The Strain in the 1,2-Dithiolane Ring.

The Scission Of The Sulfur-Sulfur Bond

“…In view of the above model, in cyclic disulfides (of, say, three carbon atoms) the favorable geometric orientation of the sulfur-carbon bonds cannot be accommodated, partly as a result of resistance to rotation about the sulfur-sulfur bond (139). This is an important factor in considerations of the stability of cyclic disulfides, a subject which has received much attention in recent years, especially because of the interest in -lipoic acid (16,25,177).…”

“…RS+ + R'SH fí RS-SR' + H+ (16) The extent of disulfide mixing is very sensitive to acid concentration and reaction 13 is apparently slow, since an induction period is observed. Equilibrium 13 lies well to the left, so that disulfide mixing is very slow in hydrochloric acid weaker than 9 N (15).…”

“…Both displace ethyl mercaptide from diethyl disulfide (16) and cystine (33). Tabled as shown because of the principles that (a) an anion is more nucleophilic than a neutral group and (&) R decreases the nucleophilicity of arsenic.…”

Lipoates as building blocks of sulfur-containing branched macromolecules

“…[38][39][40][41][42][43][44] The propensities of cyclic disulfides to polymerize via ring-opening and of disulfide-containing polymers to depolymerize to the corresponding cyclic disulfides 45,46 are related to the ring strain, and many attempts have been made to determine experimentally or estimate computationally this important structural parameter. 40,[46][47][48][49] The formation of linear and cyclic (including catenane-type) disulfide-containing polymers derived from the six-membered heterocyclic compound 1,2-dithiane [50][51][52] and its derivatives with a fused benzene ring 53 as well as from LpA 54 and its derivatives 55,56 has been extensively studied due to the interesting mechanical properties as well as the degradability of these materials. Owing to the unique ability of cyclic disulfides to participate in both radical and ionic ring-opening reactions, and that of the respectively formed sulfur-centered radicals or anions to either open another unreacted cyclic disulfide or add to a carbon-carbon double bond, it was envisioned that compounds containing both a cyclic disulfide and a reactive vinyl group would be suitable precursors of various highly branched (andat high conversionsnetwork) polymers.…”

The reaction of some cyclic and open-chain disulphides with methyl trifluoromethanesulphonate

“…importance of entropy and enthalpy strain on kinetic acceleration in cyclic disulphides, we now report a detailed study of the activation parameters for the reaction of methyl trifluoromethanesulphonate (triflate) with a number of cyclic and openchain disulphides (1)-(5).…”