Other Oxidizing Agents

However, when the primary amino group is on a suitably substituted tertiary carbon, nitro group formation (Equation 10.36) and degradation by carbon-carbon bond cleavage occur. 

More extensive oxidation at both nitrogen-bearing sites 

The oxidation of the primary aromatic amine, aminobenzene (aniline), has been the subject of countless lectures and at least one book. It has been claimed on a number of occasions that this oxidation reaction, which served (in theory if not in practice) as the basis for the establishment of the chemical dye industry (beginning in about 1856), can therefore be thought of as serving as the parent reaction for the entire chemical industry. 

Studies continue into systems involving Ag(II) as an oxidant. The reactions with cyclohexanol, pentan-2-ol, and benzyl alcohol proceed via two pathways  

Evidence has been presented for an atom transfer redox process in the reduction of Au(III) by dialkyl sulfides in aqueous methanol. The two-stage reaction involves initially a substitution equilibrium which is strongly dependent on the bulkiness of the entering sulfide. A second mole of disulfide is required in the subsequent redox reaction leading to Au(I) and sulfoxide. The attack occurs via a chlorine atom of the AuCl reagent which is transferred to the sulfur, leaving an electron pair at the metal center. The reaction is markedly solvent dependent. 

The oxidation of tellurium(IV) by chloramine T is thought to proceed via a reaction with CI2 as the reacting species with the product toluene-p-sulfon-amide acting as an inhibitor to the process. Although [H ] does not appear to affect the rate of reduction of Te(IV) by ascorbic acid, which is first order with respect to each reagent, chloride ions from the HCl medium are involved in the overall reaction. 

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Because of their use in the rubber industry various sulfenamido thiazoles (131) have been prepared. They are obtained in good yields through the oxidation of A-4-thiazoline-2-thiones (130) in aqueous alkaline solution in the presence of an amine or ammonia (Scheme 66) <123, 166, 255, 286, 308, 309). Other oxidizing agents have been proposed (54, 148. 310-313) such as iodine (152), chlorine, or hydrogen peroxide. Disulfides can also be used as starting materials (3141. 

Thiazolecarboxaldehydes are very easily oxidized to carboxylic acids by most oxidizing agents, the most common being KMn04 in cold pyridine or boiling acetone. Thiazolecarboxylic acids are obtained in 50% yield (29). Other oxidizing agents such as Ag 0 in dioxane and water (29, 103), chromic acid, and so forth are also used. 

The quantitative conversion of thiosulfate to tetrathionate is unique with iodine. Other oxidant agents tend to carry the oxidation further to sulfate ion or to a mixture of tetrathionate and sulfate ions. Thiosulfate titration of iodine is best performed in neutral or slightly acidic solutions. If strongly acidic solutions must be titrated, air oxidation of the excess of iodide must be prevented by blanketing the solution with an inert gas, such as carbon dioxide or... 

Pyridazine-3,6-diones (diazaquinones) are prepared from cyclic hydrazides by oxidation with lead tetraacetate or other oxidizing agents, such as r-butyl hypochlorite, chlorine or nickel peroxide. 

Measures color of iodine liberated Other oxidizing agents... 

Wet Oxidation (WO) The oxidation of oxidizable substances in water using the oxygen in air, pure or enriched oxygen, hydrogen peroxide, nitric acid or some other oxidizing agent as the source of the oxidant. The oxidation process is conducted at subcritical temperatures (<374°C). 

Other oxidizing agents that can be used include nitric acid, hydrogen peroxide, peroxydisulfate, chlorate and the pervanadyl ion. The anhydrous... 

Fortunately, the oxidation of l,2 5,6-di-0-isopropylidene-a-D-glucofura-nose to l,2 5,6-di-0-isopropylidene-a-D-nfoo-hexofuranos-3-ulose (1) can be accomplished using either phosphorus pentoxide (10, 44) or acetic anhydride (10, 52) in methyl sulfoxide although this oxidation is effected with ruthenium tetroxide (6,7, 46), it is exceeding difficult with other oxidizing agents (53). Keto-sugar 1 is reduced stereospecifically... 

Most other oxidizing agents, such as chromium trioxide (0rO3) in aqueous acid, oxidize primary alcohols directly to carboxylic acids. An aldehyde is involved as an intermediate in this reaction but can t usually be isolated because it is further oxidized too rapidly. 

Iodoxybenzene has been prepared by the disproportionation of iodosobenzene,4Hi by oxidation of iodosobenzene with hypo-chlorous add or bleaching powder,7 and by oxidation of iodobenzene with hypochlorous acid or with sodium hydroxide and bromine.8 Other oxidizing agents used with iodobenzene include air,3 chlorine in pyridine,9 Caro s acid,19-11 concentrated chloric acid,15 and peracetic acid solution.13 Hypochlorite oxidation of iodobenzene dichloride has also been employed.14... 

Other oxidizing agents may he used to degrade cyclobutadieneiron tricarbonyl in those cases in which the reactants or products are sensitive to the acidic ceric ammonium nitrate solutions, lead tetraacetate in pyridine can be used. 

Lithium dialkylcopper reagents can be oxidized to symmetrical dimers by O2 at -78°C in THF. The reaction is successful for R = primary and secondary alkyl, vinylic, or aryl. Other oxidizing agents (e.g., nitrobenzene) can be used instead of O2. Vinylic copper reagents dimerize on treatment with oxygen, or simply on standing at 0°C for several days or at 25°C for several hours, to yield LS-dienes." ... 

With other oxidizing agents, mechanisms are less clear. It seems certain that... 

When hydrazones are oxidized with HgO, Ag20, Mn02, lead tetraacetate, or certain other oxidizing agents, diazo compounds are obtained ... 

Among other oxidizing agents that have been used to accomplish the conversion of ArCHs to ArCHO are ceric ammonium nitrate, ° ceric trifluoroa-cetate, and silver(II) oxide.Oxidation of ArCHa to carboxylic acids is considered at 19-11. 

The ortho diphenolic structure of apomorphine makes it a strongly reducing substance hence, in acid medium it forms the blue colored or//io-qulnone (6) with iodine or other oxidizing agent which is in equilibrium with its zwitterionic limiting structure (7) (Pellargi s reaction [14]). 

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