Modern Approaches to the Synthesis and Transformations of Practically Valuable Benzothiazole Derivatives

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.

Copper(I)-Catalyzed Tandem One-Pot Synthesis of 2-Arylthiobenzothiazoles and 2-Arylthiobenzoxazoles in Water

An efficient tandem process for the preparation of 2-arylthiobenzothiazoles has been developed. By condensation of 2-aminobenzenethiol with tetramethylthiuram disulfide (TMTD), 2-mercaptobenzothiazoles was in situ generated, which susequently underwent coupling with iodobenzenes to give the desired 2-arylthiobenzothiazoles fluently in a one-pot manner. This method can also be used for the synthesis of 2-arylthiobenzoxazoles. Inexpensive metal catalyst and ligand, mild reaction temperature, and water as solvent make this protocol practically valuable and useful in organic synthesis.

Base-promoted synthesis of N-arylbenzamides by N-benzoylation of dimethylphenylthioureas

An efficient synthesis of 10 N-arylbenzamides was achieved by N-benzoylation of N,N-dimethyl-( N′-phenyl)thioureas with 4-substituted benzoyl chlorides in dimethylacetamide in the presence of K2CO3. The features of this method include good yields, short reaction times and broad substrate scope. This work showed that arylthiourea derivatives can be alternative and useful starting materials for the preparation of N-arylbenzamides.