Carboxylic acids with potassium permanganate

Methyl groups in pyridopyrazines (64IMC240) and pyridopyrazinones (71TH21500) are oxidized to carboxylic acids with potassium permanganate. Aryl carbinol substituents are also very readily oxidized to benzoyl derivatives in alkaline conditions (76CPB238). Bromina-tion of 2,3-dimethylpyrido[3,4-f ]pyridazine gives the 2,3-bisbromomethyl derivative, whilst... 

D-Arabotetrahydroxybutylbenzo[g]quinoxaline (19) has been oxidized to the 2-carboxylic acid with potassium permanganate and to the 2-aldehyde with potassium metaperiodate. It is converted into the phenylhydrazone of the 2-aldehyde 20 on treatment with phenylhyd-razine under neutral conditions and into the pyrazoloquinoxaline 21 on treatment with phenylhydrazine under acid conditions. ... 

D,L-Ketopinic acid has been prepared by oxidation of bornyl chloride with nitric acid at 20° or with perbenzoic acid in acetic acid from 10,10-dinitrocamphan-2-on or apocamphan-2-ol-l-carboxylic acid with alkaline permanganate and from the oxidation of 10-camphorchlorosulfoxide, obtained from 10-camphorsulfonyl chloride by the action of pyridine, with potassium permanganate. The present procedure represents a simplification of the latter and gives as high an overall yield. ... 

Benzyltriethylammonium permanganate (c/. 3, 9 ) has been suggested as a mild oxidant suitable for converting aldehydes into acids/ but there are problems associated with the handling of this reagent (see refs. 169, 170). Disubstituted acetylenes are oxidatively cleaved to carboxylic acids by potassium permanganate, the nature of the products depending on the solvent mixture used yields are very respectable in a number of cases. ... 

Pyridazine aldehydes and ketones with the carbonyl group at the ring or in a side chain react in the usual manner. They form hydrazones, semicarbazides, oximes, etc. Side-chain aldehydes can be easily oxidized to pyridazinecarboxylic acids with silver nitrate and side-chain ketones are oxidized to carboxylic acids by treatment with potassium permanganate or hydrogen peroxide. 

Alkynyltiiazoles 94 are readily oxidized with potassium permanganate in acetone to the corresponding l,2,3-tiiazole-5-carboxylic acids (95). 

Cyanide and thiocyanate anions in aqueous solution can be determined as cyanogen bromide after reaction with bromine [686]. The thiocyanate anion can be quantitatively determined in the presence of cyanide by adding an excess of formaldehyde solution to the sample, which converts the cyanide ion to the unreactive cyanohydrin. The detection limits for the cyanide and thiocyanate anions were less than 0.01 ppm with an electron-capture detector. Iodine in acid solution reacts with acetone to form monoiodoacetone, which can be detected at high sensitivity with an electron-capture detector [687]. The reaction is specific for iodine, iodide being determined after oxidation with iodate. The nitrate anion can be determined in aqueous solution after conversion to nitrobenzene by reaction with benzene in the presence of sulfuric acid [688,689]. The detection limit for the nitrate anion was less than 0.1 ppm. The nitrite anion can be determined after oxidation to nitrate with potassium permanganate. Nitrite can be determined directly by alkylation with an alkaline solution of pentafluorobenzyl bromide [690]. The yield of derivative was about 80t.with a detection limit of 0.46 ng in 0.1 ml of aqueous sample. Pentafluorobenzyl p-toluenesulfonate has been used to derivatize carboxylate and phenolate anions and to simultaneously derivatize bromide, iodide, cyanide, thiocyanate, nitrite, nitrate and sulfide in a two-phase system using tetrapentylammonium cWoride as a phase transfer catalyst [691]. Detection limits wer Hi the ppm range. 

Primary alcohols are readUy oxidised to carboxylic acids with common oxidising agents such as potassium permanganate (KMn04) in neutral, acidic or alkaline media or by potassium dichromate (K2Cr207) and chromium trioxide (CrOg) in acidic media (Jones reagent). 

Oxidation of 6-formyl-5,7,8,9-tetrahydro-ll//-pyrido[2,l-b]quinazolin-11-one with potassium permanganate in pyridine at ambient temperature for 3 h gave 11 -oxo-5,7,8,9-tetrahydro-l 17/-pyrido[2,l-b]quinazoline-6-carboxylic acid in 24% yield (84JHC1301). 

Oxidation of 2-methylpyrrole under more vigorous conditions with potassium permanganate or chromic acid produces pyrrole-2-carboxylic acids or maleimides (see Section 3.05.1.4). 

Potassium permanganate oxidation of a vinyl group to a carboxyl group can be used to prepare fluorinated carboxylic acids with aliphatic (. < ] (equauon 30) or alicyclic [39] (equation 31) skeletons... 

Stearoyloxyethyl) - 2 - (N - piperidinomethyl)quinuclidine (66) was converted by Kraft s reaction into an unsaturated compound (67) which formed 2-Ar-piperidinomethylquinuclidine-3-carboxylic acid (68) by oxidation with potassium permanganate.123... 

In the course of investigations on allylic and acetylene-allene rearrangements of 3-substituted quinuclidines, it was found that by oxidation and ozonolysis of compounds with functional groups at positions allylic to the double bond, not only the double bonds but also the adjacent carbon-carbon bonds are broken. For example, in the oxidation of 3-hydroxy-3-vinylquinuclidine (119), with potassium permanganate under mild conditions, and in its ozonolysis, qui-nuclidin-3-one (2) is formed along with 3-hydroxy quinuclidine-3-carboxylic acid.161 The positions of double bonds in such systems can be firmly established by NMR spectroscopy, but not by oxidative methods.101... 

Alkenes can be cleaved with potassium permanganate to produce carboxylic acids (Following fig.). A vinylic proton must be present, that is a proton directly attached to the double bond. 

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