5-Chloro-2-methylbenzothiazole

White solid

5-Chloro-2-methylbenzothiazole undergoes an acid-catalyzed reaction with 3,4,5,6-tetrachloro-1,2-benzoquinone to give 5,6,7-trichloro-2-(5-chlorobenzothiazol-2-yl)-1,3-tropolone and 4,5,6,7-tetrachloro-2-(5-chlorobenzothiazol-2-yl)-1,3-tropolone[2]. 5-Chloro-2-methylbenzothiazole serves as a coupling partner to incorporate benzothiazole units into arylation products[3].

5-Chloro-2-methylbenzothiazole is obtained in 41% yield as a white solid (mp 68–70 °C) by reacting aliphatic pyruvic acid with bis(2-aminophenyl) diselenide-type reagents[1].

[1]Lima, D. B., Penteado, F., Vieira, M. M., Alves, D., Perin, G., Santi, C., & Lenardão, E. J. (2017). α‐Keto Acids as Acylating Agents in the Synthesis of 2‐Substituted Benzothiazoles and Benzoselenazoles. European Journal of Organic Chemistry, 2017(26), 3830–3836. https://doi.org/10.1002/ejoc.201700648
[2]Bondareva, I. O., Sayapin, Y. A., Komissarov, V. N., Tkachev, V. V., Shilov, G. V., Aldoshin, S. M., & Minkin, V. I. (2011). New 2-(benzothiazol-2-yl)-1,3-tropolones derived from 3,4,5,6-tetrachloro-1,2-benzoquinone. Russian Chemical Bulletin, 60(7), 1384–1386. https://doi.org/10.1007/s11172-011-0207-7
[3]Jin, C., Xu, K., Fan, X., Liu, C., & Tan, J. (2020). Direct benzylic functionalization of pyridines: Palladium-catalyzed mono-α-arylation of α-(2-pyridinyl)acetates with heteroaryl halides. Chinese Chemical Letters, 31(1), 91–94. https://doi.org/10.1016/j.cclet.2019.06.028