A synthetic approach to diverse 3-acyltetramic acids via O- to C-acyl rearrangement and application to the total synthesis of penicillenol series

For the efficient approach to medicinally important α-branched 3-acyltetramic acids, the key reaction of O- to C- acyl rearrangement using α-amino-acid-derived 4-O-acyltetramic acids was extensively examined in the presence of various metal salts. Use of CaCl(2) or NaI dramatically changed the results in the reaction efficiency and rapidly brought about the desired α-branched 3-acyltetramic acids in markedly improved yields. We also discuss an epimerization at C5 stereocenter under the rearrangement conditions as well as the tolerance for structural variation at C3 and C5. In addition to the preceding success in the total synthesis of new cytotoxic tetramic acid, penicillenol A(1), this methodology could be also applied to the first total synthesis of penicillenol A(2).     

Synthesis of novel mucic acid 1,4-lactone methyl ester 3-O-ferulate related to an extractive component isolated from the peels of Citrus sudachi

Synthesis of a new type of mucic acid 1,4-lactone methyl ester 3-O-ferulate related to an extractive component isolated from Citrus sudachi, and its diastereomer has been achieved by employing stereodivergent dihydroxylation as a key step. The structures of the final products are fully characterized by spectroscopic methods and compared with that of the natural product.     

Platinum‐Catalyzed Friedel–Crafts‐Type C−H Coupling–Allylic Amination Cascade to Synthesize 3,4‐Fused Tricyclic Indoles

A novel platinum‐catalyzed cascade cyclization reaction was developed by intramolecular Friedel–Crafts‐type C?H coupling of aniline derivatives with a propargyl carbonate unit‐allylic amination sequence. Treatment of various propargyl carbonates tethered to meta‐aniline derivatives with a Pt(dba)₃/DPEphos catalyst system afforded the corresponding 3,4‐fused tricyclic 3‐alkylidene indolines in 42–99 % yield, which were transformed into 3,4‐fused indole derivatives by reaction with trifluoroacetic acid. The reaction products exhibited antiproliferative activities against cancer cells, but not normal cells, revealing the potential usefulness of this reaction for medicinal chemistry.     

Spinor with Schrödinger symmetry and non-relativistic supersymmetry

We construct the d-dimensional “half” Schrödinger equation, which is a kind of the root of the Schrödinger equation, from the (d+1)-dimensional free Dirac equation. The solution of the “half” Schrödinger equation also satisfies the usual free Schrödinger equation. We also find that the explicit transformation laws of the Schrödinger and the half Schrödinger fields under the Schrödinger symmetry transformation are derived by starting from the Klein-Gordon equation and the Dirac equation in d+1 dimensions. We derive the 3- and 4-dimensional super-Schrödinger algebra from the superconformal algebra in 4 and 5 dimensions. The algebra is realized by introducing two complex scalar and one (complex) spinor fields and the explicit transformation properties have been found.     

Life Cycle Assessment in Polymer Industry Toward the 21st Century

Abstract

Life cycle assessments to protect global environment and to control waste in the polymer industry are reviewed. The focus is on 1) environmentally sound technology, 2) energy conservation, and 3) recycling of industrial products. The competitiveness of a nation depends on how it balances economic development of sustainable growth and responsible care of the global environment in a borderless economy. It fully depends on the development of both environmentally sound manufacturing and effective recycling technologies for the products. Current environmental issues of the Japanese chemical industries as well as Toray's performance and new products development for environment business are reviewed: 1) Energy conservation and technology of the Japanese manufacturing industry, 2) Development of environmentally sound technology, 3) Effective products recycling technologies, and 4) Sustainable growth in the new chemical age. The future issues of life cycle assessment and environmental protection in manufacturing industries are discussed.     

Determination of particle size by using incidence-angle dependence of spectral intensity for particle-size-measurement method by applying infrared attenuated-total-reflection technique and its simulations by using algebraic-simultaneous equations

A method using an incidence-angle dependence of the spectral intensity was proposed to determine a particle size in a particle-size measurement by applying an infrared attenuated-total-reflection (ATR) technique. A formula, which is proportional to the infrared ATR-spectral intensity, was constructed as a function of the particle size, amount of particles, and incidence angle, psi. Its psi dependences were calculated for SiO(2) particles of less than a mono layer on a Ge prism, and differed at every particle size. Some simulations of determining both particle size and particle amount were carried out for the samples of particles with sizes of 1 to 3 kinds by using algebraic-simultaneous equations with the software of Mathematica 5.2, and resulted in showing its usefulness.     

Capillary condensation in mesoporous silica with surface roughness

We construct an atomistic silica pore model mimicking templated mesoporous silica MCM-41, which has molecular-level surface roughness, with the aid of the electron density profile (EDP) of MCM-41 obtained from X-ray diffraction data. Then, we present the GCMC simulations of argon adsorption on our atomistic silica pore models for two different MCM-41 samples at 75, 80, and 87 K, and the results are compared with the experimental adsorption data. We demonstrate that accurate molecular modeling of the pore structure of MCM-41 by using the experimental EDP allows the prediction of experimental capillary evaporation pressures at all investigated temperatures. The experimental desorption branches of the two MCM-41 samples are in good agreement with equilibrium vapor–liquid transition pressures from the simulations, which suggests that the experimental desorption branch for the open-ended cylindrical pores is in thermodynamic equilibrium.     

An Ireland–Claisen rearrangement/RCM based approach for the construction of the EF-ring of ciguatoxin 3C

The EF-ring of ciguatoxin 3C, a marine toxin from the dinoflagellate Gambierdiscus toxicus, was stereoselectively synthesized by iterative use of a cyclic ether formation process based on chirality-transferring Ireland-Claisen rearrangement and ring-closing olefin metathesis.