Tetrabutylammonium permanganate oxidant

Anilines are converted into nitrosoarenes ArNO by the action of hydrogen peroxide in the presence of [Mo(0)(02)2(H20) (HMPA)]224, whereas catalysis of the reaction by titanium silicate and zeolites results in the formation of azoxybenzenes ArN (0)=NAr225. Azo compounds ArN=NAr are formed in 42-99% yields by the phase-transfer assisted potassium permanganate oxidation of primary aromatic amines in aqueous benzene containing a little tetrabutylammonium bromide226. The reaction of arylamines with chromyl chloride gives solid adducts which, on hydrolysis, yield mixtures of azo compounds, p-benzoquinone and p-benzoquinone anils 234227. 

However, the effects on the rates in nonpolar solvent systems is dramatically larger and often of apparent contradiction. For example, the Hammett rho value for the oxidation of substituted methyl cinnamates and cinnamic acids by tetrabutylammonium permanganate in methylene chloride solutions is positive (33,49). See Figure lb. However, a rho value of converse sign (-0.6) is obtained from a Taft plot (Figure Ic) for the oxidation of vinyl ethers in aqueous tetrahydrofuran (33,50). For many other compounds the Hammett relationships are no longer linear, but concave upward ... 

Tetrabutylammonium permanganate used as the oxidant, (p-Fluorobenzyl)triethylammonium permanganate used as the oxidant. 

Solvent Effects. Information on the effect of solvent polarity of the phase transfer assisted permanganate oxidation of alkenes has been obtained by studying the oxidation of methyl cinnamate by tetrabutylammonium permanganate in tv/o different solvents, acetone and methylene chloride (37). 

Homogeneous oxidations are accomplished with tetrabutylammonium permanganate prepared by treating an aqueous solution of potassium permanganate with tetrabutylammonium bromide and isolating the crystalline precipitate [845, 599]. Tetrabutylammonium permanganate is soluble in dichloromethane, chloroform, acetone, and pyridine and sparingly soluble in benzene ( purple benzene ). 

On the other hand, potassium permanganate is frequently used to prepare carboxylic acids from both aliphatic [86S] and aromatic aldehydes [555]. High yields of carboxylic acids are also obtained by oxidation with tetrabutylammonium permanganate [599] or benzyltriethylammonium permanganate [903] (equation 350). Recently, doubts about the safety of work with quaternary ammonium permanganates have been raised [967]. 

OXIDATION WITH TETRABUTYLAMMONIUM PERMANGANATE (PURPLE BENZENE)... 

Gothe R. 1974. Oxidation with tetrabutylammonium permanganate for quantitation of DDT residues in GLC determination of chlorinated hydrocarbons. Bull Environ Contam Toxicol 11 451-455. 

FeH(CO)4] supported on Amberlyst A-26. ° Tetrabutylammonium permanganate has now been described, permitting permanganate oxidations in pyridine/ Remote positions may be oxidized regioselectively by ozone adsorbed on silica gel/ ... 

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