as fluorophore groups have been successfully synthesized and characterized, and their photophysical properties studied. The first set, comprising fluorene‐containing carboranes 6 – 9 , was prepared by catalyzed hydrosilylation reactions of ethynylfluorene with appropriate carboranylsilanes. The compound 1‐[(9,9‐dioctyl‐fluorene‐2‐yl)ethynyl]carborane ( 11 ) was synthesized by the reaction of 9,9‐dioctyl‐2‐ethynylfluorene and decaborane (B10H14). Furthermore, reactions of the lithium salt of 11 with 1 equivalent of 4‐(chloromethyl)styrene or 9‐(chloromethyl)anthracene yielded compounds 12 and 13 . Members of the second set of derivatives, comprising anthracene‐containing carboranes, were synthesized by reactions of monolithium or dilithium salts of 1‐Me‐1,2‐C2B10H11, 1‐Ph‐1,2‐C2B10H11, and 1,2‐C2B10H12 with 1 or 2 equivalents of 9‐(chloromethyl)anthracene, respectively, to produce compounds 14 – 16 . In addition, 2 equivalents of the monolithium salts of 1‐Me‐1,2‐C2B10H11 (Me‐o‐carborane) and 1‐Ph‐1,2‐C2B10H11 (Ph‐o‐carborane) were reacted with 9,10‐bis(chloromethyl)anthracene to produce compounds 17 and 18 , respectively. Fluorene derivatives 6 – 9 exhibit moderate fluorescence quantum yields (32–44 %), whereas 11 – 13 , in which the fluorophore is bonded to the Ccluster (Cc), show very low emission intensity (6 %) or complete fluorescence quenching. The anthracenyl derivatives containing the Me‐o‐carborane moiety exhibit notably high fluorescence emissions, with ?F=82 and 94 %, whereas their Ph‐o‐carborane analogues are not fluorescent at all. For these compounds, we have observed a correlation between the Cc?Cc bond length and the fluorescence intensity in CH2Cl2 solution, comparable to that observed for previously reported styrene‐containing carboranes. Thus, our hypothesis is that for systems of this type the fluorescence may be tuned and even predicted by changing the substituent on the adjacent Cc. 相似文献
68.
69.
Daniel E. Vicentes Andrea L. Romero Ricuarte Rodríguez Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(5):446-453
An efficient synthesis of 1‐arylisochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐ones, involving the diazotization of 3‐amino‐4‐arylamino‐1H‐isochromen‐1‐ones in weakly acidic solution, has been developed and the spectroscopic characterization and crystal structures of four examples are reported. The molecules of 1‐phenylisochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐one, C15H9N3O2, (I), are linked into sheets by a combination of C—H…N and C—H…O hydrogen bonds, while the structures of 1‐(2‐methylphenyl)isochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐one, C16H11N3O2, (II), and 1‐(3‐chlorophenyl)isochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐one, C15H8ClN3O2, (III), each contain just one hydrogen bond which links the molecules into simple chains, which are further linked into sheets by π‐stacking interactions in (II) but not in (III). In the structure of 1‐(4‐chlorophenyl)isochromeno[3,4‐d][1,2,3]triazol‐5(1H)‐one, (IV), isomeric with (III), a combination of C—H…O and C—H…π(arene) hydrogen bonds links the molecules into sheets. When compound (II) was exposed to a strong acid in methanol, quantitative conversion occurred to give the ring‐opened transesterification product methyl 2‐[4‐hydroxy‐1‐(2‐methylphenyl)‐1H‐1,2,3‐triazol‐5‐yl]benzoate, C17H15N3O3, (V), where the molecules are linked by paired O—H…O hydrogen bonds to form centrosymmetric dimers. 相似文献
70.
Noe Oña Antonio Romero Carmen Assiego Claudia Bello Pierre Vogel M. Soledad Pino-González 《Tetrahedron: Asymmetry》2010,21(17):2092-2099
An approach to the synthesis of polyhydroxyazepane derivatives from sugar-based epoxyamides or epoxyalcohols, in which the total regioselective epoxide opening by nitrogen nucleophiles is the key step, is described. Thus, novel polyhydroxyazepane carboxamides and aminomethyl polyhydroxyazepanes, with potential pharmacological interest, are synthesized from diacetone d-mannose. Configurational assignments of the obtained products were determined. 相似文献