Thiols, reaction + aldehydes

Mino and Kaizerman [12] established that certain. ceric salts such as the nitrate and sulphate form very effective redox systems in the presence of organic reducing agents such as alcohols, thiols, glycols, aldehyde, and amines. Duke and coworkers [14,15] suggested the formation of an intermediate complex between the substrate and ceric ion, which subsequently is disproportionate to a free radical species. Evidence of complex formation between Ce(IV) and cellulose has been studied by several investigators [16-19]. Using alcohol the reaction can be written as follows ... 

Transition metals such as iron can catalyze oxidation reactions in aqueous solution, which are known to cause modification of amino acid side chains and damage to polypeptide backbones (see Chapter 1, Section 1.1 Halliwell and Gutteridge, 1984 Kim et al., 1985 Tabor and Richardson, 1987). These reactions can oxidize thiols, create aldehydes and other carbonyls on certain amino acids, and even cleave peptide bonds. The purposeful use of metal-catalyzed oxidation in the study of protein interactions has been done to map interaction surfaces or identify which regions of biomolecules are in contact during specific affinity binding events. 

The reaction of thiols with aldehydes and ketones parallels that of alcohols. However, the reactions are more favourable because sulfur is a better nucleophile than oxygen (see Section 6.1.2). Electrons in larger atoms are more easily polarizable and it becomes easier for them to be donated to an electrophile. 

With nucleophiles such as alcohols (enolates) and thiols, reaction with aldehydes yields the corresponding addition products.31... 

Reaction of thiols with aldehydes or ketones leads to formation of water and geminal bis(alkylthio) compounds, which, when derived from aldehydes, are known as mercaptals or, when derived from ketones, as mercaptols ... 

Nnmerons flavor componnds are formed by caramelization, Maillard or Strecker reactions, or the oxidation of phenolic compounds and terpenes. Some classes of flavor componnds fonnd in frying foods are furan derivatives, pyrrole derivatives, pyrazines, thiols, snlfldes, aldehydes, and aromatic compounds from phenol oxidation (Pokomy, 1999). 

These polymers form from reactions of di thiols with aldehydes or ketones ... 

Chapter 12, Alcohols, Thiols, Ethers, Aldehydes, and Ketones, previously titled Organic Compounds with Oxygen and Sulfur, describes the functional groups and names of alcohols, thiols, ethers, aldehydes, and ketones. The solubility of alcohols, phenols, aldehydes, and ketones in water is discussed. Section 12.4 is now titled Reactions of Alcohols, Thiols, Aldehydes, and Ketones. ... 

Miscellaneous Curing Reactions. Other functional groups can react with the thiol terminal groups of the polysulfides to cross-link the polymer chains and build molecular weight. For example, aldehydes can form thioacetals and water. Organic and inorganic acids or esters can form thioesters. Active dienes such as diacrylates can add to the thiols (3). Examples of these have been mentioned in the Hterature, but none have achieved... 

A wide variety of products can be obtained by thioalkylation (42). The reactants ate usually an aldehyde, a thiol, and either a phenol, a sulfone, an amine, or a heterocychc compound. Phenols primarily react with formaldehyde in a process known as thiomethylation (eq. 26). Other types of reactions are depicted in equations 27 and 28. 

Aldehydes and ketones react with thiols to yield thioacetals just as they react with alcohols to yield acetals. Predict the product of the following reaction, and propose a mechanism ... 

Osmium tetroxide, reaction with alkenes, 235-236 toxicity of, 235 Oxalic add, structure of, 753 Oxaloacetic acid, structure of, 753 Oxetane, reaction with Grignard reagents, 680 Oxidation, 233, 348 alcohols, 623-626 aldehydes, 700-701 aldoses, 992-994 alkenes, 233-236 biological, 625-626 phenols, 631 sulfides, 670 thiols, 668... 

Penicilloic acid 5, the substrate for the projected lactamization reaction, could be derived from the suitably protected intermediate 6. Retrosynthetic disassembly of 6, in the manner illustrated, provides D-penicillamine hydrochloride (7) and tert-butyl phthalimido-malonaldehydate (8) as potential building blocks. In the synthetic direction, it is conceivable that the thiol and amino groupings in 7 could be induced to converge upon the electrophilic aldehyde carbonyl in 8 to give thiazolidine 6 after loss of a molecule of water. 

Aldehydes, both aliphatic and aromatic, can be decarbonylated by heating with chlorotris(triphenylphosphine)rhodium or other catalysts such as palladium. The compound RhCl(Ph3P)3 is often called Wilkinson s catalyst.In an older reaction, aliphatic (but not aromatic) aldehydes are decarbonylated by heating with di-tert-peroxide or other peroxides, usually in a solution containing a hydrogen donor, such as a thiol. The reaction has also been initiated with light, and thermally (without an initiator) by heating at 500°C. 

Aldehydes and ketones have been converted to sulfides by treatment with thiols and pyridine-borane, RCOR -I- R"SH —+ RR CHSR", in a reductive alkylation reaction, analogous to 16-6. 

Reaction between an aldehyde, anunonia, and a thiol (Mannich)... 

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