Efficient preparation of c(2)-symmetrical chiral ferrocenyl diols by catalytic enantioselective reduction of diacylferrocenes

[reaction: see text] Enantioselective borohydride reduction, catalyzed by the optically active beta-ketoiminato cobalt(II) complex, was successfully applied to the 1,1'-dialkanoyl- and 1,1'-dibenzoylferrocenes to afford the corresponding C(2)-symmetrical chiral ferrocenyl diols with high diastereoselectivity and excellent enantioselectivity.     

Improvement of substrate conversion to molecular hydrogen by three-stage cultivation of a photosynthetic bacterium,Rhodovulum sulfidophilum

In photosynthetic bacteria, after transition to light-anaerobic and nitrogen-deficient conditions, hydrogen evolution starts with expression of nitrogenase activity. Until the expression of enough activity,Rhodovulum sulfidophilum consumed substrates and converted them to poly(3-hydrox-ybutyrate) (PHB), resulting in a decrease in the proportion of substrate converted into hydrogen gas. To prevent conversion to PHB during the period when nitrogenase activity is derepressed, the authors employed a cultivation method consisting of three stages: cell growth, nitrogenase derepression, and hydrogen production. Cells cultivated by this method exhibited no lag time before the commencement of hydrogen evolution and gave an improved yield of hydrogen from the algal fermentative products.     

Novel enhancement of diastereoselectivity of [2 + 2] photocycloaddition of chiral cyclohexenones to ethylene by adding naphthalenes

The additive effect on the diastereoselective [2 + 2] photocycloaddition of chiral cyclohexenones 1 to ethylene is examined. A novel and fairly efficient method of increasing the diastereoselectivity in the reaction of 1a was elucidated. The de value increased from 56% to 83% by the addition of 1-phenylnaphthalene. The major product 2a was isolated by the recrystallization of the diastereomeric mixture (major/minor = 11/1), of which X-ray analysis confirmed the absolute configuration of the bicyclic system of 2a. Hydrolysis for removing the chiral auxiliary and subsequent esterification afforded the optically pure bicyclo[4.2.0]octanone derivative 5. From the fluorescence spectral analyses and other experimental results, the additive effect is attributed to the complex formation of chiral cyclohexenone 1a and added naphthalenes.     

N-Arylpiperazine-1-carboxamide derivatives: a novel series of orally active nonsteroidal androgen receptor antagonists

A novel series of N-arylpiperazine-1-carboxamide derivatives was synthesized and their androgen receptor (AR) antagonist activities and in vivo antiandrogenic properties were evaluated. Reporter assays indicated that trans-2,5-dimethylpiperazine derivatives are potent AR antagonists, and in this series trans-N-4-[4-cyano-3-(trifluoromethyl)phenyl]-N-(2,4-difluorophenyl)-2,5-dimethylpiperazine-1-carboxamide (18 g, YM-175735) exhibited the most potent antiandrogenic activity. Compared to bicalutamide, YM-175735 is an approximately 4-fold stronger AR antagonist and has slightly increased antiandrogenic activity, suggesting that YM-175735 may be useful in the treatment of prostate cancer.     

Production of (2R,3S)-3-(4-methoxyphenyl)glycidic acid methyl ester using an emulsion bioreactor containing lipase fromSerratia marcescens

An emulsion bioreactor for production of (2R,3S)-3-(4-methoxyphenyl) glycidic acid methyl ester ([-]MPGM) from a racemic mixture ([±]MPGM) using the lipase fromSerratia marcescens has been proposed. Kinetics of hydrolyzing reaction and purification of (-)MPGM from the reaction mixture were investigated to provide a basis for industrial application of this bioreactor. The hydrolyzing reaction in the bioreactor proceeded at a rate that was first order in substrate concentration. The reaction rate was affected by a stirring speed and the ratio of the aqueous phase containing lipase to the toluene phase containing substrate. Phase separation after the enzymatic reaction was accomplished by addition of surfactant to the reaction mixture, and crystalline (-)MPGM with a chemical purity of 100% and optical purity of 100% enantiomeric excess was obtained in a high yield of 40–43% by concentration of the toluene solution.     

A versatile tRNA aminoacylation catalyst based on RNA

Aminoacyl-tRNA synthetase (ARS) ribozymes have potential to develop a novel genetic coding system. Although we have previously isolated such a ribozyme that recognizes aromatic amino acids, it could not be used as a versatile catalyst due to its limited ability of aminoacylation to a particular tRNA used for the selection. To overcome this limitation, we used a combination of evolutionary and engineering approaches to generate an optimized ribozyme. The ribozyme, consisting of 45 nucleotides, displays a broad spectrum of activity toward various tRNAs. Most significantly, this ribozyme is able to exhibit multiple turnover activity and charge parasubstituted Phe analogs onto an engineered suppressor tRNA (tRNA(Asn)(CCCG)). Thus, it provides a useful and flexible tool for the custom synthesis of mischarged tRNAs with natural and nonnatural amino acids.     

A self-consistent approach for the SmA–SmC* phase transition

By using an analogy with the Maier–Saupe theory of the nematic phase, a mean field theory of the chiral smectic-C (SmC*) phase is constructed. As an order parameter of the SmC* phase, the tilt angle θ is selected, and the feedback effect of θ is introduced into the hindered rotational potential about the molecular long axis. By solving the self-consistent equation for the order parameter θ, the second-order phase transition appears. Also, to describe the SmA–SmC* phase transition under an electric field, a coupling term between a molecular dipole moment and an external electric field is introduced to the potential function. The electroclinic effect in the SmA phase and the hysteresis effect in the SmC* phase, which were described phenomenologically in the past, are found directly from the microscopic theory.     

Synthesis and pharmacological evaluation of novel arylpiperazine derivatives as nonsteroidal androgen receptor antagonists

The search for novel antiandrogens by high-throughput screening (HTS) of the Yamanouchi chemical library led to the discovery of the lead compound (5), which possesses an arylmorpholine moiety. Through the optimization of the lead compound (5), we have found a series of novel arylpiperazine derivatives. Among them, 4-[4-cyano-(3-trifluoromethyl)phenyl]-N-(4-fluorophenyl)piperazine-1-carboxamide (22; YM-92088) exhibited a potent AR antagonistic activity with an IC(50) value of 0.47 microM in the reporter assay, which is more potent than bicalutamide (4) which has an IC(50) value of 0.89 microM.     

Enzymatic N-methylaminoacylation of tRNA using chemically misacylated AMP as a substrate

Using "chemically misacylated AMP" which is photogeneratable, tRNA can be enzymatically acylated with N-methylamino acids in an efficiency comparable to that of the corresponding natural aminoacylation process with amino acids.     

Imidazole‐type thermal latent curing agents with high miscibility for one‐component epoxy thermosetting resins

Epoxy resins are important thermosetting resins widely employed in industrial fields. Although the epoxy–imidazole curing system has attracted attention because of its reactivity, solidification of a liquid epoxy resin containing imidazoles proceeds gradually even at room temperature. This makes it difficult to use them for one‐component epoxy resin materials. Though powder‐type latent curing agents have been used for one‐component epoxy resin materials, they are difficult to apply for fabrication of fine industrial products due to their poor miscibility. To overcome this situation and to improve the shelf life of epoxy–imidazole compositions, we have developed a liquid‐type thermal latent curing agent 1 , generating an imidazole with a thermal trigger via a retro‐Michael addition reaction. The latent curing agent 1 has superior miscibility toward epoxy resins; in addition, it was confirmed that the epoxy resin composition has both high reactivity at 150 °C, and long‐term storage stability at room temperature. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2680–2688