Combination of LFP‐TRIR spectroscopy and DFT computation as a tool to determine the intermediate during the photooxidation of triarylphosphine

Laser flash photolysis‐time‐resolved infrared spectroscopy (LFP‐TRIR) was performed on an acetonitrile or dichloromethane solution of triarylphosphines, Ar₃P, in air. A transient spectrum consisting of several absorption bands appeared in the region of 1050–1300 cm^?1 on the TRIR on a microsecond timescale, which disappeared on a millisecond timescale. To identify the observed transient intermediate, the IR spectra of possible intermediates of the photoreaction were simulated by theoretical calculations based on density functional theory (DFT). The IR spectrum simulated for the phosphine peroxidic radical cation, Ar₃P⁺OO^?, well predicted the observed IR spectrum, showing that Ar₃P⁺OO^? is formed as a transient intermediate upon the LFP of Ar₃P in air. Copyright © 2014 John Wiley & Sons, Ltd.     

Method validation by interlaboratory studies of improved hydrophilic oxygen radical absorbance capacity methods for the determination of antioxidant capacities of antioxidant solutions and food extracts

Hydrophilic oxygen radical absorbance capacity (H-ORAC) is a method for evaluating antioxidant capacities of solutions of hydrophilic compounds. In this study, we improved the original method for H-ORAC determination, and evaluated the precision of the two improved methods (methods A and B) by interlaboratory studies using 5 antioxidant solutions and 5 food extracts as test samples. An interlaboratory study of method A, in accordance with the harmonized protocol, demonstrated satisfactory performance (intermediate precision relative standard deviations (RSD(int)) ranging from 4.6 to 18.8%; the reproducibility relative standard deviations (RSD(R)) ranging from 7.0 to 21.1%, and the HorRat values ranging from 0.40 to 1.93). However, methodological problems remained, and a further improved method, method B, was thus developed. An interlaboratory study of method B by 5 participating laboratories showed better intermediate precision and reproducibility (RSD(int) and RSD(R) ranging from 1.8 to 9.4%, and from 4.4 to 13.8%, respectively), and all HorRat values for the test samples were less than 1.3, suggesting good performance for the H-ORAC measurement.     

Total Synthesis of the 7,10‐Epimer of the Proposed Structure of Amphidinolide N,Part II: Synthesis of C17–C29 Subunit and Completion of the Synthesis

The total synthesis of 7,10‐epimer of the proposed structure of amphidinolide N was accomplished. The requisite chiral C17–C29 subunit was assembled stereoselectively via Keck allylation, Shi epoxidation, diastereoselective 1,3‐reduction, and a later oxidative synthesis of the THF framework. The C1–C13 and C17–C29 subunits were successfully coupled using a Enders RAMP “linchpin” as the C14–C16 three carbon unit, thereby controlling the chirality at C14 and C16. The labile allyl epoxy moiety was successfully constructed by Grieco–Nishizawa olefination at a final stage of the synthesis.     

A compact AMORS (atomic magneto-optical rotation spectrometer) usable on a motorcar for in-situ field analysis of trace amounts of elements by direct atomization, utilizing the atomic Faraday effect

Summary A compact spectrometer usable on a motorcar was constructed for in-situ field analysis of trace amounts of elements by direct atomization, utilizing the atomic Faraday effect. Two fully charged car batteries, which supplied all the power required for the spectrometer, served for more than 100 atomizations. The basic performance of the constructed spectrometer, involving the capability to remove background signals, was evaluated in the direct determination of Mn and/or Cu in juices of tomato and mandarin orange, in oyster mantle and in volcanic ashes. Rapid analysis in max. 5 min could be performed with freedom from background signals caused by non-atomic species resulting from sample matrix.

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Kompaktes magneto-optisches Atomrotations-Spektrometer (AMORS) zur Benutzung in einem Kraftfahrzeug für die In-situ-Feldanalyse von Elementspuren durch direkte Atomisierung, unter Ausnutzung des Faraday-Effektes

Zusammenfassung Das kompakte Spektrometer, das in einem Kraftfahrzeug leicht untergebracht werden kann, wurde zur Elementspurenbestimmung vor Ort konstruiert. Zwei voll geladene Autobatterien, die die benötigte Energie liefern, reichen für mehr als 100 Atomisierungen aus. Die Leistungsfähigkeit des Gerätes, das auch Untergrundsignale eliminieren kann, wurde an Hand der direkten Bestimmung von Cu und/oder Mn in Tomaten- und Orangensaft, in Austernschalen sowie in Vulkanasche demonstriert. Eine Analyse läßt sich in 5 min ohne Beeinflussung durch Untergrundsignale aus der Matrix durchführen.

     

Correlation in spatial intensity distribution between volumetric bubble oscillations and sonochemiluminescence in a multibubble system

The correlation in spatial intensity distribution between volumetric oscillation of multibubble and sonochemiluminescence in an ultrasonic standing-wave field is investigated through the measurements of scattered light from bubbles by changing the measuring position in the direction of sound propagation and sonochemiluminescence with luminol. When a thin light sheet, finer than half the wavelength of sound, is introduced into the cavitation bubbles at the anti-node of the sound pressure, the scattered light intensity oscillates temporally. The peak-to-peak light intensity corresponds to the number of the bubbles which contribute to the sonochemical reaction because the radius for oscillating bubbles at pressure antinode is restrictive in a certain range due to the shape instability and the action of Bjerknes force that expels from anti-node bubbles larger than the resonant size. The experimental results show that at the side near the water surface, the peak-to-peak light intensity is larger in comparison with the intensity near the sound source, and this tendency becomes apparent at higher input power. These light scattering results correspond with the spatial intensity distribution of the sonochemiluminescence with luminol. Therefore, it is interpreted that most of the cavitation bubbles contributing to the sonochemical reactions in the standing wave field exist near liquid surface. Present method of light scattering in reference with the image of the sonochemiluminescence is promising for evaluating spatial distribution of violently oscillating cavitation bubbles effective for sonochemical reactions.     

Total synthesis of (+/-)-mycoepoxydiene,a novel fungal metabolite having an oxygen-bridged cyclooctadiene skeleton

[reaction: see text] The first total synthesis of (+/-)-mycoepoxydiene has been accomplished. A ring-closing olefin metathesis (RCM) approach was employed for the construction of the oxygen-bridged eight-membered bicyclic skeleton. The RCM product was converted to the target natural product featuring the oxidative rearrangement of a furfuryl alcohol introduced as the side chain and the stereoselective 1,2-reduction of a delta-keto-beta,gamma-unsaturated alpha-lactol intermediate.     

The correlation of serum parathyroid hormones among patients with dementia of vascular type, hemodialysis, and bone-joint disorders

PTH levels were analysed in sera of patients receiving maintenance hemodialysis, with the vascular type of dementia and orthopedic patients with bone-joint disorders, using PTH assay kits. There were significant interrelationship among all kinds of PTH levels in the hemodialysis patients, but not in patients with the vascular type of dementia and the bone-joint disorders. Renal functions might be responsible for fragmentation of PTH in blood stream. These results suggested that the measurement of PTH levels is needed to examine various kinds of amino-sequence of PTH levels in keeping normal function of kidney.     

Study on optimal packing materials for high-performance hydrophobic-interaction chromatography of proteins

Summary The nature and effects of bonded phases and analytical conditions on protein retention in high-performance hydrophobic-interaction chromatography (HIC) were investigated. Silica-based packing materials with different surface hydrophobicity were prepared and evaluated with respect to protein retention. The contact of proteins with the hydrophobic stationary phases caused conformational changes of proteins to some extent, but the extent of these changes was dependent on the hydrophobicity of the stationary phases, column temperature and the proteins themselves. Thermal behavior of some proteins in HIC on these phases is also shown.     

Studies on topical antiinflammatory agents. V. 17-(Alkylthio)- and methoxyalkanoates of corticosteroids

As part of our search for new topical antiinflammatory agents, a series of corticosteroid 17-(alkylthio)- and methoxyalkanoate derivatives was prepared and tested for vasoconstrictive activities. Several compounds were proved to have activity superior or comparable to that of 9 alpha-fluoro-11 beta,21-dihydroxy-16 beta-methyl-17 alpha-valeryloxy-1,4-pregnadiene-3,20-dione (betamethasone 17-valerate, BV). Among these compounds, 21-chloro-11 beta-hydroxy-17 alpha-(methylthio)acetoxy-4-pregnene-3,20-dione (5Aa) was found to have the most potent activity, being more active than BV. The structure-activity relationships of the series revealed that introduction of a (methylthio)acetate function into the 17-position as well as the 21-position of corticosteroids was effective for enhancing the topical antiinflammatory activity.