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Benzothiazole
Space filling model of benzothiazole	Ball-and-stick model of benzothiazole
Names
	Preferred IUPAC name 1,3-Benzothiazole
Identifiers
CAS Number	95-16-9 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:45993 ;
ChEMBL	ChEMBL510309 ;
ChemSpider	6952 ;
ECHA InfoCard	100.002.179
PubChem CID	7222;
UNII	G5BW2593EP ;
CompTox Dashboard (EPA)	DTXSID7024586 ;
	InChI InChI=1S/C7H5NS/c1-2-4-7-6(3-1)8-5-9-7/h1-5H Key: IOJUPLGTWVMSFF-UHFFFAOYSA-N ; InChI=1/C7H5NS/c1-2-4-7-6(3-1)8-5-9-7/h1-5H Key: IOJUPLGTWVMSFF-UHFFFAOYAC;
	SMILES n1c2ccccc2sc1;
Properties
Chemical formula	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)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

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.

Structure and preparation

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

Uses

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] Some drugs contain this group, examples being riluzole and pramipexole. 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]

References

^ T. E. Gilchrist "Heterocyclic Chemistry" 3rd Edition, Longman, 1992.
^ Le Bozec, Lucille; Moody, Christopher J. (2009). "Naturally Occurring Nitrogen–Sulfur Compounds. The Benzothiazole Alkaloids". Australian Journal of Chemistry. 62 (7): 639. doi:10.1071/CH09126.
^ "Benzothiazole". The Good Scents Company. Retrieved 2020-10-06.
^ "Flavouring Group Evaluation 76, (FGE.76) - Consideration of sulphur-containing heterocyclic compounds evaluated by JECFA (59th meeting) structurally related to thiazoles, thiophene, thiazoline and thienyl derivatives from chemical group 29, miscellaneous". EFSA Journal. 6 (11): 875. 2008. doi:10.2903/j.efsa.2008.875.
^ Gill, Rupinder K.; Rawal, Ravindra K.; Bariwal, Jitender (2015). "Recent Advances in the Chemistry and Biology of Benzothiazoles". Archiv der Pharmazie. 348 (3): 155–178. doi:10.1002/ardp.201400340. PMID 25682746. S2CID 10421792.
^ Engels, Hans-Wilhelm; Weidenhaupt, Herrmann-Josef; Pieroth, Manfred; Hofmann, Werner; Menting, Karl-Hans; Mergenhagen, Thomas; Schmoll, Ralf; Uhrlandt, Stefan (2004), "Rubber, 4. Chemicals and Additives", Ullmann's Encyclopedia of Industrial Chemistry, doi:10.1002/14356007.a23_365.pub2, ISBN 3-527-30673-0
^ Hrobarik, P.; Sigmundova, I.; Zahradnik, P.; et al. (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.
^ Chauhan, Kalpana; Singh, Prem; Kumari, Bhawana; Singhal, Rakesh Kumar (2017-03-16). "Synthesis of new benzothiazole Schiff base as selective and sensitive colorimetric sensor for arsenic on-site detection at ppb level". Analytical Methods. 9 (11): 1779–1785. doi:10.1039/C6AY03302D. ISSN 1759-9679.