E. V. Grigor'ev

Effect of Organotin Compounds and Their Complexes with Phosphatidylcholine on Peroxide Oxidation of Lipid Structural Fragments

Oxidation of a lipid structural fragment, oleic acid, in the presence of a series of organotin compounds and their complexes with phosphatidylcholine was studied at 25, 37, 65, and 95°C. At a nearly physiological temperature, acceleration of hydroperoxide accumulation in the presence of these complexes was observed. At 65°C, addition of organotin derivatives leads to increase in the initial rate of hydroperoxide accumulation, but the kinetic curves acquire an S-like character as the reaction progresses. These data indicate that the rate of decomposition of hydroperoxides exceeds the rate of their accumulation. In the presence of 2,6-di-tert-butylphenol as antioxidant, the promoting effect of organotin compounds disappears. A possible reaction mechanism and the role of radical species arising from dissociation of the CÄSn bond are discussed.

Dual Effect of Organomercury Compounds on Peroxide Oxidation of Oleic Acid

Oxidation of oleic acid with atmospheric oxygen in the presence of HgCl2 and various organo- mercury compounds (methylmercury iodide, isopropylmercury bromide, n-hexylmercury bromide, phenylmercury bromide, diphenylmercury, p-tolylmercury bromide, bis-p-tolylmercury) was studied. Mercury compounds exert a dual effect on accumulation of oleic acid hydroperoxide in the temperature range 20-90°C. Below 50°C, the concentration of the hydroperoxides formed in the presence of mercury compounds is lower, and at higher temperatures, higher than in the experiments performed without mercury compounds. Comparison of the concentrations of oleic acid hydroperoxides with those of their transformation products, carbonyl compounds, determined spectrophotometrically, shows that actually organomercury compounds and HgCl2 accelerate peroxide oxidation at all the studied temperatures. Decreased accumulation of peroxides below 50°C is apparently due to the fact that the rate of their reaction with organomercury compounds is higher than the rate of their formation.

Reaction of bis(trimethylsiloxy)phosphine with methyl(phenyl)divinylsilane

Bis(trimethylsiloxy)phosphine is successfully used in various addition reactions to unsaturated synthons, leading to promising types of organophosphorus compounds [1]. We showed that the reaction of an excess of bis(trimethylsiloxy)phosphine with methyl(phenyl)divinylsilane provides a mixture of phosphonite I and bisphosphonite II in equal amounts. Phosphonites I and II were isolated in high yield. The reaction was initiated with 2,2 -azobisisobutyronitrile (AIBN) under conditions of its thermolysis (100 130 C).