Synthesis and photophysical properties of azuleno[1′,2′:4,5]pyrrolo[2,1-b]quinazoline-6,14-diones: Azulene analogs of tryptanthrin

Azulene analog of tryptanthrin, azuleno[1′,2′:4,5]pyrrolo[2,1-b]quinazoline-6,14-dione, was successfully prepared by the condensation reaction of azuleno[2,1-b]pyrrole-2,3-dione with isatoic anhydride in the presence of sodium hydride or diisopropylethylamine (DIPEA). Its 2-halo derivatives were also obtained in high yields by the condensation reaction with 5-haloisatoic anhydrides in the presence of DIPEA. Reactivity toward electrophilic reagents was revealed by halogenation with N-bromosuccinimide (NBS) or N-iodosuccinimide (NIS) to afford 12-halo derivatives in high yields. Among the halo derivatives, 2-iodo and 12-iodo derivatives were reactive enough to afford phenylethynyl derivatives under Pd-catalyzed Sonogashira cross-coupling conditions. Within the phenylethynyl derivatives, only 12-phenylethynyl derivative was transformed into its 1,1,4,4-tetracyanobutadiene (TCBD) derivative by the reaction with TCNE. Amphoteric redox properties of the novel azulene analogs of tryptanthrin were characterized by spectroscopic and voltammetric analyses.     

Simultaneous separation of common mono- and divalent cations on a zirconium-modified silica gel column by ion chromatography with non-suppressed conductimetric detection and tartaric acid–15-crown-5 as eluent

The application of laboratory-made zirconium-modified silica gels (Zr-silicas) as cation-exchange stationary phases to ion chromatography with conductimetric detection (IC–CD) for common mono- and divalent cations (Li⁺, Na⁺, NH₄⁺, K⁺, Mg²⁺ and Ca²⁺) was carried out. Zr-silicas were prepared by the reaction of the silanol group on the surface of silica gel with zirconium tetrabutoxide (Zr(OCH₂CH₂CH₂CH₃)₄) in ethanol. Zr-silica adsorbed on 10 mg zirconium g⁻¹ silica gel was a suitable cation-exchange stationary phase in IC–CD for the separation of these mono- and divalent cations. Excellent simultaneous separation and highly sensitive detection for these cations were achieved in 10 min by IC–CD using a Zr-silica column (150×4.6 mm I.D.) and 10 mM tartaric acid containing 10 mM 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane) as the eluent. The proposed IC–CD method was successfully applied to the determination of major mono- and divalent cations in natural water samples.     

Synthesis of 1,8- and 2,8-dihydrocycloheptapyrazol-8-one derivatives by the reactions of 3-acetyltropolone and its methyl ethers with phenylhydrazine

3-Acetyltropolone ( 1 ) reacted with phenylhydrazine to give 3-acetyltropolone phenylhydrazone ( 3 ) and 3-methyl-1-phenyl-1,8-dihydrocycloheptapyrazol-8-one ( 4 ). The former ( 3 ) cyclized to afford the latter ( 4 ). The reaction of 3-acetyl-2-methoxytropone ( 2a ) with phenylhydrazine gave 4 , 3-methyl-2-phenyl-2,8-dihydrocyclo-heptapyrazol-8-one ( 5 ), and 3-methyl-2-phenyl-2,8-dihydrocycloheptapyrazol-8-one phenylhydrazone ( 6 ). The compound ( 5 ) reacted with phenylhydrazine to afford 6 . The reaction of 7-acetyl-2-methoxytropone ( 2b ) with phenylhydrazone gave 7-acetyl-2-methoxytropone phenylhydrazone ( 7 ), 7-acetyl-2-(N′-phenylhydrazino)-tropone phenylhydrazone ( 8 ), 3-methyl-1-phenyl-1,8-dihydrocycloheptapyrazol-8-one phenylhydrazone ( 9 ), and 6 . The compound ( 7 ) was heated to afford 4 and reacted with phenylhydrazine to afford 8 and 9 . The compound ( 8 ) was also refluxed to give 9 .     

Cross-coupling of alkenyl,aryl or allylic selenides and grignard reagents catalyzed by nickel-phosphine complexes

Alkenyl, aryl or allylic selenides smoothly couple with Grignard reagents in the presence of Ni(II)-phosphine complexes as catalysts to afford the corresponding unsaturated compounds in good yields. The reactivity order of coupling reaction with BuMgBr catalyzed by NiCl₂ [Ph₂PCH₂CH₂CH₂PPh₂] was found to be PhSeMe « PhCl > PhSMe by the competitive reactions.     

Optimal promotion planning—depth and frequency—for a two-stage supply chain under Markov switching demand

In considering the retailer–supplier supply chain, this paper analyzes how a retailer reasonably decides both the depth and frequency of the price discount promotion including or excluding a supplier’s inventory decision. Assuming that the promotion frequency used by the retailer is probabilistic, we model a promotion-inventory decision under an AR(1) demand with a Markov switching promotion regime. After obtaining the optimal promotion plan, our analysis also considers the behavior of the optimal promotion decision; the retailer’s price format selection, either an Every-Day-Low-Price policy (EDLP) or a Promotion policy (HiLo); and the impact of information sharing of promotion status on the system’s performance. Our results suggest that a retailer tends to overpromote if inventory cost is excluded in its promotion decision, that increasing the market share is a preferable action for both the retailer and the supplier, that total margin and price-elasticity play an important role in selecting the price format, and that the profitability for a supplier of sharing promotion information depends on the transition probabilities of the Markov switching regime.     

Structural and electrical properties of crystalline (1−x)Ta2O5−xTiO2 thin films fabricated by metalorganic decomposition

Polycrystalline (1−x)Ta₂O₅−xTiO₂ thin films were formed on Si by metalorganic decomposition (MOD) and annealed at various temperatures. As-deposited films were in the amorphous state and were completely transformed to crystalline after annealing above 600 °C. During crystallization, a thin interfacial SiO₂ layer was formed at the (1−x)Ta₂O₅−xTiO₂/Si interface. Thin films with 0.92Ta₂O₅–0.08TiO₂ composition exhibited superior insulating properties. The measured dielectric constant and dissipation factor at 1 MHz were 9 and 0.015, respectively, for films annealed at 900 °C. The interface trap density was 2.5×10¹¹ cm⁻² eV⁻¹, and flatband voltage was −0.38 V. A charge storage density of 22.8 fC/μm² was obtained at an applied electric field of 3 MV/cm. The leakage current density was lower than 4×10⁻⁹ A/cm² up to an applied electric field of 6 MV/cm.     

In vivo time‐resolved X‐ray fluorescence mapping measurements of Egeria densa immersed in Cr(VI) aqueous solution

In vivo time‐resolved Cr and Ca X‐ray fluorescence (XRF) mapping measurements were performed in a laboratory over a period of 69 days on a living common aquatic plant Egeria densa that was immersed in 5 mM K₂CrO₄ aqueous solution. The time and spatial resolution for each time‐resolved XRF map were ~1.6 days and 1 × 1 mm², respectively. The obtained XRF maps exhibited characteristic localized Cr and Ca areas where the XRF signals were especially strong (‘hot spots’), and this indicated the necessity of preliminary millimeter‐resolution surveying in XRF microscopy. Ca hot spots were detected prior to Cr(VI) immersion and nearly disappeared after immersion in deionized water for 2 weeks and the Cr(VI) solution for 1 week. After these immersions, a Cr hot spot was formed at approximately the same location of the missing Ca hot spot, which suggests that the original Ca‐accumulated regions were substituted for the isolation of Cr species when they were introduced. The sizes and intensity distributions of the Cr hot spots were sensitive to the Cr(VI) exposure approximately 1 week prior to each XRF measurement. This sensitivity suggests potential applications of E. densa as a Cr(VI) biomonitor in aquatic environments. Copyright © 2014 John Wiley & Sons, Ltd.     

Differences between PREMIER combustion in a natural gas spark-ignition engine and knocking with pressure oscillations

PREMIER (PREmixed Mixture Ignition in the End-gas Region) combustion occurs with auto-ignition in the end-gas region when the main combustion flame propagation is nearly finished. Auto-ignition is triggered by the increases in pressure and temperature induced by the main combustion flame. Similarly to engine knocking, heat is released in two stages when engines undergo this type of combustion. This pattern of heat release does not occur during normal combustion. However, engine knocking induces pressure oscillations that cause fatal damage to engines, whereas PREMIER combustion does not. The purpose of this study was to elucidate PREMIER combustion in natural gas spark-ignition engines, and differentiate the causes of knocking and PREMIER combustion. We applied combustion visualization and in-cylinder pressure analysis using a compression–expansion machine (CEM) to investigate the auto-ignition characteristics in the end-gas region of a natural gas spark-ignition engine. We occasionally observed knocking accompanied by pressure oscillations under the spark timings and initial gas conditions used to generate PREMIER combustion. No pressure oscillations were observed during normal and PREMIER combustion. Auto-ignition in the end-gas region was found to induce a secondary increase in pressure before the combustion flame reached the cylinder wall, during both knocking and PREMIER combustion. The auto-ignited flame area spread faster during knocking than during PREMIER combustion. This caused a sudden pressure difference and imbalance between the flame propagation region and the end-gas region, followed by a pressure oscillation.