Synthesis of N-alkyl-N-hydroxyamphetamines and related nitrones

The action ofm-chloroperbenzoic acid on various amphetamines and on dibenzylamine is shown to yield N-hydroxy derivatives and related nitrones.     

Basic strength and hydrogen bonding in some aminoalcohols of bicyclo(2,2,2) octane and bornane

The effects are discussed of H-bonding, and steric and electronic features on pK_a values and rates of quaternization of some aminoalcohols based on the rigid, bornane and the slightly more flexible, bicyclo[2,2,2]octane structures.     

Initial observations of dynamically heated bone

Understanding the chemical changes within bone during heat treatment has become essential within many fields including biomaterials, archaeology and forensic science. All current approaches report the systematic heating and cooling of bone specimens (a ‘static’ approach). These provide information on modifications to mineral structure and chemistry including recrystallisation and thermal decomposition from bone specimens cooled to room temperature. In order to understand these fundamental processes further, we adopted, for the first time, a dynamic heating protocol coupled to an X‐ray diffraction probe, which provides in situ analysis at temperature. This approach allows physico‐chemical processes to be observed at elevated temperatures for five different bone types: bovine, porcine, human, rostrum and red deer antler. The results, when compared to static heating studies, illustrate individually the effects of heating and cooling upon bone mineral. On heating, the onset of recrystallisation occurs rapidly over a short temperature range for all bone types. It is proposed the continued growth of the hydroxyapatite crystals is limited by the mineral to organic ratio. Investigation of the lattice parameters has also indicated significant differences between the bone types, suggesting species differentiation is possible using X‐ray diffraction analysis. Statistical analysis of the ‘a’ axis lattice parameter data revealed human bone is distinguishable from the other bone types.     

Liquid chromatography of lanthanide chelates of 1-(p-nitrophenyl)ethylenediamine-N,N,N',N' -tetra-acetic acid

Preparation of the chelating agent, 1-(p-nitrophenyl)ethylenediamine-N,N,N',N'-tetra-acetic acid (p-nitrophenylEDTA), is described in detail. Separation of p-nitrophenylEDTA chelates of ytterbium(III), erbium(III), dysprosium(III) and europium(III) has been achieved by reversed-phase ion-pair liquid chromatography. With spectrophotometric detection at 254 nm, linear responses over about four orders of magnitude were achieved with detection limits (S/N = 2) of about 0.5 pmole.     

Non-linear oscillations of a spherical particle in a rotating fluid

The motion of a spherical particle contained within a rotating fluid is analysed using equations of classical mechanics. Conditions are established under which the second order differential system simplifies to the well known Svedberg equation which describes the radial motion in centrifugation theory. The complete particle trajectories are obtained by solving the second order system numerically and approximations to these are derived using perturbation methods.     

Artifacts produced by using dichloromethane in the extraction and storage of some antihistaminic drugs.

The use of dichloromethane for the extraction of amines may lead to the formation of artifacts. Dichloromethane reacts rapidly (37.5 degrees) with brompheniramine, diphenylpyraline, cyclizine, cyproheptadine but not with antazoline and lignocaine. This difference in reactivity as well as the thin-layer chromatographic, gas-liquid chromatographic, nuclear magnetic resonance, and mass spectrometric characteristics of cyclizine and diphenylpyraline chloromethochlorides are investigated.