Reactions with KMnO

Reaction of ethene with KMnO and the formation of brown Mn02 solution. 

Alkynes. like alkenen, can be cleaved by reaction with powerful oxidiziif af nts such as ozone or KMnO. A triple bond is generally less reactive tha a double bond, however, and yields of denva products are sotnetimeskw The products obtained from cleavage of an tncsmal alkyne are carboxvik acids from a terminal alkyne. CO is formed as one product. 

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 ... 

Diols are oxidatively cleaved by reaction with periodic acid (HIO4) to yield carbonyl compounds, a reaction similar to the KMnO cleavage of aJkenes just discussed. The sequence of (1) alkene hydroxylation with OsO< j followed by (2) diol cleavage with HIO4 is often an excellent alternative to direct alkene cleavage with ozone or potassium permanganate. 

Confirm completion of tfie reaction by TLC with elution of a few drops of the reaction mixture with hexane/ethyl acetate (2 1 v/v). Reveal with KMnO solution. Consider the reaction completed when the spot for A-501 is no longer visible on TLC or when no intensity changes in the spots are detectable (see Note 3). 

The redox titration is carried out using permanganate and oxalic acid. First, a known excess amount of KMnO is added into the sample HCOOH solution, which is adjusted to alkaline pH using Na,CO. prior to the addition of permanganate warm the solution to facilitate the redox reaction then add a known excess amount of oxalic acid solution and a small amount of H,SO, to the mixture to dissolve the precipitated MnO. Excess oxalic acid is back titrated with KMnO. A blank titration should be conducted to determine the background values of the reagents and the water used. 

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

Figure 5. Sequential scanning of the reaction from 350 nm to 700 nm during the Mn04 reaction with TCE at conditions [KMnO = 0.158 mM,...

PHAs containing pendant diol groups were synthesized from unsaturated polymers poly[(/ )-3-hydroxyoctanoate-ct)-(/ )-3-hydroxyundecenoate] by treatment with KMnO in cold alkaline solution (pH 8-9) at 20°C (Lee et al. 2000b). The chemical reaction did not cause PHA hydrolysis (or at least not to a high extent) since no severe rednction in molecular weight was observed. The hydroxylated polymers had a considerably enhanced hydrophilicity since they showed increased solnbility in polar solvents such as an acetone/water mixture, methanol and dimethyl sulphox-ide (Lee et al. 2000b). 

Oxidation of toluene with KMnO under normal conditions of refluxing takes 10-12 hr compared to reaction in microwave conditions which takes only 5 min and the yield is 40% (Scheme 5). 

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... 

Similarly to ONSH reaction in nitroarenes with carbanions proceeds ONSH with diphenylphos-phine anion. At low temperature in liquid ammonia, this anion adds to p-fluoronitrobenzene at the ortho position subsequent oxidation of the produced a -adduct with KMnO gives... 

The exo face of bicyclo[2.2.1]hept-2-ene (norbornene) is less sterically hindered than the mdo face. Based on this information, write the product of reaction of norbornene with KMnO. ... 

They worked out such reactions with alcohols also along with aldehydes (2007). Use of hydrogen peroxide and KMnO as oxidants for HjPV2MOjqO catalyzed oxidation of aromatic aldehydes to the corresponding carboxylic acids under mild conditions has been reported by Shojaei et al. (2011). This system provides an efficient, convenient and practical method for the oxidation of aromatic aldehydes. 

Ketones are inert to most oxidizing agents but undergo a slow cleavage reaction when treated with hot alkaline KMnO The C-C bond next to the carbonyl group is broken, and carboxylic acids are produced. The reaction is useful primarily for symmetrical ketones such as cyclohexanone because product mixtures are formed from unsymmetrical ketones. 

Problem 13.22 Give the main products of reaction of 1-propanol with (a) alkaline aq. KMnO solution during distillation (b) hot Cu shavings (c) CH3COOH, H". 

If 4 mL of 0.001 M KMnO solution is used to react completely with 250 mL of saturated CaC204 solution according to the above reaction, what will be the Kj,p of CaC204 under the same conditions ... 

Filter the ppt of CaC204 through paper, wash the ppt thoroughly with boiling w and transfer it quantitatively into a 250-mi beaker. Add 100 ml of boiling w and 20 ml of 1 3 sulfuric acid. Titrate the hot mixt with N/10 KMnO,. The following reaction takes place ... 

J0. A good approach to 1, 2-diols is the hydroxylation of an olefin with reagents such as OsQ or KMnO - The olefin can be made by the Wittig reaction so the disconnections are ... 

This reaction can be used to confirm whether or not a compound is an alkene. When an alkene is treated with cold, alkaline KMnO solution, the violet color of KMn04 solution disappears and turns brown. This is called Baeyer s reaction. 

Our own experience with reactions on crystal surfaces has been confined to oxidations on solid KMnO, and NaMnO, (12). The work began with a curious observation in conflict with literature statements. We found that solid KMnO, stirred with a benzene solution of a secondary alcohol would oxidize the alcohol to a ketone. 

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