Halichonines A, B, and C, novel sesquiterpene alkaloids from the marine sponge Halichondria okadai Kadota

Novel sesquiterpene alkaloids, halichonines A (1), B (2), and C (3), were identified from the marine sponge Halichondria okadai Kadota. By spectroscopic analyses and synthesis, their structures were revealed to include a 6,6-bicyclic ring system and two prenylated amine moieties. In addition, 2 induced apoptosis in HL60 human leukemia cells.     

The liquid-liquid extraction using hydrophilic solvents occluded to an oil-adsorbent as an organic phase: extraction of 8-quinolinolato complexes of alkaline earth metals into tetrahydrofuran.

In order to use a hydrophilic solvent as an organic phase in liquid-liquid extraction by retaining it to a solid support, the occlusion and desorption of nine hydrophilic solvents, such as methanol, to three kinds of commercially available oil-adsorbent were examined. The combination of tetrahydrofuran and WOSEP made by fibrous polypropylene was finally selected, and was subjected to the extraction of alkaline Earth metals with 8-quinolinol. It was proved that Mg2+, Ca2+, and Sr2+ ions could be successfully extracted into the tetrahydrofuran phase in the form of 8-quinolinolato complexes, which could not be extracted into CHCl3.     

Diffusion Coefficients of Tris(<Emphasis Type="Italic">β</Emphasis>-diketonato)ruthenium Complexes of Different Charge Numbers in Acetonitrile Solutions,Measured by Chronoamperometry

The diffusion coefficients of several tris(β-diketonato) ruthenium complexes in acetonitrile solutions containing a supporting electrolyte were determined by chronoamperometry. The diffusion coefficients of the charged complexes, which were produced by electrochemical oxidation or reduction, were also determined by double potential step chronoamperometry. Two kinds of radii of the complexes were evaluated. One was the Van der Waals radius and the other was the geometric distance from the center of the complex to the outer surface of the farthest atom. The latter quantity was determined from X-ray diffractometric data. The diffusion coefficients of the neutral complexes were discussed on the basis of the Stokes-Einstein equation. Those of charged complexes could not be explained by the theoretical equation presented by Hubbard and Onsager.     

Molecular structure and puckering potential of gas-phase 1-pyrroline as determined by microwave and infrared spectroscopy

The microwave spectrum of 1-pyrroline has been measured from 8 to 48 GHz. The transitions have been assigned to those of the ground state and the four lowest excited states of the ring-puckering vibration of monomer, which is a five-membered ring molecule with one CN double bond. The trimer, which exists in the liquid phase, has not been detected in the gas phase. The geometrical structure of the monomer has been estimated by an ab initio calculation and the trimer by a molecular mechanics calculation. The former is consistent with the experimental rotational constants. A gas-phase infrared spectrum has also been measured, and the ring-puckering potential has been determined by an analysis of the combination bands of the ring-puckering mode and the ring-stretching modes. The potential is described using a puckering coordinate, z, as V(z) = az² + bz⁴, where $\text{a = ?3.358(16) × 10}{}^4\text{cm}{}^{\mathrm{?1}}\text{A}\text{?}{}^{\mathrm{?2}}$ and $\text{b = 1.345(9) × 10}{}^6\text{cm}{}^{\mathrm{?1}}\text{A}\text{?}{}^{\mathrm{?4}}$; these values are intermediate of the corresponding values for cyclopentene and 1-pyrazoline. The nuclear quadrupole coupling constants, χ_aa = ?4.39(10), χ_bb = 1.04(10), and χ_cc = 3.35(10) MHz, have been determined by an analysis of well-resolved hyperfine splittings. These constants have been reproduced by an ab initio calculation with a 4-31G(N¹) basis set.     

Almost Complex Structures Which Are Compatible with Kähler or Symplectic Structures

In this note we prove that half of all homotopy classes of almost complex structures on M is not compatible with any symplectic structure for a certain class of oriented compact 4-manifolds M. In particular, half of all homotopy classes of almost complex structures on an oriented 4-manifold is not compatible to any Kähler structure.     

Structure of consistent ground state: Re—derivation of RPA vacuum and inclusion of higher RPA effects

Here is presented a method to determine the consistent ground state (CGS ) which satisfies the so-called killer condition for the excitation operator. This method may be called an extended application of the procedure employed by Weiner and Goscinski in deriving the random phase approximation (RPA ) vacuum. The RPA vacuum is derived by solving the recurrence formula of the configuration coefficients of a multiconfigurational state vector. The role of boson approximation to the primitive p-h excitation operator is also investigated and by using the present formalism the cluster-expansion-type CGS is derived as the RPA vacuum under the boson approximation. Inclusion of the effects of a higher RPA in the CGS leads to the simultaneous equations of the configuration coefficients of the CGS . In including the effect of the second RPA , only the symmetry-broken CGS can exist. When the third RPA effect is involved instead of the second RPA , there can be a symmetry-adapted CGS , in which the picture of electron pairs acquired in the standard RPA vacuum is modified. Thus the exact CGS vectors are analytically obtained in the case of simple model systems of two or four electrons.     

Carbon chemical shifts of 1,1-diphenylethylene and α-methylstyrene dimer dianions

The natural abundance C-13 NMR spectra of 1,1-diphenylethylene and α-methylstyrene dimer dianions have been obtained using the proton noise decoupling technique. The extra negative charge distributions in the carbanions have been discussed and compared with those obtained from the proton chemical shifts. The chemical shifts of the two ortho carbons in a phenyl ring are equivalent to each other for the former carbanion but not for the latter.     

Concepts of probabilistic sets

In the field of pattern recognition or decision making theory, the important subjects are as follows: (1) ambiguity of property of objects, (2) variety of character of objects, (3) subjectivity of observers, (4) evolution of knowledge of observers (i.e. learning). Considering these points, the concept of probabilistic set is proposed. It is based on both probability theory and fuzzy concepts. A probabilistic set on a total space is defined by a point wise measurable function from a parameter space (which is a probability space) to a characteristic space (which is a measurable space). It is shown that the family of all probabilistic sets constitutes a complete pseudo-Boolean algebra. Moment analysis is possible by using a probability measure of the parameter space. Other useful concepts are also mentioned such as probabilistic mappings and expected cardinal numbers.