Potassium permanganate primary amines

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. 

Since many aliphatic primary amines are usually prepared by methods not involving the reduction of a nitroalkane (cf. aromatic amines), their oxidation may provide a useful route to this class of compound. For amines which lead to tertiary nitroalkanes, potassium permanganate appears to be the most satisfactory reagent198 (the preparation of 2-nitro-2-methylpropane, Expt 5.191). In the case of amines which lead to primary or secondary nitroalkanes the oxidant of choice is m-chloroperbenzoic acid, and Expt 5.191 includes a general procedure for this reaction.199... 

A great variety of 3-alkyl- and 3-aryl-1,2,4,5-tetrazines can also easily be alkylaminated when treated with appropriate primary alkylamines in the presence of potassium permanganate (Scheme 30). The yields vary depending on the size of the alkyl group in the amine. Attempts to introduce an arylamino group were unsuccessful. 

The popularity of the Nef reaction is due in part to the ready availability of nitro compounds. Primary and secondary halides react with sodium nitrite in dimeAyl sulfoxide (DMSO) or dimethylform-amide (DMF) to give useful yields of nitro compounds. Primary amines can be oxidized to nitro compounds with potassium permanganate, m-chloroperbenzoic acitP or ozone. Chlorination of oximes with hypochlorous acid and reduction with magnesium, zinc or hydrogen/lpalladium gives secondary nitro compounds. Stabilized carbanions can be nitrated by treauitent with a nitrate ester, and enol acetates are nitrated by acetyl nitrate to give nitro ketones. ... 

The spectrum of applications of potassium permanganate is very broad. This reagent is used for dehydrogenative coupling [570], hydrox-ylates tertiary carbons to form hydroxy compounds [550,831], hydroxylates double bonds to form vicinal diols [707, 296, 555, 577], oxidizes alkenes to a-diketones [560, 567], cleaves double bonds to form carbonyl compounds [840, 842, 552] or carboxylic acids [765, 841, 843, 845, 852, 869, 872, 873, 874], and converts acetylenes into dicarbonyl compounds [848, 856, 864] or carboxylic acids [843, 864], Aromatic rings are degraded to carboxylic acids [575, 576], and side chains in aromatic compounds are oxidized to ketones [566, 577] or carboxylic acids [503, 878, 879, 880, 881, 882, 555]. Primary alcohols [884] and aldehydes [749, 868, 555] are converted into carboxylic acids, secondary alcohols into ketones [749, 839, 844, 863, 865, 886, 887], ketones into keto acids [555, 559, 590] or acids [559, 597], ethers into esters [555], and amines into amides [854, 555] or imines [557], Aromatic amines are oxidized to nitro compounds [755, 559, 592], aliphatic nitro compounds to ketones [562, 567], sulfides to sulfones [846], selenides to selenones [525], and iodo compounds to iodoso compounds [595]. 

While oxidative amination of 1,2,4,5-tetrazines 1 occasionally proceeds with high yield (18-81%) to give l,2,4,5-tetrazin-3-amines 2,17 the Chiehibabin hydrazination of 1 affords hydrazines 3 in 9-15% yield. For the oxidative amination ammonia and primary amines are used while for the Chiehibabin hydrazination only hydrazine itself is used. The oxidizing agent of choice is potassium permanganate. 

Dissolving 3-aryl(alkyl)-1,2,4,5-tetrazines (21) in liquid ammonia or primary aliphatic amines at — 35°C to — 40°C, followed by addition of potassium permanganate, gives 6-alkylamino-3-aryl-(alkyl)-1,2,4,5-tetrazines (23) in reasonable to excellent yields. This shows that, under the reaction conditions, addition of A-nucleophiles to the tetrazine ring must have occurred (Scheme 1) <8 JHC123>. The presumption of a 1,6-dihydro intermediate (22) rests on the experimental result that tetrazines can be transformed by sodium borohydride into the isolable 1,6-dihydro-1,2,4,5-tetrazines, which can be considered as neutral homoaromatic systems <8UOC2i38>. 

Amination of 1,2,4-triazine 4-oxides 26 by the action of primary and secondary alkylamines, as well as cycloalk-ylimines, takes place smoothly in acetone solution at -60 to -40 °C through the intermediacy of the ct -adducts 126, which are easily oxidized by potassium permanganate into the corresponding 5-amino-l,2,4-triazine 4-oxides 125 (Scheme 67 Table 11) . 

Compounds whose structure possesses a weakly acidic NH group, such as primary amines, amides, imides, and lactam can be detected by performing a redox reaction through the formation of intermediary N-chloro derivatives. Potassium permanganate reacting with hydrochloric acid generates chlorine (probably at oxidation state +1), which transforms the invoked derivatives in N-chloroamines. The latter derivatives oxidize iodide ions into iodine detected with a starch solution ... 

Rapid oxidation of secondary alcohols may be carried out using hydrated copper permanganate in dichloromethane. Water is an essential component in the reaction. Mixtures of potassium permanganate and copper sulphate may also be used, as may a variety of hydrated metal salts, although in these cases experimental details and yields were not reported. Bispyridinesilver permanganate has been shown to be an efficient reagent, soluble in organic solvents, for the oxidation of benzylic primary amines and alcohols to benzaldehydes. The intermediacy of nitrite esters is implicated in oxidations of alcohols with ferric nitrate on KIO bentonite. ... 

---