Optics of nuclear diffraction with synchrotron radiation using α-57Fe2O3 single crystals

Nuclear Bragg diffraction of synchrotron radiation with -⁵⁷Fe₂O single crystals has achieved a counting rate as high as 20,000 cps at the accumulation ring AR of TRISTAN, KEK. The development of crystal optics using nuclear monochromators is described. Topographic images of -⁵⁷Fe₂0 nuclear diffraction has been observed.     

Practical optical resolution of dl-muscone using tartaric acid derivatives as a chiral auxiliary

A simple and practical synthesis of (R)-(−)-muscone was achieved by optical resolution of dl-muscone using tartaric acid derivatives. The acetalization of dl-muscone with N,N′-dibenzyl-l-tartaramide in the presence of Sc(OTf)₃ and methyl orthoformate furnished a diastereomeric mixture of acetals, which were readily separated by simple recrystallization. Diastereomerically pure acetal was hydrolyzed to give optically pure muscone and recovered N,N′-dibenzyl-l-tartaramide.     

Characterization of perovskite related oxides by nuclear resonance inelastic scattering of synchrotron radiation

Resonant nuclear inelastic scattering (NIS) spectra of (Sr,Ca)(Fe,Co)O_{3- d} and (Ba,Ca)(Fe,Co)O_{3- d} were measured with the energy resolution of 3.5 MeV by detecting the 6.3 keV Fe K_a X-rays following after Mössbauer effect on ⁵⁷Fe transition excited by the monochromatized 14.41 keV synchrotron radiation. Both series of oxides annealed in air and in CO₂ were examined. Soft phonon peak arising at ~8 MeV in NIS spectra of (Sr_0.5Ca_0.5)(Fe_0.5Co_0.5)O_{3- d} and (Ba_0.5Ca_0.5)FeO_{3- d} was found to be correlated with the oxygen ordering into brownmillerite structure, whereas more complex multi-phonon structure was observed in the spectra of less oxygen-deficient oxides such as (Sr_0.95Ca_0.05)(Fe_0.5Co_0.5)O_{3- d} and (Sr_0.7Ca_0.3)(Fe_0.5Co_0.5)O_{3- d} showing rather random distrubution of the oxygen vacancies. The changes in phonon DOS after CO₂ absorbtion were also detected. Lam-Mössbauer factors of these oxides were calculated on the base of Debye Model.     

Conjugate addition to chiral γ-heterosubstituted δ-lactones as pivotal synthons from L-glutamic acid. Synthesis of an optically active lignan lactone; (−)-hinokinin

Asymmetric induction in conjugate addition of new chiral γheterosubstituted-,β-unsaturated -lactones from L-glutamic acid was accomplished in high diastereoselectivity with the formation of trans(R,S)-adducts and was disclosed to serve as a versatile procedure for the asymmetric synthesis of antileukemic lignan lactones.     

Synthesis and molecular characterization of A-B-A type block copolymer consisting of poly(γ-benzyl l-glutamate) as the a component and polyisoprene as the B component

A-B-A type block copolymers (GIG) composed of poly(γ-bezyl l-glutamate) (PBLG) as the A component and polyisoprene (PI) as the B component were prepared. The method of synthesis consists of the polymerization of the γ-benzyl l-glutamate N-carboxy anhydride initiated by the amine groups capped at both ends of the PI block which has a moderate degree of polymerization. When dissolved in a helicogenic solvent, such as N,N′-dimethylformamide (DMF) or ethylene dichloride (EDC), the GIG is expected to take a conformation which may be pictured as two rigid blocks linked by a flexible joint, since the PI block portion is intolerant of intrachain hydrogen bonding. Hence, the GIG block copolymers would be considered as a macromolecular model of a once-broken rod with equal rod sections, if the molecular weight of the PBLG portion was relatively much higher than that of the PI portion. After molecular characterization on GIG by the circular dichroism measurement, the viscosity behavior in a helicogenic solvent was determined, and the result was compared with the corresponding data on PBLG, which assumes the form of a straight rod in a helicogenic solvent. It was found that the value of [η] of GIG block copolymers was about 5/8 of those of PBLG of the equal molecular weight. This finding is in good agreement with the theoretical prediction.     

Resin glycosides. XV. Simonins I-V, ether-soluble resin glycosides (jalapins) from the roots of Ipomoea batatas (cv. Simon).

Five new ether-soluble resin glycosides (jalapins), simonins I-V, have been isolated from the roots of Ipomoea batatas and characterized on the bases of chemical and spectral data. Simonin I is the first example of resin glycoside with aromatic acid (trans-cinnamic acid) as a component organic acid.     

One pot synthesis using supported reagents system KSCN/SiO2-RNH3OAc/Al2O3: synthesis of 2-aminothiazoles and N-allylthioureas

A simple and efficient method has been developed for the synthesis of 2-aminothiazoles and N-allylthioureas from commercially available materials in one pot by using a supported reagents system, KSCN/SiO₂-RNH₃OAc/Al₂O₃, in which α-halo ketone reacts first KSCN/SiO₂ and the product, α-thiocyanatoketone, reacts with RNH₃OAc/Al₂O₃ to give the final product, 2-aminothiazoles, in good yield and allyl bromide reacts with KSCN/SiO₂ and the product, allyl isothiocyanate, reacts with RNH₃OAc/Al₂O₃ to give N-allylthiourea.     

Detailed process of adsorption of alkanes and alkenes on zeolites

The adsorption of alkanes and alkenes on zeolites is investigated by comparing the adsorption characteristics for three types of zeolite: ferrierite, ZSM-5, and mordenite. The activation energy for the diffusion of propane and n-butane on ferrierite and the heat of adsorption of C(2)-C(4) alkanes and alkenes on zeolites and silica are estimated based on Fourier transform infrared spectroscopy, and the diffusion processes in the micropores are elucidated by comparing the results with previously reported activation energies for n-butene diffusion. The adsorption of 1-butene on mordenite is also examined. The structure and process of experimentally observable adsorption is found to differ depending on the type of zeolite and adsorbing molecule, reflecting differences in the sizes of molecules and pores. This differing behavior is utilized to interpret the elementary adsorption processes of alkanes and alkenes on zeolites.