Highly Reactive, General and Long-Lived Catalysts for Palladium-Catalyzed Amination of Heteroaryl and Aryl Chlorides, Bromides, and Iodides: Scope and Structure-Activity Relationships was written by Shen, Qilong;Ogata, Tokutaro;Hartwig, John F.. And the article was included in Journal of the American Chemical Society in 2008.Name: N-Phenylbenzo[d]thiazol-2-amine This article mentions the following:
The authors describe a systematic study of the scope and relation between ligand structure and activity for a highly efficient and selective class of catalysts containing sterically hindered chelating alkylphosphines for the amination of heteroaryl and aryl chlorides, bromides, and iodides. In the presence of this catalyst, aryl and heteroaryl chlorides, bromides, and iodides react with many primary amines in high yields with part-per-million quantities of palladium precursor and ligand. Many reactions of primary amines with both heteroaryl and aryl chlorides, bromides, and iodides occur to completion with 0.0005-0.05 mol % catalyst. A comparison of the reactivity of this catalyst for the coupling of primary amines at these loadings is made with catalysts generated from hindered monophosphines and carbenes, and these data illustrate the benefits of chelation. Studies on structural variants of the most active catalyst indicate that a rigid backbone in the bidentate structure, strong electron donation, and severe hindrance all contribute to its high reactivity. Thus, these complexes constitute a fourth-generation catalyst for the amination of aryl halides, whose activity complements catalysts based on monophosphines and carbenes. In the experiment, the researchers used many compounds, for example, N-Phenylbenzo[d]thiazol-2-amine (cas: 1843-21-6Name: N-Phenylbenzo[d]thiazol-2-amine).
N-Phenylbenzo[d]thiazol-2-amine (cas: 1843-21-6) belongs to thiazole derivatives. The higher aromaticity of thiazole is due to delocalization of a lone pair of sulfur electrons across the ring, which is evidenced by chemical shifts of ring hydrogen at δ 7.27 and 8.77 ppm (C2 and C4), indicating diamagnetic ring current. The nitrogen in thiazole is sp2 hybridized and the lone pair of electrons localized on the nitrogen is less reactive due to increased aromatic character and decreased basicity. It is protonated and alkylated/acylated at nitrogen forming hydrochloride and quaternary thiazolium salt.Name: N-Phenylbenzo[d]thiazol-2-amine
Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica