20‐Di­cyano­methyl­ene‐5,8,11,14‐tetraoxa‐2,17‐di­thia­bi­cyclo­[16.4.1]­tricosa‐1(23),18,21‐triene and its mercury(II) dichloride complex

The structures of the title compound, C₂₀H₂₄N₂O₄S₂, and its mercury(II) dichloride complex, dichloro{20‐di­cyano­methyl­ene‐5,8,11,14‐tetraoxa‐2,17‐di­thia­bi­cyclo­[16.4.1]­tricosa‐1(23),18,­21‐tri­ene‐κ⁴O,κS¹⁷}mercury(II), [HgCl₂(C₂₀­H₂₄­N₂­O₄­S₂)], have been determined by X‐ray crystallographic analyses. The mercury(II) dichloride complex has two independent mol­ecules of [HgCl₂(C₂₀H₂₄N₂O₄S₂)] in the lattice. The mercury(II) ion has pentagonal bipyramidal coordination which involves one S atom, four O atoms and two Cl^? ions.     

Bioinspired Total Synthesis of the Dimeric Indole Alkaloid (+)‐Haplophytine by Direct Coupling and Late‐Stage Oxidative Rearrangement

A bioinspired convergent total synthesis of (+)‐haplophytine, a dimeric indole alkaloid with diazabicyclo[3.3.1]nonane and hexacyclic aspidosperma segments, is described. This synthesis involves the direct coupling of the two segments in a AgNTf₂‐mediated Friedel–Crafts reaction and construction of the diazabicyclo[3.3.1]nonane skeleton through late‐stage chemoselective aerobic oxidation of the 1,2‐diaminoethene moiety and a sequential semipinacol‐type rearrangement.     

Using a polyelectrolyte to fabricate porous polyimide nanoparticles with crater‐like pores

We have used the reprecipitation method and subsequent two‐step imidization to fabricate highly porous polyimide (PI) nanoparticles possessing crater‐like surface pores (depths, diameters: tens of nanometers) from poly(amic acid) (PAA) derivatives in the presence of poly(sodium‐4‐styrenesulfonate) (PSS) as a polyelectrolytic porogen. The porous structures arose presumably through segregative microphase separation of PAA and PSS (i.e. repulsion between PAA and PSS in the presence of a common solvent) and subsequent removal of PSS. The addition of this strong polyelectrolyte improved the degree of porosity of the resulting PI nanoparticles and allowed controllable release of the porogen. The resulting porous PI nanoparticles exhibited a high thermal stability (5% weight loss at temperature 450°C). This technique is suitable for the preparation of novel low‐k materials and their surface‐related applications. Copyright © 2008 John Wiley & Sons, Ltd.     

Positional isomer differentiation of synthetic cannabinoid JWH‐081 by GC‐MS/MS

Like many new designer drugs of abuse, synthetic cannabinoids (SC) have structural or positional isomers which may or may not all be regulated under law. Differences in acute toxicity may exist between isomers which impose further burden in the fields of forensic toxicology, medicine and legislation. Isomer differentiation therefore becomes crucial from these standpoints as new designer drugs continuously emerge with just minor positional modifications to their preexisting analogs. The aim of this study was to differentiate the positional isomers of JWH‐081. Purchased standard compounds of JWH‐081 and its positional isomers were analyzed by gas chromatography‐electron ionization‐mass spectrometry (GC‐EI‐MS) first in scan mode to investigate those isomers who could be differentiated by EI scan spectra. Isomers with identical or near‐identical EI spectra were further subjected to GC‐tandem mass spectrometry (MS/MS) analysis with appropriate precursor ions. EI scan was able to distinguish 3 of the 7 isomers: 2‐methoxy, 7‐methoxy and 8‐methoxy. The remaining isomers exhibited near‐identical spectra; hence, MS/MS was performed by selecting m/z 185 and 157 as precursor ions. 3‐Methoxy and 5‐methoxy isomers produced characteristic product ions that enabled the differentiation between them. Product ion spectrum of 6‐methoxy isomer resembled that of JWH‐081; however, the relative ion intensities were clearly different from one another. The combination of EI scan and MS/MS allowed for the regioisomeric differentiation of the targeted compounds in this study. Copyright © 2015 John Wiley & Sons, Ltd.     

Steroidal glycosides from the underground parts of Solanum sodomaeum

A new steroidal glycoside has been isolated from the underground parts of Solanum sodomaeum L., along with seven known steroidal glycosides. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence, and the structure of one known pregnane type glycoside was corrected. In addition, their antiproliferative activity against human promyelocytic leukemia (HL-60) cells was investigated, and five compounds exhibited stronger activity than cisplatin.     

Copper(II)-terbium(III) single-molecule magnets linked by photochromic ligands

Two assemblies composed of single-molecule magnets (SMMs) linked by photochromic ligands, [Cu(II)(2)Tb(III)(2)(L)(2)(NO(3))(2)(dae-o)(2)]·2(n-BuOH) (1) and {[Cu(II)Tb(III)(L)(n-BuOH)(0.5)](2)(dae-c)(3)}·5(DMF)·4(n-BuOH)·2(H(2)O) (2), were synthesized by reacting the SMM [Cu(II)Tb(III)(L)(NO(3))(3)] (H(2)L = 1,3-bis((3-methoxysalicylidene)amino)propane) and photochromic molecules, H(2)dae-o and H(2)dae-c, which are open- and closed-ring isomers of 1,2-bis(5-carboxyl-2-methyl-3-thienyl)perfluoropentene (H(2)dae), respectively. 1 has a tetranuclear ring-like structure comprised of two [CuTb] units and two dae-o(2-) ligands. On the other hand, 2 has a one-dimensional ladder-type structure involving the [CuTb] and dae-c(2-) units in a 3?:?2 ratio. Magnetic studies revealed that 1 and 2 had ferromagnetic interactions between the Cu(II) and Tb(III) ions and that both compounds exhibited frequency dependence of ac susceptibilities owing to freezing the magnetization of the [CuTb] SMM. Upon irradiation with ultraviolet light and visible light, an absorption band at ～600 nm changed, indicating that photochromic reactions involving the dae(2-) ligands occurred. After irradiation, the magnetic behaviour of 1 did not change, whereas magnetic behaviour of 2 changed, due to the modification of intermolecular environment.     

Submillimeter wave esr and far infrared spectroscopy measurements of CuGeO3

Submillimeter wave ESR and far infrared transmission measurements of first inorganic spin-Peierls system CuGeO₃ have been performed using the single crystals. Our new results are discussed in connection with the magnetic properties of the spin-Peierls systems and the recent neutron measurements of CuGeO₃.     

Comparative studies on excitation of nickel ionic lines between argon and krypton glow discharge plasmas

The emission characteristics of nickel ionic lines in a glow discharge plasma are investigated when argon or krypton was employed as the plasma gas. Large difference in the relative intensities of nickel ionic lines which are assigned to the 3d⁸4p–3d⁸4s transition is observed between the krypton plasma and the argon plasma. Different intense Ni II lines appear in the krypton spectrum and in the argon spectrum, such as the Ni II 231.601 nm for Kr and the Ni II 230.009 nm for Ar. The excitation energy of these Ni II emission lines can give a key in considering their excitation mechanisms. The explanation for these experimental results is that charge-transfer collisions between nickel atom and the plasma gas ion play a major role in exciting the 3d⁸4p excited levels of nickel ion. The conditions for energy resonance in the charge-transfer collision determine particular energy levels having much larger population; for example, the 3d⁸4p ⁴D_7/2 level (6.39 eV) for Kr and the 3d⁸4p ⁴P_5/2 level (8.25 eV) for Ar.     

Some Factors Affecting the Photosensitized Polymerization of Methyl Methacrylate

The effects of sensitizer, alcohol, and reaction temperature on the photosensitized polymerization of methyl methacrylate in cyclohexane-alcohol mixtures were investigated. A maximum conversion was indicated at a certain concentration of alcohol in the mixture for the systems sensitized with quinones such as anthraquinone, 2-tert-butylanthraquinone, and α-naphthoquinone, while it was not observed for the benzophenone-sensitized system. The concentration of alcohol corresponding to the maximum conversion increased in the order methanol < ethanol < n-propanol < n-butanol, and shifted to the lower side by raising the reaction temperature from 20 to 40°C. Based on the absorption and ESR spectra of irradiated solution of quinones, reasons for maximum conversion at an optimum concentration of alcohol are discussed.