Synthesis of [1]benzopyrano[2,3,4-kl]acridin-3-ol and its analogues as pentacyclic compounds

A new heterocyclic compound, [1]benzopyrano[2,3,4-kl]acridin-3-ol was synthesized by cyclization of xanthone derivatives. The key compound, 1-(3'-methoxyanilino)-xanthone, was prepared from 1-aminoxanthone. [1]benzopyrano[2,3,4-kl]acridin-3-ol analogues, [1]benzothiopyrano[2,3,4-kl]acridin-3-ol, pyrido[3',2':5,6]pyrano[2,3,4-kl]acridin-3-ol and pyrido[3',2':5,6]thiopyrano[2,3,4-kl]acridin-3-ol were synthesized by the same method.     

Electronic polarizability and crystallization of K2O-TiO2-GeO2 glasses with high TiO2 contents

Some K₂O-TiO₂-GeO₂ glasses with a large amount of TiO₂ contents (15-25 mol%) such as 25K₂O-25TiO₂-50GeO₂ have been prepared, and their electronic polarizability, Raman scattering spectra, and crystallization behavior are examined to clarify thermal properties and structure of the glasses and to develop new nonlinear optical crystallized glasses. It is proposed that the glasses consist of the network of TiO₆ and GeO₄ polyhedra. The glasses show large optical basicities of Λ=0.88-0.92, indicating the high polarizabity of TiO_n (n=4-6) polyhedra in the glasses. K₂TiGe₃O₉ crystals are formed through crystallization in all glasses prepared in the present study. In particular, 20K₂O-20TiO₂-60GeO₂ glass shows bulk crystallization and 18K₂O-18TiO₂-64GeO₂ glass exhibits surface crystallization giving the c-axis orientation. The crystallized glasses show second harmonic generations (SHGs), and it is suggested that the distortion of TiO₆ octahedra in K₂TiGe₃O₉ crystals induces SHGs.     

Inclusion Complex Formation of Thiacalix[4]arene and Xe in Aqueous Solution Studied by Hyperpolarized 129Xe NMR

The inclusion complex formation of 4-sulfothiacalix[4]arene sodium salt (STCAS) and Xe has been investigated by using hyperpolarized ¹²⁹Xe NMR spectroscopy. Our new continuous-flow type hyperpolarizing system has advantageous capabilities that can supply hyperpolarized gases continuously and directly to a sample solution in a NMR tube. Consequently saturated Xe concentration in the aqueous solution of STCAS is maintained during the NMR experiment, and ¹²⁹Xe NMR spectra can be obtained in remarkably short time. STCAS concentration dependence of ¹²⁹Xe chemical shift has been analyzed in an elaborated way by a computer method as well as a simple graphic method that we have proposed. The association constant K:13.6±0.8 M⁻¹ at 25 °C was obtained, and further analysis of the temperature dependence has successfully given thermodynamic parameters of enthalpy (ΔH) and entropy (ΔS) for the inclusion complex formation: ΔH = −11.9±1.9 kJ mol⁻¹ and ΔS = −17.4±5.8 JK⁻¹ mol⁻¹. The energetic aspects of complex formation are discussed from the size effect and from the molecular theory of standard entropy, and a release of definite number of water molecules from STCAS cavity is suggested in the inclusion complex formation with Xe.     

An indication of magnetic-field-induced superconductivity in a bifunctional layered organic conductor,kappa-(BETS)(2)FeBr(4)

Hybrid systems consisting of the conducting layers of organic donor molecules and the magnetic layers of inorganic anions have been focused on as possible bifunctional materials, whose conducting properties can be tuned by controlling the magnetic state of the anion layers on an application of magnetic field. Here we report the magnetoresistance of the antiferromagnetic organic superconductor, kappa-(BETS)2FeBr4 [BETS = bis(ethylenedithio)tetraselenafulvalene], consisting of the two-dimensional superconducting layers of the BETS semications and the insulating layers of the FeBr4- anions. Due to the metamagnetic nature of the Fe3+ spin system, characteristic resistivity decrease was observed just below the antiferromagnetic superconductor-to-ferromagnetic metal transition at 1.6 T. Furthermore, an indication of the onsets of the magnetic-field-induced superconductivity was discovered around 12.5 T.     

Formulation study for lansoprazole fast-disintegrating tablet. II. Effect of triethyl citrate on the quality of the products

The purpose of this study was to develop enteric-coated microgranules for the lansoprazole fast-disintegrating tablet (LFDT), which is a rapidly disintegrating tablet containing enteric-coated microgranules. In our previous study, it was clarified that sufficient flexibility of the enteric layer was achieved by the optimized combined ratio of methacrylic acid copolymer dispersion to ethyl acrylate-methyl methacrylate copolymer dispersion and adding the optimized concentration of triethyl citrate to reduce the damage during the compression process. However, since triethyl citrate has an unpleasant bitter taste and is especially incompatible with lansoprazole, it adversely affects the taste and stability of lansoprazole in the enteric-coated microgranules. The enteric layer containing macrogol 6000 was proven useful to improve the unpleasant bitter taste and stability of lansoprazole, because macrogol 6000 does not have an unpleasant bitter taste and is more compatible than triethyl citerate. By covering the inner (first enteric layer) and outer side (third enteric layer) of the enteric layer containing triethyl citrate (second enteric layer) with the enteric layer containing macrogol 6000, we resolved the stability problem of lansoprazole and the unpleasant bitter taste. Finally, we developed enteric-coated microgranules comprising seven layers: 1) core, 2) active compound layer, 3) intermediate layer, 4) first enteric layer, 5) second enteric layer, 6) third enteric layer, and 7) over coating layer. The enteric-coated microgranules have the multiple functions of reducing the damage to the enteric layer during the compression process, improving the stability of lansoprazole, and masking the unpleasant bitter taste.     

High-pressure synthesis of cyclic phenylacetylene oligomer

New conjugated oligomers were prepared by reacting phenylacetylene under high pressure of 0.11 to 0.92 GPa at 100–200°C for 0–5 h. The number-average molecular weight M?_n, the weight-average molecular weight M?_w, and the oligomer yield increased with pressure, tem-perature, and time. The average molecular weight of the oligomer showed the maximum value (M?_n: 830, M?_w: 2400) under 0.92 GPa, the maximum pressure, where phenylacetylene was oligomerized at a constant temperature. The structure of the oligomer was investigated from ESR, infrared, UV–VIS, field desorption mass (FDMS) spectra, and ¹³C NMR spec-trum. Analysis of the FDMS spectrum revealed that the molecular weight of the oligomer was multiple of the monomer. ¹³C NMR spectrum of the oligomer showed the absence of sp-carbon (? C?). We found that the oligomer had a cyclic structure. The cyclic oligomers of pentamer or more were new compounds. © 1995 John Wiley & Sons, Inc.     

Gas chromatography of manganese(II) and manganese(III) trifluoroacetylacetonates by the ligand vapour technique

The thermal properties and gas Chromatographie behaviour of manganese(II) and manganese(III) trifluoroacetylacetonates (TFA) were investigated by using the ligand vapour technique. The two chelates, Mn(TFA); and Mn(TFA)₃, can be quantitatively eluted on a mixed-liquid phase (1.9% OV-17 ÷ 0.1% PEG-20M) at column temperatures above 210°C and 130–150°C, respectively; Mn(TFA)₃ is completely converted to Mn(TFA)₂ by thermal dissociation at column temperatures above 180°C and completely eluted as Mn(TFA)₂ above 210°C. The chelates can be determined separately within errors of about 1% after a preliminary extraction.     

Point to string transformation,or framedependent notion of “locality”: An attempt to finitize field theories including gravitation

A novel approach has been made to the divergence problem in local field theories, in which the notion of locality is still retained but loses its absolute meaning, just like simultaneity. The basic idea is to introduce a pure-imaginary elementary length into 3-dimensional space, while keeping time structureless so as to retain the unitarity of theS-matrix. Consequently, light becomes dispersive at sufficiently short wavelengths, and Lorentz transformation becomes a point-to-string transformation. When reformulated to meet the new Lorentz invariance, all the localfield (in the above sense) theories in a flat space become finite,while retaining their conventional form. This has been demonstrated by the derivation of finitized Coulomb potential and correct high-momentum behavior of quantum-electrodynamic coupling constant. For diagrams including gravitons, evaluation of the superficial degrees of divergence shows that only a restricted number of 1-(and 2-) loop diagrams might be divergent, while those of more than 3 loops are definitely convergent, thus indicating possible renormalizability (or something better) of quantum gravity in Einstein's formalism of general relativity. Since 4-dimensional simple supergravity removes 1-and 2-loop divergence, a combination of the theory and the present one might lead to a more interesting result.     

Reaction mechanisms in the six-nucleon system with the multi-configuration resonating-group method

The properties of the six-nucleon system are examined with a multi-configuration resonating-group method consisting of thed+ configuration, thep+⁵He andn+⁵Li configurations, and deuteron pseudo-inelastic configurations. The main purpose is to study the reaction mechanisms in this system. The results obtained are quite satisfactory, with the calculatedd+ total reaction cross sections equal to around 90% of the empirically determined values. The one-nucleon transfer process turns out to be significantly more important than the deuteron direct-breakup process; however, the latter process must still be properly taken into consideration, since it does contribute to about one third of thed+ total reaction cross section. The process of one-nucleon transfer is shown to occur mainly in the peripheral region, while the process of deuteron direct-kreakup is found to take place predominantly in the interior region of the compound nucleus. The convergence property with respect to the number of deuteron pseudo-inelastic configurations has also been investigated. Here it is found that, with the dominant configurations included, the number of such configurations required can be rather small, which is an important finding because it greatly simplifies the computational aspects of multi-configuration resonating-group calculations.