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
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and ...
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. I ...
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 for ...
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
Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), salt (salt ...
. It has a sulfurous
odor
An odor (American English) or odour (English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is caused by one or more volatilized chemical compounds ...
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
In organic chemistry, a methine group or methine bridge is a trivalent functional group , derived formally from methane. It consists of a carbon atom bound by two single bonds and one double bond, where one of the single bonds is to a hydrogen. T ...
centre in the thiazole ring. It is a thermally stable electron-withdrawing moiety with numerous applications in dyes such as
thioflavin
Thioflavins are fluorescent dyes that are available as at least two compounds, namely Thioflavin T and Thioflavin S. Both are used for histology staining and biophysics, biophysical studies of protein aggregation. In particular, these dyes have be ...
. Some drugs contain this group, examples being
riluzole and
pramipexole
Pramipexole, sold under the brand Mirapex among others, is medication used to treat Parkinson's disease (PD) and restless legs syndrome (RLS). In Parkinson's disease it may be used alone or together with levodopa. It is taken by mouth. Pramipex ...
. Accelerators for the
sulfur vulcanization
Sulfur vulcanization is a chemical process for converting natural rubber or related polymers into materials of varying hardness, elasticity, and mechanical durability by heating them with sulfur or sulfur-containing compounds. Sulfur forms cros ...
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 typica ...
(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 for ...
s, which lack the fused benzene ring.
*
Benzoxazole
Benzoxazole is an aromatic organic compound with a molecular formula C7H5NO, a benzene-fused oxazole ring structure, and an odor similar to pyridine. Although benzoxazole itself is of little practical value, many derivatives of benzoxazoles are co ...
s, which substitute an oxygen for the sulfur atom.
References
External links
MSDS
{{Simple aromatic rings
Aromatic bases
Simple aromatic rings