Asymmetric synthesis of γ-alkayl-α-methylene-γ-butyrolactones via 1,6-remote induction using 2-[(tributylstannyl) methyl]propenamides

Reaction of chiral 2-[(tributylstannyl)methyl]propenamides with aldehydes proceeded with 1,6-asymmetric induction to give, after hydrolysis, α,-methylene-γ-butyrolactones in enantiomeric excesses as high as 80%.     

A general method for the synthesis of 3,4-epoxy-2-methylenealkanoic acid derivatives using dianion of N-phenyl-2-(phenylsulfonylmethyl)-propenamide

A general procedure has been developed for the synthesis of 3,4-epoxy-2-methylenealkanoic acid derivatives using dianion of N-phenyl-2-(phenylsulfonylmethyl)propenamide and aldehydes.     

Application of liquid-crystal thermometry to drop temperature measurements

A technique has been developed that enables remote sensing of the temperatures of liquid drops in a medium of an immiscible, transparent liquid with the aid of dispersing microcapsules of thermochromic liquid crystal in each drop under illumination by either a planar floodlight or a light sheet which cuts the drop at a meridian. Based on appropriate hue-temperature calibrations made with an isothermal, stationary drop/medium system, one can analyze spatial and time variations of temperature within drops in motion under transient convective heating (or cooling) from the medium.List of Symbols B tristimulus blue component - D drop diameter - G tristimulus green component - H hue angle - h ₀ constant term in the expression for H - H _m mean value of H over drop surface - h vertical coordinate fixed onto test column - R tristimulus red component - Re drop Reynolds number, UD/v _c - r, g, b chromaticity coordinates - r drop radius - s penetration depth of light into drop - T temperature - T _d instantaneous drop temperature - T _d0 initial drop temperature - T _c continuous-phase temperature - U velocity of rise of drop - z vertical coordinate laid on drop - v _c kinematic viscosity of continuous phase - angle of lighting measured from camera axis - _s local view angle (azimuth) - polar angle     

13C-NMR Study of Anomalous Linkages in Polyurethane

Several kinds of model compounds for anomalous linkages in polyurethanes (branching or crosslinking; allophanate and biuret) were prepared. The phenylisocyanate (PHI) based models were identified by IR and NMR. The ¹³C-NMR chemical shifts effects due to the anomalous linkages were determined. The 4,4′-diphenylmethane diisocyanate (MDI) based models were purified incompletely but the characteristic signals of the aromatic carbons were nevertheless found in their spectra. Two types of segmented polyurethane (SPU) were prepared and the anomalous linkages were investigated by ¹³C-NMR. The signals due to the allophanate (Al) and the triphenylbiuret (TB) linkages were observed in the spectra of the SPU prepared at high temperature (>80°C) or prepolymer gels yielded by abnormal reaction. A small signal due to a phenyl carbon of biuret (Bi) linkage was observed even in a normally prepared SPU (polyetherurethane-urea). Employing the phenyl carbon signals was advantageous for the determination of anomalous linkages because of their larger intensities.     

A stereochemically accurate chemical substance database based on the systematic names of organic compounds. 1. Low molecular weight organic compounds

A chemical substance database, containing chemical structures generated automatically from their IUPAC systematic names, is described. The structure generation program can convert the names of natural products, peptides, and stereochemically complex names into stereochemically correct connection tables. More than 300,000 commonly encountered compounds are stored in the database and are publicly accessible through the JOIS-F online system, which also offers mass spectral, thermochemical, and other factual databases.     

Tritium concentrations of river water on northern and southern islands of Japan

Tritium concentrations were measured for river waters on two islands in Japan. Significant difference was observed on the distribution of tritium concentrations on both islands, the river water samples from the northern island had higher concentrations and the average was about twice compared to that from the southern island. Higher tritium concentration in precipitation and the larger area of the northern island would be responsible for higher tritium concentrations in river waters.     

THE WHITE MEMBRANE OF CRYSTALLINE BACTERIOOPSIN IN HALOBACTERIUM HALOBIUM STRAIN R1mW AND ITS CONVERSION INTO PURPLE MEMBRANE BY EXOGENOUS RETINAL

Abstract— A new strain isolated from Halobacterium halobium designated R₁mW, contained negligible amounts of isoprenoid pigments, had a yellowish white color due to respiratory pigments and showed no proton movement in response to light. However, addition of all-trans-retinal converted R₁mW into purple cells. Formation of both halorhodopsin and bacteriorhodopsin was indicated by induction of light-dependent proton uptake and release, respectively. Both haloopsin and bacterioopsin were thus postulated to be present in R₁mW. Electron micrographs of freeze-fractured cytoplasmic membranes revealed patches in a hexagonal array of trimeric particles, comparable to the purple membrane structure. These white membrane patches were isolated by procedures similar to those for the purple membrane. The white membrane's buoyant density was about 1.18 g/m/, and its main component migrated on sodium dodecylsulfate polyacrylamide gels at the same rate as bacteriorhodopsin. The white membrane showed only a small absorption peak at ～410nm due to contaminating respiratory pigments and a strong absorption at around 275 nm and shorter wavelengths. The white membrane was thus considered to be mainly composed of bacterioopsin, which was readily converted into bacteriorhodopsin by an addition of all-trans-retinal. The absorption and CD spectra of the white membrane were measured before and after addition of retinal. The molar extinction coefficient of dark-adapted bacteriorhodopsin formed was determined to be 53000M^?1 cm^?1 at 560 nm from retinal binding studies. The CD spectrum of the white membrane was negligible in the visible region but showed several bands assigned to aromatic and backbone structures in the UV region. Retinal addition caused considerable changes in the spectrum, yielding the CD spectrum of crystalline purple membrane bacteriorhodopsin. The white membrane thus appears to be a preparation suitable for structure-function studies of bacteriorhodopsin.     

Quinolone analogues 8 [1‐6]. Synthesis of 3‐aminopyridazino‐[3,4‐b]quinoxalin‐4(lH)‐one

The 3‐amino‐1‐methylpyridazino[3,4‐b]quinoxalin‐4(1H)‐one 6 and N‐(1,4‐dihydro‐1‐methyl‐4‐oxopyridazino[3,4‐b]quinoxalin‐3‐yl)carbamates 17a,b were synthesized from the 1,4‐dihydro‐1‐methyl‐4‐oxopyridazino[3,4‐b]quinoxa‐line‐3‐carboxylate 1b via the 1,5‐dihydro‐4‐hydroxy‐1‐methylpyridazino[3,4‐b]quinoxaline‐3‐carbohydrazide 13b and then 1,4‐dihydro‐1‐methyl‐4‐oxopyridazino[3,4‐b]quinoxaline‐3‐carboxazide 8 . Heating of compound 13b and arylalde‐hydes afforded the 1,4‐dihydro‐1‐methyl‐4‐oxopyridazino[3,4‐b]quinoxaline‐3‐carbo(2‐arylmethylene)hydrazides 14a‐d.     

Recent environmental tritium levels in Japan-II Coastal seawater and lake water

Tritium concentrations were analyzed for coastal seawater and lake water collected from various places in Japan. Low tritium concentrations were observed for coastal seawater of small islands and it was attributed to a short residence time of the ground-water in such a small island. Tritium concentrations in lake water showed a significant variation. And it was revealed that the size of the lake and its drainage area were the dominant factors controlling the tritium concentrations in lakes.