Direct determination of benzamides in serum by column-switching high-performance liquid chromatography.

A column-switching high-performance liquid chromatographic method with fluorescence detection was developed for the simultaneous determination of four benzamide-type anti-psychotic drugs: sulpiride, tiapride, sultopride and metoclopramide in human serum. In this method, a TSKgel Super-ODS column was used as an analytical column, and a TSKgel G 2000SW was prepared as a pretreatment column. Under the optimized analytical conditions, four benzamide-type anti-psychotic drugs were eluted within 18 min. The detection limits (S/N = 3) for sulpiride, tiapride, sultopride and metoclopramide are 1 ng/ml, 4 ng/ml, 2 ng/ml and 0.5 ng/ml, respectively. Finally, the method was applied to the determination of sulpiride in human serum samples obtained after a single oral dose of sulpiride.     

Hydrothermal Synthesis of Mo-Based Oxide Catalysts and Selective Oxidation of Alkanes

Mo-V-M(=Al, Ga, Bi, Sb and Te)–O mixed oxide catalysts were synthesized hydrothermally for the first time, characterized structurally, and tested for ethane and propane oxidation after activation by various ways. These catalysts were black solids of rod-shaped (fiber like) crystals, which had a layer structure in the direction of fiber axis and a high dimensional arrangement of metal octahedra in the cross-section plane. These fresh crystalline materials became active for catalytic oxidation of alkanes after heat-treatment at 600 °C and subsequent grinding in order to increase exposed plane of the cross-section. The resulting catalysts were very active for an oxidative dehydrogenation of ethane with 80% of the ethylene selectivity in the reaction temperature range of 300 to 400 °C and also showed about 50% selectivity to acrylic acid in the propane oxidation. Multi-functional character which derived from the high dimensional structure of the catalysts and mechanism of the selective alkane oxidation were discussed.     

Effect of surface covering of lactose carrier particles on dry powder inhalation properties of salbutamol sulfate

The effect of the surface covering of lactose carrier particles on the dry powder inhalation properties of salbutamol sulfate was investigated. Lactose carrier surfaces were covered with sucrose tristearate (J-1803F) by a high-speed elliptical-rotor-type powder mixer (Theta-Composer). In the present study, drug/carrier powder mixtures were prepared consisting of micronized salbutamol sulfate and lactose carriers with various particle surface conditions prepared by surface covering. These powder mixtures were aerosolized by a Jethaler), and the in vitro inhalation properties of salbutamol sulfate were evaluated by a twin impinger. Compared with the powder mixed with uncovered lactose carrier, the in vitro inhalation properties of the powder mixture prepared using the surface covering lactose carrier were significantly different, showing that the in vitro inhalation properties of salbutamol sulfate were improved. In vitro inhalation properties increased with the percentage of J-1803F added. Using this surface covering system would thus be valuable for increasing the inhalation properties of dry powder inhalation with lactose carrier particles.     

Influence of storage humidity on the in vitro inhalation properties of salbutamol sulfate dry powder with surface covered lactose carrier

The influence of storage humidity on the in vitro inhalation properties of salbutamol sulfate dry powder with surface covered lactose carrier was investigated. In the present study, drug/carrier powder mixtures were prepared consisting of micronized salbutamol sulfate and lactose carriers with different particle surface conditions prepared by surface covering. Lactose carrier surfaces were covered with vegetable magnesium stearate (Mg-St-V) by a high-speed elliptical-rotor-type powder mixer (Theta-Composer). These powder mixtures were aerosolized by a Jethaler), and the in vitro inhalation properties of salbutamol sulfate were evaluated by a twin impinger. Compared with the powder mixed with uncovered lactose carrier, the in vitro inhalation properties of the powder mixture prepared using the surface covered lactose carrier were little decreased with increased in relative humidity (RH), showing that the in vitro inhalation properties of salbutamol sulfate were improved at high RH. Using this surface covering technique would thus be valuable for storage humidity of dry powder inhalation (DPI) with lactose carrier particles.     

Synthetic studies on cyathins: enantioselective total synthesis of (+)-allocyathin B2

[reaction: see text] The enantioselective total synthesis of (+)-allocyathin B(2) has been achieved. Our approach features a convergent enantioselective construction of the 5-6-7 tricyclic core system using the originally developed chiral building blocks via asymmetric catalysis, the intramolecular aldol reaction in high yield, successful samarium diiodide-mediated ring expansion, and a newly developed double-bond installation method.     

A hybrid density-functional study of the one-dimensional ferromagnetic ordering of (BDTA)[Ni(mnt)2]

The one-dimensional intermolecular ferromagnetic interaction of a charge-transfer (CT) complex, (BDTA)[Ni(mnt)₂] (BDTA: 1,3,2-benzodithiazolyl, mnt: maleonitriledithiolate), is studied by the Kohn–Sham hybrid density functional method, in order to understand the mechanism of the magnetism. All possible effective exchange integrals, J, between the spin pairs of the system indicate that a ferromagnetic interaction (J = 172 cm⁻¹) exists along the b-axis. Magnetic susceptibility, simulated with the ab initio determined J values by the quantum Monte Carlo (QMC) method, is qualitatively consistent with that measured experimentally.     

Small angle X-ray scattering from lamellar phase for β-3,7-dimethyloctylglucoside/water system: comparison with β-n-alkylglucosides

Small angle X-ray scattering (SAXS) is measured for the lamellar phase in aqueous systems of 1-o-β-3,7-dimethyoctyl-D-glucopyranoside (β-Glc(Ger)), which has recently been prepared by us, 1-o-β-decyl-D-glucopyranoside (β-GlcC₁₀), and 1-o-β-octyl-D-glucopyranoside (β-GlcC₈). The repeat distance d obtained from the position of the diffraction peak does not follow the swelling law d = 2δ_hc/_hc, where δ_hc and _hc are the thickness and the volume fraction of the hydrophobic layer, respectively. This may result from the fact that δ_hc increases and, equivalently, the surface area per surfactant molecule (a_s) decreases with increasing concentration. So we calculate δ_hc and a_s from the observed d value at each concentration using the above swelling law. The half-thickness δ_hc increases in the order β-GlcC₈ < β-Glc(Ger) < β-GlcC₁₀ at a fixed concentration. On the other hand, the data on a_s for β-GlcC₁₀ and β-GlcC₈ lie on the same line and the data for β-Glc(Ger) lies above this line. These results suggest that the cross-sectional area of the geranyl chain is larger than that of the glucose headgroup. Existence of water filled defects in bilayer sheets is also discussed based on the SAXS pattern and the concentration dependence of d.     

7,7,8,8‐Tetraaryl‐o‐quinodimethane Stabilized by Dibenzo Annulation: A Helical π‐Electron System That Exhibits Electrochromic and Unique Chiroptical Properties

When two benzene rings are fused to a tetraaryl‐o‐quinodimethane skeleton, sterically hindered helical molecules 1 acquire a high thermodynamic stability. Because the tetraarylbutadiene subunit contains electron‐donating alkoxy groups, 1 undergo reversible two‐electron oxidation to 2 ²⁺, which can be isolated as deeply colored stable salts. Intramolecular transfer of the point chirality (e.g., sec‐butyl) on the aryl groups to helicity induces a diastereomeric preference in dications 2 b ²⁺ and 2 c ²⁺, which represents an efficient method for enhancing circular‐dichroism signals. Thus, those redox pairs can serve as new electrochiroptical response systems. X‐ray analysis of dication 2 ²⁺ revealed π–π stacking interaction of the diarylmethylium moieties, which is also present in solution. The stacking geometry is the key contributor to the chirosolvatochromic response.     

The Impact of C2 Insertion into a Carbazole Donor on the Physicochemical Properties of Dibenzo[a,j]phenazine-Cored Donor–Acceptor–Donor Triads

Novel electron donor–acceptor–donor (D-A-D) compounds comprising dibenzo[a,j]phenazine as the central acceptor core and two 7-membered diarylamines (iminodibenzyl and iminostilbene) as the donors have been designed and synthesized. Investigation of their physicochemical properties revealed the impact of C₂ insertion into well-known carbazole electron donors on the properties of previously reported twisted dibenzo[a,j]phenazine-core D-A-D triads. Slight structural modification caused a drastic change in conformational preference, allowing unique photophysical behavior of dual emission derived from room-temperature phosphorescence and triplet–triplet annihilation. Furthermore, electrochemical analysis suggested sigma-dimer formation and electrochemical polymerization on the electrode. Quantum chemical calculations also rationalized the experimental results.     

Serine‐Selective Aerobic Cleavage of Peptides and a Protein Using a Water‐Soluble Copper–Organoradical Conjugate

The site‐specific cleavage of peptide bonds is an important chemical modification of biologically relevant macromolecules. The reaction is not only used for routine structural determination of peptides, but is also a potential artificial modulator of protein function. Realizing the substrate scope beyond the conventional chemical or enzymatic cleavage of peptide bonds is, however, a formidable challenge. Here we report a serine‐selective peptide‐cleavage protocol that proceeds at room temperature and near neutral pH value, through mild aerobic oxidation promoted by a water‐soluble copper–organoradical conjugate. The method is applicable to the site‐selective cleavage of polypeptides that possess various functional groups. Peptides comprising D ‐amino acids or sensitive disulfide pairs are competent substrates. The system is extendable to the site‐selective cleavage of a native protein, ubiquitin, which comprises more than 70 amino acid residues.