Thioethers and Disulfides

Mercaptans, thioethers, and disulfides are readily oxidized by ozone. 

Problematic functional groups, however, are thioethers and disulfides [28] as well as free amines which poison catalysts of type 1 [4c]. In case of amines this problem is easily solved by choosing either an appropriate protecting group for nitrogen (e.g. amide, sulfonamide, urethane), or simply by protonation since ammonium salts were found to be compatible with 1 [4c]. As will be discussed in Sect. 4, free amines can also be metathesized in supercritical C02 as the reaction medium [7]. 

Examples of polymeric carriers are presented in Table 1 and typical methods of covalent conjugation are shown below. Drugs may be bound to macromolecular carriers via, e.g., ester, amide, urethane, hydrazone, thioether, and disulfide... 

As mentioned above, the grafting to technique enables in a one-pot reaction the synthesis of Au NPs stabilized by sulfur-containing polymers, which bear functional groups such as dithioester, trithioester, thiol, thioether and disulfide at the end of a polymer chain or in the middle. This method leads to nanoparticles similar to those obtained by the Brust-Schiffrin method in which alkanethiol-protected Au NPs of small size are obtained. This grafting to technique leads to very stable nanomaterials that also present a high surface graft density of polymer brush on the Au NP surface. 

Various sulfur-containing compounds, including thioamides, thioureas, thiols, thioethers and disulfides, are oxidized by this enzyme system. However, unlike cytochromes P-450, it cannot catalyze hydroxylation reactions at carbon atoms. It is clear that this enzyme system has an important role in the metabolism of xenobiotics, and examples will appear in the following pages. Just as with the cytochromes P-450 system, there appear to be a number of isoenzymes, which exist in different tissues, which have overlapping substrate specificities. 

Sodium sulfide and sodium sulfide -f- sulfur Sym. thioethers and disulfides from halides... 

Ar. thiocyanates. A soln. of N-(phenylthio)isatin in chloroform stirred vigorously 1 hr. at room temp, with excess aq. NaCN-soln. phenyl thiocyanate. Y 90%. F. e., also prepn. of thioethers and disulfides, s. M, Furukawa, T. Suda, and S. Hayashi, Chem. Lett. 1974, 881. 

Characteristic IR-Absorption Bands of Mercaptans, Thioethers and Disulfides (in cm )... 

Table 5.18 - Sulfur bases thiols, thioethers and disulfides.

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