Asymmetric Three-Component Coupling Reaction of Alkyne, Enone, and Aldehyde Catalyzed by Chiral Phebox Ruthenium Catalysts

Catalytic asymmetric three-component coupling reactions of terminal alkynes, α,β-unsaturated ketones, and aldehydes were studied. The chiral ruthenium complexes containing bis­(oxa­zolinyl)­phenyl ligands were found to serve as efficient catalysts for a tandem reaction based on conjugate addition of terminal alkynes to α,β-unsaturated ketones and subsequent aldol reaction with aldehydes, giving β-hydroxyketone derivatives containing α-propargyl groups in high yields with moderate to good enantioselectivities. This method can produce various functional molecules from commercially available substrates in a one-pot procedure. The absolute configuration of the major product was determined by X-ray analysis. The control experiments suggested that a ruthenium enolate species generated in situ by conjugate addition could be involved as an intermediate for the aldol coupling with an aldehyde

Asymmetric Three-Component Coupling Reaction of Alkyne, Enone, and Aldehyde Catalyzed by Chiral Phebox Ruthenium Catalysts

Catalytic asymmetric three-component coupling reactions of terminal alkynes, α,β-unsaturated ketones, and aldehydes were studied. The chiral ruthenium complexes containing bis­(oxa­zolinyl)­phenyl ligands were found to serve as efficient catalysts for a tandem reaction based on conjugate addition of terminal alkynes to α,β-unsaturated ketones and subsequent aldol reaction with aldehydes, giving β-hydroxyketone derivatives containing α-propargyl groups in high yields with moderate to good enantioselectivities. This method can produce various functional molecules from commercially available substrates in a one-pot procedure. The absolute configuration of the major product was determined by X-ray analysis. The control experiments suggested that a ruthenium enolate species generated in situ by conjugate addition could be involved as an intermediate for the aldol coupling with an aldehyde

Levels of Tetrodotoxins in Spawning Pufferfish, <i>Takifugu alboplumbeus</i>

Tetrodotoxin (TTX), also known as pufferfish toxin, is an extremely potent neurotoxin thought to be used as a biological defense compound in organisms bearing it. Although TTX was thought to function as a chemical agent for defense and anti-predation and an attractant for TTX-bearing animals including pufferfish, it has recently been demonstrated that pufferfish were also attracted to 5,6,11-trideoxyTTX, a related compound, rather than TTX alone. In this study, we attempted to estimate the roles of TTXs (TTX and 5,6,11-trideoxyTTX) in the pufferfish, Takifugu alboplumbeus, through examining the location of TTXs in various tissues of spawning pufferfish from Enoshima and Kamogawa, Japan. TTXs levels in the Kamogawa population were higher than those in the Enoshima population, and there was no significant difference in the amount of TTXs between the sexes in either population. Individual differences were greater in females than in males. However, the location of both substances in tissues differed significantly between sexes: male pufferfish accumulated most of their TTX in the skin and liver and most of their 5,6,11-trideoxyTTX in the skin, whereas females accumulated most of their TTX and 5,6,11-trideoxyTTX in the ovaries and skin

A Study of the Modern Public Sphere and Communication : The Case of NANOHANA Project

滋賀県東近江市(旧愛東町)から全国に展開した「菜の花プロジェクト」による循環型地域社会形成の試みを採り上げ、現代の公共圏とコミュニケーションのあり方について、ハーバーマス(Jürgen Habermas)の「市民的公共圏(性)」の概念に基づく分析を行った。具体的には、市民的公共圏には、対等性・柔軟性・公開性という3つの基準があることに着目し、菜の花プロジェクトが、「対等性」の面では多様な主体の参加とその促進、「柔軟性」の面では地域の問題解決の枠組みの住民への開放、「公開性」の面ではウェブサイトを通じた情報公開や、研究交流イベントのオールセッション型の開催などを通じ、3つの基準を満たすことを検証した。また、現代の市民的公共圏の複合化という状況において、菜の花プロジェクトが「地域」と「全国」、あるいは「市民と市民」「専門家と専門家」と「市民と専門家」間の「二層のコミュニケーション」を維持することで、生活世界との関係を保ち、3つの基準を維持していることを明らかにした。以上のことから、現代の市民的公共圏の形成・存続には、親密圏たる生活世界に根づいた継続的なコミュニケーションのある活動から立ち上がっていること、対等性・柔軟性・公開性の3つの基準を満たしていること、自らの複合化を受け入れ発展させつつ、その中で二層のコミュニケーションを維持していくことが必要であると考える。研究ノート(Note

Crystallization and preliminary neutron diffraction studies of HIV-1 protease cocrystallized with inhibitor KNI-272

In order to determine the protonation states of the residues within the active site of an HIV-1 protease–inhibitor complex, a crystal of HIV-1 protease complexed with inhibitor (KNI-272) was grown to a size of 1.4 mm3 for neutron diffraction study. The crystal diffracted to 2.3 Å resolution with sufficient quality for further structure determination