Benzothiazole, or more specifically 1,3-benzothiazole, is an aromaticheterocyclic 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.
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]
See also
Benzothiazoles are related to thiazoles, which lack the fused benzene ring.
Benzoxazoles, which substitute an oxygen for the sulfur atom.
References
^T. E. Gilchrist "Heterocyclic Chemistry" 3rd Edition, Longman, 1992.
^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
^"Benzothiazole". The Good Scents Company. Retrieved 2020-10-06.
^Engels, H.-W., Weidenhaupt, H.-J., Pieroth, M., et al. "Rubber, 4. Chemicals and Additives" in Ullmann's Encyclopedia of Industrial Chemistry 2004, Wiley-VCH, Weinheim. doi:10.1002/14356007.a23_365.pub2
^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.