Oxidation, acid permanganate

A few kinetic measurements on the acid permanganate oxidation of cyclohexanone have been reported by Littler . The reaction is first order in ketone but the order in oxidant was not clearly established. 

No published work exists on the kinetics of acid permanganate oxidation of hydroxy-acids although Pink and Stewart have noted that benzilic acid is oxidised by acid permanganate to benzophenone in an autocatalytic process with knjo/ Dio of unity. 

Fig. I. Isotope effect for acid permanganate oxidation of mandelic acid. Temperature = 26.2 °C [MnO -] = 1.4x10- M [H SO ] = 1.69 M.

Additional evidence for the stereospecific conversion of fi-O-4 and arylglycerol lignin models to tetronic acids under conditions that selectively oxidize aryl rings also comes from acidic permanganate oxidation (Tsutsumi et al. 1990). This method gives essentially the same products as ozonation. 

Tsutsumi Y, Islam A, Anderson CD, Sarkanen KV (1990) Acidic permanganate oxidations of lignin and model compounds comparison with ozonolysis Holzforschung 44 59-66... 

Oxidation affects both rings of the quinoline system. Alkaline permanganate causes oxidative cleavage of the benzene ring in quinoline and 2-substituted quinolines to give pyridine-2,3-dicarboxylic acid 39 (R = H quinolinic acid). In contrast, acidic permanganate oxidizes the pyridine ring with formation of A-acylanthranilic acid 40 ... 

Bhale VM, Mohammad S, Bhagwat WV, Bafna SL (1953) Acid permanganate oxidation of... 

The close chemical relationship among these stmctural entities, as well as the uniqueness of (1) and (2), have been evident from the time of the earhest stmctural studies. Permanganate oxidation of (1) (2) produces 2,3-pyridinedicarboxyhc acid (quinolinic acid [89-00-9]) (3), whereas similar treatment of (2) (3) yields a mixture of 3,4-pyridinedicarboxyhc acid (cinchomeronic acid [490-11 -9]) (4) and phthaUc acid. 

Potassium permanganate oxidizes succinic acid to a mixture of malic and tartaric acid [133-37-9]. 3-Hydroxypropionic acid [503-66-2] is obtained with sodium perchlorate. Cerium(IV) sulfate in sulfuric acid medium oxidizes succinic acid to oxaloacetic acid (71). 

Chromic acid, permanganic acid, and ferric chloride do not oxidize sulfamic acid. 

Many reactions catalyzed by the addition of simple metal ions involve chelation of the metal. The familiar autocatalysis of the oxidation of oxalate by permanganate results from the chelation of the oxalate and Mn (III) from the permanganate. Oxidation of ascorbic acid [50-81-7] C HgO, is catalyzed by copper (12). The stabilization of preparations containing ascorbic acid by the addition of a chelant appears to be negative catalysis of the oxidation but results from the sequestration of the copper. Many such inhibitions are the result of sequestration. Catalysis by chelation of metal ions with a reactant is usually accomphshed by polarization of the molecule, faciUtation of electron transfer by the metal, or orientation of reactants. 

There are many synthetic routes to alloxan. Probably the best is direct oxidation of barbituric acid (1004 R = H) with chromium trioxide (5208(32)6) but it may be made from barbituric acid via its benzylidene derivative by direct or indirect oxidation of uric acid from 5-chlorobarbituric acid (1004 R = C1) by nitration or from 5-nitrobarbituric acid (1004 R = N02) by chlorination, both via the intermediate (1005) (64M1057) or by permanganate oxidation of uracil (1006) under carefully controlled conditions (73BSF1167). 

The cleavage of fused pyrazines represents an important method of synthesis of substituted pyrazines, particularly pyrazinecarboxylic acids. Pyrazine-2,3-dicarboxylic acid is usually prepared by the permanganate oxidation of either quinoxalines or phenazines. The pyrazine ring resembles the pyridine ring in its stability rather than the other diazines, pyridazine and pyrimidine. Fused systems such as pteridines may easily be converted under either acidic or basic conditions into pyrazine derivatives (Scheme 75). 

Isoxazoles are stable toward peracids and are fairly stable to other acidic oxidizing agents such as chromic and nitric acids, and acidic permanganate. 3-Substituted isoxazoles are... 

---