Synthesis of Acylphosphonates by a Palladium‐Catalyzed Phosphonocarbonylation Reaction of Aryl Iodides with Phosphites

Acylphosphonates are conveniently synthesized from aryl iodides by a palladium‐catalyzed reaction with dialkyl phosphites under an atmospheric pressure of carbon monoxide. The reaction demonstrates the first example of the use of phosphorus nucleophiles in related metal‐catalyzed carbonylation reactions.     

Water‐Mediated Recognition of Simple Alkyl Chains by Heart‐Type Fatty‐Acid‐Binding Protein

Long‐chain fatty acids (FAs) with low water solubility require fatty‐acid‐binding proteins (FABPs) to transport them from cytoplasm to the mitochondria for energy production. However, the precise mechanism by which these proteins recognize the various lengths of simple alkyl chains of FAs with similar high affinity remains unknown. To address this question, we employed a newly developed calorimetric method for comprehensively evaluating the affinity of FAs, sub‐Angstrom X‐ray crystallography to accurately determine their 3D structure, and energy calculations of the coexisting water molecules using the computer program WaterMap. Our results clearly showed that the heart‐type FABP (FABP3) preferentially incorporates a U‐shaped FA of C10–C18 using a lipid‐compatible water cluster, and excludes longer FAs using a chain‐length‐limiting water cluster. These mechanisms could help us gain a general understanding of how proteins recognize diverse lipids with different chain lengths.     

Thermal characterization and compatibility studies of norfloxacin for development of extended release tablets

Norfloxacin (NFX) is a synthetic antibacterial drug. The development of extended release tablets improves the patients’ comfort and compliance, resulting in lower discontinuation of the therapy; with consequently decrease in bacterial resistance. In the present work, the thermal behavior of NFX was investigated using TG and DSC techniques. Isothermal and non-isothermal methods were employed to determine kinetic data of decomposition process. Compatibility studies between NFX and pharmaceutical excipients, including three hydrophilic polymers were carried out in order to develop a new formulation of NFX to obtain extended release tablets with an approved quality.     

Dynamical observation of structural transition of polymers using an X‐ray diffraction system with imaging plates. II. Crystalline transition of poly(butylene terephthalate)

Poly(butylene terephthalate) has two crystalline forms of α and β. The α form is more stable and is transformed into the β form by stretching. The α↔β transition stress was measured at various temperatures with the use of an X‐ray diffraction system with imaging plates, and the relationship between the transition stress and temperature was obtained. Further, using the X‐ray diffraction system, the drawing behavior of the nearly amorphous, undrawn polymer film was observed by taking up dynamically a series of X‐ray diffraction patterns while a film was being drawn. The α form never occurred during drawing at any temperature because the stress to draw the film exceeded the α→β transition stress. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 838–845, 2000     

Enhancement of the shape-selectivity in alkylation of methylnaphthalene over the ZSM-5 modified by chemical vapor deposition of SI(OCH3)4

Shape-selectivity of alkylation of 2-methylnaphthalene over the ZSM-5 zeolite has been improved by a method of chemical vapor deposition of silicon methoxide. The deposition of silica on ZSM-5 increased the β-selectivity, which was defined as the sum of distributions of 2,3-, 2,6-, and 2,7-dimethylnaphthalenes; however, it did not increase selectively the product distribution of 2,6-dimethylnaphthalene. From the characterization of two kinds of the silica-deposited ZSM-5, it was found that the β-selectivity was enhanced by the inactivation of the external surface as well as by the control of pore-opening size.     

Application of multiple prompt gamma-ray analysis (MPGA) to geochemical and cosmochemical samples

A prompt gamma-ray analysis system using multiple detection method (MPGA system) was constructed at the neutron guide hall of the JRR-3M reactor of the Japan Atomic Energy Agency. We applied MPGA method to geochemical and cosmochemical samples to evaluate its analytical performance on signal to noise (S/N) ratio, sensitivity, and detection limit. The S/N ratio measured by MPGA system was larger than that by normal prompt gamma ray activation analysis (PGAA) at JRR-3M. For some elements, the S/N ratio was improved more than ten times. Several elements that are not detected by PGAA were detected by MPGA. At the present time, concentrations of major elements and trace elements with high neutron capture cross section in geochemical and cosmochemical samples were determined accurately by the MPGA system installed at JRR-3M. It is expected that it will determine a lot of trace elements after appropriate adjustments and modifications.     

Thermal decomposition kinetics and compatibility studies of primaquine under isothermal and non-isothermal conditions

Primaquine (PQ) is the drug of choice for the radical cure of Plasmodium vivax malaria, and currently being administered in solid dosage form. In this study, the compatibility studies were carried out using differential scanning calorimetry (DSC), thermogravimetry (TG), and fourier transformed infrared (FT-IR). Non-isothermal and isothermal methods were employed to investigate kinetic parameters under nitrogen and air atmospheres using TG. The DSC investigations obtained by physical mixtures showed slight alterations in the melting temperatures of PQ with some excipients. The FT-IR confirmed the possible interactions obtained by DSC for the physical mixtures with PQ and lactose, magnesium stearate and mannitol. The results showed that the thermal decomposition followed a zero order kinetic in both atmospheres in non-isothermal method. The activation energy in both methods using nitrogen atmosphere was similar, and in air atmosphere the activation energy decreased.     

Electrosynthesis of cholesta-4,6-dien-3-one from cholesterol on a laboratory synthetic scale

Cholesterol has been shown to be electrochemically oxidized at a carbon electrode to form cholesta-4,6-dien-3-one in acetonitrile [Hosokawa, Y. Y.; Hakamata, H.; Murakami, T.; Aoyagi, S.; Kuroda, M.; Mimaki, Y.; Itoh, A.; Morosawa, S.; Kusu, F. Electrochim. Acta, 2009, 54, 6412-6416]. To further expand on this reaction in the field of organic synthesis, the electrolysis conditions of cholesterol were optimized on a laboratory synthetic scale. Using a flow-through column electrolysis system, cholesta-4,6-dien-3-one was efficiently produced at the applied potential of 1.9 V versus Ag/AgCl with a flow rate of 2.5 mL/min, providing a green tool for the synthesis of cholesta-4,6-dien-3-one.     

Electrochemical fabrication of single-walled carbon nanotubes-DNA complexes by poly(ethylenedioxythiophene) and photocurrent generation by excitation of an intercalated chromophore

It was found that single-walled carbon nanotubes (SWNTs) solubilized into water by complexation with DNA (salmon testes) can be readily deposited on the ITO electrode by electrochemical oxidative polymerization of ethylenedioxythiophene (EDOT). The driving force for this novel deposition is an electrostatic interaction between the anionic charges of wrapping DNA and the cationic charges of poly(EDOT) formed in the oxidative polymerization process. The presence of poly(EDOT), SWNTs and DNA in the composite was confirmed by measurements of UV-Vis, IR, resonance Raman spectra, cyclic voltammetry (CV) and confocal laser scanning microscopy (CLSM). The composite adsorbed a DNA intercalator (ethidium bromide: EB) very efficiently, which is regarded to be further evidence for inclusion of DNA. The surface morphology, characterized by CLSM, SEM and AFM, featured the network structure consisting of 0.5-ca. 10 microm nanorods. Very interestingly, we found that photoexcitation of EB bound to the DNA generates the photocurrent, indicating that the excited energy of EB is injected into SWNTs, which is collected by the electroconductive poly(EDOT) film on the ITO electrode. We believe, therefore, that the present system is a very convenient method to explore new materials related to redox and photochemical functions.