Synthesis of the proposed structure of fudecalone, an anticoccidial drimane terpenoid

[formula: see text] The proposed structure of fudecalone (1), an anticoccidial drimane sesquiterpene, was synthesized as a racemate in six steps starting from a known phthalide (5). Interestingly, our synthetic 1 showed conformation 1b, while the natural one was reported as 1a, and the NMR spectral data were not identical.     

Thermal formation of triphenodithiazinequinone and triphenodiselenazinequinone

Thermal treatment of 2, 5-bis(2-thioanisidino)-3, 6-dichloro-1, 4-benzoquinone and its selenium derivative brought about demethylchlorination to give triphenodithiazinequinone and triphenodiselenazinequinone, respectively.     

Fluctuation and relaxation of macrovariables

Assuming that a macrovariable follows a Markovian process, the extensive property of its probability distribution is proved to propagate. This is a generalization of the Gaussian properties of the equilibrium distribution to nonequilibrium nonstationary processes. It is basically a WKB-like asymptotic evaluation in the inverse of the size of the macrosystem. Evolution of the variable along the most probable path and fluctuation properties around the path are considered from a general point of view with an emphasis on the relation of nonlinearity of evolution and the associated fluctuation. Anomalous behavior of the fluctuation is discussed in connection with unstable, critical, or marginal states. A general treatment is given for the asymptotic properties of relaxation eigenmodes.     

The new isotopes247Md,243Fm,239Cf,and investigation of the evaporation residues from fusion of206Pb,208Pb,and209Bi with40Ar

The evaporation residues produced in heavy ion fusion reactions between⁴⁰Ar and²⁰⁶Pb,²⁰⁸Pb, and²⁰⁹Bi, respectively, were investigated. They were separated in-flight using a velocity filter (SHIP) and identified after implantation into an array of position sensitive surface barrier detectors by measuring their decay characteristics. Three newα-emitting isotopes were found:²⁴⁷Md,²⁴³Fm, and²³⁹Cf.²⁴⁷Md was identified by correlation to its known daughter decay²⁴³Es, and²⁴³Fm and²³⁹Cf were observed as correlated decays. Moreover, all previously known deexcitation channels, characterized by spontaneous fission or byα decay, could be observed for the first time in one experimental setup. Our results for formation cross sections and decay characteristics are in agreement with known data.     

Asymmetric conjugate addition of 5-benzylfurfurals to nitroalkenes using a diaminomethylenemalononitrile organocatalyst

A pyrrolidine–diaminomethylenemalononitrile organocatalyst efficiently promotes the asymmetric direct bisvinylogous Michael addition of 5-benzylfurfural derivatives to nitroalkenes, affording the corresponding ε-regioselective addition products in high yields with up to 86% ee.     

Chemistry and biology of moverastins, inhibitors of cancer cell migration, produced by Aspergillus

Cancer cell migration is a required step in cancer metastasis. We screened for inhibitors of cancer cell migration of microbial origin, and obtained moverastin, a member of the cylindrol family, from Aspergillus sp. F7720. However, the results of an NMR spectroscopic analysis raised the possibility that moverastin is a mixture of two diastereomers. Separation of the C-10 epimers of synthetic moverastin and a bioassay revealed that both diastereomers (moverastins A and B) had inhibitory effects on cell migration. Furthermore, we demonstrated that moverastins A and B inhibited FTase in vitro, and they also inhibited both the membrane localization of H-Ras and the activation of the PI3K/Akt pathway in EC17 cells. Thus, moverastins inhibited the migration of tumor cells by inhibiting the farnesylation of H-Ras, and subsequent H-Ras-dependent activation of the PI3K/Akt pathway.     

Reversible hydrogen-storage functions for mixtures of Li3N and Mg3N2

The hydriding and dehydriding reactions occurring in mixtures of lithium and magnesium nitrides (Li₃N and Mg₃N₂) were investigated for the first time in fixed composition ratios. A mixture of Li₃N–20 at.%Mg₃N₂ after heat treatment at 833 K was hydrogenated at 523 K in 35 MPa according to the following overall reaction: 4Li₃N+Mg₃N₂+12H₂ 12LiH+3Mg(NH₂)₂. This reaction is one of the candidates for reversible hydrogen-storage functions in which 9.1 mass% of hydrogen can be stored in the solid state. PACS 81.05.Zx; 71.20.Ps; 82.30.-b     

Separatrix reconnection and periodic orbit annihilation in the Harper map

Structure of the periodic accelerator orbits of the Harper map is investigated in detail from the viewpoint of underlying scenario of chaos in the area preserving nontwist map. Since the twist function of the Harper map is free from the polynomial local approximation, it admits rigorous treatment for the entire range of phase variable. The results obtained in the present analysis describes generic novel phenomena, which are outside of the applicability of the Kolmogorov-Arnol'd-Moser theory. (c) 1997 American Institute of Physics.