6265-91-4Relevant articles and documents
Recyclable copper-catalyzed cyclization of o-haloanilides and metal sulfides: An efficient and practical access to substituted benzothiazoles
Cai, Mingzhong,Hao, Wenyan,Huang, Wencheng,Ye, Qian
, (2022/01/19)
An efficient heterogeneous copper-catalyzed cyclization of o-haloanilides and metal sulfides has been achieved via the C–S coupling in DMF at 80 or 140 °C in the existence of an MCM-41-bound NHC-Cu(I) catalyst and then intramolecular condensation, delivering a wide range of substituted benzothiazoles in mostly good to high yields. This new MCM-41-NHC-CuI complex can facilely be obtained by a two-step procedure starting from easily accessible and inexpensive reagents and reused more than seven times without any significant loss of its catalytic efficiency. The present protocol has been successfully applied to the gram-scale synthesis of two antitumor agents 5F203 and PMX 610.
Graphene oxide-catalyzed synthesis of benzothiazoles with amines and elemental sulfur via oxidative coupling strategy of amines to imines
He, Haiping,Duan, Dehao,Li, Hong,Wei, Yifei,Nie, Liang,Tang, Bo,Wang, Hanyu,Han, Xiaowei,Huang, Panpan,Peng, Xiangjun
, (2022/01/13)
The graphene oxide-catalyzed coupling and cyclization reactions of primary amines with elemental sulfur was developed to afford various optically property benzothiazoles. This coupling and cyclization strategies proceeded under the oxidant system graphene oxide/O2 and constructed carbon-heteroatom (N, S) bonds with amines and elemental sulfur. Due to benzothiazoles as common chromophores, these products exhibited intriguing fluorescence properties, including outstanding Stokes shifts (up to 161 nm) and quantum yields (up to 74%). Utilizing the products’ unique fluorescence response in different solvents, β-naphthothiazole 4a showed excellent aggregation-induced emission properties in 1,2-dichloroethane, which was 60 times higher than in tetrahydrofuran.
Ionic-Liquid-Catalyzed Synthesis of Imines, Benzimidazoles, Benzothiazoles, Quinoxalines and Quinolines through C?N, C?S, and C?C Bond Formation
Adimurthy, Subbarayappa,Badhani, Gaurav,Joshi, Abhisek
, p. 6705 - 6716 (2021/12/31)
We report the tetramethyl ammonium hydroxide catalyzed oxidative coupling of amines and alcohols for the synthesis of imines under metal-free conditions by utilizing oxygen from air as the terminal oxidant. Under the same conditions, with ortho-phenylene diamines and 2-aminobenzenethiols the corresponding benzimidazoles and benzothiazoles were obtained. Quinoxalines were obtained from ortho-phenylene diamines and 1-phenylethane-1,2-diol, the conditions were then extended to the synthesis of quinoline building blocks by reaction of 2-amino benzyl alcohols either with 1-phenylethan-1-ol or acetophenone derivatives. The formation of C?N, C?S and C?C bonds was achieved under metal-free conditions. A broad range of amines (aromatic, aliphatic, cyclic and heteroaromatic) as well as benzylic alcohols including heteroaryl alcohols reacted smoothly and provided the desired products. The mild reaction conditions, commercially available catalyst, metal-free, good functional-group tolerance, broad range of products (imines, benzimidazoles, benzothiazoles, quinoxalines and quinolines) and applicability at gram scale reactions are the advantages of the present strategy.