Oxidation by KMnO

Salts containing tetravalent tungsten have been prepared by various methods. The most important are the octacyanides, M(I)4(W(CN)g), which form yellow crystals and are very stable. They are isolated as salts or free acids and can be oxidized by KMnO in H2SO4 to compounds containing pentavalent tungsten, M(I)2(W(CN)g) (yellow). 

Table 17. Oxidations by KMnO in benzene in the presence of dicyclohexyl-18-croum-6 at 25 °C (S3)...

Formation of enaminoesters from acetylated 1- and 2-amino sugars (JV-Gluco- and A -Galacto-pyranosylamines) and successive oxidation by KMnO -NaTO allowed the... 

Thermolysis of syn- and anri-perfluoro-octamethyltricyclo[4,2,0,0 ]octa-3,7-diene, perfluoro-octamethylcubane, or perfluoro-octamethylcuneane at 300 C gave perfluoro-octamethylcyclo-octatetraene, which was stable at 400°C, was not oxidized by KMnO in acetone, and could not be chlorinated at temperatures below 200°C. Photolysis of perfluoro-octamethylcyclo-octatetraene gave mixtures of starting materials. 

K Cr O or benzylic oxidations by KMnO. In these examples Cr and Mn, in the oxide form, will be generated as byproducts. 

The ONSH in nitroarenes with carbanions carried out at low temperature and KMnO in liquid ammonia or DDQ and DMD in THF/DMF is a general process. For instance, this reaction has found valuable application for introduction of nitroaryl and hydroxyaryl substituents into molecules of a-amino acids. Thus, carbanions of esters of protected amino acids upon addition to nitroarenes form o -adducts that are oxidized by KMnO in liquid ammonia or DDQ in THF/ DMF. The subsequent hydrolysis produces a-nitroaryl a-amino acids (Scheme 11.7) [15]. 

Ketones are oxidized by potassium permanganate or by sodium hypochlorite (91) in aqueous solution to the corresponding acids. For example, oxidation of 5-acetylthiazole with aqueous KMnO at 70°C gives 5-thia-zolecarboxylic acid. 

Oxidation of Sucrose. Sucrose can be oxidized by HNO, KMnO, and peroxide. Under selected conditions using oxygen with palladium or platinum, the 6- or 6 -hydroxyls can be oxidized to form sucronic acid derivatives (29). 

Oxidation to adds by KMnO 100 °C subsequent acces to acyl chlorides nitriles, amides J deprotcnation by tBuOK followed by alkylation or functionalization fay electrophiles... 

Problem 11.50 Explain why the oxidation of PhCH, to PhCOOH by KMnO, or K Cr O, and H goes in poor yield, whereas the same oxidation of p-O NC HjCH, to p-O.NCjH COOH goes in good yield. -4... 

Problem 16.53 Deduce a possible structure for each of the following, (a) Compound (A), CftHdilute acid and base and its dipole moment is zero, (b) Compound (B). CgH,NO, is insoluble in dilute acid and base. (B) is transformed by KMnO, in HjS04 to compound (C), which is free of N, soluble in aqueous NaHCO, and gives only one mononitro substitution product, (c) Compound (D), C,H,N02, undergoes vigorous oxidation to form compound (E), C,HjN04, which is soluble in dilute aqueous NaHCOj and forms two isomeric monochloro substitution products. ... 

Alkenes give diols after oxidation by cold, dilute KMnO solution, n bonds are broken but a bonds are not affected by this oxidation. 

Unfortunately, such selective oxidations were not possible because primary alcohols form small amounts of carboxylic acid under the reaction conditions these acids efficiently inhibit oxidation, thereby accounting for the apparent Inertness of primary alcohols. When a secondary alcohol was mixed with a primary alcohol, neither was oxidized by the solid reagent in good yield. An oxidation of a secondary alcohol over crystalline KMnO would immediately cease when octanolc acid was added in tiny amounts to the benzene. The octanolc acid presumably binds to "active sites" at the crystal surface and Impedes the reaction by an unknown mechanism. 

The oxidation of maleic acid by KMnO gives mesotartaric acid. 

Alkyne oxidation reactions are of little value now but were used bi > tortcally in Uie structure -detemiination of substances isolated fron) nau-ral sources. For example, the location of the triple bond in the chain of tariric acid was established by finding that oxidation with KMnO., gax e dodecar. c add and hexanedioic acid ... 

Problem 8.A Prapot stmeiures for olkynei that ipve the followirtt product on oxidative cleif age by KMnO, ... 

Tetrachloropyridine may be prepared from pentachloropentadiene nitrile by Grignard reaction, followed by oxidation with KMnO and decarboxylation according to the following reaction scheme ... 

Zinnes and co-workers have observed oxidative ring contraction of compound 125 to N-methylsaccharin (126) by KMnO and 10% sulfuric acid at reflux. 

The most common nncleophiles that are resistant toward oxidation are ammonia and hydroxide anion. Indeed, such strong oxidant as KMnO is soluble in liquid ammonia and forms solutions that are stable even at room temperature (under pressure). These solutions are efficient agents for amination of electron-deficient nitroarenes and azines that proceeds via addition of ammonia to the ring, followed by oxidation of the o -adducts with KMnO. This amination process of azines is often referred to as the oxidative Chichibabin reaction [7]. For instance, the reaction... 

Diels-Alder reaction followed by dehydrogenation of the cycloadduct using KMnO supported on alumina under mild conditions has been reported (Scheme 16.20) [21]. Two other dihydroaromatic substrates (cycloadducts shown in the box) that have been oxidized by this method are also... 

The effects of various solvents in which HxBr is to react with solid KCl in order to convert it to HxCl with the PTC of Bu NBr at 70°C were studied by Danilova and Yufit [83]. Expressed as the rate constants log( /s ) they are shown in Table 8.10, reaction A. Also shown in Table 8.10 are the rate constants log(A /s ) for fewer, but all water-immiscible solvents in biphasic reactions for the following reaction B—oxidation of 5-vinylnorbomene with a combination of aqueous Na WO, HjPO, and with Bu N HSO as the PTC at 30°C studied by Wang et al. [84] reaction C— phenolysis of 1-bromoethylbenzene by aqueous KOH with Bu N+Br as the PTC at 50°C studied by Wu et al. [85] reaction D—conversion of BuBr with aqueous Na S and the same PTC at 30°C studied by Wang et al. [86] and reaction E—oxidation of 3,5-di-t-butyl-catechol by KMnO catalyzed by dicyclohexyl-8-crown-6 (Section 8.3.1) at 25°C studied by Nakamura et al. [87]. Some authors attempted to relate the rates to the... 

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