''N'',''N''-Dimethylphenylenediamine is an

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

with the formula . It is one of the

phenylenediamine Phenylenediamine may refer to: * ''o''-Phenylenediamine or OPD, a chemical compound C6H4(NH2)2 * ''m''-Phenylenediamine or MPD, a chemical compound C6H4(NH2)2 * ''p''-Phenylenediamine or PPD, a chemical compound C6H4(NH2)2 Related compounds * ''N ...

s, a class of compounds that have long attracted attention for their redox properties. This

diamine A diamine is an amine with two amino groups. Diamines are used as monomers to prepare polyamides, polyimides, and polyureas. The term ''diamine'' refers mostly to Primary (chemistry), primary diamines, as those are the most reactive. In terms of ...

is, for example, easily oxidized to a deep red

radical cation Radical cations are denoted M^. Salts of these species have been isolated in the cases of dibenzocyclooctatetraene, various tertiary amines, and some polymethylated derivatives of azulene. Radical cations, like radical anions, have one unpaire ...

, which is called Wurster's Red. The related

Wurster's Blue Tetramethylphenylenediamine (TMPD) is an organic compound with the formula . It is most studied of three isomers of this formula. It is a colorless solid. With two dimethylamino substituents, the ring is particularly electron rich. Redox b ...

cation has four N-methyl groups

Synthesis

Dimethyl-4-phenylenediamine is prepared by the

nitration In organic chemistry, nitration is a general class of chemical processes for the introduction of a nitro group () into an organic compound. The term also is applied incorrectly to the different process of forming nitrate esters () between Alcohol ...

dimethylaniline ''N'',''N''-Dimethylaniline (DMA) is an organic chemical compound, a substituted derivative of aniline. It is a tertiary amine, featuring a dimethylamino group attached to a phenyl group. This oily liquid is colourless when pure, but commercial ...

followed by reduction of the resulting 4-nitrodimethylaniline. A variety of methods have been examined.

Applications

Dimethyl-4-phenylenediamine can be converted to

methylene blue Methylthioninium chloride, commonly called methylene blue, is a salt used as a dye and as a medication. As a medication, it is mainly used to treat methemoglobinemia. It has previously been used for treating cyanide poisoning and urinary trac ...

by reaction with

and

sodium thiosulfate Sodium thiosulfate (sodium thiosulphate) is an inorganic compound with the formula . Typically it is available as the white or colorless pentahydrate (x = 5), which is a white solid that dissolves well in water. The compound is a reducing agent an ...

in several steps: : Synthesis_of_methylene_blue

It reacts with

carbon disulfide Carbon disulfide (also spelled as carbon disulphide) is an inorganic compound with the chemical formula and structure . It is also considered as the anhydride of thiocarbonic acid. It is a colorless, flammable, neurotoxic liquid that is used as ...

to give the corresponding mercaptobenzothiazole: :

History

Casmir Wurster discovered tetramethylphenylenediamine and its easy oxidation. Subsequent work revealed the variety of redox properties of the phenylenediamines.

References

{{reflist Anilines Diamines Dimethylamino compounds