A cooperative group study of clinical efficacy of the liver SPECT

The purpose of this study is to evaluate the clinical efficacy of the liver SPECT about detectability of SOLs (space occupying lesion). The images were interpreted with the planar scintigram (PS) only and combination of PS and SPECT (single photon emission computed tomography) by 11 physicians. Changes of false positive and false negative rate were calculated to evaluate the influence of the diffuse parenchymal liver disease and the localization of the SOLs. Addition of SPECT to PS in the cases who are suspected SOLs is effective in right hepatic lobe (right anterior and posterior segment) to detect the SOLs, but not effective in left lateral segment. Addition of SPECT to PS in the cases with diffuse parenchymal liver disease and SOLs increases the false positive rate.     

Deoxygenation of dithiirane 1-oxides with Lawesson's reagent leading to the corresponding dithiiranes

3,3-Disubstituted dithiirane 1-oxides were efficiently reduced with Lawesson's reagent (LR) to give the corresponding dithiiranes. X-ray diffraction analysis of 3,3-di(1-adamantyl)dithiirane is reported. Reaction of (34)S-labeled 3,3-di(1-adamantyl)dithiirane 1-oxide with LR produced the corresponding dithiirane in which the (34)S atoms were retained quantitatively.     

Interaction of arsenic and selenium on the metabolism of these elements in hamsters

The interaction of arsenic and selenium compounds on the metabolism of these elements in golden hamsters was studied. Golden hamsters were divided into three groups and administered sodium selenite (Na₂SeO₃), sodium arsenite (NaAsO₂) and Na₂SeO₃ with NaAsO₂, respectively, by a single Subcutaneous injection of 25 m?mol kg^?1 body weight as As or Se (arsenic and selenium were calculated as weight of elemental arsenic and selenium). Selenium and arsenic metabolites were determined by high-performance liquid chromatography–graphite furnace atomic absorption spectrometry (HPLC–GFA AA) and gas chromatography (GC). The results show (1): About 10% by weight of the given dose of selenium was excreted in expiration air as dimethylselenide (Me₂Se) during 12 h after administration of Na₂SeO₃. Excretion of dimethylselenide with the respiratory air was inhibited by administration of Na₂SeO₃ simultaneously with NaAsO₂. (2) Giving Na₂SeO₃ plus NaAsO₂ had no appreciable effect on the excretion of the trimethylselenonium ion (Me₃Se⁺) into the urine and the feces. (3) Giving Na₂SeO₃ plus NaAsO₂ increaed the excretion into the feces of an insoluble unknown-structure selenium compound, the proportion of which was 10.9% by weight of the given dose of selenium. (4) Giving NaAsO₂ plus Na₂SeO₃ decreased the excretion of dimethylarsinic acid (Me₂AsOOH) and inorganic arsenic into the urine during 120 h after the administration of the reagents, the decreased amount being 5.3% (dimethylarsinic acid) and 7.7% (inorganic arsenic) of the given dose of arsenic, respectively. (5) Giving NaAsO₂ plus Na₂SeO₃ increased the excretion into feces of insoluble unknown-structure arsenic compound and inorganic arsenic, the increased amounts being 10.6% and 7.0% of the given dose of arsenic, respectively. (6) Giving NaAsO₂ plus Na₂SeO₃ decreased the excretion into feces of extractable unknown-structure arsenic compound, and the decreased amount was 4.9% of the given dose of arsenic. (7) It made little difference to the excretion of monomethylarsonic acid [MeAsO(OH)₂] into urine and feces and of dimethylarsinic acid (Me₂AsOOH) into feces whether NaAsO₂ was administered alone or with Na₂SeO₃.     

Blue/red linear dichroic emission from a highly anisotropic crystal of triarylmethane dye conjugated with phenoxo-zinc complexes

We have developed a novel triphenylmethane-based hexanuclear zinc complex that exhibits peculiar photochemical and photophysical properties. Upon UV irradiation, the compound turned from colorless to reddish purple, while the color of emission turned from blue to red. The color change was attributed to an oxidation of the ligand part. It was suggested that an intramolecular energy-transfer mechanism operates to give rise to the red emission. The UV treatment of a single crystal results in simultaneous emission of orthogonally polarized blue and red light. This color switching, namely linear dichroic emission was so distinct that one can recognize with by sight through optical microscope. The columnar arrangement of molecules in the crystal clearly accounts for the observed polarization of the emission.     

Development of microchannel reactors using polysilane-supported palladium catalytic systems in capillaries

A new method of immobilizing Pd catalysts on the channel wall of a capillary by using polysilane with metal oxide has been developed, and applied to hydrogenation reactions.     

Synthesis and structure of bis(dialkylamino)carbeniumdithiocarboxylates

2-Chloro and 2-phenoxy substituted 1,1-bis(diethylamino)ethylenes ( 4a and 4c ) react with elemental sulfur at room temperature to give the inner salt, bis(diethylamino)carbeniumdithiocarboxylate ( 1a ), in excellent yields with extrusion of hydrogen chloride and phenol, respectively, thus providing a new and convenient synthesis of the structurally interesting inner salt. X-ray single crystal structure analysis of 1a reveals that the N C N and S C S planes are nearly vertical to each other with a dihedral angle of 82.0° and that the positive and negative charges are delocalized over the N C N and S C S moieties, respectively. Results of solid-state ¹³C NMR of 1a are also briefly described.     

Reversible 1,3‐dipolar cycloaddition of dimethyl 2‐thiono‐1,3‐dithiole‐4,5‐dicarboxylate with dimethyl acetylenedicarboxylate

It was shown that dimethyl 2‐thiono‐1,3‐dithiole‐4,5‐dicarboxylate ( 2 ) and dimethyl acetylenedicarboxylate (DMAD) undergo a 1,3‐dipolar cycloaddition to produce a short‐lived ylide intermediate ( 3 ). The 1,3‐dipolar cycloaddition took place even at room temperature, although sluggishly, but took place much more rapidly under application of a high pressure of 500 MPa. The 1,3‐dipolar cycloaddition is reversible and the ylide 3 immediately splits into 2 and DMAD. When the reaction of 2 with DMAD was carried out at room temperature without solvent, a spiro‐1,3‐dithiole ( 11 ) was formed in 11% yield, whereas the reaction at 150°C provided a thiophene derivative ( 13 ) in 41% yield. It was found that 11 undergoes a thermal rearrangement to 13 . Results of attempted chemical trapping of the ylide 3 are also reported. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:434–440, 2000     

Reactions of benzeneselenyl and benzenesulfenyl chlorides with syn‐ and anti‐9,9′‐bibenzonorbornenylidenes

Reaction of syn‐9,9′‐bibenzonorbornenylidene (1a) with benzeneselenyl chloride produced vic‐dichloride (4) exclusively, which corresponds to the cis‐addition product of 1a with molecular chlorine, with retention of the original alkene configuration. Moreover, the reaction of anti‐9,9′‐bibenzonorbornenylidene (1b) with benzeneselenyl chloride gave the same vic‐dichloride (4) exclusively with inversion of the original alkene configuration. No expected benzeneselenyl chloride adducts were formed in both cases. On the other hand, reactions of 1a and 1b with benzenesulfenyl chloride only resulted in the syn–anti isomerization of the alkenes without any adduct formation. Mechanisms of these reactions are discussed in some detail. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:625–629, 2001