Release behavior of capsules loaded by volatile liquid in multicores

The vapor release behavior of capsules containing volatile liquids in multicores was derived theoretically and compared with experimental data. The time course of the release amount was expressed by the same polynomial functional form as that for capsules having a single core, neglecting the interaction between the releases from different cores. Alginate capsules containing tea tree oil in multicores prepared by the insolubilization reaction were used for vapor release experiment. The time course of the release amount was well expressed by the polynomial equation suggested by the theory. From the parameters determined by fitting of the data to the theoretical equations, the activation energy for permeation of vapor through the wall membrane was estimated.     

Triflumizole as a Novel Lead Compound for Strigolactone Biosynthesis Inhibitor

Strigolactones (SLs) are carotenoid-derived plant hormones involved in the development of various plants. SLs also stimulate seed germination of the root parasitic plants, Striga spp. and Orobanche spp., which reduce crop yield. Therefore, regulating SL biosynthesis may lessen the damage of root parasitic plants. Biosynthetic inhibitors effectively control biological processes by targeted regulation of biologically active compounds. In addition, biosynthetic inhibitors regulate endogenous levels in developmental stage- and tissue-specific manners. To date, although some chemicals have been found as SL biosynthesis inhibitor, these are derived from only three lead chemicals. In this study, to find a novel lead chemical for SL biosynthesis inhibitor, 27 nitrogen-containing heterocyclic derivatives were screened for inhibition of SL biosynthesis. Triflumizole most effectively reduced the levels of rice SL, 4-deoxyorobanchol (4DO), in root exudates. In addition, triflumizole inhibited endogenous 4DO biosynthesis in rice roots by inhibiting the enzymatic activity of Os900, a rice enzyme that converts the SL intermediate carlactone to 4DO. A Striga germination assay revealed that triflumizole-treated rice displayed a reduced level of germination stimulation for Striga. These results identify triflumizole as a novel lead compound for inhibition of SL biosynthesis.     

Direct resolution of enantiomers by liquid chromatography with the novel chiral stationary phase derived from (R,R)-tartramide

The synthesis of the novel chiral stationary phase (CSP) derived from (R,R)-tartramide and direct resolution of a series of β-hydroxycarboxylic acid derivatives on this CSP are described.     

Hierarchical enumeration of Kekulé’s benzenes,Ladenburg’s benzenes,Dewar’s benzenes,and benzvalenes by using combined-permutation representations

The group hierarchy for each skeleton of ligancy 6 is formulated to be: point group (PG \({\varvec{G}}_{\sigma }\)) \(\subseteq \) RS-stereoisomeric group (RS-SIG \({\varvec{G}}_{\sigma \widetilde{\sigma }\widehat{I}}\)) \(\subseteq \) stereoisomeric group (SIG \(\widetilde{{\varvec{G}}}_{\sigma \widetilde{\sigma }\widehat{I}}\)) \(\subseteq \) isoskeletomeric group (ISG \(\widetilde{\widetilde{{\varvec{G}}}}_{\sigma \widetilde{\sigma }\widehat{I}}\) = \({\varvec{S}}^{[6]}_{\sigma \widehat{I}}\)), where we start from the PG \({\varvec{G}}_{\sigma }\) = \({\varvec{D}}_{6h}\) for the Kekulé benzene skeleton, from the PG \({\varvec{G}}_{\sigma }\) = \({\varvec{D}}_{3h}\) for the Ladenburg benzene skeleton, from the PG \({\varvec{G}}_{\sigma }\) = \({\varvec{C}}_{2v}\) for the Dewar benzene skeleton, or from the PG \({\varvec{G}}_{\sigma }\) = \({\varvec{C}}_{2v}\) for the benzvalene skeleton. After these groups are constructed as combined-permutation representations, the calculation of the respective cycle indices with chirality fittingness (CI-CFs) and the introduction of ligand-inventory functions are conducted to give generation functions for 3D-based enumerations (for PGs and RS-SIGs) and 2D-based enumerations (for SIGs and ISGs). The enumeration results are discussed by means of isomer-classification diagrams, in which equivalence classes under enantiomerism (for PGs), RS-stereoisomerism (for RS-SIGs), stereoisomerism (for SIGs), and isoskeletomerism (for ISGs) are illustrated schematically. The implicit connotations of the conventional terms “skeletal isomerism”, “positional isomerism”, and “constitutional isomerism” are discussed, where the effects of the concept of isoskeletomerism are emphasized.     

Graphs to chemical structures 2. Extended sphericity indices of cycles for stereochemical extension of Pólya’s coronas

In order to enumerate nonrigid isomers, we have proposed the proligand approach, where extended sphericity indices of k-cycles have been defined according to the enantiospheric, homospheric, or hemispheric nature of each k-cycle. Then, cycle indices with chirality fittingness have been defined so as to enumerate nonrigid stereoisomers with chiral and achiral ligands. Results of the proligand approach using tetramethylmethane as an example have been compared with those based on Pólyas corona. Thereby, Pólyas corona is concluded to be concerned with graphs, but not with chemical structures, where it is incapable of treating chiral ligands properly.     

Group-theoretical discussion on the E/Z-nomenclature for ethylene derivatives. Discrimination between RS-stereoisomeric groups and stereoisomeric groups

The hierarchy of point groups, RS-stereoisomeric groups, stereoisomeric groups, and isoskeletal groups is discussed to comprehend the chirality, RS-stereogenicity, stereogenicity, and isoskeletal isomerism for ethylene derivatives. The RS-stereoisomeric groups for ethylene derivatives have been clarified not to coincide with their stereoisomeric groups, so that diastereomers (E/Z-isomers) are not identical with RS-diastereomers. To discuss the relationship among RS-diastereomers, m-diastereomers, and isoskeletal isomers, we have proposed the concepts of extended stereoisograms and extended stereoisogram sets, where the term "m-diastereomers" is coined to show its difference from the traditional term "diastereomer". Thereby, ethylene derivatives are classified into Types II-II/II-II/II-II, IV-IV/IV-IV/IV-IV, etc. on the basis of relevant stereoisograms (Types I to V). The stereoisomerism of ethylenes has been concluded to be treated in terms of m-diastereomers characterized by the E/Z-nomenclature but not to be treated in terms of RS-diastereomers characterized by the RS-nomenclaure.     

Doubly-Colored Graphs as Graphical Models for Subductions of Coset Representations, Double Cosets, and Unit Subduced Cycle Indices

The concept of doubly-colored graphs is proposed to model subductions of coset representations, double cosets, and unit subduced cycle indices, which have been mathematically formulated in coset algebraic theory developed by Fujita (Symmetry and Combinatorial Enumeration in Chemistry, Springer-Verlag, Berlin, 1991).     

Catalytic reaction of methane with carbon dioxide

High activities and selectivities of Ni on SiO₂ catalysts producing CO in the reaction of CH₄ with CO₂, have been obtained at relatively low temperatures. These aspects are considerably different from the activities or selectivities of other catalysts, and have been explained by assuming that the Ni on SiO₂ catalyst markedly suppresses carbon deposition.

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CO Ni SiO₂ CH₄ CO₂. , Ni SiO₂.

     

Stereoselective iodine atom transfer [3 + 2] cycloaddition reaction with alkenes using unsymmetrical allylated active methine radicals

Treatment of 1-diethylphosphonyl- or 1-phenylsulfonyl-2-(iodomethyl)cyclopropane-1-carboxylate with Et(3)B leads to an unsymmetrical allylated active methine radical species that gives functionalized cyclopentane derivatives with high stereoselectivity through iodine atom transfer [3 + 2] cycloaddition reaction with alkenes.