Thiiranation of 2′‐adamantylidene‐9‐benzonorbornenylidene using 4,4′‐oligothiodimorpholine and brønsted acid

On leaving 4,4′‐dithiodimorpholine 6 powder undisturbed at room temperature over 10 years, it led to the formation of 4,4′‐tetrathiodimorpholine 7 . Reactions of 2′‐adamantylidene‐9‐benzonorbornenyidene 1 with 6, 7 , and 4,4′‐thiodimorpholine 8 and a Brønsted acid in CH₂Cl₂ at room temperature proceeded to afford the corresponding thiiranes, 2 and 3 . The order of reactivity of 4,4′‐oligothiodimorpholines combined with a Brønsted acid is 7 > 6 > 8 . The thiirane 3 was transformed to 1 and 2 under the reaction conditions. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:12–18, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20505     

Pressure effect to chemical reaction,hydrogen isotope recombination reactions in liquid helium at cryogenic temperature — Part II

Behavior of the hydrogen isotope in recombination reactions, H+H→H₂ H+T→HT and T+T→T₂ under pressurized conditions at 1.6 K were investigated using liquid helium as cryogenic reaction media by radiochemical methods. Pressure effects were observed in changes of isotope ratio HT/T₂. It became clearer that the balance of changes in bubble energy effective mass associated with energy and chemical potential contributed to the recombination reactions through bubble states. It was suggested that bubble radius was decreased significantly at higher pressure.     

Photoinduced magnetization in copper octacyanomolybdate

This article describes the studies of a photomagnetic cyanide-bridged Cu-Mo bimetallic assembly, Cu(II)(2)[Mo(IV)(CN)(8)].8H(2)O (Cu(II), S = (1)/(2); Mo(IV), S = 0) (1), which has an intervalence transfer (IT) band from Mo(IV)-CN-Cu(II) to Mo(V)-CN-Cu(I) around 480 nm. Wide-angle X-ray scattering and X-ray spectroscopic studies provide precise information about the 3D connectivity and the local environment of the transition metal ions. Irradiating with blue light causes solid 1 to exhibit a spontaneous magnetization (Curie temperature = 25 K). The thermal reversibility is carefully studied and shows the long-time stability of the photoinduced state up to 100 K. Photoreversibility is also observed; i.e., the magnetization is induced by irradiation with light below 520 nm, while the magnetization is reduced by irradiation with light above 520 nm. The UV-vis absorption spectrum after irradiation shows a decrease of the IT band and the appearance of the reverse-IT band in the region of 600-900 nm (lambda(max) = 710 nm). This UV-vis absorption spectrum is recovered to the original spectrum by irradiation with 658-, 785-, and 840-nm light. In this photomagnetic effect, the excitation of the IT band causes an electron transfer from Mo(IV) to Cu(II), producing a ferromagnetic mixed-valence isomer of Cu(I)Cu(II)[Mo(V)(CN)(8)].8H(2)O (Cu(I), S = 0; Cu(II), S = (1)/(2); Mo(V), S = (1)/(2)) (1'). 1' returns to 1 by irradiation of the reverse-IT band, which obeys the scheme for the potential energy surface in mixed-valence class II compounds.     

Masking mechanisms of bitter taste of drugs studied with ion selective electrodes

The masking mechanisms of the bitter taste of propantheline bromide (PB) and oxyphenonium (OB) bromide by native and modified cyclodextrins, saccharides, surfactants, organic acids, nonionic and anionic polymers, and other compounds were investigated with ion selective electrodes. The intensity of the bitter taste for a mixed solution of cyclodextrin with PB or OB was quantitatively explained from the observed electromotive force with the following assumptions: the complex and the masking agent do not have any tastes and the bitter taste is independent of other tastes. Sodium dodecyl sulfate reduced the bitter taste remarkably, and this reduction was also explicable on the basis of the same mechanism. Sodium taurodeoxycholate enhanced the bitter taste, because of its strong bitterness, although it formed 1 : 1 complexes with PB and OB. The masking mechanism of saccharides was ascribed to overcoming the weak bitterness of the drug by the strong sweetness. Lambda-carrageenan suppressed the bitter taste remarkably. This suppression was ascribed to the binding of PB and OB to lambda-carrageenan, the effect of the solution viscosity on the bitter taste, and the covering of the bitter taste receptor by lambda-carrageenan. It was suggested that the moderate masking by other polymers was attributable to the effect of the solution viscosity or the receptor covering. Native and modified beta-cyclodextrins, sodium dodecyl sulfate, lambda-carrageenan, Tween 20, and sodium carboxymethyl cellulose are good masking agents for the bitter tastes of PB and OB. The drug ion selective electrode is a useful tool for understanding of the masking mechanism of the bitter taste, screening of masking agents, and estimation of appropriate concentrations of the masking agents.     

Enantioselective hydrogenation of aromatic ketones catalyzed by Ru complexes of Goodwin-Lions-type sp2N/sp3N hybrid ligands R-BINAN-R'-Py

Goodwin-Lions-type sp2N/sp3N hybrid ligands R-BINAN-R'-Py possessing a C2 axis binaphthyl skeleton have been designed and synthesized. Combination of the new non-phosphine ligand with Ru(pi-CH2C(CH3)CH2)2(cod) has been revealed to catalyze the hydrogenation of aromatic ketones with high enantioselectivity of up to 99% ee. The reaction proceeds essentially without the need for any bases, but the reactivity is enhanced by the addition of KOt-C4H9 attaining an S/C ratio of up to 10 000. The success should expand the range of possibilities in designing catalysts not only for hydrogenation but also for many other reactions.     

Sarcospan: ultrastructural localization and its relation to the sarcoglycan subcomplex

Sarcospan is a 25 kDa transmembrane component of dystrophin-associated glycoprotein. We generated a rabbit polyclonal antibody against synthetic peptide of the N-terminal domain of human sarcospan. Using this antibody we investigated the localization of sarcospan and its spacial relation to the components of sarcoglycan subcomplex in normal human skeletal myofibers by immunofluorescent microscopy and immunogold electron microscopy. In immunofluorescence the reaction was observed continuously at the myofiber surface. Ultrastructurally the gold signals of rabbit anti sarcospan antibody were present along the muscle plasma membrane, mainly at its inside surface. The triple immunogold labeled muscle samples showed that the signals of rabbit or sheep polyclonal anti alpha-, beta-, gamma- and delta-sarcoglycan antibodies and/or mouse monoclonal anti beta-, gamma- and delta-sarcoglycan antibodies were located along the muscle plasma membrane, and the cluster formation of different two or three sarcoglycan molecules was observed. The triple immunogold labeling also revealed that the signal of sarcospan molecules are present frequently in doublets and/or triplets with the components of sarcoglycan subcomplex, resulting in the cluster formation of signals of sarcoglycan and sarcospan molecules. The result of this study showed that sarcospan was expressed at the myofiber surface and that sarcospan was present in close association with alpha-, beta-, gamma- and delta-sarcoglycans and formed a functional unit with sarcoglycan subcomplex.     

Enhanced renal image contrast by ethanol fixation in phase‐contrast X‐ray computed tomography

Phase‐contrast X‐ray imaging using a crystal X‐ray interferometer can depict the fine structures of biological objects without the use of a contrast agent. To obtain higher image contrast, fixation techniques have been examined with 100% ethanol and the commonly used 10% formalin, since ethanol causes increased density differences against background due to its physical properties and greater dehydration of soft tissue. Histological comparison was also performed. A phase‐contrast X‐ray system was used, fitted with a two‐crystal X‐ray interferometer at 35 keV X‐ray energy. Fine structures, including cortex, tubules in the medulla, and the vessels of ethanol‐fixed kidney could be visualized more clearly than that of formalin‐fixed tissues. In the optical microscopic images, shrinkage of soft tissue and decreased luminal space were observed in ethanol‐fixed kidney; and this change was significantly shown in the cortex and outer stripe of the outer medulla. The ethanol fixation technique enhances image contrast by approximately 2.7–3.2 times in the cortex and the outer stripe of the outer medulla; the effect of shrinkage and the physical effect of ethanol cause an increment of approximately 78% and 22%, respectively. Thus, the ethanol‐fixation technique enables the image contrast to be enhanced in phase‐contrast X‐ray imaging.     

Drastic high magnetic field effect on suppression of Escherichia coli death

When Escherichia coli B was aerobically grown in a medium containing one-fourth the concentration of the LB medium supplemented with glutamic acid at 43 degrees C under an inhomogeneous 5.2-6.1 T magnetic field, the number of cells in the stationary phase under the high magnetic field was 100,000 times higher than that under a geomagnetic field. The finding that the amount of sigma S factor encoded by the rpoS gene under the high magnetic field was larger than that under the control geomagnetic field indicated that the activity of the rpoS gene was affected by the high magnetic field.     

Multiferroics by rational design: implementing ferroelectricity in molecule-based magnets

Multiferroic materials: A novel class of multiferroics based on organic-inorganic hybrid materials is synthesized. The ferromagnetic properties originate from the coordination network, whereas the ferroelectricity results from the polar organic ions (see picture, M=magnetization and P=polarization).     

Palladium-catalyzed amidation by chemoselective C(sp3)-H activation: concise route to oxindoles using a carbamoyl chloride precursor

Quite select: a new strategy was developed for the synthesis of various oxindoles from carbamoyl chlorides. Under the optimum reaction conditions, with Ad(2)PBu as a ligand, tBuCONHOH as an additive, and a CO atmosphere, selective C(sp(3))-H activation proceeded in the presence of a C(sp(2))-H bond. Ad=adamantyl.