Preparation of optically active allylsilanes by catalytic asymmetric hydrosilylation of 1-arylbutadienes1

Asymmetric hydrosilylation of 1-arylbutadienes with trichlorosilane in the presence of a chiral ferrocenylphosphine-palladium catalyst gave optically active allylsilanes, ($\text{Z}$)-1-aryl-1-silyl-2-butenes and their regioisomers.     

Synthesis and antibacterial activity of 2-phenyl-4H-benzo[b]thiopyran-4-ones (Thioflavones) and related compounds

A number of 2-phenyl-4H-benzo[b]thiopyran-4-ones (thioflavones) and related compounds have been prepared to test their antibacterial activity. The flavone derivatives were also prepared to compare with their antibacterial activity. It was found that hydroxythioflavones were easily prepared by demethylation of methoxythioflavones with aluminium chloride. In the test of antimicrobial activity, methoxy- or hydroxythioflavones were found to be inactive. It is suggested that the sulfone or sulfoxide of thioflavone is required for antimicrobial activities against yeast funguses and molds. These thioflavone derivatives exhibit low acute toxicity.     

Errata to “A revised taxonomy of the ammonoid genus Desmoceras from Japan and southern Sakhalin”: [Proc. Jpn. Acad., Ser. B 80, No. 5, 225–229 (2004)]

Based on the stratigraphically well sorted material from Japan and southern Sakhalin, the ammonoid species belonging to the genus Desmoceras are classified as follows in ascending order: D. latidorsatum (Michelin) (Middle to mid-Upper Albian), D. dawsoni shikokuense (Yabe and Shimizu) (Upper Albian), D. kossmati Matsumoto (uppermost Albian–Lower Cenomanian), D. japonicum Yabe (uppermost Albian–Cenomanian), and D. ezoanum Matsumoto (mid-Upper Cenomanian–mid-Lower Turonian). D. japonicum can be subdivided into the earlier and later subspecies. D. poronaicum Yabe is a junior synonym of D. japonicum. Despite the scarcely ornamented shell, each taxon can be defined by its own characters.     

Sound attenuation by multiple barriers

A method (tentatively called ‘the method of equivalent sound source’) of predicting the sound attenuation achieved by multiple barriers with knife edges and/or right-angled wedges is proposed. This paper shows that the sound pressure level in the shadow region behind the multiple barriers can be obtained by successively setting imaginary sound sources for respective edges and/or wedges. The locations of the imaginary sound sources are determined by means of the traditional solution for sound attenuation by a single edge. The calculated results for several kinds of small-scale model, obtained by ‘the method of equivalent sound source’, are compared with experimental results.     

Noise reduction by various shapes of barrier

This paper shows that noise reduction by various shapes of finite barrier can be achieved by applying the Fresnel-Kirchhoff diffraction theory and primarily follows the ideas of Maekawa.¹ The calculated results for several kinds of small-scale model, obtained by our procedure, are compared with experimental results.     

Asymmetric hydrosilylation of olefins catalyzed by a chiral ferrocenylphosphine-palladium complex. Asymmetric synthesis of optically active alcohols and bromides from olefins

Optically active norbornyl and 1-phenylethyl alcohols and bromides were obtained, respectively, from norbornyl- and 1-phenylethylpentafluorosilicates which were prepared by asymmetric hydrosilylation of norbornene and styrene with trichlorosilane catalyzed by a chiral ferrocenylphosphine-palladium complex followed by treatment with potassium fluoride.     

On the orientational relationship between eutectic α-Fe2Si5 and ϵ-FeSi

The undirectional solidification of the eutectic between α-Fe₂Si₅ and ?-FeSi was carried out. The temperature gradient at the liquid-solid interface was 70°C/cm. Microstructures of the aligned composite were fibrous and lamellar, for last and slow growth rates respectively. The growth direction of α and the preferred axial orientation relationships between α and ? were determined for both structures.