Two Stage Solid Phase Extraction with Subsequent HPLC Isolation for Structure Elucidation of Major Metabolites of (+)-(R)-2-{3-(benzo[1,4]dioxan-2-yl-methylamino)-1-propyl}-3(2H)-pyridazinone (GYKI-16084)

GYKI-16084 – (+)-(R)-2-{3-(benzo[1,4]dioxan-2-yl-methylamino)-1-propyl}-3(2H)-pyridazinone hydrochloride – is a new drug candidate for the treatment of benign prostatic hyperplasia. In our study the major metabolites formed in the rat and dog were isolated from dog and rat urine, then their structures were elucidated by means of MS and NMR. A two stage solid phase extraction (SPE) procedure and a semi-preparative HPLC method were developed utilizing various mechanisms of separation. The major metabolites proved to be isomeric glucuronides of the benzodioxane moiety hydroxylated at positions 6 or 7 and {2-(2-carboxyethyl)-3(2H)-pyridazinone}.     

Pressure‐Tuneable Visible‐Range Band Gap in the Ionic Spinel Tin Nitride

The application of pressure allows systematic tuning of the charge density of a material cleanly, that is, without changes to the chemical composition via dopants, and exploratory high‐pressure experiments can inform the design of bulk syntheses of materials that benefit from their properties under compression. The electronic and structural response of semiconducting tin nitride Sn₃N₄ under compression is now reported. A continuous opening of the optical band gap was observed from 1.3 eV to 3.0 eV over a range of 100 GPa, a 540 nm blue‐shift spanning the entire visible spectrum. The pressure‐mediated band gap opening is general to this material across numerous high‐density polymorphs, implicating the predominant ionic bonding in the material as the cause. The rate of decompression to ambient conditions permits access to recoverable metastable states with varying band gaps energies, opening the possibility of pressure‐tuneable electronic properties for future applications.     

Thin-Layer Chromatographic Characterization of Metabolites Formed from an AMPA Antagonist Drug Candidate

JPC – Journal of Planar Chromatography – Modern TLC - A pilot study has been conducted to develop sample preparation procedure and TLC separation of radiolabeled metabolites of an AMPA...     

Particle‐Stabilized Water Droplets that Sprout Millimeter‐Scale Tubes

Millimeter‐scale tubes are observed to sprout from water droplets injected into a bath of toluene containing ethanol and silica colloids. This phenomenon requires that first a membrane is formed by the colloids which self‐assemble at the droplet interface, and second, that the ethanol preferentially partitions into the aqueous phase leading to an internal over‐pressure. Tube growth, eruption, and shuffling droplets are subsequently observed, depending on the concentration of ethanol and colloids selected. This work opens many possibilities in the field of biomimetic droplets for fundamental studies of artificial growth at the microscale and for emulsion‐related applications.     

Synthesis of 1′,3,3′,4-tetrahydrospiro[chromene-2,2′-indoles] as a new class of ultrafast light-driven molecular switch

A new class of ultrafast light-driven molecular switch has been designed and synthesized. The reaction of 1-substituted 2-methylidene-3,3-dimethyl-2,3-dihydro-1H-indoles with 2-chloromethyl-4-nitrophenol afforded 1′,3,3′,4-tetrahydrospiro[chromene-2,2′-indoles], following a basic workup. The spectroscopic properties and nanosecond-resolved photoinduced dynamics of five compounds in the 1′,3,3′,4-tetrahydrospiro[chromene-2,2′-indole] family were investigated.     

Superconductivity in doped polyethylene at high pressure

In this work we study the pressure-dependent phase diagram of polyethylene (H₂C)_x from 50 to 200 GPa. Low-symmetry, organic polymeric phases, that are dynamically stable and thermodynamically competitive with elemental decomposition, are reported. Electronic structure calculations reveal that the band gap of the lowest energy polymeric phase decreases from 5.5 to 4.5 eV in the 50–200 GPa range, but metalization occurs only for pressures well above 500 GPa. The possibility of metalization via doping was also investigated, observing that it can be achieved through boron substitution at carbon sites. We report a sizable electron-phonon coupling (λ ? 0.79) in this metallic phase, with an estimated superconducting transition temperature of about 35 K. However, a rather narrow domain of stability is found; most of the dopant elements render the polymeric phases unstable and induce amorphization. This suggests that doping under pressure, though presenting an alternative route to find high temperature superconductors, would be challenging to achieve experimentally.     

Colorimetric Cyanide Chemosensor Based on 1′,3,3′,4-Tetrahydrospiro[chromene-2,2′-indole]

A new class of chemosensors based on the 1′,3,3′,4-tetrahydrospiro[chromene-2,2′-indole] ring system, which detects cyanide with high specificity, is described. These chemosensors show a distinct color change when treated with cyanide in acetonitrile solution buffered with sodium phosphate, and this procedure is not affected by the presence of other common anions. The chemisensors exhibit high sensitivity to low concentrations of cyanide, meeting the European Union water quality control criterion of sensitivity below 0.05 mg L⁻¹, and show a very fast response within tens of seconds. The mechanism for detection is rationalized by the nucleophilic substitution of the phenolic oxygen atom at the indoline C-2 atom by the cyanide anion to form a stable indolylnitrile adduct and to generate the colored 4-nitrophenolate chromophore. These chemosensors can be synthesized by a simple procedure from commercially available starting materials.