Search results for "Methanol"
showing 10 items of 1026 documents
Nuclease activity of [Cu(sulfathiazolato)2(benzimidazole)2]2MeOH. Synthesis, properties and crystal structure
2002
The [Cu(sulfathiazolato)(2)(benzimidazole)(2)]2MeOH complex has been synthesised and characterised. It crystallises in the monoclinic system, space group C1c1, with unit cell dimensions a=18.829(7) A, b=12.206(3) A, c=17.233(5) A, alpha=90.06(2) degrees, beta=97.28(3) degrees, gamma=90.21(3) degrees and Z=4. The geometry around the copper(II) ion is intermediate between tetrahedral and square planar. The complex produces cleavage of plasmid pUC18 in presence of reducing agents. The efficiency of cleavage reaction of the title compound with pUC18 and with different reducing agents follows the order ascorbate-H(2)O(2)>ascorbate>MPA>dithiothreitol>H(2)O(2).
Coordination Diversity in Mono- and Oligonuclear Copper(II) Complexes of Pyridine-2-Hydroxamic and Pyridine-2,6-Dihydroxamic Acids
2013
Solution and solid state studies on Cu(II) complexes of pyridine-2-hydroxamic acid (HPicHA) and pyridine-2,6-dihydroxamic acid (H2PyDHA) were carried out. The use of methanol/water solvent allowed us to investigate the Cu(II)-HPicHA equilibria under homogeneous conditions between pH 1 and 11. In agreement with ESI-MS indication, the potentiometric data fitted very well with the model usually reported for copper(II) complexes of α-aminohydroxamate complexes ([CuL](+), [Cu5(LH-1)4](2+), [CuL2], [CuL2H-1](-)), however with much higher stability of the 12-MC-4 species. A series of copper(II) complexes has been isolated in the solid state and characterized by a variety of spectroscopic methods, …
Synthesis and Self-Organization of Zinc β-(Dialkoxyphosphoryl)porphyrins in the Solid State and in Solution
2012
The first synthesis and self-organization of zinc β-phosphorylporphyrins in the solid state and in solution are reported. β-Dialkoxyphosphoryl-5,10,15,20-tetraphenylporphyrins and their Zn(II) complexes have been synthesized in good yields by using Pd- and Cu-mediated carbon-phosphorous bond-forming reactions. The Cu-mediated reaction allowed to prepare the mono-β-(dialkoxyphosphoryl)porphyrins 1 Zn-3 Zn starting from the β-bromo-substituted zinc porphyrinate ZnTPPBr (TPP = tetraphenylporphyrin) and dialkyl phosphites HP(O)(OR)(2) (R = Et, iPr, nBu). The derivatives 1 Zn-3 Zn were obtained in good yields by using one to three equivalents of CuI. When the reaction was carried out in the pres…
Phycocyanobilin in solution – a solvent triggered molecular switch
2014
We present a computational investigation of the conformational response of phycocyanobilin (PCB) to the ability of solvents to form hydrogen bonds. PCB is the chromophore of several proteins in light harvesting complexes. We determine the conformational distributions in different solvents (methanol and hexamethylphosphoramide HMPT) by means of ab initio molecular dynamics simulations and characterize them via ab initio calculations of NMR chemical shift patterns. The computed trajectories and spectroscopic fingerprints illustrate that the energy landscape is very complex and exhibits various conformations of similar energy. We elucidate the strong influence of the solvent characteristics on…
On the reactivity of nitrosoimidazoles with acids (the Cusmano–Ruccia reaction): a continuous source of new ring-into-ring interconversion
2014
Abstract An extension of the ‘Cusmano–Ruccia’ reaction is reported. 6-(4-chlorophenyl)-3-methyl-5-nitrosoimidazo[2,1- b ]oxazole by the action of hydrochloric acid gives 3-(4-chlorobenzoyl)-5-methyl-1,2,4-oxadiazole ( 13 ); presumably via ammonium ion, CO 2 and methanol elimination. The relevance of the nature of the atom of the B -ring linked to C-2 of the imidazole for the occurrence of the ring-into-ring interconversion has been once more confirmed.
Simultaneous Determination of Thiamin and Riboflavin in Mushrooms by Liquid Chromatography
2001
A simple, fast, inexpensive, and reliable method useful for the simultaneous, routine determination of thiamin and riboflavin in mushrooms is examined. It uses the extraction procedure, with slight modifications, proposed by the AOAC for the extraction of thiamin and riboflavin, followed by a liquid chromatographic separation on a reversed-phase Spherisorb ODS column with methanol/water as mobile phase gradient. Fluorometric detection is used at the following excitation and emission wavelengths, respectively, 360 and 425 nm in the case of thiamin and 422 and 515 nm for riboflavin. The analytical parameters of linearity, the precision of the method (RSD = 2.45 and 2.51% for thiamin and ribof…
CCDC 1008820: Experimental Crystal Structure Determination
2015
Related Article: Bernd Elsler, Anton Wiebe, Dieter Schollmeyer, Katrin M. Dyballa, Robert Franke, Siegfried R. Waldvogel|2015|Chem.-Eur.J.|21|12321|doi:10.1002/chem.201501604
CCDC 1966174: Experimental Crystal Structure Determination
2020
Related Article: Kwaku Twum, J. Mikko Rautiainen, Shilin Yu, Khai-Nghi Truong, Jordan Feder, Kari Rissanen, Rakesh Puttreddy, Ngong Kodiah Beyeh|2020|Cryst.Growth Des.|20|2367|doi:10.1021/acs.cgd.9b01540
Selective mono-de-O-acetylation of the per-O-acetylated brasilicardin carbohydrate side chain
2021
Abstract Methanol dried over powdered 4 A molecular sieves can be used for a selective mono-de-O-acetylation of the phenolic acetyl group of the per-O-acetyl protected brasilicardin A carbohydrate side chain. This reaction opens a practical procedure for a synthetic access to derivates of the immunosuppressive and cytotoxic natural product brasilicardin A.
Ursolic acid from the Chinese herb Danshen (Salvia miltiorrhiza L.) upregulates eNOS and downregulates Nox4 expression in human endothelial cells
2007
Danshen, the dried root of Salvia miltiorrhiza Bunge (Lamiaceae), is one of the most commonly used traditional Chinese medicines for cardiovascular indications. In EA.hy 926 cells, a cell line derived from human umbilical vein endothelial cells (HUVEC), an aqueous extract of danshen, and also a methanol extract of the plant, increased eNOS promoter activity, eNOS mRNA and protein expression, as well as endothelial NO production. A dichloromethane extract, in contrast, did not change eNOS gene expression. Thus, the active danshen constituent(s) responsible for eNOS upregulation is (are) hydrophilic and/or alcohol-soluble. One such compound is ursolic acid that significantly increased eNOS ex…