Search results for "Reagent"

FIA-Fluorimetric assembly for the determination of noradrenaline hydrochloride by a solid-phase reactor with immobilized hexacyanoferrate(III)

1997

An FIA assembly provided with immobilized hexacyanoferrate(III) is proposed for the fluorimetric determination of noradrenaline hydrochloride. The oxidative reagent is immobilized by means of a strong anion-exchange resin. The FIA manifold is very simple and the calibration graph is linear over the range 0.5–75mgl−1 noradrenaline hydrochloride with an r.s.d of 0.88% (17 replicates) and a sample throughput of 84h−1. Foreign compounds such as NaCl, sucrose, lactose and sodium sulfate caused no significant errors. The procedure is applied to the determination of noradrenaline in a medicinal formulation.

Synthesis and characterization of the [Ru(η5-C5Me4CF3)(CO)2]2 and Ru6(μ3-H)(η2-μ4-CO)2(μ-CO)(CO)12(η5-C5Me4CF3) complexes

1998

The reaction of Ru3(CO)12 with tetramethyltrifluoromethylcyclopentadiene at various ratios of the reagents was studied. Refluxing of Ru3(CO)12 with a sixfold excess of tetramethyltrifluoromethylcyclopentadiene in octane in an inert atmosphere gave a complex, which is, according to X-ray diffraction data, a dimer,trans-[Ru(η5-C5Me4CF3)(CO)2]2. The reaction under the same conditions but starting from Ru3(CO)12 and C5Me4CF3H in 2∶1 molar ratio gave a hexaruthenium cluster [Ru6(μ3-H)(η2-μ4-CO)2(μ-CO)(Co)12(η5-C5Me4CF2)], which was characterized by IR as well as1H,13C, and19F NMR spectroscopy. According to X-ray diffraction data, an Ru4 tetrahedron, in which two edges are bound by additional “br…

(−)-(4R,5R)-4,5-Bis[hydroxy(diphenyl)methyl]-2,2-dimethyl-1,3-dioxolane

2008

[93379-48-7] C31H30O4 (MW 466.57) InChI = 1S/C31H30O4/c1-29(2)34-27(30(32,23-15-7-3-8-16-23)24-17-9-4-10-18-24)28(35-29)31(33,25-19-11-5-12-20-25)26-21-13-6-14-22-26/h3-22,27-28,32-33H,1-2H3/t27-,28-/m1/s1 InChIKey = OWVIRVJQDVCGQX-VSGBNLITSA-N (chiral shift reagent; chiral host in inclusion compounds; chiral reagent; chiral ligand for asymmetric catalysis) Alternate Name: TADDOL. Physical Data: mp: 190–192 °C1a; 195–196.5  °C1b; 192–193 °C;1c,e 193.5–195 °C;1d [α]RTd=−68.5 °(c = 1, CH3Cl);1a [α]d = −60.6 °(c = 1, CH3Cl);1b [α]20d = −67 ° (c = 1, CH3Cl);1c [α]20d = −65.1° (c = 1, CH3Cl);1d [α]20d = −64.6°(c = 1, CH3Cl)1e Solubility: soluble in toluene, cyclohexane, dichloromethane and tetra…

A dft study of the regioselectivity in intramolecular diels-alder reactions with formation of a tricyclodecane skeleton

2011

Three different intramolecular Diels-Alder (IMDA) reactions associated with the formation of fused and bridged tricyclodecane skeletons have been studied at the B3LYP/6-31G(d) computational level. While substitution on the diene and dienophile fragments modulates the polar character of the reaction, the strain effect produced by the methylene tether affects the activation energy, and its torsion controls the different regioisomeric channels of the IMDA process. Analysis of the reactivity indices recently proposed (J. Soto-Delgado et al., Org. Biomol. Chem., 2010, 8, 3678) within the conceptual density functional theory allows for the characterization of the mechanism including the charge tr…

Comparative assessment of solid-phase extraction clean-up procedures, GC columns and perfluoroacylation reagents for determination of type B trichoth…

2005

Abstract Various solid-phase extraction (SPE) procedures for clean-up, two perfluoroacylation reagents (pentafluoropropionic anhydride (PFPA) and heptafluorobutyric anhydride (HFBA)) and two chromatographic columns (HP-1701 and HP-5) have been assessed comparatively to achieve the determination of type B trichothecenes (deoxynivalenol (DON), nivalenol (NIV), 3- and 15-acetyldeoxynivalenol (3- and 15-ADON)) in wheat grain by gas chromatography (GC)–electron-capture detection (ECD). Spiked wheat samples were extracted with acetonitrile–water (84:16, v/v). Tested SPE procedures were MycoSep 225 column, Florisil and different cartridges prepared in the laboratory with mixtures of various sorben…

I(py)2BF4, a New Reagent in Organic Synthesis: General Method for the 1,2-Iodofunctionalization of Olefins

1985

ChemInform Abstract: Imidazolium and Potassium Hydrogen Carbonate Salts as Ecofriendly Organocatalysts for Oxazolidinone Synthesis.

2016

Although oxazolidinones are valuable intermediate compounds for industrial applications, no synthetic method is suitable for their production on a large scale owing to the use of reagents/catalysts that are hazardous or toxic to human health or ecotoxic for the environment. In this manuscript, we describe new and efficient catalysts, that is, the nontoxic hydrogen carbonate anion in combination with a potassium or diisobutylimidazolium ([iBu(2)IM]) countercation, for the conversion of -amino alcohols into cyclic oxazolidinones in high yields of 69 to 90%. Depending on the catalytic conditions, both catalysts could be easily recovered from the crude reaction products and reused several times…

Identification of drying oils used in pictorial works of art by liquid chromatography of the 2-nitrophenylhydrazides derivatives of fatty acids.

2004

A new HPLC-UV-Vis method for identification of drying oils from binding media or protective film used in pictorial works of art prior to conservation or restoration is proposed. Chromophore derivatization of fatty acids released by hydrolysis of structural drying oils is studied. The derivatization reagent selected was 2-nitrophenylhydrazine with 1-ethyl-3-(3-dimethyl animopropyl)carbodiimide hydrochloride/pyridine as catalyst. This reaction was carried out using microwave heating. Mobile phase was methanol/water/n-propanol/acetic acid (80:14:5:1) running in isocratic mode. Absorbance was measured at 400nm. In these conditions, hydrazides of myristic, palmitic, oleic, and stearic acids were…

Propanephosphonic Acid Anhydride–Mediated Cyclodehydration of Maleic Acid Monoamides

2013

Abstract Propanephosphonic acid anhydride (T3P) has been proposed as a novel reagent for the preparation of maleic acid isoimides from the corresponding monoamides. A series of substituted aromatic and aliphatic isoimides have been prepared in good yields. The main advantage of this synthetic method is the use of environmentally benign, cost-efficient reagents and solvents, which are also safer to handle than the ones employed previously. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.

Influence of synthesis conditions on the morphology of Dodecasil 1H

1993

Abstract The synthesis of Dodecasil 1H was studied in the system SiO2/1-adamantylamin/NH3/water with the objective of controlling the particle size and the morphology of the crystals. Since nucleation occurs in a very early stage of the synthesis, the heating rate to the final temperature and/or holding points during heat up have a strong influence on both parameters. Crystals smaller than 150 μm could only be obtained by the use of seed crystals, which are completely consumed in the synthesis with subsequent new nucleation. Using seed crystals, the expensive template 1-adamantylamine can be substituted with cheaper reagents such as sodium dodecyl sulfate or trimethylethylammonium bromide a…