نتایج جستجو برای: carboxylic acid extractant
تعداد نتایج: 751271 فیلتر نتایج به سال:
Reductions of carboxylic acid derivatives might be expected to lead either to aldehydes or alcohols, functional groups having a lower oxidation state of the carboxyl carbon. that carboxylic acids themselves are reduced to alcohols by lithium aluminum hydride. At this point it will be useful to consider three kinds of reductions: (i) catalytic hydrogenation (ii) complex metal hydride reductions ...
Cephalosporin acylase (EC 3.5.1.11) obtained from Kluyvera citrophila ATCC 21285 was found to catalyze synthesis of 7-[2-(2-thienyl)acetamido]-3-trifluoromethyl-3-cephem-4-carboxylic acid from methyl thienylacetate and dl-7-amino-3-trifluoromethyl-3-cephem-4-carboxylic acid. The enzymatically-synthesized compound showed [alpha]25 D + 42.7 degrees (c 0.058, MeOH) and its biological activity was ...
In the dimeric title compound, [Zn(2)(C(14)H(9)O(4))(4)(C(10)H(8)N(2))(2)], the Zn(II) ions are penta-coordinated by one 2,2'-bipyridyl ligand and by three O atoms from three 2'-carboxyl-atobiphenyl-2-carboxylic acid ligands. Two of the 2'-carboxyl-atobiphenyl-2-carboxylic acid ligands act as bridging ligands and, together with two zinc(II) cations, produce an 18-membered ring system. The remai...
In this paper, extractants are presented which made it possible to separate actinides(III) and lanthanides from strong nitric acid solutions (0.05 1 mol/L). For this purpose, new aromatic dithiophosphinic acids were synthesised and characterised, and the distribution ratios of Am(III), Eu(III) and all relevant lanthanides were determined in batch extraction experiments. The extractant used was ...
Abstract Coumarin and its nitrogen analogue 1-aza coumarin are a class of lactones lactams, respectively, which indispensable heterocyclic units to both chemists biochemists. 1-Aza derivatives, ultimately metabolize as the corresponding 8-hydroxy coumarins in biological system therefore found be very good anti-inflammatory, anti-cancer, analgesic agents. A series hybrid substituted azacoumarin-...
This work studies the solvent extraction of lithium ions from alkaline aqueous solutions by chelating agent 3-benzoyl-1,1,1-trifluoroacetone (HBTA). To develop a more eco-friendly system for than currently used, various hydrophobic room-temperature ionic liquids were investigated as diluents. The influence several experimental parameters on was examined, including phase pH, nature counter-ion, ...
The reactivity of radical cation carboxylic acids is investigated on the basis of mass spectrometry, infrared-vacuum ultraviolet (IR-VUV) photoionization spectroscopy, and high level correlated ab initio calculations. Their reactivity is found to be highly conformation specific and is governed by their initial charge distribution following ionization. In the present work, the radical cations of...
[1,4]Diazepino[2,3-h]quinolone carboxylic acid 3 and its benzo-homolog tetrahydroquino[7,8-b]benzodiazepine-3-carboxylic acid 5 were prepared via PPAcatalyzed thermal lactamization of the respective 8-amino-7-substituted-1,4-dihydroquinoline-3-carboxylic acid derivatives 8, 10. The latter compounds were obtained by reduction of their 8-nitro-7-substituted-1,4-dihydroquinoline-3-carboxylic acid ...
Reactions of 3-bromo-4-phenylisothiazole-5-carboxamide and 3-bromoisothiazole-5-carboxamide with NaNO2 (4 equiv.), in TFA, at ca. 0 °C gave the carboxylic acid products 99% 95% yields, respectively. The two compounds were fully characterized.
In the title compound, C(5)H(5)NO(2), the pyrrole ring and its carboxyl substituent are close to coplanar, with a dihedral angle of 11.7 (3)° between the planes. In the crystal structure, adjacent mol-ecules are linked by pairs of O-H⋯O hydrogen bonds to form inversion dimers. Additional N-H⋯O hydrogen bonds link these dimers into chains extending along the a axis.
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