868522-85-4Relevant academic research and scientific papers
The conversion of stilbenols to stilbenethiols via N,N- dimethylthiocarbamates
Nowakowska, Zdzislawa
, p. 707 - 715 (2006)
A series of O-stilbenyl N,N-dimethylthiocarbamates has been prepared by the reaction of N,N-dimethylthiocarbamoyl chloride with stilbenols in the presence of DABCO and DMF. The thermal rearrangement of O-stilbenyl N,N- dimethylthiocarbamates into S-stilbe
Extraordinary radical scavengers: 4-mercaptostilbenes
Cao, Xiao-Yan,Yang, Jie,Dai, Fang,Ding, De-Jun,Kang, Yan-Fei,Wang, Fu,Li, Xiu-Zhuang,Liu, Guo-Yun,Yu, Sha-Sha,Jin, Xiao-Ling,Zhou, Bo
supporting information; experimental part, p. 5898 - 5905 (2012/06/30)
In the past decade, there was a great deal of interest and excitement in developing more active antioxidants and cancer chemoprevention agents than resveratrol, a naturally occurring stilbene. In this work, eight resveratrol-directed 4-mercaptostilbenes were constructed based on the inspiration that thiophenol should be a stronger radical scavenger than phenol, and their reaction rates with galvinoxyl (GO.) and 2,2-diphenyl-1-picrylhydrazyl (DPPH.) radicals in methanol and ethyl acetate were measured by using stopped-flow UV/Vis spectroscopy at 25 °C. Kinetic analysis demonstrates that 4-mercaptostilbenes are extraordinary radical scavengers, and the substitution of the 4-SH group for the 4-OH group in the stilbene scaffold is an important strategy to improve the radical-scavenging activity of resveratrol. Surprisingly, in methanol, some of the 4-mercaptostilbenes are 104-times more active than resveratrol, dozens of times to hundreds of times more effective than known antioxidants (α-tocopherol, ascorbic acid, quercetin, and trolox). The detailed radical-scavenging mechanisms were discussed based on acidified-kinetic analysis. Addition of acetic acid remarkably reduced the GO. and DPPH. radical-scavenging rates of the 4-mercaptostilbenes in methanol, a solvent that supports ionization, suggesting that the reactions proceed mainly through a sequential proton loss electron transfer mechanism. In contrast, an interesting acid-promoted kinetics was observed for the reactions of the 4-mercaptostilbenes with DPPH. in ethyl acetate, a solvent that weakly supports ionization. The increased ratio in rates is closely correlated with the electron-rich environment in the molecules, suggesting that the acceleration could benefit from the contribution of the electron transfer from the 4-mercaptostilbenes and DPPH.. However, the addition of acetic acid had no influence on the GO.-scavenging rates of the 4-mercaptostilbenes in ethyl acetate, due to the occurrence of the direct hydrogen atom transfer. Our results show that the radical-scavenging activity and mechanisms of 4-mercaptostilbenes depends significantly on the molecular structure and acidity, the nature of the attacking radical, and the ionizing capacity of the solvent. Copyright
