Primuline is a

dye Juan de Guillebon, better known by his stage name DyE, is a French musician. He is known for the music video of the single "Fantasy Fantasy is a genre of speculative fiction that involves supernatural or Magic (supernatural), magical ele ...

containing the

benzothiazole Benzothiazole, or more specifically 1,3-benzothiazole, is an aromatic heterocyclic compound with the chemical formula . It is colorless, slightly viscous liquid. Although the parent compound, benzothiazole is not widely used, many of its derivativ ...

ring system. Primuline itself is also known as Direct yellow 59 or C.I. 49000. The primulines are considered derivatives of dehydrothiotoluidine (aminobenzenyltoluylmercaptan), which is obtained when

para-toluidine There are three isomers of toluidine, which are organic compounds discovered and named by James Sheridan Muspratt and August Wilhelm von Hofmann in 1845. These isomers are O-Toluidine, ''o''-toluidine, ''m''-toluidine, and ''p''-toluidine, with the ...

is heated with

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

for eighteen hours at 180–190 °C and then for a further six hours at 200–220 °C Dehydrothiotoluidine is not itself a dye-stuff, but if the heating is carried out at a higher temperature in the presence of more sulfur, then a base is formed, which gives primuline yellow upon sulfonation. Primuline yellow is a mixture of sodium salts and probably contains at least three thiazole rings in combination. It is a substantive

cotton Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...

dye of rather fugitive shade, but can be

diazo In organic chemistry, the diazo group is an organic moiety consisting of two linked nitrogen atoms at the terminal position. Overall charge-neutral organic compounds containing the diazo group bound to a carbon atom are called diazo compounds ...

tized on the fibre and then developed with other components, yielding a series of ingrain colors.{{cite EB1911 , wstitle=Primuline , volume=22 , page=342 Primuline is usually available as a sodium salt. Primuline is

fluorescent Fluorescence is one of two kinds of photoluminescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. When exposed to ultraviolet radiation, many substances will glow (fluoresce) with color ...

. Thioflavin T is obtained by the

methylation Methylation, in the chemistry, chemical sciences, is the addition of a methyl group on a substrate (chemistry), substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replac ...

of dehydrothiotoluidine with

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...

in the presence of

hydrochloric acid Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is ...

. Thioflavin S results from the methylation of dehydrothiotoluidine with

sulfonic acid In organic chemistry, sulfonic acid (or sulphonic acid) refers to a member of the class of organosulfur compounds with the general formula , where R is an organic alkyl or aryl group and the group a sulfonyl hydroxide. As a substituent, it is kn ...

. This sulfonic acid on

oxidation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...

with bleaching powder or with lead peroxide, in alkaline solution yields chloramine yellow, which dyes

a beautiful yellow.

References

Anilines Benzothiazoles Sulfonic acids Thiazole dyes

See also

References