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The S−H bond in thiols is weak compared to the O−H bond in alcohols. For CH 3 X−H, the bond enthalpies are 365.07 ± 2.1 kcal/mol for X = S and 440.2 ± 3.0 kcal/mol for X = O. [21] Hydrogen-atom abstraction from a thiol gives a thiyl radical with the formula RS •, where R = alkyl or aryl.
Thiol–disulfide exchange is the principal reaction by which disulfide bonds are formed and rearranged in a protein. The rearrangement of disulfide bonds within a protein generally occurs via intra-protein thiol–disulfide exchange reactions; a thiolate group of a cysteine residue attacks one of the protein's own disulfide bonds.
Thioesters can be prepared by condensation of thiols and carboxylic acids in the presence of dehydrating agents: [2] [3] RSH + R'CO 2 H → RSC(O)R' + H 2 O. A typical dehydration agent is DCC. [4] Efforts to improve the sustainability of thioester synthesis have also been reported utilising safer coupling reagent T3P and greener solvent ...
The functional groups on the thiol and alkene compounds can affect the reactivity of the radical species and their respective rate constants. The structure of the alkene determines whether the reaction will be propagation or chain-transfer limited, and therefore first order with respect to alkene or thiol concentration respectively.
Alternatively, sulfides can be synthesized by the addition of a thiol to an alkene in the thiol-ene reaction: R-CH=CH 2 + H-SR' → R-CH 2-CH 2-S-R' This reaction is often catalysed by free radicals produced from a photoinitiator. [6] Sulfides can also be prepared by many other methods, such as the Pummerer rearrangement. Trialkysulfonium salts ...
A common 1,4-dithiol is dithiothreitol (DTT), HSCH 2 CH(OH)CH(OH)CH 2 SH, sometimes called Cleland's reagent, for to reduce protein disulfide bonds. Oxidation of DTT results a stable six-membered heterocyclic ring with an internal disulfide bond. Reduction of a typical disulfide bond by DTT via two sequential thiol-disulfide exchange reactions.
[11] [12] For example, the trichlorosilane head group of an FDTS molecule reacts with a hydroxyl group on a substrate to form a very stable covalent bond [R-Si-O-substrate] with an energy of 452 kJ/mol. [citation needed] Thiol-metal bonds are on the order of 100 kJ/mol, making them fairly stable in a variety of temperatures, solvents, and ...
DTT is a reducing agent; once oxidized, it forms a stable six-membered ring with an internal disulfide bond.It has a redox potential of −0.33 V at pH 7. [1] The reduction of a typical disulfide bond proceeds by two sequential thiol-disulfide exchange reactions and is illustrated below.