76625-87-1Relevant academic research and scientific papers
OXIDATION OF DISULPHIDES BY HYDROGEN PEROXIDE UNDER INTERPHASE CATALYSIS CONDITIONS
Anisimov, A. V.,Mohammed, R. A.,Tarakanova, A. V.,Borisenkova, S. A.
, p. 407 - 412 (2007/10/02)
It has been shown that aliphatic and aromatic disulphides are oxidized by hydrogen peroxide in the presence of sodium tungstate and molybdate and an interphase catalyst to the corresponding thiolsulphonates and disulphones.The structure of the oxidation products depends on the interphase catalyst used: in the presence of triethylbenzylammoniumbromide, thiosulphonates are formed, while in the presence of cetyltrimethylammoniumbromide, disulphones are formed.The main reason for this difference is the solubility in the organic phase of the intermediate peroxy complex formed by the reaction of hydrogen peroxide with the metal compound in the presence of phosphoric acid.The rate of the reaction and the yields of oxidation products depend on the temperature, the solvent used and the ratio of the reactants.
OXIDATION OF DISULPHIDES BY HYDROGEN PEROXIDE IN THE PRESENCE OF SUBSTITUTED PHTHALOCYANINES OF TRANSITION METALS
Anisimov, A. V.,Mohammed, R. A.,Borisenkova, S. A.,Tarakanova, A. V.,Barkanova, S. V.,Et Al.
, p. 347 - 352 (2007/10/02)
A study has been made of the oxidation of disulphides of different structure by hydrogen peroxide in the presence of nitrosubstituted phthalocyanines of transition metals.It has been established that phthalocyanines in a homophase system ensure a higher initial oxidation rate of disulphides to disulphones and thiosulphonates than Na2WO4 in a two-phase system with the use of interphase transfer catalysts.
A facile and general method for the preparation of α-disulfones (R1SO2SO2R2)
Bartmann
, p. 490 - 496 (2007/10/02)
Dialkyl, diaryl and alkyl aryl disulfones are easily prepared by oxidation of N,N'-disulfonylhydrazines with nitric acid. The method is compatible with a wide variety of substituents (R1,R2) on the sulfur atoms.
Substitution Reactions of Alkanesulfonyl Derivatives: Direct Substitution vs. Elimination-Addition Mechanisms in Substitution Reactions of Alkyl α-Disulfones
Fang, Lieh-pao O.,Kice, John L.
, p. 1137 - 1145 (2007/10/02)
The reactions of a series of alkyl and aralkyl α-sulfones, RSO2SO2R ( R = Me, n-Bu, i-Pr, ArCH2) with a variety of nucleophiles in aqueous dioxane have been examined.Both rates of reaction and whether a given reaction takes place by an elimination-addition (sulfene intermediate) or a direct substitution (attack of nucleophile on SO2 group of α-sulphone) mechanism have been determined.The great majority of substitution reactions of alkyl α-disulfones take place via an elimination-addition mechanism (eq 3a), with formation of a sulphene from the α-disulphone being rate determining.Only when nucleophile is one, like azide ion, that is weakly basic while still being a good nucleophile is a direct substitution the preferred pathway.Even with azide the reaction pathway changes to elimination-addition when the acidity of the hydrogens on the carbon adjacent to the sulfonyl group is increased sufficiently, as in (PhCH2SO2)2.Comparison of rates of elimination of α-disulphones (R'CH2SO2)2 with rates of base-catalyzed hydrogen exchange of the corresponding trifluoromethyl sulfones R'CH2SO2CF3 indicates that formation of sulfenes from α-disulfones involves either an irreversible E1cB or a very E1cB-like E2 mechanism, a conclusion that is also supported by the observed variation of the rate of elimination of RR'CHSO2SO2R'' with changes in R and R'.Comparison of the behavior of an alkyl α-disulfone with that of the corresponding alkanesulfonyl chloride reveals that changing Y in RCH2SO2Y from RSO2 to Cl causes direct substitution to be able to compete much more effectively with elimination-addition.Kinetic studies show that this arises because, for a given nucleophile, (a) elimination-addition is 5-10 times slower for the alkanesulfonyl chloride than for the α-disulfone while (b) the rate of direct substitution is 5-10 times faster for the sulfonyl chloride.The origin of these rate differences is discussed and explained.
