57Fe Mössbauer Spectroscopic Study of Fe–B Compounds

Hyperfine Interactions - 57Fe Mössbauer measurements of Fe doped β-rhombohedral boron (β-B) were performed in the temperature range between 300 K and 4.5 K. The spectra of Fe doped...     

Chemical speciation of chromium in sea water: Part 3. The determination of chromium species

A method for the determination of chromium(III), chromium(VI) and organicallybound chromium in sea water is reported. It is confirmed that sea water contains about 9 × 10^-9 M dissolved chromium. This is shown to be divided as ca. 15% inorganic Cr(III), ca. 25% inorganic Cr(VI) and ca. 60% organically-bound chromium. It is suggested that the inconsistency of earlier results on the dominant chromium species and its concentration in sea water is largely due to the fact that organically bound chromium species were not considered.     

Preparation of highly potent and selective non-peptide antagonists of the arginine vasopressin V1A receptor by introduction of a 2-ethyl-1H-1-imidazolyl group

To find a new series of arginine vasopressin (AVP) V1A receptor antagonists, the influence of the 2-phenyl group of 2-phenyl-4'-[(2,3,4,5-tetrahydro-1H-1-benzazepin-1-yl)carbonyl]benzanilide (7) was investigated. Replacement of the 2-phenyl group by a 2-ethyl-1H-imidazol-1-yl group was effective in yielding a V1A-selective compound. Moreover, this imidazolyl group was introduced in the same position in YM-35471 (6), and further studies of these compounds were performed. Consequently, we found that the (Z)-4'-({4,4-difluoro-5-[(N-cyclopropylcarbamoyl)methylene]-2,3,4,5-tetrahydro-1H-1-benzazepin-1-yl}carbonyl)-2-(2-ethyl-1H-1-imidazol-1-yl)benzanilide (9f) exhibited highly potent affinity and selectivity, and was the most potent antagonist for the V1A receptor among our compounds. The synthesis and pharmacological evaluation of these compounds are described in this paper.     

Design and synthesis of dual inhibitors of acetylcholinesterase and serotonin transporter targeting potential agents for Alzheimer's disease

Highly efficient acetylcholinesterase (AChE) and serotonin transporter (SERT) dual inhibitors, (S)-4 and (R)-13 were designed and synthesized on the basis of the hypothetical model of AChE active site. Both compounds showed potent inhibitory activities against AChE and SERT. [structure: see text]     

Nonlinear magnetooptical effects caused by piezoelectric ferromagnetism in F3m-type Prussian blue analogues

The second harmonic generation (SHG) and magnetization-induced SHG (MSHG) of AMA[MB(CN)6]-type (F3m) Prussian blue analogues (i.e., CsCo[Cr(CN)6].0.5H2O and RbMn[Fe(CN)6]) were observed. A large interaction between the nonlinear optical response and magnetic spins was observed in CsCo[Cr(CN)6].0.5H2O. These observations of SHG and MSHG imply that AMA[MB(CN)6]-type Prussian blue analogues are piezoelectric above the Curie temperature (TC) and piezoelectric ferromagnet below TC.     

Characterization and synthesis of a new calcium antagonist from the venom of a fishing spider

A new calcium antagonist, CNS 2103, is isolated from the venom of a fishing spider, Dolomedes okefinokensis. The structure of this compound is derived from spectroscopic data, including tandem mass spectrometry. A flexible, convergent synthesis of CNS 2103 is described.     

An sp2 ylide carbon-to-metal bonding: x-ray molecular structure of [PtII(NH2CH2CH2NH2)(C5H4NC(O)CNC5H3(CH3)2-3,5)]ClO4-2H2O

An X-ray structure analysis for the title complex obtained by the reaction of Pt^IICL₂(C₅H₄NC(O)C?H+NC₅H₃(CH₃)₂-3.5) with ethylenediamine in water has revealed the presence of an ylide carbon atom which is coordinated to the platinum(II) ion with an sp² configuration.     

Disposition of triazolam in the rat by brain microdialysis and semi-micro column high-performance liquid chromatography with UV absorbance detection

A semi-micro column high-performance liquid chromatography with ultraviolet detection for the determination of triazolam is described. The method was applied to determine plasma and brain microdialysate concentrations of triazolam after single intravenous bolus of 2.5 mg/kg to rat. The separation was achieved on a 250 x 1.5 mm i.d. C(18) column and the column effluent was monitored at 222 nm. The detection limits at a signal-to-noise ratio of 3 obtained using spiked plasma and artificial cerebrospinal fluid were 2.1 and 0.7 ng/mL, respectively. The intra- and inter-day reproducibility of the present method were satisfactory with the highest relative standard deviation of 9.1 (n > or = 5). The present method was successfully applied to study the disposition of triazolam in rat (n = 5) by analyzing plasma and brain microdialysate samples.     

A 4 k matrix esr study of the radical cations of methyl formate: The primary radical cation and its rearrangement

It is found that an oxygen-centred n_π radical of HCOOCH₃ is produced radiolytically in CFCl₃ at 4.2 K without forming a σ* complex with a matrix molecule. This cation converts into the carbon-centred radical cation HC⁺(OH)OCH₂ by an intramolecular hydrogen-atom transfer upon warming to 77 K. This is clear experimental evidence for a McLafferty rearrangement of ester radical cations.