Toshiyasu Inuzuka

Chemical studies on Goniothalamus tapis Miq.

Ten secondary metabolites were identified from Goniothalamus tapis Miq. The structures of these compounds were elucidated using spectroscopic analyses. It was revealed for the first time that 3-methyl-1H-benz[f]indole-4,9-dione was produced by the organism.

Molecular shape of palytoxin in aqueous solution

Palytoxin, one of the most toxic non-peptide substances, formed an associated dimer of 5 nm length in aqueous solution.

Indium-Catalyzed Amide Allylation of N-Carbonyl Imides: Formation of Azaspiro-γ-lactones via Ring Opening–Reclosure

A novel and facile synthesis of azaspiro-γ-lactones with a methylene-lactam framework from N-carbonyl imides is described. Mechanistic investigations provide evidence for a two-step reaction process involving ZnCl(2)-promoted addition of β-amido allylindium species followed by an unexpectedly molecular-sieves-mediated ring opening-reclosure concomitantly with the loss of an N-carbonyl unit.

Recent insights into natural venoms

Toxic substances that occur in nature have various structures and functions. In fact, the very novelty of their structures and functions sometimes extends far beyond the realm of human imagination, and the capabilities of these compounds are still largely untapped despite the major advances of modern science. In this report we focus on the most recent developments in this field, with a particular emphasis on natural venoms, marine sunscreen, and marine huge molecules.

Wide-Range Near-Infrared Sensitizing 1H-Benzo[c,d]indol-2-ylidene-Based Squaraine Dyes for Dye-Sensitized Solar Cells

NIR absorbing squaraine dyes SQ1-SQ7 having 1 H-benzo[ c, d]indol-2-ylidene as a donor moiety were designed for application in DSSCs. Annulation of the benzene ring to an 3 H-indolium-based anchor moiety led to a red-shifted and broadened absorption band on TiO2 film, which were reflected in the improved short-circuit current density of SQ2 (6.22 mA cm-2) compared to the nonbenzene fused derivative SQ1 (4.39 mA cm-2). Although the introduction of a butoxy (SQ4: 806 nm) or dialkylamino group (SQ5-SQ7: 815-820 nm) to the 1 H-benzo[ c, d]indol-2-ylidene-based donor moiety resulted in red-shifted absorption maxima in ethanol compared to the nonsubstituted derivative SQ2 (784 nm), the HOMO energy level of SQ4-SQ7 gave rise to an undesirable approximation to the redox potential of I-/I3-. Thus, the butoxy (SQ4: 0.56) and dialkylamino (SQ5-SQ7: 0.25-0.30) derivatives had relatively lower conversion efficiencies. Since the 2-ethylhexyl derivative SQ3 exhibited red-shifted absorption (λmax: 796 nm), suitable HOMO and LUMO energy levels, and relatively efficient restriction of charge recombination, this dye achieved the highest conversion efficiency (1.31%), along with a high IPCE response of over 20% over a wide range from 640 to 860 nm and an onset of IPCE at 1000 nm.

Controllable monobromination of perylene ring system: synthesis of bay-functionalized perylene dyes

Practical synthesis of bay-monofunctionalized perylene dyes has been developed based on controllable NBS bromination of tetrabenzyl perylene-3,4,9,10-tetracarboxylate. The ability to perform the convenient and high-yielding synthesis highlights the potential utility of our multifunctional approach to access a diverse range of new perylene systems.

New Synthetic Methodology toward Macrolides/Macrolactams via Palladium-Catalyzed Carbon―Heteroatom Bond-Forming Reactions

A concise and versatile syntheses of 11—16—membered macrolides and 13―15-membered macrolactams have been achieved using a Tsuji―Trost type reaction. This approach is composed of intramolecular cyclization employing ethyl carbonate with carboxylic acids and catalytic amount of Pd(PPh 3 ) 4 to form carbon― heteroatom covalent bonds with no use of stoichiometric reagents.