Benzothiazole

Benzothiazoles consist of a 5-membered 1,3-thiazole ring fused to a benzene ring. The nine atoms of the bicycle and the attached substituents are coplanar. The heterocyclic core of the molecule is readily substituted at the methyne (CH) centre in the thiazole ring. Thiazole is electron-withdrawing. ==Synthesis and biosynthesis==

Benzothiazoles are typically prepared by treatment of 2-mercaptoaniline. For example, acid chlorides are effective: :C6H4(NH2)SH + RC(O)Cl → C6H4(N)SCR + HCl + H2O Many other precursors have been used, commonly aldehydes in the presence of oxidants. In some cases, benzothiazoles are prepared directly from anilines, a process that entails ortho functionalization. Naturally occurring benzothiazoles are proposed to arise by condensation of cysteine with quinones. ==Uses==

Dyes The dye thioflavin is a benzothiazole derivative. Food additives Benzothiazole occurs naturally in some foods but is also used as a food additive. The European Food Safety Authority assessment had "no safety concern at estimated levels of intake as a flavouring substance". Rubber additive Accelerators for the sulfur vulcanization of rubber are based on 2-mercaptobenzothiazoles. Pharmacology is used to treat schizophrenia and bipolar disorder. Benzothiazoles have been widely investigated for their bioactivity. The benzothiazole moiety is, for example, seen in certain dopamine-acting drugs, e.g. riluzole and pramipexole. Moreover, benzothiazole derivatives act as monoamine oxidase inhibitors or dopamine antagonists: • 6-oxoethers and derivatives of thiadiazole, thiazolyhydrazine that act selectively on either MAO-A or MAO-B depending on the O-sidechain • 1-alkylpiperidines that act on dopamine D4 receptor ==See also==

Benzothiazoles are widely used in the vulcanization of rubber, so their possible role in the environment has attracted attention. Evidence suggests that they biodegrade readily. ==References==