29878-59-9Relevant academic research and scientific papers
Photostimulated Reactions of Alkanethiolate Ions with Haloarenes. Electron Transfer vs. Fragmentation of the Radical Anion Intermediate
Rossi, Roberto A.,Palacios, Sara M.
, p. 5300 - 5304 (1981)
The photostimulated reactions of RS(1-) ions (R = methyl, n-butyl, tert-butyl, and benzyl) with haloarenes in liquid ammonia were studied.Two main products were formed: alkyl aryl sulfide and arenethiolate ions.The formation of these compounds is explained by the SRN1 mechanism of aromatic nucleophilic substitution.The radical anion intermediate formed in the coupling of an aryl radical with an alkanethiolate ion undergoes two competing reactions: transfer of the odd electron to the substrate leading to the substitution product or bond fragmentation leading to arenethiolate ion and an alkyl radical.It is concluded that the ratio of these products depends mainly on changes in the rate of fragmentation and not on changes in the electron-transfer reaction.
Effects of aromatic thiols on thiol-disulfide interchange reactions that occur during protein folding
DeCollo,Lees
, p. 4244 - 4249 (2007/10/03)
The folding of disulfide containing proteins from denatured protein to native protein involves numerous thiol-disulfide interchange reactions. Many of these reactions include a redox buffer, which is a mixture of a thiol (RSH) and the corresponding disulfide (RSSR). The relationship between the structure of RSH and its efficacy in folding proteins in vitro has been investigated only to a limited extent. Reported herein are the effects of aliphatic and especially aromatic thiols on reactions that occur during protein folding. Aromatic thiols may be particularly efficacious as their thiol pKa values and reactivities match those of the in vivo catalyst, protein disulfide isomerase (PDI). This investigation correlates the thiol pKa values of aromatic thiols with their reactivities toward small molecule disulfides and the protein insulin. The thiol pKa values of nine para-substituted aromatic thiols were measured; a Hammett plot constructed using σp- values yielded ρ = -1.6 ± 0.1. The reactivities of aromatic and aliphatic thiols with 2-pyridyldithioethanol (2-PDE), a small molecule disulfide, were determined. A plot of reactivity versus pKa of the aromatic thiols had a slope (β) of 0.9. The ability of these thiols to reduce (unfold) the protein insulin correlates strongly with their ability to reduce 2-PDE. Since the reduction of protein disulfides occurs during protein folding to remove mismatched disulfides, aromatic thiols with high pKa values are expected to increase the rate not only of protein unfolding but protein folding as well.
