Copper(I)-Catalyzed Cascade Synthesis of 2-Substituted 1,3-Benzothiazoles: Direct Access to Benzothiazolones
作者:Siva Murru、Pravat Mondal、Ramesh Yella、Bhisma K. Patel
DOI:10.1002/ejoc.200900711
日期:2009.11
An efficient cascade process for the preparation of 2-substituted 1,3-benzothiazoles directly from 2-haloaryl isothiocyanates and O or S nucleophiles by a Cu-catalyzed, intramolecular, C–S bond formation has been developed. This cascade method is viable for the efficient syntheses of both O- and S-substituted 1,3-benzothiazoles. Furthermore, 1,3-benzothiazol-2(3H)-ones having an alkyl group allow easy
and mild carbon-sulfur coupling was realized by nickel catalysis under ball-milling conditions. The desired thioether products were generated from aryl iodides and aromatic thiol/disulfides with broad substrate scope. The Ni(i)/Ni(III) catalytic cycle was facilitated by the mechanochemistry process, thus providing an eco-friendly and time-saving strategy for the construction of the C−S bond in practical
N-heterocyclic carbene (NHC) copper(I) complexes based on imidazol-2-ylidene and 1,2,3-triazol-5-ylidene catalyzed the direct C-H thiolation of benzothiazoles and benzoxazoles with aryl and alkyl thiols to give 2-aryl and 2-alkylthiobenzothiazoles in moderate-to-good yields. The NHC copper(I) complex [(IPr)CuI] was the most effective catalyst for the reaction among the NHC-Cu(I) complexes examined in this study. (C) 2013 Elsevier Ltd. All rights reserved.
Intra- and Intermolecular C−S Bond Formation Using a Single Catalytic System: First Direct Access to Arylthiobenzothiazoles
作者:Siva Murru、Harisadhan Ghosh、Santosh K. Sahoo、Bhisma K. Patel
DOI:10.1021/ol9017535
日期:2009.10.1
We have for the first time developed two ligand-assisted Cu(I)-catalyzed sequential intra- and intermolecular Sarylations leading to the direct synthesis of arylthiobenzothiazoles in one pot without an inert atmosphere. Low catalyst loading, inexpensive metal catalyst and ligand, lower reaction temperature, and shorter reaction times make this method superior to all reported methods for the synthesis of arylthiobenzothiazole.