Bis(2,2-bipyridyl)copper(II) Permanganate

[86609-17-8]  · C20H16CuMn2N4O8  · Bis(2,2-bipyridyl)copper(II) Permanganate  · (MW 613.79)

(oxidant, used for the oxidation of thiols to disulfides,1 benzylic alcohols to carbonyl compounds,2 aromatic amines to azo compounds,2 benzylamine and oximes to the corresponding carbonyl compounds2)

Alternate Name: bis(2,2-bipyridine-N,N)copper(2+) permanganate.

Physical Data: purple solid; decomposes at 105-110 °C.2

Solubility: sol water, acetone, and methylene chloride.2

Analysis of Reagent Purity: lmax (log ε) (H2O): 290 nm (4.50), 296 (4.59), 306 (4.58), 458, (3.23), 474 (3.28), 491 (3.38), 510 (3.49), 529 (3.57), 552 (3.54), 576 (3.35).

Preparative Methods: Potassium Permanganate (0.01 mol) dissolved in a minimum of water is added to bis(2,2-bipyridyl)copper(II) chloride (0.02 mol) in water (25 mL). On cooling a purple precipitate is collected and air dried.2 The yield is 95%.

Handling, Storage, and Precautions: oxidant, store in a glass vessel at or below rt. The reagent should be filtered and dried on a filter paper, not on a sintered glass funnel. It should be transferred with nonmetallic spatulas; if metallic spatulas are used the reagent may burst into flame.1

Oxidation of Thiols to Disulfides.1

Bis(2,2-bipyridyl)copper(II) permanganate can be used to prepare disulfides from the corresponding sulfides. The reactions are carried out in methylene chloride at rt, times range from 5-45 min (eqs 1 and 2).

Oxidation of Aromatic Amines to Azo Compounds.2

In a somewhat similar reaction, aromatic amines are oxidatively coupled to give azo compounds. The reactions are carried out in refluxing methylene chloride. Some examples are shown in eqs 3 and 4.

Oxidation of Benzylic Secondary Alcohols.2

Benzyl and cinnamyl alcohols are oxidized to the corresponding aldehydes by this reagent. Of particular interest is the observation that benzylic secondary alcohols are selectively oxidized, as in eq 5.

Oxidation of Alkenes.2

When acetone is used as the solvent, carbon-carbon double bonds adjacent to an aromatic ring are cleaved, as in eq 6.

Conversion of Oximes to Carbonyl Compounds.

Oximes are converted into the corresponding carbonyl compounds when treated with this reagent (eq 7).

The reactions of bis(2,2-bipyridyl)copper(II) permanganate are very similar to those of Bis(pyridine)silver(I) Permanganate. Kinetic studies of the oxidation of aliphatic aldehydes3 and thioacids4 by bis(2,2-bipyridyl)copper(II) permanganate have been reported.

1. Firouzabadi, H.; Naderi, M.; Sardarian, A.; Vessal, B. SC 1983, 13, 611.
2. Firouzabadi, H.; Sardarian, A. R.; Naderi, M.; Vessal, B. T 1984, 40, 5001.
3. Kothari, S.; Sharma, V.; Sharma, P. K.; Banerji, K. K. PIA 1992, 104, 583.
4. Kothari, S. PIA 1991, 103, 747.

Donald G. Lee

University of Regina, SK, Canada

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