127074-24-2Relevant academic research and scientific papers
Selective and mild oxidation of sulfides to sulfoxides by oxodiperoxo molybdenum complexes adsorbed onto silica gel
Batigalhia, Fabiana,Zaldini-Hernandes, Marcelo,Ferreira, Ant?nio G,Malvestiti, Ivani,Cass, Quezia B
, p. 9669 - 9676 (2007/10/03)
Aliphatic and aromatic sulfides, ketosulfides, sulfinyl acids and esters, and olefinic sulfides were oxidized to sulfoxides using oxodiperoxo complexes of molybdenum coated on silica gel (150 ? pore size) in very high yields. Complete chemoselectivity was observed for the oxidation of all functional sulfides. Sulfones were, however, the main products of the reaction when the complexes were not coated on silica gel. The influence of silica gel as the support of these reactions was also investigated and it was demonstrated that it alters the reactivity of the complex but it is not responsible for the excellent chemoselectivity of the complexes. The complex [MoO(O2)2(pyrazole) (H2O)] proved to be more reactive than [MoO(O2)2(Opyr) (H2O)].
PYROLYSIS OF α-ACYL SUBSTITUTED ETHYL PHENYL SULFOXIDE
Tsukurimichi, Eiichi,Yoshimura, Toshiaki,Yoshizawa, Masaki,Itakura, Hiromi,Shimasaki, Choichiro
, p. 113 - 120 (2007/10/02)
The effect of pyrolysis of the acyl group substituted on α-position carbon in S-ethyl group of ethyl phenyl sulfoxide was investigated by using two kinds of substrates, 1-ethoxycarbonylethyl phenyl sulfoxide (1) and 1-ethoxycarbonyl-1-methylethyl phenyl sulfoxide (2) together with 2-methoxycarbonylethyl phenyl sulfoxide (4).The rate of pyrolysis of (1) was found to be about 740 ca. 890 times faster than that of ethyl phenyl sulfoxide (5), while (2) was 5700 times faster.The rate enhancement effect on α-ethoxycarbonyl group was larger than that on β-methoxycarbonyl group.Large deuterium kinetic isotope effect (kH/kD=5.5 for PhS(O)C(CD3)2CO2Et (3)) was observed.Activation energy for (2) is about 110 kJ/mol, which is just about the same as that of (5) (108 kJ/mol), while activation entropy lies in ca. 1 Jdeg-1 mol-1.Hammett plot for substituted (2) gave ?=0.69.These kinetic results reveal that the pyrolysis of the sulfoxides proceeds via a loose transition state involving advanced C-S bond cleavage.The remarkably large rate enhancement by α-carbonyl group might be due mainly to the conjugation of that group and developing double bond acidifying the β-proton in the transition state.Key words: Pyrolysis; elimination; mechanism; isotope effect; kinetics; sulfoxide,
