6,6'-Dibromoindigo is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...

with the formula (BrC₆H₃C(O)CNH)₂. A deep purple solid, the compound is also known as

Tyrian purple Tyrian purple ( grc, πορφύρα ''porphúra''; la, purpura), also known as Phoenician red, Phoenician purple, royal purple, imperial purple, or imperial dye, is a reddish-purple natural dye. The name Tyrian refers to Tyre, Lebanon. It i ...

, a dye of historic significance. Presently, it is only a curiosity, although the related derivative

indigo Indigo is a deep color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine, based on the ancient dye of the same name. The word "indigo" comes from the Latin word ''indicum'', m ...

is of industrial significance. The molecule consists of a pair of monobrominated

indole Indole is an aromatic heterocyclic organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other c ...

rings linked by a carbon-carbon double bond. It is produced by molluscs of the ''Muricidae'' species.

Biosynthesis

The biosynthesis proceeds by the intermediacy of tyrindoxyl sulphate. 6BrIG can also produced enzymatically in vitro from the

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...

tryptophan Tryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromatic ...

. The sequence begins with bromination of the benzo ring followed by conversion to 6-bromo

. Flavin-containing monooxygenase then couples two of these indole units to give the dye.

Chemical synthesis

The main chemical constituent of the Tyrian dye was discovered by Paul Friedländer in 1909 to be 6,6′-dibromoindigo, derivative of indigo dye, which had been synthesized in 1903. Although the first chemical synthesis was reported in 1914, unlike indigo, it has never been synthesized at commercial level. An efficient protocol for laboratory synthesis of dibromoindigo was developed in 2010.

References

{{DEFAULTSORT:Dibromoindigo, 6,6'- Indigo structure dyes Bromoarenes