Benzothiazole is an
aromatic
In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...
heterocyclic compound with the chemical formula . 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
Firefly luciferin (also known as beetle luciferin) is the luciferin, or light-emitting compound, used for the firefly (Lampyridae), railroad worm ( Phengodidae), starworm ( Rhagophthalmidae), and click-beetle (Pyrophorini) bioluminescent systems. ...
can be considered a derivative of benzothiazole.
Structure and preparation
Benzothiazoles consist of a 5-membered 1,3-
thiazole
Thiazole, or 1,3-thiazole, is a heterocyclic compound that contains both sulfur and nitrogen. The term 'thiazole' also refers to a large family of derivatives. Thiazole itself is a pale yellow liquid with a pyridine-like odor and the molecular fo ...
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 chloride
In organic chemistry, an acyl chloride (or acid chloride) is an organic compound with the functional group . Their formula is usually written , where R is a side chain. They are reactive derivatives of carboxylic acids (). A specific example o ...
s:
:C
6H
4(NH
2)SH + RC(O)Cl → C
6H
4(NH)SCR + HCl + H
2O
Uses
Benzothiazole occurs naturally in some foods but is also used as a
food additive. It has a sulfurous
odor and meaty flavor. The
European Food Safety Authority
The European Food Safety Authority (EFSA) is the agency of the European Union (EU) that provides independent scientific advice and communicates on existing and emerging risks associated with the food chain. EFSA was established in February 2002, ...
assessment had "no safety concern at estimated levels of intake as a flavouring substance".
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. Some drugs contain this group, examples being
riluzole and
pramipexole. Accelerators for the
sulfur vulcanization of rubber are based on
2-mercaptobenzothiazoles. This ring is a potential component in
nonlinear optics
Nonlinear optics (NLO) is the branch of optics that describes the behaviour of light in ''nonlinear media'', that is, media in which the polarization density P responds non-linearly to the electric field E of the light. The non-linearity is typic ...
(NLO). A benzothiazole derivative is suggested as a dye for arsenic detection.
See also
* Benzothiazoles are related to
thiazole
Thiazole, or 1,3-thiazole, is a heterocyclic compound that contains both sulfur and nitrogen. The term 'thiazole' also refers to a large family of derivatives. Thiazole itself is a pale yellow liquid with a pyridine-like odor and the molecular fo ...
s, which lack the fused benzene ring.
*
Benzoxazoles, which substitute an oxygen for the sulfur atom.
References
External links
MSDS
{{Simple aromatic rings
Aromatic bases
Simple aromatic rings