Benzothiazole

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Benzothiazole
Benzothiazole numbering.png
Space filling model of benzothiazole Ball-and-stick model of benzothiazole
Identifiers
CAS number 95-16-9 YesY
PubChem 7222
ChemSpider 6952 YesY
UNII G5BW2593EP YesY
ChEBI CHEBI:45993 YesY
ChEMBL CHEMBL510309 YesY
Jmol-3D images Image 1
Properties
Molecular formula C7H5NS
Molar mass 135.19 g mol−1
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)
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Benzothiazole is an aromatic heterocyclic compound with the chemical formula C
7
H
5
NS
. 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. A derivative of benzothiazole is the light-emitting component of luciferin, found in fireflies.

Structure and preparation[edit]

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.

Benzothiazole are prepared by treatment of 2-aminobenzenethiol with acid chlorides:[1]

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

Uses[edit]

This heterocyclic scaffold is readily substituted at the unique methyne centre in the thiazole ring. Its a thermally stable electron-withdrawing moiety with numerous applications in dyes such as thioflavin. Some drugs contain this group, an example being riluzole. The heterocycle is found in nature.[2] Accelerators for the vulcanization of rubber are based on 2-mercaptobenzothiazole.[3] This ring is a potential component in nonlinear optics (NLO).[4]

See also[edit]

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

References[edit]

  1. ^ T. E. Gilchrist "Heterocyclic Chemistry" 3rd Edition, Longman, 1992.
  2. ^ Lucille Le Bozec, Christopher J. Moody "Naturally Occurring Nitrogen–Sulfur Compounds. The Benzothiazole Alkaloids" Australian Journal of Chemistry 62(7) 639–647.doi:10.1071/CH09126
  3. ^ Hans-Wilhelm Engels, Herrmann-Josef Weidenhaupt, Manfred Pieroth, Werner Hofmann, Karl-Hans Menting, Thomas Mergenhagen, Ralf Schmoll, Stefan Uhrlandt “Rubber, 4. Chemicals and Additives” in Ullmann's Encyclopedia of Industrial Chemistry 2004, Wiley-VCH, Weinheim. doi:10.1002/14356007.a23_365.pub2
  4. ^ Hrobarik, P.; Sigmundova, I.; Zahradnik, P.; Kasak, P.; Arion, V.; Franz, E.; Clays, K. (2010). "Molecular Engineering of Benzothiazolium Salts with Large Quadratic Hyperpolarizabilities: Can Auxiliary Electron-Withdrawing Groups Enhance Nonlinear Optical Responses?". Journal of Physical Chemistry C 114 (50): 22289–22302. doi:10.1021/jp108623d. 

External links[edit]