Ammonium nitrite permanganate

Finally, some ammonium salts undergo an oxidation-reduction reaction when heated. Common salts of this type are ammonium dichromate, ammonium permanganate, ammonium nitrate, and ammonium nitrite. When these salts decompose, they give off nitrogen gas and water. 

The immediate outcome of the Hantzsch synthesis is the dihydropyridine which requires a subsequent oxidation step to generate the pyridine core. Classically, this has been accomplished with nitric acid. Alternative reagents include oxygen, sodium nitrite, ferric nitrate/cupric nitrate, bromine/sodium acetate, chromium trioxide, sulfur, potassium permanganate, chloranil, DDQ, Pd/C and DBU. More recently, ceric ammonium nitrate (CAN) has been found to be an efficient reagent to carry out this transformation. When 100 was treated with 2 equivalents of CAN in aqueous acetone, the reaction to 101 was complete in 10 minutes at room temperature and in excellent yield. 

More accurate results may be secured by adding the nitrite to an acidified solution in which permanganate is present in excess (the tip of the pipette containing the nitrite solution should be below the surface of the liquid during the addition), and back-titrating the excess potassium permanganate with a solution of ammonium iron(II) sulphate which has recently been compared with the permanganate solutioa... 

Several explosive salts including the acetylide, azide, borate, bromate, chlorate, chromate, iodate (and ammonium iodate double salt), nitrite, perchlorate (and ammonium perchlorate double salt), periodate, permanganate, picrate and trinitrobenzoate were prepared. The 3 latter salts and the acetylide, azide and bromate are impact-sensitive detonators [1], It appears probable that many of the explosively unstable compounds [2], formed in various ways from interaction of mercury or its compounds with ammonia or its salts, may have the common polymeric structure now recognised for Millon s base [3], This is a silica-like network of N+ and Hg in 4- and 2-coordination, respectively, with OH and water in the interstitial spaces. Individually indexed compounds are Poly(dimercuryimmonium acetylide)... 

Ammonium Salts Which are Explosive, examined by H.Kast and described in SS 21, 205-9(1926) and SS 22, 6-9, 30-4, 56-61, 77-80, 99-102 131-5(1925) included azide, bichromate, chlorate, nitrate, nitrite, perchlorate, permanganate and trichromate... 

Preparation of Fremy s salt a freshly prepared sodium bisulfite solution (100 ml) is added to a mixture of sodium nitrite (345 g) and ice (200 g) in a 1-1 beaker. On addition of 20 ml of glacial acetic acid, the reaction mixture turns black. Concentrated ammonium hydroxide (25 ml) is added and the mixture is cooled in an ice bath. A 0.2 M solution (400ml) of potassium permanganate is added dropwise over 1 h and the black precipitate which forms is immediately removed by filtration. A saturated solution of potassium chloride (250 ml) is added slowly over a 45-min period while the filtrate is gently stirred in an ice water bath. The precipitate that forms is collected by filtration and washed successively with a saturated solution of potassium chloride and methanol, each containing 5% of concentrated ammonium hydroxide and, finally, with acetone. Fremy s salt should be stored in a desiccator over calcium oxide. A small amount of ammonium carbonate in a desiccator is also very effective in protecting Fremy s salt against deeomposition. 

Methylene groups adjacent to aromatic rings are oxidized to keto groups by oxygen with chromium sesquioxide as a catalyst [1128] or by mercuric bromide [11], ceric ammonium nitrate [380, 417, 422], selenium dioxide [509], sodium dichromate [622, 625], pyridinium chlorochromate [607], manganese dioxide [814], potassium permanganate [866, 877], and alkyl nitrites [452]. 

---