Superacid cyclization of 13E,17E- and 13E,17Z-bicyclogeranylfarnesols and their acetates — An effective structurally selective stereospecific route to scalarane sesterterpenoids

Institute of Chemistry, Moldavian SSR Academy of Sciences, Kishinev. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 759–760, September–October, 1988.     

Adsorption of dyes on activated carbon and graphitic thermal carbon black

The adsorption of a basic dye (Methylene Blue; MB) and an acidic dye (Acid Orange; AO) has been studied on three activated carbons (ACs; FAS, SKD, and BAU) significantly differing in their porous structures and surface concentrations of ion-exchange groups and on graphitic thermal carbon black (GTCB). The effective specific surface area of FAS, SKD, and BAU determined by dye adsorption is, respectively, 60, 50, and 40% of the BET nitrogen adsorption surface area. The MB uptake on ACs and GTCB increases with rising pH, while the AO uptake decreases. Addition of an electrolyte (0.3 M NaCl) virtually does not effect the adsorption of dyes on ACs and GTCB. It is suggested that hydrophobic interactions, and not ionic ones, are the major contributors to the adsorption of dyes on ACs.     

Determination of individual rare earth elements in Vietnamese monazite by radiochemical neutron activation analysis

Radiochemical neutron activation analysis (RNAA) has been applied for determination of rare earth elements (REE) in Vietnamese monazite. The chemical separation procedure used is based on the chromatographic elution of rare earth groups, after the separation of²³³Pa(Th) in irradiated monazite samples by coprecipitation with MnO₂, the rare earth elements were retained by Biorad AG1×8 resin column in 10% 15.4M HNO₃-90% methanol solution. The elution of heavy rare earth (HREE) and middle rare earth (MREE) groups was carried out with 10% 1M HNO₃-90% methanol and 10% 0.05M HNO₃-90% methanol solution, respectively; while the light rare earths (LREE) were eluted from the column by 0.1M HNO₃ solution. The accuracy of the method was checked by the analysis of granodiorite GSP-I and the rare earth values were in good agreement.     

Synthesis of D-D4FC, a biologically active nucleoside via an unprecedented palladium mediated Ferrier rearrangement-type glycosidation with an aromatization prone xylo-furanoid glycal

D-D4FC (1) is an anti-HIV agent currently under phase II clinical trial (Pharmaset Inc). Its molecular architecture is suitable for a Ferrier rearrangement kind of operation on a furanoid glycal to fix the position of the double bond and the relative stereochemistry. Despite the fact that classical Ferrier rearrangement does not work on furanoid glycals, a palladium mediated modified protocol has been developed for the glycosidation of an aromatization prone xylo-furanoid glycal (5) for the synthesis of D-D4FC.     

Theoretical study of “deep” fragmentation of hemin ion with successive loss of methyl and vinyl groups

The electronic and geometric structures, energy stability, normal mode frequencies, and spin density distribution have been calculated by the density functional theory B3LYP method with the Gen = 6-31+G*(Fe) + 6-31G(C,H,N,O), 6-31G*, and 6-311++G** basis sets for the deep fragmentation products of the free hemin ion with successive removal of methyl and vinyl groups in the electronic states with different multiplicities. The computation results are compared with the available experimental data and previous computation results for the fragmentation products of the isolated heme molecule and hemin ion with removal of carboxymethyl groups. The trends in the behavior of these properties are analyzed as a function of multiplicity, external charge, and the number of peripheral substituents at the porphyrin core.     

Pheromones of coleoptera. Communication 6. Synthesis of R,Z-14-methyl-8-hexadecenal (cis-trogodermal)

Conclusions The simple synthesis of optically active R,Z-14-methyl-8-hexadecenal (cis-trogodermal), the principal components of the aggregation pheromone ofTrogoderma granarium, was accomplished. The synthesis was based on the use of R-1-bromo-4-methylhexane and Z-4-chloro-2-buten-1-ol as the sources of the chiral and olefin fragments.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 906–910, April, 1987.     

The light 1P-shell nuclei

The binding energies and other characteristics of the light 1P-shell nuclei (N, Z8) are calculated. We use the method denoted as modified oscillator shell model (MOSM), proposed by one of the authors (Nguyen tien Nguyen: Czech. J. Phys. B31 (1981) 16). We succeed in choosing the parameter set of the Skyrme-type force, which gives satisfactory and interesting results.On leave fromFaculty of Physics, Hanoi University, Vietnam.The authors would like to thank I. Wilhelm for the useful discussion.