127022-75-7Relevant academic research and scientific papers
Formation of S,S-diphenyl-S-methoxythiazyne Ph2S(OMe)(≡N) in the alkaline hydrolysis of S,S-diphenyl-N-halosulfilimines
Yoshimura,Tsukurimichi,Kita,Fujii,Shimasaki
, p. 6339 - 6340 (1989)
The structure of a compound formed during the alkaline hydrolysis of S,S-diphenyl-N-halosulfilimines to the corresponding sulfoximine in methanol was assigned to PhS(OMe) (≡N) Ph, S,S-diphenyl-S-methoxythiazyne, on the basis of spectroscopic analyses and chemical reactions.
Kinetic Study on the Alkaline Hydrolysis of S,S-Diaryl-N-halosulfilimines
Yoshimura, Toshiaki,Tsukurimichi, Eiichi,Kita, Hiroshi,Fujii, Hiroshi,Shimasaki, Choichiro
, p. 1764 - 1769 (1990)
Kinetics for the alkaline hydrolysis of S,S-diaryl-N-bromosulfilimines were carried out in aqueous methanol.The observed pseudo-first-order rate constants were found to give a linear correlation with the concentration of sodium hydroxide, k=k1+k2.The first-order rate constants k1 showed a large negative Hammett ρ value (-2.43) for the substituent effect on the phenyl group, nearly zero activation entropy (-0.9+/-13.1 JK-1mol-1) and a relatively large m value (0.638) against the solvent ionizing power Y value suggesting that the reaction process fork1 close to SN1.The salt effect, the deuterium solvent isotope effect and the steric effect are also in accord with the SN1 mechanism.On the other hand, the second order rate constants k2 revealed a small Hammett ρ value, a negative activation entropy (-44.0+/-4.0 JK-1mol-1), a small m value (0.153) and a steric deceleration by ortho substituents showing that the reaction for k2 is SN2-like.The salt effect and the solvent isotope effect are also compatible with the SN2-like mechanism.Meanwhile, the k1 for S,S-diphenyl-N-halosulfilimines remarkably increased in the order of N-iodo N-bromo N-chloro.This reactivity might be due to the lone pair-lone pair repulsion at the reactant state.From these observations, the alkaline hydrolysis of S,S-diaryl-N-halosulfilimines was confirmed to proceed via concurrent two mechanisms, the SN1-like mechanism involving nitridosulfonium cation as an intermediate and the SN2'-like mechanism with the transition state in which the N-X bond cleavage is more progressed than the S-O bond formation with nucleophiles (-OH, -OMe).
Synthesis, Structure, and Thermolysis Mechanism of S-Alkoxythiazynes
Yoshimura, Toshiaki,Ohkubo, Masanori,Fujii, Takayoshi,Kita, Hiroshi,Wakai, Youko,Ono, Shin,Morita, Hiroyuki,Shimasaki, Choichiro,Horn, Ernst
, p. 1629 - 1637 (2007/10/03)
S-Alkoxy-S,S-diarylthiazynes were prepared by two methods: the alkaline hydrolysis of S,S-diaryl-N-halosulfilimines in aqueous alcohols and the reaction of S,S-diaryl-S-fluorothiazynes with sodium alkoxides. The structure of S,S-diphenyl-S-propoxythiazyne was determined by an X-ray crystallographic analysis, which showed a short SN bond length of 1.441(3) A. The thermolysis of S-alkoxythiazynes gave elimination products, which were identified as the corresponding carbonyl compounds and N-unsubstituted S,S-diarylsulfilimines. Kinetic experiments for the thermolysis of the S-alkoxy-S,S-diarylthiazynes were carried out. The first-order kinetic behavior, a large kinetic isotope effect (kHkD = 6.1 ) using S,S-diphenyl-S-[1,1-2H2]propoxythiazyne, a negative activation entropy (ΔS? = -30 J K-1mol-1), and a negative Hammett ρ-value (ρ= -0.35) on the phenyl group were obtained, suggesting that the reaction proceeds via a concerted five-membered cyclic transition state. A deviation from the ideal concerted transition state is discussed in comparison with that for sulfoxides.
Mechanism of Reaction of S,S-Diphenyl-S-methoxythiazyne with Thiole
Yoshimura, Toshiaki,Tsukurimichi, Eiichi,Sugiyama, Yasuhisa,Kita, Hiroshi,Shimasaki, Choichiro,Hasegawa, Kiyoshi
, p. 3176 - 3178 (2007/10/02)
The reaction of S,S-diphenyl-S-methoxythiazyne with various thiols gave methyl sulfides.Kinetic investigations support a mechanism involving an initial protonation of the thiazyne nitrogen with thiol followed by a nucleophilic attack of thiolate anion on the methyl group.
