Design and synthesis of a diverse morpholine template library

Efficient and general procedures have been developed for the solution-phase preparation of substituted morpholine derivatives, and a library has been produced around generic structure 1. This library was designed with proprietary modeling software for use as a general screening library. The 30 R1 reagents were phenols, and the 275 R2 reagents were taken from five different reagent classes, giving a variety of product classes in the final library of 8250 potential products. All of the library members were generated from a common intermediate, mesylate (5), which was synthesized efficiently, in bulk, in three steps from N-benzylethanolamine (2). High-throughput chemistry using robotics was carried out to produce the 7907 library members, which were individually characterized by reversed-phase LC/MS analysis.     

Neutron Compton scattering investigation of sodium hydride: from bulk material to encapsulated nanoparticulates in amorphous silica gel

In this study we utilize neutron Compton scattering (NCS) to determine differences in nuclear momentum distributions in NaH, both as bulk material and encapsulated as nanoscale particles (from 20 to 50 nm in diameter) within an amorphous silica-gel matrix (SiGNaH). In addition, elemental Na dispersed in such a matrix is also studied (SiGNa). Data treatment and fitting of experimental spectra yields comparison of the nuclear Compton profiles and radial momentum distributions for the proton in both bulk NaH and nanoscale SiGNaH, with resultant proton kinetic energies being in agreement with previous inelastic neutron studies of bulk NaH. Slight differences in proton radial momentum distributions for bulk and nanoscale systems are witnessed and discussed. The technique of stoichiometric-fixing is applied to the backscattering spectra of each system in order to examine changes in the Na profile width, and NCS is shown to be sensitive to the chemical environment change of this heavier nucleus. Examination of the Si and O profile widths in the gel samples also supports this method.     

Raman spectroscopic and structural studies of indigo and its four 6,6'-dihalogeno analogues

The Raman and electron impact mass spectra of synthetic indigo and its four 6,6'-dihalogeno analogues are reported and discussed. The influence of varying the halogen on these Raman spectra is considered. Particular emphasis is laid on distinguishing indigo from 6,6'-dibromoindigo and differentiating between the dihalogenocompounds, so as to develop protocols for determining whether artefacts are coloured with dyes of marine or terrestrial origin and whether such artefacts are dyed with genuine "Tyrian Purple" or with dihalogenoindigo substitutes that do not contain bromine. The value of even low resolution electron impact mass spectrometry in a forensic context as a means of identifying authentic 6,6'-dibromoindigo and distinguishing it from its dihalogenoanalogues is emphasised     

Effects of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers on structure and stability of liposomal dioleoylphosphatidylethanolamine

The effects caused by poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO; Pluronic) copolymers on the structure and stability of dioleoylphosphatidylethanolamine (DOPE) liposomes were studied by means of turbidity, leakage, and cryo-transmission electron microscopy investigations. The results show that by inclusion of Pluronics in the DOPE dispersion it is possible to stabilize the lamellar Lalpha phase and to produce liposomes that are stable and nonleaky at low pH (pH 5). The stabilizing capacity was observed to depend critically on the molecular composition of the Pluronics. Block copolymers with comparably long PPO and PEO segment lengths, such as F127 and F108, most effectively protected DOPE liposomes prepared at high pH from aggregation and subsequent structural rearrangements induced by acidification. A sufficiently long PPO block was found to be the most decisive parameter in order to obtain adequate coverage of the liposome surface at low Pluronic concentrations. Upon increasing the copolymer concentration, however, Pluronics with comparably short PPO and PEO segment lengths, such as F87 and P85, could also be used to stabilize the DOPE liposomes. Essentially the same trends were observed when the Pluronics were added to preformed DOPE liposomes instead of being included in the preparation mixture. In this case the least effective copolymers failed, however, to completely prevent the DOPE liposomes from releasing encapsulated hydrophilic markers.