A new synthetic route to tropane alkaloids. Pseudotropine and tropacocaine

Pseudotropine and tropacocaine have been synthesized by a facile route involving the [4 + 2] nitroso cycloaddition followed by internal S_N2 displacement.     

Evaluation of left atrial function by 99mTc gated blood pool scan

99mTc gated blood pool scans were studied to assess the left atrial function. Relationship between filling time and rapid emptying time was y = 0.695 x + 109 (r = 0.761, p less than 0.05, n = 14) in LAO and LPO projections. On the other hand, relationship between slow filling and rapid emptying time was good closely (y = 0.846 x + 16.9 (p less than 0.01, r = 0.975, n = 8] in standard and retrograde acquisition. To assess the left atrial function by standard acquisition in LAO projection should be available for clinical use.     

Specific effects of simple organic sulphonate anions on the mercury ion-assisted aquation of chlorocobalt(III) complexes: Deviations from the primary s

Kinetic effects of various 1-1 electrolytes on the CoClL_n² + Hg² reaction (L_n: neutral ligands) were studied with varying concentra     

Fast and slow dynamics in single and mixed alkali silicate glasses

A molecular dynamics (MD) simulation for single and mixed alkali metasilicates has been performed. The mixed alkali effect (MAE) in the diffusion coefficients is reproduced. The motion of lithium ions in Li₂SiO₃ can be divided into slow (type A) and fast (type B) categories clearly in the glassy state. It turns out that the slow dynamics are caused by localized jump motions with a long tail of the waiting time distribution. On the other hand, fast dynamics of the lithium ions are caused by successive cooperative jump motions and are identified as Lévy flights. The MAE in LiKSiO₃ occurs due to mutual interception of jump paths of both kinds of mobile ions. In such paths, the fast component is considerably suppressed. Namely, the cooperative forward-correlated jump process is sensitive to the blockage of the jump paths. Propagation of the immobilization in the MAE is discussed in relation with the mechanism of the cooperative jump motion. The ratio of the fast and slow dynamics plays an important role to determine the transport properties in the glassy state.     

Concise synthesis of polymethoxyflavone sudachitin and its derivatives,and biological evaluations

We accomplished a divergent synthesis of sudachitin (2), a polymethoxyflavone isolated from citrus fruits, and six derivatives from acetophenone 9, which was an intermediate in our previous synthesis of nobiletin (1). Compound 2 enhanced glucose-induced insulin secretion in INS-1D cells, but was less potent than 1. Compared with 1, compound 2 and two derivatives were more potent inhibitors of cAMP-specific phosphodiesterase.     

Successful preparation of metabolite of troglitazone by in-flow electrochemical reaction on coulometric electrode

A simple, rapid and efficient system utilizing a coulometric electrode was developed for the preparation of drug metabolites. Trace amounts of reactants are usually generated in electrochemical reactions, which are not suitable for the sufficient preparation of products to obtain NMR and other spectral data for chemical structure confirmation or to obtain data from pharmacological activity screening tests of products. In the developed system, called the "in-flow electrochemical reaction system," a drug, troglitazone, was dissolved in a volatile flow solvent, and pumped into a coulometric electrode under optimized conditions, and the effluent was evaporated. Without any further purification, milligram amounts of a pure oxidation product of troglitazone could be obtained within several hours. The amount obtained was enough for (1)H- and (13)C-NMR analysis by which the structure could be confirmed and was found to be identical to one of the metabolites of troglitazone detected in human plasma. This system will be useful to prepare standard compounds of the required amount for pharmacokinetic study and for toxicokinetic study.     

Highly selective double chalcogenation of isocyanides with disulfide-diselenide mixed systems

A highly selective method for introducing thio and seleno groups into a variety of isocyanides has been developed based on the elucidation of the relative reactivities of organic dichalcogenides and chalcogen-centered free radicals. When the reactions of aromatic isocyanides (ArNC) with organic disulfides (R'SSR') and diselenides (R'SeSeR') are conducted upon irradiation with a tungsten lamp through Pyrex (hnu>300 nm), simultaneous introduction of both thio and seleno groups into the isocyanides takes place to provide the corresponding thioselenation products (R'S-C(=NAr)-SeR') in good yields with excellent selectivity. In the cases of aliphatic isocyanides (RCN), a novel diselenide-assisted bisthiolation of RNC with diaryl disulfides (Ar'SSAr') proceeds successfully to give the corresponding bisthiolation products (Ar'S-C(=NR)-SAr'), although the same photoirradiated reaction of RNC with diaryl disulfides does not occur in the absence of diselenide. These double chalcogenation reactions are assumed to proceed via the formation of imidoyl radical intermediates by the reaction of isocyanides with relatively reactive thio radicals (compared with seleno radicals). The obtained thioselenation products can be employed as useful precursors for the construction of beta-lactam framework by the formal [2+2] cyclization with ketene equivalents.     

Fabrication of silver nanoparticles deposited on boehmite sol for surface enhanced Raman scattering

The composite consisting of silver nanoparticles deposited on boehmite hybrid was synthesized by NaBH₄ reduction technique. The morphology of the composite was studied by TEM, UV/Vis spectrophotometer and particle sizer. The size of the silver nanoparticles deposited on the surface of the boehmite ranged from 10 nm to 100 nm. The contact of silver nanoparticles increased by means of deposition of silver nanoparticles on the boehmite sol and the aggregation of the composites. This leads to the appearance of a shoulder at 450 nm in the UV-Vis absorption spectra with the addition of 0.15 mg and 1.5 mg boehmite. It was found that the intensity of the SERS in the case of the composite was higher than for silver colloids consisting of a concentration of silver greater than 3.2 mM.     

Multiplicative isometries on the Smirnov class

We show that T is a surjective multiplicative (but not necessarily linear) isometry from the Smirnov class on the open unit disk, the ball, or the polydisk onto itself, if and only if there exists a holomorphic automorphism Φ such that T(f)=f ○ Φ for every class element f or T(f) = [`(f<sup>°</sup> [`(j)] )]\overline {f^\circ \bar \varphi } for every class element f, where the automorphism Φ is a unitary transformation in the case of the ball and Φ(z ₁, ..., z _n ) = (l₁ z_i1 ,...,l_n z_in )(\lambda _1 z_{i_1 } ,...,\lambda _n z_{i_n } ) for |λ _j | = 1, 1 ≤ j ≤ n, and (i ₁; ..., i _n )is some permutation of the integers from 1through n in the case of the n-dimensional polydisk.