Preparation of quinoline hexose analogs as novel chloroquine-resistant malaria treatments (1). Synthesis of 4-hydroxyquinoline-beta-glucosides

Quinoline hexose analogs are expected to be useful as novel agents for treatment of chloroquine-resistant malaria. Here, we report preparation of 4-hydroxy quinoline-beta-glucosides from anilines in 4 steps.     

Solution of the Rayleigh problem for a powerlaw non-Newtonian conducting fluid via group method

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New rhodium---ruthenium heterobimetallic complexes with bridging bi- or tri-dentate phosphine ligands

The mononuclear chelated complex [RuCl(Cp)(η²-dppa)] has been synthesised and reacted with [Rh₂Cl₂(CO)₄] to form the heterobimetallic complex [(Cp)Ru(μ-CO)₂{(μ-Ph₂PN(H)PPh₂}RhCl₂]. Complexes of [RuCl(Cp){(PPh₂)₂CHCH₂PPh₂}] have been reacted with [Rh₂Cl₂(CO)₄] or [RhCl(CO)₂(p-toluidene)]. Characterisation of these new ruthenium complexes was carried out using ³¹P-NMR, FAB mass spectroscopy, elemental analysis and IR spectrophotometry.     

Efficacy of Ficus spp. on renal injury induced by hypercholesterolaemia

The ethanol and hexane extracts of Ficus microcarpa, Ficus religiosa and Ficus mysorensis leaves were evaluated against renal injury induced by hypercholesterolaemia. Phytochemical screening of the investigated plants was undertaken. For the in vivo study, all rats were orally given cholesterol (30?mg?kg?1 body weight, BW) and leaves extract (500?mg?kg?1 BW) five times per week for 9 weeks. Hypercholesterolaemic rats showed significant increases in urea nitrogen and creatinine while serum protein and albumin levels, nitric oxide (NO), Na?-K?-ATPase and phospholipids in kidney tissue were all decreased. Treatment with leaves extract improved kidney function indices (urea nitrogen, creatinine, serum protein and albumin), kidney disorder biochemical parameters (NO, Na?-K?-ATPase and phospholipids), haematological profile (haemoglobin, RBCs and WBCs) and kidney histopathology. In conclusion, Ficus spp. succeeded in improving renal injury induced by hypercholesterolaemia, with the most potent effects seen while using Ficus microcarpa hexane extract.     

Spectral Characteristics of the Reaction Products of 5-Phenyl-2,3,4-furantrione with o-Diamines

The ¹H and ¹³C NMR and mass spectra of 2-(2-amino-4,5-dimethylphenylcarbamoyl)-3-(hydroxyphenylmethyl)-6,7-dimethylqinoxaline (2), 3-(hydroxyphenylmethyl)-6,7-dimethylquinoxalin-2-carboxylic-γ-lactone (5), 3-(hydroxyphenylmethyl)-6,7-dimethylquinoxalin-2-carboxylic acid phenylhydrazide (6), 3-[2-hydroxy-2-phenyl-1-(phenylhydrazono)ethyl]-6,7-dimethyl-2(1H)-quinoxalinone (7), 2,3-dihydro-6,7-dimethyl-3-phenylhydrazono-2-phenylfuro[2,3-b]auinoxaline (8), 3-(hydroxyphenylmethyl)-6,7-dimethyl-1-phenylflavazole (9), and 3-(acetoxyphenylmethyl)-6,7-dimethyl-1-phenylflavazole (10) have been studied.     

Coordination compounds of hydrazine derivatives with transition metals. Part 21. Reaction of 1,5-thiocarbodihydrazones with nickel(II) and copper(II) salts

Summary A series of 1,5-thiocarhodihydrazones (HL) were reacted with nickel(II) acetate to give neutral bisligand nickel(II) chelates, Ni(L)₂. Reaction of nickel(H) chloride, however. results in partial hydrolysis of the dihydrazones to give Ni(RCH=NNHCSNHNH₂)₂Cl₂ chelate complexes. Deprotonation of these chelates with pyridine gave the neutral chelates Ni(RCH=NN=CSNHNH₂)₂. Copper(H) salts are readily reduced by the dihydrazone ligands to copper(I) chelates of the type CuL, Cu(HL)₂CI and Cu₂(HL)₃CI₂.     

Selective square wave voltammetric determination of (+)-catechin in commercial tea samples using beta-cyclodextrin modified carbon paste electrode

Osteryoung square wave cathodic or anodic voltammetry has been used for the determination of (+)-catechin (CAT) at physiological pH in the presence of 0.05 mol · L⁻¹ phosphate/borate buffer using beta-cylcodextrin modified carbon paste electrode. A linear range up to 70.0 μg · mL⁻¹ CAT in cathodic voltammetry and up to 45.0 μg · mL⁻¹ CAT in anodic voltammetry was achieved. The method gave reproducible and reliable results with 1.35 μg · mL⁻¹ CAT as a detection limit with R.S.D. less than 2%. The proposed electrode was applied successfully for the determination of CAT in commercial tea samples with acceptable recovery range (98–102%). The extraction of CAT from commercial tea samples was rather simple, making it suitable for studies with a large number of commercial tea samples giving high accuracy of the proposed method. Correspondence: Deia El-Hady, Department of Chemistry, Faculty of Science, Assiut University, 71516 Assiut, Egypt     

Synthesis,spectral and antimicrobial activity studies of o-aminoacetophenone o-hydroxybenzoylhydrazone complexes

Coordination compounds of Mn^II, Co^II, Ni^II, Cu^II, Zn^II, Cd^II and Hg^II ions with o-aminoacetophenone o-hydroxybenzoylhydrazone (AAOHBH) were synthesized and characterized by elemental analyses, molar conductivity, magnetic moments (at ca. 25°C) and spectral (i.r., u.v., n.m.r. and m.s.) studies. The i.r. spectra show that the ligand acts in a monovalent bidentate, neutral bidentate and/or neutral tridentate fashion, depending on the metal salt used and the reaction medium. Tetrahedral structures are proposed for both Co^II and Ni^II complexes and square planar for Cu^II complexes on the basis of magnetic and spectral evidence. The complex formation in solution was investigated potentiometrically and spectrophotometrically. Spectral studies in solution show that the ligand can be used for the microdetermination of Co^II ion within a metal concentration up to 46.3p.p.m. The electrical conductivity of AAOHBH and its metal complexes was determined. The tendency of AAOHBH to form complexes with Co^II, Ni^II, Cu^II, Cd^II and Hg^II ions in 50% aqueous-dioxane was studied by pH measurements.The antimicrobiol activity of AAOHBH and its complexes derived from Co^II, Ni^II and Cu^II illustrates that the Ni^II complex seems to be inert towards Escherichia coli and Bacillus subtilis. The antimicrobial activity of the Cu^II complex was higher against E. coli and lower against B. subtilis than the corresponding organic ligand. The Co^II complex has the same activity as the organic ligand against E. coli.     

Optimization parameters for adsorption and desorption of Zn(II) and Se(IV) using rice husk ash: kinetics and equilibrium

An attempt at the use of rice husk ash, an agricultural waste, as an adsorbent of Zn(II) and Se(IV) from their aqueous solution is studied. Studies are carried out as a function of contact time, metal ion concentration, adsorbent dose, and pH at 25 °C. Its adsorption capability and adsorption rate are considerably higher and faster for Zn(II) ions than for Se(IV) ions. Zn(II) adsorption was found fast reaching equilibrium within ≃1 h while Se(IV) adsorption was slow reaching equilibrium within ≃100 h. The Bangham equation can be used to express the mechanism for adsorption. The experimental isotherm data were analyzed using Langmiur, Freundlich, and Temkin models. Desorption experiments were carried out using different media with a view to regenerate the spent adsorbent and to recover the adsorbed metal ion.     

Effect of lateral bromo substituent on the phase behavior of four-ring azo/ester/azo liquid crystalline materials

ABSTRACT

In order to study the influence of lateral Br substitution on mesophase behaviour, five homologous series of 4-substituted phenylazo phenyl 4?-(3?-bromo-4?-alkoxyphenylazo) benzoates (In_a–e) have been synthesised. Within each homologous series, the alkoxy group varies from 6 to 16 carbons, while other terminal group substituents, X, are CH₃O, CH₃, H, Br and NO₂ groups; the mesophase behaviour of these series is compared with previously prepared laterally neat analogues, 4-substituted phenylazo phenyl 4?-(4?-alkoxyphenylazo) benzoates (IIn_a–e) and laterally methyl analogues, 4-substituted phenylazo phenyl 4?-(3?-methyl-4?-alkoxyphenylazo) benzoates (IIIn_a–e). Similar to lateral methyl analogues, the present series, lateral Br substitution showed that, independent of the polarity of the substituent X or the alkoxy-chain length, the nematic phase is predominant with relatively high stability and broad temperature ranges. The mesophase stability varies between 204.0°C and 335.0°C for the nematic phase and 169.6°C and 281.0°C for the SmA phase. Their total mesophase temperature ranges vary between 87.2°C and 201.4°C. All compounds were found to be thermally stable within the mesophase temperature range, except the lower homologue of the nitro and Br substituted derivatives. The obtained results are discussed in terms of molecular polarisability.