Thioethers Sulfides

14-10 Sulfides are also called thioethers because they are the sulfur analogues of ethers. 

Sulfides ate easily synthesized by the Williamson ether synthesis, using a thiolate ion as the nucleophile. 

Thiols ate more acidic than water. Therefore, thiolate ions are easily generated by treating thiols with aqueous sodium hydroxide. 

Because sulfur is larger and mote polarizable than oxygen, thiolate ions are even better nucleophiles than alkoxide ions. Thiolates are such effective nucleophiles that secondary alkyl halides often react to give good yields of 8 2 products. 

Show how you would synthesize butyl isopropyl sulfide using 1-butanol, 2-propanol, and any 

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In general most of the commercial polymers are not comparable to metals and ceramics in terms of load-bearing property, mechanical strength, and thermal stability. To overcome these difficulties the aromatic ether or sulfide (thioether) linkages in the polymer backbone... 

Alone formed by the reaction of lithium aluminum hydride and aluminum chloride in ether cleaves exclusively the carbon-oxygen bond in cyclic monothioketals derived from ketones and mercaptoethanol, and on refluxing in 100% excess for 2 hours produces -hydroxyethyl sulfides (yields 66-91%) on prolonged heating with the reagent these -hydroxyethyl sulfides are further reduced to the corresponding ethyl sulfides (thioethers) (yields 28-81%) [936]. 

S-oxidation. Aromatic and aliphatic sulfides, thioethers, thiols, thioamides, and thiocarba-mates may undergo oxidation to form sulfoxides and then, after further oxidation, sulfones (Fig. 4.23). 

The product is a sulfide (thioether). Retrosynthetic analysis reveals a pathway that begins with benzene and acetic anhydride. 

Substitution of alkyl and aryl groups for H on H2S yields thiols and sulfides (thioethers). Structural formulas of examples of these compounds are shown in Figure 17.2. 

A minor change from previous volumes is the inclusion of thiols with all alcohol classifications and sulfides (thioethers) are classified with ethers. Both of these changes are reflected in the chapter titles, section titles, and citations. These changes do not alter the fundamental organization. 

One-electxon oxidation of organic sulfides (thioethers) leads primarily to a sulfur-centered radical cation, R2S, which is stabilized either by resonance (e.g. if R = Aryl) or interaction with a free electron pair provided by a second sulfur atom (typically in the case of aliphatic sulfides). The latter stabilization occurs inter- or intm-molecularly with the former depending on the sulfide concentration, while the intramolecular process requires a geometry of the two interacting p orbitals which is favorable for overlap. This concept has been verified in numerous experiments and supported by theoretical calculations. ... 

Judging from the commonly used structures I, II, and III, we might expect each of these compounds to have the properties of a conjugated diene and of an amine, an ether, or a sulfide (thioether). Except for a certain tendency to undergo addi-... 

SULFIDES, THiOETHERS, SULFOXIDES, SULFONES, AND AMINE-OXIDES RSR, RSOR, OR RSO2R ... 

The metabolism of sulfides (thioethers) is rather straightforward. Besides the S-deal-kylation reactions discussed earlier, these compounds can also be oxygenated by monooxygenases to sulfoxides (reaction 2-A) and then to sulfones (reaction 2-C). Here, it is known with confidence that reaction 2-A is indeed reversible, as documented by many examples of reduction of sulfoxides (reaction... 

The first step in the addition of hydrogen sulfide to unsaturated compounds is the formation of thiols, but further reaction can occur, yielding sulfides (thioethers), the latter being favored by using an excess of the olefin.5... 

In the presence of Friedel-Crafts catalysts, sulfur may replace an atom of hydrogen in each of two molecules, yielding sulfides (thioethers, RSR ) this method was used, for example, for preparation of diphenyl sulfide245 and of phenothiazine246 and its derivatives.247... 

Sulfides (thioethers) can be obtained by replacing the halogen of alkyl and suitable aryl halides in a reaction with sodium sulfide, this being analogous to the preparation of thiols and disulfides. The reaction is usually carried out... 

Once simple sulfides (thioethers) enter the systemic circulation, they are rapidly oxidized to sulfoxides and, depending on the structure of the thioether, may be further oxidized to sulfones. Aliphatic thioethers yield mixtures of sulfoxide and sulfone urinary metabolites (Damani, 1987). Enzymes of the cytochrome P450 superfamily and flavin-containing monooxygenases catalyse the oxidation of thioethers to sulfoxides (Renwick, 1989). Oxidation of sulfoxides to the corresponding sulfones occurs both in tissues and in aerobic microorganisms and is an irreversible metabolic reaction in mammals (Damani, 1987). Sulfoxides can also be metabolized back to the thioether by thioredoxin and its reductase and by the gut microflora in the anaerobic environment of the lower bowel (Lee Renwick, 1995). 

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