The reaction of allyl and benzylarsonic acids with thiols: mechanistic aspects and implications for dioxygen activation by trivalent arsenic compounds

Preparation of dehydro-l-(+)-ascorbic acid dimer by oxidation of ascorbic acid with arsenic acid/iodine and formation of complexes between arsenious acid and ascorbic acid

“…(1), to the best of our knowledge, is the first example of a non-transition element ''catalysis''. We have recently proposed that As(III) bound to suitable groups, e.g., in diphenyl allyldithioarsonite or benzyldithioarsonite, RAs(SPh) 2 , can interact with dioxygen, thus activating it [39]. In the present case we can also invoke such an interaction, giving a diradical of the type Å As(III)-O-O Å .…”

The Autoxidation of Triaryl Trithioarsenites, (ArS)3As: Evidence for Binding and Activation of Triplet Dioxygen by Arsenic(III)

“…It is a free radical process involving RṠ, O 1− . 2 , and O 2 2− species generated by the reaction of RS − with O 2 in a rate determining step. 12 The autoxidation of thiols in neutral media at r.t. does not take place in the absence of radical initiators, e.g., trace metals, UV, and peroxides.…”

“…12 The second route requires the formation of an (ArS) 3 As/O 2 adduct and the ability of 3 O 2 in air to combine with the As(III) in certain compounds has been inferred in previous reports. [1][2][3][4]23 The adduct can most likely be a loosely bound complex, (ArS) 3 As: . .…”

“…Thus, ascorbic acid complexed with arsenous acid, H 3 AsO 3 , in a ratio of 1:2 As(III)/ascorbic acid is oxidized by air to dehydroascorbic acid much faster than in the absence of As(III). 1 The reaction of allyl and benzylarsonic acids with thiophenol gave not only the expected diphenyl alkyldithioarsonites, R As(SPh) 2 , and diphenyl disulfide, PhSSPh, but also various other products, some of which (As 2 O 3 , (PhS) 3 As, PhCH 2 OH, PhCH O) arose from the reaction of these alkyldithioarsonites with the dissolved dioxygen. 2 Attempted oxidation 3 of the esters 1-3, 5, 7, and 8 (without exclusion of air) by octasulfur in refluxing solvent, as melts, or in solution in the presence of triethylamine, as an activator of octasulfur, did not give the expected arsenic(V) esters, (ArS) 3 As S, but various amounts of As 2 O 3 and disulfides, ArSSAr, (in the case of 8, the parent thiol, 2-mercaptopyridine, in its thioketo form was also coproduced) were obtained according to Eq.…”

Design of functionalized nanoparticles for the applications in nanobiotechnology

“…In the presence of the reducing agent such as GSH, the transformation from As(V) to As(III) proceeds with the bond cleavage of As-C, resulting in the generation of highly-toxic arsenic species ( Figure 6). 47,48 Since the concentrations of GSH in tumor cells are higher than those in normal cells, the transformation from As(V) to As(III) could be enhanced.…”