Benzothiazole

Names Preferred IUPAC name Identifiers ChEBI ChEMBL ChemSpider ECHA InfoCard 100.002.179 Edit this at Wikidata UNII Properties C₇H₅NS Molar mass 135.1863 g/mol Density 1.238 g/mL Melting point 2 °C (36 °F; 275 K) Boiling point 227 to 228 °C (441 to 442 °F; 500 to 501 K)

Benzothiazole, or more specifically 1,3-benzothiazole, is an aromatic heterocyclic compound with the chemical formula C
₇H
₅NS. It is colorless, slightly viscous liquid. Although the parent compound, benzothiazole is not widely used, many of its derivatives are found in commercial products or in nature. Firefly luciferin can be considered a derivative of benzothiazole.

The three structural isomers of benzothizaole are 1,3-benzothiazole, 1,2-benzothiazole and 2,1-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.

Benzothiazoles are prepared by treatment of 2-mercaptoaniline with acid chlorides:^[1]

C₆H₄(NH₂)SH + RC(O)Cl → C₆H₄(NH)SCR + HCl + H₂O

Benzothiazole occurs naturally in some foods but is also used as a food additive.^[2] It has a sulfurous odor and meaty flavor.^[3] The European Food Safety Authority assessment had "no safety concern at estimated levels of intake as a flavouring substance".^[4]

The heterocyclic core of the molecule is readily substituted at the unique methyne centre in the thiazole ring. It is a thermally stable electron-withdrawing moiety with numerous applications in dyes such as thioflavin.^[5] Accelerators for the sulfur vulcanization of rubber are based on 2-mercaptobenzothiazoles.^[6] This ring is a potential component in nonlinear optics (NLO).^[7] A benzothiazole derivative is suggested as a dye for arsenic detection.^[8]

Benzothiazole moiety is seen in certain dopamine-acting drugs, e.g. riluzole and pramipexole. Moreover, novel benzothiazole derivatives were shown to act as monoamine oxidase inhibitors or dopamine antagonists; these include:

• 6-oxoethers and derivatives of thiadiazole, thiazolyhydrazine that act selectively on either MAO-A or MAO-B depending on the O-sidechain^{[9] [10] [11]}
• 1-alkylpiperidines that act on dopamine D₄ receptor ^{[12] [13]}

• Benzothiazoles are related to thiazoles, which lack the fused benzene ring.
• Benzoxazoles, which substitute an oxygen for the sulfur atom.

• MSDS