Scope and Limitation for the Reaction of α,β-Unsaturated Carbonyl Compounds with Phosphorus Nucleophiles by Determination of the Half-Wave Potential

Abstract

During the formation of oxaphospholenes the phosphorus in the reagent gets oxidized and the double bond in the enones gets reduced.     

P-Mannich Reaction on Wool Fibre for Activation in Dyeing

Abstract

Chemical modification of wool by means of dimethyl phoaphitc and D-glucose results in an increase in dye pickup, while colour and light fastness properties did not decrease, in fact some features bccpme more favourable. Our invesigations showed that increase in fibre diameter occurred. which could rise the rate of dye penetration. Amino acid analysis of the treated wool sample h w e d a decrease in lysine and arginim content, which allows of supposing covalent bond formation betweecl dimcthyl phosphite, D-glucose and the amino and guanidino groups of wool.     

Computer-Assisted HPLC Method Development for Determination of Tolmetin and Possible Kinetic Modulators of Its Oxidative Metabolism in Vivo

Following administration of the acidic drug tolmetin (TOL) anaphylactic reactions occurred, which have been hypothesized to be related to the formation of reactive acyl glucuronides. Recently, glutathione adducts have been detected upon incubation of TOL with human liver microsomal preparations, which proved that oxidative activation might also be a pathway of formation of reactive—possibly toxic—glutathione metabolites of TOL. The aim of this work was to develop a new and robust HPLC method to investigate the in vivo effect of 2 coadministered drugs/nutritional supplements on the kinetics of TOL in rats (cimetidine; CIM) known to be a potent inhibitor of CYP3A4, an enzyme that catalyzes the oxidative metabolism and Quercetin; and QUE which induces UGT1A6, an enzyme involved in glucuronidation of acidic drugs. DryLab^®, a computer simulation software package, was used to assist in the development and optimization of the HPLC method used for separation of TOL and the two potential kinetic modulators together with three potential internal standards (zomepirac, carvedilol and fexofenadine). The method was validated in biological samples obtained from rats. Non-compartmental pharmacokinetic analysis of data obtained from plasma and rat liver tissue showed significantly higher concentrations of TOL in the presence of CIM; and significantly longer elimination half-life lives in presence of QUE, which implies that drugs or food components interacting with CYP3A4 cause alteration in the metabolic oxidative biotransformation of TOL in vivo leading to accumulation of TOL in the body through a decrease of its clearance. These findings might account for to the side-effects associated with TOL when co-administered with such kinetic modulators.

     

DIHALOCARBENE ADDITION TO ARYLSUBSTTTUTED VINYL PHOSPHATES UNDER PHASE TRANSFER CATALYTIC CONDITIONS

Abstract

Dihalocarbene addition to aryl-substituted vinyl phosphates was carried out both in solid-liquid and in liquid-liquid two phase systems. The dihalocyclopropane adducts of vinyl phosphates could be obtained in better yield using dihalocarbenes generated by the latter method and no hydrolysis of the vinyl phosphate and of the adduct occurred under these circumstances. Eighteen new vinyl phosphate-dihalocarbene adducts were synthetized and characterized.     

Aryl‐Phosphonate Lanthanide Complexes and Their Fluorinated Derivatives: Investigation of Their Unusual Relaxometric Behavior and Potential Application as Dual Frequency 1H/19F MRI Probes

A series of low molecular weight lanthanide complexes were developed that have high ¹H longitudinal relaxivities (r₁) and the potential to be used as dual frequency ¹H and ¹⁹F MR probes. Their behavior was investigated in more detail through relaxometry, pH‐potentiometry, luminescence, and multinuclear NMR spectroscopy. Fitting of the ¹H NMRD and ¹⁷O NMR profiles demonstrated a very short water residence lifetime (<10 ns) and an appreciable second sphere effect. At lower field strengths (20 MHz), two of the complexes displayed a peak in r₁ (21.7 and 16.3 mM ^?1 s^?1) caused by an agglomeration, that can be disrupted through the addition of phosphate anions. NMR spectroscopy revealed that at least two species are present in solution interconverting through an intramolecular binding process. Two complexes provided a suitable signal in ¹⁹F NMR spectroscopy and through the selection of optimized imaging parameters, phantom images were obtained in a MRI scanner at concentrations as low as 1 mM . The developed probes could be visualized through both ¹H and ¹⁹F MRI, showing their capability to function as dual frequency MRI contrast agents.     

Typical curvature behaviour of bodies of constant width

It is known that an n-dimensional convex body, which is typical in the sense of Baire category, shows a simple, but highly non-intuitive curvature behaviour: at almost all of its boundary points, in the sense of measure, all curvatures are zero, but there is also a dense and uncountable set of boundary points at which all curvatures are infinite. The purpose of this paper is to find a counterpart to this phenomenon for typical convex bodies of given constant width. Such bodies cannot have zero curvatures. A main result says that for a typical n-dimensional convex body of constant width 1 (without loss of generality), at almost all boundary points, in the sense of measure, all curvatures are equal to 1. (In contrast, note that a ball of width 1 has radius 1/2, hence all its curvatures are equal to 2.) Since the property of constant width is linear with respect to Minkowski addition, the proof requires recourse to a linear curvature notion, which is provided by the tangential radii of curvature.     

Surface and Structural Properties of Gold Nanoparticles and Their Biofunctionalized Derivatives in Aqueous Electrolytes Solution

Gold nanoparticles reduced by sodium citrate (d ～ 10 nm) and purchased gold colloid particles (d ～ 500 nm) were examined and compared. The properties of both gold particles and their biofunctionalized derivatives with L-cysteine and L-glutathione were studied in the presence of sodium nitrate. The structural investigations indicated an aggregated inner structure.

The isoelectric points of pure gold, citrate reduced gold, and functionalized gold were measured and compared. The low isoelectric point of pure gold/water interface was explained by considering the distribution and accumulation of H⁺ and OH^? ions within the interfacial water layer, being more pronounced for OH^? ions.      

Fingerprinting pre-historical symbolic artefacts by a non-destructive methodological approach

Journal of Radioanalytical and Nuclear Chemistry - A contribution to the discussion about Vila Nova de São Pedro (VNSP) as a production centre of symbolic lithic artefacts, the origin of raw...