Arihiro Yashiro

Syntheses and Biological Evaluations of α-d-Mannosyl [60]fullerenols

[60]Fullerenols carrying mono- and bis-alpha-D-mannosyl linkages on the surface were prepared via a [3+2]-cycloaddition reaction between 2-azidoethyl alpha-D-mannoside and C(60) followed by polyhydroxylation with aqueous NaOH. Their biological activity was evaluated in terms of binding affinity to lectins by hemagglutination assay and surface plasmon resonance. [60]Fullerenols without the mannosyl linkage caused aggregation of erythrocytes and binding to a beta-D-galactopyranoside specific lectin (RCA(120)). In contrast, mono- and bis-mannosyl fullerenols were found to decrease the activity for both aggregating erythrocytes and binding to RCA(120), and mono-mannosyl fullerenols turned to binding to alpha-D-mannose specific lectin (Con A).

Fullerene glycoconjugates: A general synthetic approach via cycloaddition of per-O-acetyl glycosyl azides to [60]fullerene

Abstract A general synthetic way to incorporate oligosaccharides into [60]fullerene via cycloadditon and deacetylation is presented. The cycloaddition reaction in refluxing chlorobenzene gave a mixture of two unseparable stereoisomers of N-β-glycopyranosyl [5,6]-azafulleroids in 13∼28% yields for per-O-acetyl glycosyl azide of d -glucopyranose, d -galactopyranose, lactose, maltose, and maltotriose.

Syntheses and EELS characterization of water-soluble multi-hydroxyl Gd@C82 fullerenols

Abstract Various water-soluble multi-hydroxyl fullerenes (fullerenols), C60(OH)n, C70(OH)n and C84(OH)n, and a Gd metallo-fullerenols, Gd@C82(OH)n have been synthesized by the Kitazawa method. Elementary chemical analyses indicate that all of these fullerenols have 30–40 hydroxyl groups and 11–15 coordinated water molecules via hydrogen bonds. Electron energy loss spectroscopy (EELS) on Gd@C82 fullerenols shows that the π ∗ peak area in the C K-edge spectra decreases on going from intact Gd@C82 metallofullerene to Gd@C82 fullerenols, indicating an increase in sp3 character of the fullerenols. Furthermore, Gd M4,5-edge EELS spectra show that the encapsulated Gd atom has a trivalent Gd3+ state.

Base-catalysed oxidative [3 + 2]cycloaddition reaction of [60]fullerene with β-dicarbonyl compounds

The ambiphilic nature of β-keto esters and β-diketones allows cycloaddition to C60 in the presence of piperidine to give dihydrofuran-fused C60 derivatives via oxidative cyclization complimentary to the concerted process.

Synthesis of Heterocycle-Containing [60]Fullerene Derivatives

Abstract Fullerene functionalization with heterocycles is reviewed, focusing attention on cycloaddition methodology and oxidative heterocyclization. 1 1This paper was presented before the Symposium 3 on ‘Expanded Horizons of Fullerene Science and Technology’ organized by L. Y. Chiang, E.Osawa, H. Terrones and M. Saunders at the 4th International Conference on Advanced Materials (ICAM-IV), Aug. 27 to Sept. 1, 1995, Cancun, Mexico.

Unusual redox-type addition of nitroalkanes on the C60 surface

Nitroethanes underwent base-catalyzed addition to C60 to give 2-hydroxy-1,2-dihydrofulleryl ketoximes by way of a unique intramolecular redox process, which is not observed in normal alkenes.