molecules Review Modern Approaches to the Synthesis and Transformations of Practically Valuable Benzothiazole Derivatives Larisa V. Zhilitskaya, Bagrat A. Shainyan * and Nina O. Yarosh E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky Street, 664033 Irkutsk, Russia;
[email protected] (L.V.Z.);
[email protected] (N.O.Y.) * Correspondence:
[email protected] Abstract: The review is devoted to modern trends in the chemistry of 2-amino and 2-mercapto substituted benzothiazoles covering the literature since 2015. The reviewed heterocycles belong to biologically active and industrially demanded compounds. Newly developed synthesis methods can be divided into conventional multistep processes and one-pot, atom economy procedures, realized using green chemistry principles and simple reagents. The easy functionalization of the 2-NH2 and 2-SH groups and the benzene ring of the benzothiazole moiety allows considering them as highly reactive building blocks for organic and organoelement synthesis, including the synthesis of pharmacologically active heterocycles. The review provides a summary of findings, which may be useful for developing new drugs and materials and new synthetic approaches and patterns of reactivity. Keywords: benzothiazole; 2-aminobenzothiazole; 2-mercaptobenzothiazole; synthesis; reactivity; biological activity Citation: Zhilitskaya, L.V.; Shainyan, B.A.; Yarosh, N.O. Modern Approaches to the Synthesis and 1. Introduction Transformations of Practically Benzothiazoles, as a bicyclic heterocycles with fused benzene and thiazole rings con- Valuable Benzothiazole Derivatives. taining electron-rich heteroatoms, nitrogen and sulfur, attract great interest from researchers Molecules 2021, 26, 2190. https:// for drug design due to their high biological and pharmacological activity [1–5].