A new 9-methoxyyohimbine-type indole alkaloid from Mitragyna africanus

A new yohimbine-type indole alkaloid (1). was isolated from the stem bark of Mitragyna africanus (WILLD.) collected in Nigeria, along with known seven Corynanthe-type oxindole alkaloids, two secoiridoids, three lignans, and a quinovic acid derivative. Their structures were elucidated by spectroscopic analyses.     

In situ organogelation at room temperature: direct synthesis of gelators in organic solvents

Organogels are formed through a conventional organogelation involving a heating process and an in situ organogelation at room temperature. The conventional organogelation is carried out by dissolution of gelators by heating, while the in situ organogelation is performed by mixing of highly reactive methyl 2,6-diisocyanatohexanoate (LDI) or 2-isocyanatoethyl 2,6-diisocyanatohexanoate (LTI) and alkylamines. The in situ organogelation produced the organogels within several seconds after mixing. The organogels prepared by the in situ organogelation showed quite similar FT-IR spectra and SEM photographs to those formed by conventional organogelation. Moreover, the in situ organogelation using LTI and octylamine as well as dodecylamine produced organogels of acetone, ethyl acetate, and acetonitrile that gelators 5 and 6 cannot gel through conventional organogelation.     

Frequency dependence of acoustic properties of aqueous glucose solutions in the VHF/UHF range

The bioultrasonic spectroscopy system was employed for measurements of velocity and attenuation coefficient of glucose solutions in the VHF/UHF range. The relation between the slope of the square of velocity and the relaxation parameters, and the relation between the frequency exponent on attenuation coefficient and the relaxation parameters are investigated. In order to carry out numerical calculations, a model for a single relaxation process is employed, wherein the attenuation coefficient is expressed as (A/( 1 + (f/falpha)2) + B)f2 where falpha is the attenuation relaxation frequency, and A and B are constants. The numerical calculations show that the slope of the square of the velocity is determined uniquely by the velocity relaxation frequency fv and v(infinity)2 - v(0)2 where v0 is the zero-frequency velocity and v(infinity) is the infinite-frequency velocity, and that the frequency exponent on the attenuation coefficient is determined uniquely by falpha and A/B. For experimental considerations, the velocities and the attenuation coefficients of 5, 15, and 25% concentration aqueous solutions of glucose were measured in the frequency range 20 to 700 MHz. The data for the 5 and 15% aqueous solutions can be explained using the single relaxation model. However, the data for the 25% aqueous solution suggest the existence of multirelaxation processes.     

Ten new Lycopodium alkaloids having the lycopodane skeleton isolated from Lycopodium serratum Thunb

Ten new alkaloids, lycoposerramines-F (1), -G (2), -H (3), -I (4), -J (5), -K (6), -L (7), -M (8), -N (9), and -O (10), having lycopodine-related structures, were isolated from the club moss Lycopodium serratum THUNB. and their structures were elucidated on the basis of spectroscopic analysis and/or chemical transformation.     

A remark on the definitions of viscosity solutions for the integro-differential equations with Lévy operators

We prove the equivalence of the three different definitions of the viscosity solution for the integro-differential equation with the Lévy operator. The two of the definitions are known in the preceding works of the author and the others, and the last one is new. A construction of a sequence of the approximating test functions to the subsolution (or the supersolution) is indispensable for the proof, and it is done explicitly in the paper.     

Specific recognition of syndiotactic poly(methacrylic acid) in porous isotactic poly(methyl methacrylate) thin films based on the effects of stereoregularity,temperature, and solvent

The effects of stereoregularity, temperature, and solvent on the specific recognition of syndiotactic (st)‐poly(methacrylic acid) (PMAA) in macromolecularly porous isotactic (it)‐poly(methyl methacrylate) films were investigated to give important insights into the regularity and stability of nanospaces in the it‐PMMA films as well as template polymerization. The porous it‐PMMA films were fabricated on quartz crystal microbalance (QCM) substrates via the layer‐by‐layer (LbL) assembly of it‐PMMA/st‐PMAA, plus the st‐PMAA extraction from the assembly. QCM analysis and infrared spectroscopy revealed the first case of stereocomplex formation using st‐PMAA with lower stereoregularity (rr = 73%) in the LbL films, while st‐PMAA obtained with conventional free radical polymerization (rr = 62%) was barely incorporated into the porous it‐PMMA films. The maximum st‐PMAA incorporation increased from 25 to 40 °C, but there were almost no difference between 40 and 55 °C, indicating that the it‐PMMA crystallization would also be accelerated with increasing temperature. The studies on st‐PMAA incorporation with various complexing solvents revealed that the host it‐PMMA in the porous films could only form the original stereocomplex with 2/1 unit‐molar stoichiometry (st‐PMAA/it‐PMMA) in acetonitrile/water or ethanol/water. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3651–3657, 2010     

After effects of57Co EC-decay and radiation damage in6Li(n,α)T reaction in carbonate and oxalate compounds

Chemical effects associated with⁶Li (n,α)T reaction in Lithium compounds were studied by observing a Mössbauer spectrum for the Mössbauer nuclides introduced in the lithium compounds. The large difference between the effects of lithium carbonate and oxalate was compared with the results obtained in the emission Mössbauer spectra of⁵⁷Co-labelled triscarbonatocobaltate(III) and trisoxalatocobaltate(III), in which the former shows much less reducing effect on the produced⁵⁷Fe species than the latter.     

Nickel-catalyzed multi-component coupling reaction of aldimine, alkyne, and dimethylzinc via dimerization of butadiene

In the presence of a Ni/phosphine ligand catalyst, dimethylzinc, alkyne, butadiene, aldehyde, and primary amine were successively combined via dimerization of butadiene to provide (3E,7E,10Z)-dodecatrienylamine in good yields with excellent regio and stereoselectivities.     

Modeling of filament discharge development in a XeCl excimer laser

Dynamics of a filament discharge in a discharge-excited XeCl excimer laser medium has been simulated for a sequence of discharge pulses (shots). In the present model a filament discharge is triggered at a microprotrusion on a cathode surface. After the first discharge initiation, a hot spot is created near the cathode, then filament develops toward the anode in the second shot. Images of the filament discharge development and its properties in a XeCl excimer laser are presented