Hydrophobicity parameters determined by reversed-phase liquid chromatography. XVI: A new hydrogen-accepting parameter for monosubstituted thiophenes and furans for correlating retention factors and octanol-water partition coefficients

We recently proposed a new hydrogen-accepting parameter, S(HA), for monosubstituted (di)azines on the basis of the heat of formation calculated by the conductor-like screening model (COSMO) method. In this work, S(HA) values for monosubstituted thiophenes and furans were calculated and the results were applied to the analysis of relationships between log P (P: 1-octanol/water partition coefficient) and log k (k: retention factor obtained by reversed phase HPLC). The S(HA) parameter was found to work effectively as a hydrogen-bonding parameter in a range of heteroaromatic compounds.     

Sensing capabilities of colloidal gold modified with a self-assembled monolayer of a glucose-carrying polymer chain on a glass substrate

A disulfide-carrying polymer with pendent glucose residues (poly(2-methacryloyloxyethyl D-glucopyranoside)) was obtained by using a benzyl N,N-diethyldithiocarbamoyl derivative which shows the abilities of initiation, chain transfer, and termination (iniferter). The disulfide-carrying polymer was accumulated on a colloidal Au-immobilized glass substrate, and the usefulness of the polymer as a sensing element of concanavalin A (Con A) was examined by using a UV-visible spectrophotometer with the help of surface plasmon resonance. The sensor showed a concentration-dependent specific binding of Con A with a detection limit of 1.9 nM, and furthermore, it had a very high stability at high ionic strength. The polymer-coated device examined here was not only useful as a simple biosensor chip but is also expected to expand our knowledge of interfacial phenomena by introducing various functional polymers on colloidal Au.     

On the reaction mechanism of gamma-ray solid-state copolymerization

The gamma-ray induced solid-state polymerization of binary mixtures consisting of a maleimide derivative as the first component and acenaphthylene or trans-stilbene as the second component was investigated regarding the occurrence of copolymerization. The binary solid mixture of these compounds exhibited a phase-equilibrium diagram including a simple eutectic mixture, and the irradiation caused the formation of a random copolymer together with that of homopolymers of component comonomers. The reaction rates and the composition of products suggested that the mobility of monomer molecules in the crystals affected the solid-state polymerization significantly. The solid-state copolymerization was supposed to take place by the diffusion of comonomer molecules via a vapor phase to the nuclei where the copolymerization proceeded.     

A novel catalyst containing a platinum complex in polyethylene glycol medium supported on silica gel for vapor-phase hydrosilylation of acetylene with trichlorosilane or trimethoxysilane

Hydrosilylation of acetylene with trichlorosilane or trimethoxysilane was carried out using a vapor-phase flow reactor with use of tetraammineplatinum(II) chloride in polyethylene glycol medium supported on silica gel as a catalyst, which is an active and thermally stable supported liquid-phase catalyst prepared readily from easily available materials, tetraammineplatinum(II) chloride, polyethylene glycol and silica gel.     

Chemical structure of poly(trisubstituted vinylsilane) produced by γ irradiation

The chemical structure of polymers produced by the γ irradiation of monovinylsilanes was studied. γ-ray addition polymerization of monovinylsilanes such as trialkylvinylsilane was very slow, and only the liquid oligomers were formed from them by large radiation dose. The presence of silethylene or silmethylene linkage was ascertained in these polymers by infrared absorption spectroscopy and ¹H-NMR measurement, even when no Si? H bond existed in the monomers. The polymers were supposed to be produced by addition polymerization with intervening silalkylene linkage.     

Synthesis of quinazoline derivatives through anionic cycloaddition reactions of methyl 2,4-dimethoxy-6-methyl-5-pyrimidinecarboxylate with acetylenes and olefins

The anionic cycloaddition of methyl 2,4-dimethoxy-6-methyl-5-pyrimidinecarboxylate has been investigated. The lithium salt of methyl 2,4-dimethoxy-6-methyl-5-pyrimidinecarboxylate, generated by deprotonation with lithium diisopropylamide in ether at – 70°, reacted smoothly with electron deficient acetylenes and olefins to give quinazoline derivatives in a single step.     

Infrared characteristic bands of highly dispersed silica

Summary Infrared studies were carried out for several silica modifications. On powdering bulk silica in air, new bands were observed to appear at 3400 cm⁻¹ and 950 cm⁻¹ irrespective of its inner crystallographic structure. In addition to the bands observed for bulk silica, bands were observed for silica gel at the following frequencies: 3400, 1650, 1120, 950, and 870 cm⁻¹. Assignment of these band was made by using a deuteration technique and by preparing a transparent film of silica gel on a rock salt plate from tetramethoxy-silane and water vapor. The band at 3400 cm⁻¹ is νOH of silanol or sorbed water; 1650 cm⁻¹, δOH of sorbed water; 1120 cm⁻¹, δOH of silanol; 950 cm⁻¹,ν SiO of slanol; 870 cm⁻¹, νSiOSi of bridged ≡SiOSi≡ link on the surface.

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Zusammenfassung Es wurden Infrarot-Untersuchungen an verschiedenen Silica-Modifikationen ausgeführt. Wenn man festes Silica an Luft pulvert, werden neue Banden bei 3400 cm⁻¹ und 950 cm⁻¹ unabh?ngig von der inneren Kristallstruktur beobachtet. Zus?tzlich zu diesen Banden ergeben sich weitere in Silica-Gel bei den Frequenzen 3400, 1650, 1120, 950 und 870 cm⁻¹. Die Zuordnung dieser Banden lie? sich mit Deuterierungs-methode und durch Herstellung transparenter Filme von Silica-Gel auf Steinsalzplatten aus Tetramethoxysilan und Wasserdampf erreichen. Die Bande bei 3400 cm⁻¹ entspricht dem νOH von Silanol oder sorbiertem Wasser. 1650 cm⁻¹ dem δOH von sorbiertem Wasser, 1120 cm⁻¹ dem δOH von Silanol, 950 cm⁻¹ den δSiO vom Silanol, 870 cm⁻¹ dem νSiOSi der Brückenbindung an der Oberfl?che.

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The authors wish to express their thanks to Dr.Y. Miura, a chief of this Laboratory, for his encouragement in the course of this study, to Dr.I. Teraoka, a researcher of this Laboratory, for the preparation of sample and to Dr.R. Soda of the National Institute of Industrial Health, for his valuable discussions.     

Magnesium, parathyroid hormone and osteocalcin in the sera of hospitalized patients with chronic alcoholism

Levels of parathyroid hormone (PTH) and osteocalcin in hypomagnesemic sera of chronic alcoholism patients were carried out to evaluate the roles of chronic alcohol poisoning on bone metabolism. Serum gamma-GTP activity showed inverse relationships among serum Mg and osteocalcin in these patients and PTH levels were also more decreased in these patients than in healthy subjects. These results indicated that the direct actions of alcohol might be brought about by the deterioration of bone metabolism, due to the decrease of serum PTH and osteocalcin levels by chronic alcohol poisoning.     

Polycyclic N-heterocyclic compounds. XLV. Synthesis of 4-substituted 5,6-dihydrobenzo[h]quinazolines and 6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-d]pyrimidines and their inhibitory activity on platelet aggregation

The synthesis of 4-substituted 5,6-dihydrobenzo[h]quinazolines and 6,7-dihydro-5H-benzo[6,7]cyclohepta-[1,2-d]pyrimidines with substituents which are an electron-attracting group such as a nitrite, an amide, a thione, or a carboxyl group is described. Their inhibitory activity against collagen-induced platelet aggregation was also investigated.     

Near-field optical imaging of plasmon modes in gold nanorods

We have investigated optical properties of single gold nanorods by using an apertured-type scanning near-field optical microscope. Near-field transmission spectrum of single gold nanorod shows several longitudinal surface plasmon resonances. Transmission images observed at these resonance wavelengths show oscillating pattern along the long axis of the nanorod. The number of oscillation increases with decrement of observing wavelength. These spatial characteristics were well reproduced by calculated local density-of-states maps and were attributed to spatial characteristics of plasmon modes inside the nanorods. Dispersion relation for plasmons in gold nanorods was obtained by plotting the resonance frequencies of the plasmon modes versus the wave vectors obtained from the transmission images.