•Triarylantimony difluorides were synthesized by oxidative fluorination of triarylstibanes with NOBF4.•The antitumor activity of triarylantimony difluorides exhibited good anti-proliferation activity against tumor cell lines.•p-Tol3SbF2 exhibited the best antitumor activity among the compounds in this series.Triarylantimony difluorides were synthesized in moderate to excellent yields by oxidative fluorination of triarylstibanes with nitrosyl tetrafluoroborate (NOBF4) under aerobic conditions. This reaction is the first example of fluorination of trivalent organoantimony compounds using NOBF4 as a fluorinating agent. The triarylantimony difluorides exhibited good anti-proliferation activity against tumor cell lines. In particular, the IC50 of p-Tol3SbF2 (2c) was the lowest in each cell lines.Download high-res image (86KB)Download full-size image

The selective hydrogenation of aromatic compounds to cyclohexanes was found to be promoted by chitin-supported ruthenium nanoparticles (Ru/chitin) under near-neutral, aqueous conditions without the loss of C–O/C–N linkages at benzylic positions.

The interest in organic–inorganic hybrid molecules as molecular probes for biological systems has been growing rapidly. Such hybrid molecules exhibit unique biological activities. Herein, copper(II) bis(diethyldithiocarbamate) (Cu10) was found to activate the transcription factor NF-E2-related factor 2 (Nrf2), which is responsible for regulating antioxidant and phase II xenobiotic enzymes, in vascular endothelial cells. The copper complex rapidly accumulated within cells and induced nuclear translocation of Nrf2, leading to upregulation of the expression of downstream proteins without cytotoxic effects. However, while copper bis(2-hydroxyethyl)dithiocarbamate activated Nrf2, copper ion, diethyldithiocarbamate ligand with or without zinc or iron failed to exhibit this activity. Intracellular accumulation of Cu10 was higher than that of Cu(II) and Cu(I). While the accumulation of copper(II) bis(dimethyldithiocarbamate) was reduced by small interfering RNA (siRNA)-mediated knockdown of the copper transporter CTR1, the knockdown did not affect Cu10 accumulation, indicating that Cu10 rapidly enters vascular endothelial cells via CTR1-independent mechanisms. In addition, copper and iron complexes with other ligands tested could not activate Nrf2, suggesting that the intramolecular interaction between copper and dithiocarbamate ligand is important for the activation of the transcription factor. Cu10 induced the expression of heme oxygenase-1, NAD(P)H quinone oxidoreductase 1, and γ-glutamylcysteine synthetase, downstream proteins of Nrf2. It was suggested that Cu10-induced activation of Nrf2 was due to proteasome inhibition as well as binding to Kelch-like ECH-associated protein 1. Since the effects of Cu10 on vascular endothelial cells are unique and diverse, the copper complex may be a good molecular probe to analyze the functions of the cells.

Chitin-supported ruthenium (Ru/chitin) promotes the hydration of nitriles to carboxamides under aqueous conditions. The nitrile hydration can be performed on a gram-scale and is compatible with the presence of various functional groups including olefins, aldehydes, carboxylic esters and nitro and benzyloxycarbonyl groups. The Ru/chitin catalyst is easily prepared from commercially available chitin, ruthenium(III) chloride and sodium borohydride. Analysis of Ru/chitin by high-resolution transmission electron microscopy indicates the presence of ruthenium nanoparticles on the chitin support.

Water-soluble cobalt(III) porphyrin complexes were found to promote the hydration of terminal alkynes to give methyl ketones. The alkyne hydration proceeded in good to excellent yield with 0.1 to 2 mol % cobalt catalyst 1 and was compatible with the presence of acid/base- or redox-sensitive functional groups such as alkyl silyl ethers; allyl ethers; trityl ethers; benzyl ethers; carboxylic esters; boronic esters; carboxamides; nitriles; and nitro, iodo, and acetal groups. Some of the alkyne substrates tested here are otherwise difficult to hydrate. The alkyne hydration can be performed on a gram scale, and the catalyst can be recovered by aqueous workup.

The selective hydrogenation of aromatic compounds to cyclohexanes was found to be promoted by chitin-supported ruthenium nanoparticles (Ru/chitin) under near-neutral, aqueous conditions without the loss of C–O/C–N linkages at benzylic positions.