16325-88-5Relevant articles and documents
Hydropersulfides: H-Atom Transfer Agents Par Excellence
Chauvin, Jean-Philippe R.,Griesser, Markus,Pratt, Derek A.
supporting information, p. 6484 - 6493 (2017/09/12)
Hydropersulfides (RSSH) are formed endogenously via the reaction of the gaseous biotransmitter hydrogen sulfide (H2S) and disulfides (RSSR) and/or sulfenic acids (RSOH). RSSH have been investigated for their ability to store H2S in vivo and as a line of defense against oxidative stress, from which it is clear that RSSH are much more reactive to two-electron oxidants than thiols. Herein we describe the results of our investigations into the H-atom transfer chemistry of RSSH, contrasting it with the well-known H-atom transfer chemistry of thiols. In fact, RSSH are excellent H-atom donors to alkyl (k ～ 5 × 108 M-1 s-1), alkoxyl (k ～ 1 × 109 M-1 s-1), peroxyl (k ～ 2 × 106 M-1 s-1), and thiyl (k > 1 × 1010 M-1 s-1) radicals, besting thiols by as little as 1 order and as much as 4 orders of magnitude. The inherently high reactivity of RSSH to H-atom transfer is based largely on thermodynamic factors; the weak RSS-H bond dissociation enthalpy (～70 kcal/mol) and the associated high stability of the perthiyl radical make the foregoing reactions exothermic by 15-34 kcal/mol. Of particular relevance in the context of oxidative stress is the reactivity of RSSH to peroxyl radicals, where favorable thermodynamics are bolstered by a secondary orbital interaction in the transition state of the formal H-atom transfer that drives the inherent reactivity of RSSH to match that of α-tocopherol (α-TOH), nature's premier radical-trapping antioxidant. Significantly, the reactivity of RSSH eclipses that of α-TOH in H-bond-accepting media because of their low H-bond acidity (α2H ～ 0.1). This affords RSSH a unique versatility compared to other highly reactive radical-trapping antioxidants (e.g., phenols, diarylamines, hydroxylamines, sulfenic acids), which tend to have high H-bond acidities. Moreover, the perthiyl radicals that result are highly persistent under autoxidation conditions and undergo very rapid dimerization (k = 5 × 109 M-1 s-1) in lieu of reacting with O2 or autoxidizable substrates.
Simple synthetic protocols for tertiary alkyl and allyl thiols
Gurudutt, K. N.,Rao, Sanjay,Srinivas, P.,Srinivas, S.
, p. 1169 - 1171 (2007/10/03)
Convenient preparative methods for tertiary alkyl and allyl thiols are described. Accordingly, thiolesters and thiocyanates, obtained from the reaction of SN1-active halides and appropriate zinc salts, on hydrolysis and LAH reduction respectively, afford the corresponding thiols in near quantitative yields. Besides the well known p-menth-1-ene-8-thiol, p-menthane-1-thiol, p-mentha-1,8-diene-6-thiol and 2-(2-phenyl)propane thiol have been prepared.
Direct Conversion of Alcohols into Thiols
Nishio, Takehiko
, p. 1113 - 1118 (2007/10/02)
A simple one-pot reaction between alcohols and 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (Lawesson's reagent, LR) affords the corresponding thiols, accompanied by dehydration products, alkenes.Treatment of acyclic 1,4-diols with LR gives the 1,3-dienes. o-(Dihydroxymethyl)benzene derivatives yield the 1,3-dihydrobenzothiophenes when treated with LR.
A Novel Transformation of Alcohols to Thiols
Nishio, Takehiko
, p. 205 - 206 (2007/10/02)
Treatment of alcohols with 2,4-bis(p-methoxyphenyl)-1,3-dithiaphosphetane-2,4-disulphide (Lawesson reagent) gave the corresponding thiols.
