Disulfides reaction

Carbethoxycyclohexanone, 46, 82 2-Carbethoxycyclononanone, 47, 22 2-Carbethoxycyclooctanone, 47, 20 2-Carbomethoxycyclopentanone, conversion to 2-benzyl-2-carbometh-oxycyclopentanone, 45, 8 Carbon disulfide, reaction with /i-chloro-aniline and aqueous ammonia,... 

Because of the dependence of sulfhydryl and disulfide reactions on heat treatment. It would be expected that their Involvement In protein gelation would depend greatly on gel formation conditions. For example, Catslmpoolas and Meyer (7) have suggested that disulfides play only a minor role In the progel to gel transformation In soybean globulins. In more Irreversible soy protein gelation processes, disulfide bridging may be Involved In... 

While BSO interferes with the biosynthesis of GSH (Biaglow et al. 1983 Romero and Sies 1984), DIAMIDE oxidizes GSH to the disulfide [reaction (87) Harris 1982]. It has also been considered to act as a sensitizer by preventing low 02 concentrations from being depleted at high dose rates (Clark et al. 1983). 

Polyrotaxane networks 163 have been developed as prototype recyclable cross-linked polymers <2004AGE966>. These systems, which comprise a poly(crown ether)polyurethane and a bisammonium disulfide salt, are cross-linked via mechanical bonds ([3]rotaxane-like substructures) and are capable of undergoing reversible assembly and disassembly as they rely on thiol-disulfide reactions. Macroscopically, cross-linking determines gelation while de-cross-linking enables recovery of the starting materials. 

Cyclic disulfides. Reaction of a dithiol (I) with an aqueous solution oflead acetate gives a lead dithiolate (2) in nearly quantitative yield. These react with sulfur in benzene solution at room temperature to give the cyclic disulfide (3) in high yield. 

A thiete intermediate (225a) was proposed in the photochemical reaction of dimethyl acetylenedicarboxylate with 225,and similar intermediates were proposed in the addition of thiones or dithioesters to heteroatom-substituted acetylenes. Thiete 227 was suggested as an intermediate in the reaction of 226 with carbon disulfide. Reactions of aryl vinyl sulfide derivatives (2,4,6-trinitrobenzenesulfonate of a phenylthiovinyl alcohol, a phenacyl derivative )... 

C. The mechanism of tetraethylthiuram disulfide reaction with Ncp7... 

If halogenation is carried out in a solvent of low polarity, such as chloroform, carbon tetrachloride, or carbon disulfide, reaction can be limited to monohalo-genation. For example ... 

Carbon disulfide, reaction with J>-chloro-aniline and aqueous ammonia,... 

Considering all of these observations, a possible mechanism for this interesting biochemical reaction is shown in Figure 26. Central to this proposed mechanism is the involvement of a persulfide (R-S-SH), a thioaldehyde and a protein-bound disulfide in the proposed reaction mechanism. Persulfides are known to be widely involved in the biosynthesis of many important sulfur containing metabolites. Here they function as a protein-bound nucleophilic sulfur that can add to an aldehyde and be reductively released from the protein to form the thioaldehyde (reactions 2-3, Figure 26). The persulfide could be formed by the transfer of hydrogen sulfide to a disulfide (reaction 1, Figure 26). 

Incompatible with strong oxidizers acids, water (slowly decomposes, forming amine and carbon disulfide). Reaction with nitrosating compounds (i.e., nitrogen oxides, nitrosyl chloride, nitrite esters, metal nitrates and nitroso compounds, etc.) can cause the formation of carcinogenic N-nitrosodiethylamine. 

The first step in determining the sequence of amino acids in a peptide or a protein is to reduce any disulfide bridges in the peptide or protein. A commonly used reducing agent is 2-mercaptoethanol, which is oxidized to a disulfide. Reaction of the protein thiol groups with iodoacetic acid prevents the disulfide bridges from reforming as a result of oxidation by O2. 

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