Dechlorination of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) was catalyzed by a hydrophobic vitamin B(12), heptamethyl cobyrinate perchlorate, with a visible light irradiation system containing a [Ru(ii)(bpy)(3)]Cl(2) photosensitizer, and the hydrophobic vitamin B(12) showed high catalytic efficiency and stability during the reaction.

A vitamin B 12 derivative, heptapropyl cobyrinate perchlorate, was readily trapped onto an indium tin oxide (ITO) electrode by a sol-gel reaction. The complex was physically retained in a silica gel film which is formed on an ITO electrode. The thickness of the film could be controlled by the withdrawing speed of the dip coating process. Formation of a sol-gel film was confirmed by SEM measurements, and the total amount of the complex in the film was determined by UV-VIS absorption spectra. The complex exhibits the Co II /Co I redox couple at Ϫ0.42 V vs. Ag-AgCl. The amount of the electroactive complex in the sol-gel film deduced from electrochemical measurements is 3.0 × 10 Ϫ11 and 6.2 × 10 Ϫ11 mol cm Ϫ2 for thicknesses of 170 and 330 nm, respectively. This electroactive complex shows a high reactivity towards organic halides, and the controlled-potential electrolysis of benzyl bromide using the sol-gel modified electrode at Ϫ1.20 V vs. Ag-AgCl in aqueous solution containing 0.1 M KCl afforded dehalogenated products, bibenzyl and toluene, with a total turnover number of >1000 for 1 h.

The controlled-potential electrolysis of 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) was carried out at -1.4 V vs. Ag-AgCl in the presence of a hydrophobic vitamin B12, heptamethyl cobyrinate perchlorate. DDT was dechlorinated to form 1,1-bis(4-chlorophenyl)-2,2-dichloroethane (DDD), 1,1-bis(4-chlorophenyl)-2,2-dichloroethylene (DDE), 1-chloro-2,2-bis(4-chlorophenyl)ethylene (DDMU) and 1,1,4,4-tetrakis(4-chlorophenyl)-2,3-dichloro-2-butene (TTDB)(E/Z), and quantitative recovery of the catalyst after the electrolysis was confirmed by electronic spectroscopy. A photo-sensitive intermediate having a cobalt-carbon bond formed during the electrolysis was characterized by electronic spectroscopy. A mechanism for the formation of various dechlorinated products was investigated by using deuterium solvents and various spectroscopic measurements such as UV-VIS and the EPR spin-trapping technique.

Hydrophobic vitamin B(12) was covalently immobilized onto a platinum electrode surface, and the immobilized complex exhibits Co(ii)/Co(i) redox couple and in situ the Co(i) species reacts with phenethyl bromide to form styrene under irradiation with visible light with a turnover number of over 6000 for 1 h.

A 77-year-old patient was admitted to our hospital for the further examination of melena. A computed tomography scan detected two submucosal tumors (SMTs) in the stomach and jejunum. Double-balloon endoscopy revealed the presence of a delle on the jejunal SMT, suggesting that the SMT was the origin of the gastrointestinal bleeding. Both tumors were surgically resected and subsequently diagnosed via histology as gastrointestinal stromal tumors (GISTs). Furthermore, the two GISTs had different mutations in the c-kit gene, suggesting that they were derived from different clonal origins. This report depicts an extremely rare case of multiple synchronous sporadic GISTs in the stomach and jejunum.