Thio-compounds

Thio-schwefelsaure, /. thiosulfuric acid, -sul-fatlosung, /. ihiosulfate solution. -sulfo-saure, /. thiosulfonic acid, -verbindung, /. thio compound, -zinnsaure, /. thiostannic acid. 

The mechanism of secondary stabilization by antioxidants is demonstrated in Figure 15.5. TnT-nonylphenyl phosphites, derived from PCI3 and various alcohols, and thio-compounds are active as a secondary stabilizer [21], They are used to decompose peroxides into non-free-radical products, presumably by a polar mechanism. The secondary antioxidant is reacting with the hydroperoxide resulting in an oxidized antioxidant and an alcohol. The thio-compounds can react with two hydroperoxide molecules. 

FIGURE 15.5 Secondary stabilization by phosphates and thio-compounds. 

The process outlined above led to the provision of the necessary quantities of hydrogen for the reduction of CO2, CO, N03 and other oxidized starting materials, which were in turn converted to biomolecules in further reaction steps. The question as to whether contemporary living cells contain relicts, in the form of thioesters or thio compounds, which indicate the great importance of this class of substances, can clearly be answered positively. 

Lignin may be defined as the incrusting material of the plant which is built up mainly, if not entirely, of phenylpropane building stones it carries the major part of the methoxyl content of the wood it is unhydrolyzable by acids readily oxidizable, soluble in hot alkali and bisulfite, and readily condenses with phenols and thio compounds (14). 

Wohler s synthesis of urea by which a product of the living cell was first prepared artificially more than a century ago is the prototype of many addition reactions which take place with the reactive molecules of cyanic acid and its esters, as well as with the series of analogous thio-compounds. In these reactions NH3 is added to the C = N double bond ... 

In thio compounds, desulfuration results from substitution of sulfur by oxygen (e.g parathion). This example again illustrates that biotransformation is not always to be equated with bioinactivation. Thus, paraoxon (E600) formed in the organism from parathion (E605) is the actual active agent (p. 102). 

Some alkyl and aryl-thio compounds are known, most being prepared by nucleophilic displacement of halo or nitro groups. Examples of furazans fused to dithianes have also been described bis-furazan (75) can be prepared either by dehydration of the tetraoxime or by reaction of potassium thiocyanate with dinitrofurazan <95MI 405-03). 

Treatment of the imine (47) with phosphoryl chloride in dimethylformamide gives the Vilsmeier salt (48) which when reacted with sodium hydrogen sulfide gives the thio compound (49) (Scheme 12) <81AX(B)1449>. 

About 100 fungicides me required for these various uses in the United States. The principal ones are sulfur, liine-sulfur (polysulfides of calcium) copper sulfate (or ils equivalent in the oxides, basic sulfates, oxychloride and other relatively insnluhle copper compounds) creosote products and zinc chloride, both used as wood preservatives and a wide variety of organic compounds. Among the latter are several dithiocarbamates. such as ferbam and zineb, and other thio compounds, like N-(trichloronielhyllhio>-phthalimide (folpel) cis-NfI Irtchloroniclhy] Jthio)-4-cyclohexane- 1.2-dicaiboxyimide (captan) and 8-hydroxyquinoline. 

Table I, containing compounds 26-87, summarizes all pseudoazulenes known through July 1979, as well as the corresponding literature. Not included are hydroderivatives of known and hitherto unknown pseudo-azulene systems containing many oxo and thio compounds. Such pseudoazulenes are predominantly of the type produced by introduction of an NR group. Only one system (78) of pseudoazulenes containing a selenium group is known, whereas tellurium compounds are unknown because of difficulties...

This reaction is widely utilised in organic synthesis, when carbonyl groups may be protected as the thioacetals or thioketals. Unlike acetals or ketals, the thio compounds do not undergo acid catalysed hydration, and may be used in acidic reaction conditions. The metal-directed hydrolysis is rationalised in terms of the soft-soft interaction of the sulfur with the metal cation, in contrast to the hard-soft interaction with a proton. Hydrolysis is readily achieved on treatment with aqueous mercury(n) or silver(i) salts. Once again, the... 

Biostabilizers Copper quinolinolate, phenoxarsines, phthalimides, thio compounds... 

Cimetidine is manufactured by the action of a substituted guanidine on an amino-thio compound in the presence of methyl cyanide. 

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