24686-79-1Relevant academic research and scientific papers
Kinetics and Mechanism of the Methyltrioxorhenium-Catalyzed Sulfoxidation of Thioketones and Sulfines
Huang, Ruili,Espenson, James H.
, p. 6374 - 6376 (2007/10/03)
Kinetic studies have been carried out on the oxidation of thiobenzophenones and thiocamphor by hydrogen peroxide and on the second step in the sequence, oxidation of the resulting sulfines (Ar2C= S=O). The first reaction follows the pattern now common to methyltrioxorhenium/H2O2 reactions, in that the rate constant for the reaction between the peroxorhenium intermediate and the thioketone follows a Hammett correlation such that electron-releasing substrates react more rapidly. The reaction constant is p = -1.12. However, the plot of log(kX/kH) for the sulfines against 2σ, determined over the range -1.6 2 under these conditions rather than undergoing disproportionation to SO2 and S. Also, SO was trapped with a 1,3-diene as a thiophene-1-oxide.
Reaction of Thioketones with Carbonyl Oxides and 3,3-Dimethyl-1,2-dioxirane. Cycloaddition vs. Oxygen Atom Transfer
Tabuchi, Toshihiko,Nojima, Masatomo,Kusabayashi, Shigekazu
, p. 3043 - 3046 (2007/10/02)
The ozonolysis of vinyl ethers 1a, b in the presence of adamantane-2-thione 4a and bicyclononan-9-thione 4b gave in each case the corresponding thioozonides 5a-c in moderate yields, whilst ozonolysis of a mixture of vinyl ethers 1a-d and thiobenzophenone derivatives 4f-h gave the corresponding thione S-oxides 8f-h in isolated yields of 10-40percent, together with the benzophenones 7f-h. 3,3-Dimethyl-1,2-dioxirane, generated in situ from the reaction of acetone and 'oxone' (2KHSO5-KHSO4-K2SO4), transferred an oxygen atom to compounds 4a, f, g, i providing the thione S-oxides 8a, f, g, i in 29-97 percent yield.
Methoxide-Catalyzed Decomposition of Diarylmethyl (Arylsulfonyl)methyl Sulfoxides: A Sulfine-Forming Elimination on the (E1cB)rev/(E1cB)irrev Borderline
Kice, John L.,Kupczyk-Subotkowska, Lidia
, p. 1424 - 1430 (2007/10/02)
In 7:3 CH3OH-DMSO (v/v) in the presence of methoxide ion, diarylmethyl (arylsulfonyl)methyl sulfoxides (Ar2CHS(O)CH2SO2Ar') 4, undergo elimination remarkably easily to afford the diarylsulfine and the aryl methyl sulfone (eq 4).Comparison of the rate of cleavage of 4 (kelim) and the rate of disappearance of the 1H NMR signal (kCHSO) for the Ar2CHS(O) proton in CD3OD-DMSO shows that the mechanism for the elimination is on the (E1cB)rev/(E1cB)irrev borderline, (kCHSO/kelim) ranging from 1.2 to 5.2, depending on the nature of the Ar and Ar'groups in 4.Slight changes in structure can shift the mechanism from (E1cB)rev to (E1cB)irrev as a result of their effect on the partitioning of the α-sulfinyl carbanion intermediate (Ar2CS(O)CH2SO2Ar') 5, between cleavage to diarylsulfine plus ArSO2CH2- (step kii, eq 8) and protonation to regenerate 4 (step k-i).Structural changes that make Ar'SO2CH2 a better leaving group increase kii/k-i and shift the mechanism toward (E1cb)irrev as does also an increase in the percentage of DMSO in the solvent.Structural changes in Ar that enhance the stability of 5 decrease kii/k-i and shift the mechanism toward (E1cb)rev.It is also shown that for 4 in general kii appears larger than would be expected for a leaving group of the basicity of Ar'SO2CH2-.Repulsion between the dipoles of the S(O) and SO2 groups in 5 is thought to be responsible.
Osidation of Thiones to Sulphines (Thione S-Oxides) with N-Sulphonyloxaziridines: Synthetic and Mechanistic Aspects
Maccagnani, Gaetano,Innocenti, Annamaria,Zani, Paolo
, p. 1113 - 1117 (2007/10/02)
The kinetics of the two-step oxidation of diarylthiones by N-sulphonyloxaziridines to sulphines and then to ketones have been investigated and the results compared with those for reactions with perbenzoic acid.The synthetic utility of the oxaziridine and peracid oxidations has been compared for a few aliphatic thiones
Thermal Fragmentation of a 1,5,2-Oxathiazole 5-Oxide system via Two Parallel Pathways: Interception of a Vinyl Nitrene and of a Sulphene
Bonini, Bianca F.,Maccagnani, Gaetano,Mazzanti, Germana,Pedrini, Paola,Lammerink, Ben H. M.,Zwanenburg, Binne
, p. 2097 - 2101 (2007/10/02)
Heating of 1,5,2-oxathiazole 5-oxide (2) (obtained by cycloaddition of fluorene-9-thione S-oxide and benzonitrile oxide) in benzene resulted in the formation of the dispirothiazole-5',9"-fluorene> 1',1'-dioxide (3) (84percent).The formation of product (3) is explained by assuming thermal fragmentation of (2) via two parallel pathways, one involving the loss of benzonitrile to give fluorene-9-thione S,S-dioxide (5) and the other the elimination of sulphur dioxide to produce the vinyl nitrene (7).Cycloaddition of the sulphene (5) and the nitrene (7) then leads to the heterocycle (3).This mechanism is supported by the fact that the vinyl nitrene (7) could be trapped by reaction with 4,4'-dimethylthiobenzophenone, and the sulphene (5) by reaction with methanol.The alternative rationale for the formation of (3), viz. reaction of an azirine (4) with the sulphene (5), could be ruled out.
CARBONYL SULFIDES AS POSSIBLE INTERMEDIATES IN THE PHOTOLYSIS OF OXATHIIRANES
Carlsen, Lars,Snyder, James P.,Holm, Arne,Pedersen, Erik
, p. 1257 - 1262 (2007/10/02)
Diphenyl oxathiirane, formed by irradiation of thiobenzophenone S-oxide at 77 K, is photochemically converted into a blue, thermally unstable compound which decomposes at ca 100-110 K (λmax 550 nm, (ε ca 11,000).Lack of change in magnetic susceptibility during the light induced conversion of sulfine to ketone via the oxathiirane and the subsequent blue intermediate implies the absence of triplet and biradical singlet transients.The unknown carbonyl sulfide functionality, R2C=O=S, thereby emerges as a strong candidate for producing the visible absorption.Comparison of the wave function for CH2=S=O and CH2=O=S arising from MNDO limited CI geometry optimizations leads to the conclusion that the carbonyl sulfide structure is best described as a zwitterion rather than as a singlet biradical.The failure to observe cycloaddition products between the blue species and several dipolarophiles is rationlized in terms of a labile carbonyl sulfide intermediate capable of facile sulfur extrusion from a long, weak O-S bond.Finally, the electronic absorption spectra of a series of para-substituted benzaldehyde O-sulfide model system have been calculated with CNDO/S-CI and correlated with the λmax's of the corresponding series of diaryl blue substrates.The sum of the available experimental and theoretical data is consistent with the existence of closed shell carbonyl sulfides as observable, though labile, intermediates from the photolysis of oxathinanes.
