Preparation of 2-Azido-1-Substituted-1 <i>H</i>-Benzo[<i>d</i>]imidazoles Using a Copper-Promoted Three-Component Reaction and Their Further Conversion into 2-Amino and 2-Triazolyl Derivatives
作者:Tamminana Ramana、Tharmalingam Punniyamurthy
DOI:10.1002/chem.201202215
日期:2012.10.15
Multicomponent reaction: 2‐Azido‐1‐substituted‐1H‐benzo[d]imidazoles were prepared using a copper‐catalyzed three‐component reaction involving 2‐bromoaniline derivatives, isothiocyanates, and sodium azide. The reaction conditions were mild and the scope was broad. The azido compounds were transformed into their 2‐amino and 2‐triazolyl derivatives using copper‐mediated reduction and cycloaddition, respectively
多组分反应:使用2-铜苯胺衍生物,异硫氰酸盐和叠氮化钠的铜催化三组分反应制备2-叠氮基-1-取代-1 H-苯并[ d ]咪唑。反应条件温和,适用范围广。分别通过铜介导的还原和环加成将叠氮基化合物转化为它们的2-氨基和2-三唑基衍生物(参见方案)。
Ligand-Free Copper-Catalyzed Synthesis of Substituted Benzimidazoles, 2-Aminobenzimidazoles, 2-Aminobenzothiazoles, and Benzoxazoles
The synthesis of substituted benzimidazoles, 2-aminobenzimidazoles, 2-aminobenzothiazoles, and benzoxazoles is described via intramolecularcyclization of o-bromoaryl derivatives using copper(II) oxide nanoparticles in DMSO under air. The procedure is experimentally simple, general, efficient, and free from addition of external chelating ligands. It is a heterogeneous process and the copper(II) oxide
Synthesis of 4-substituted imino-4H-benzo[d][1,3] thiazin-2-amines via palladium-catalysed isocyanide insertion in 2-bromophenylthioureas
作者:Garima Pandey、Subhendu Bhowmik、Sanjay Batra
DOI:10.1039/c4ra06875k
日期:——
The palladium-catalysed isocyanide insertion in 2-bromophenylthioureas leads to the formation of 4-substituted imino-4H-benzo[d][1,3]thiazin-2-amines via C–S cross coupling reaction of the intermediate imidoylpalladium species.
Copper(I)-Catalyzed Synthesis of Substituted 2-Mercapto Benzimidazoles
作者:Siva Murru、Bhisma K. Patel、Jean Le Bras、Jacques Muzart
DOI:10.1021/jo802589d
日期:2009.3.6
An efficient method for the preparation of various substituted 2-mercapto benzimidazoles from their corresponding thioureas has been developed. S-Alkylation of thioureas followed by Cu-catalyzed intramolecular N-arylation furnished substituted 2-mercapto benzimidazoles in high yields and short reaction times. Furthermore, 2-mercapto benzimidazoles substituted with a p-methoxybenzyl group allowed access to benzimidazole thiones.
An “on-water” exploration of CuO nanoparticle catalysed synthesis of 2-aminobenzothiazoles
作者:Saroj Kumar Rout、Srimanta Guin、Jayashree Nath、Bhisma K. Patel
DOI:10.1039/c2gc35575b
日期:——
An âon-waterâ one-pot process has been engineered for the preparation of 2-aminobenzothiazole from ortho-halo (âF, âCl, âBr and âI) substituted unsymmetrical thioureas. For ortho âI and âBr substrates the reactions afford 2-aminobenzothiazoles under metal free condition promoted by base. However, the relatively inert ortho âCl and âF substrates undergo intramolecular arylthiolation only in the presence of CuO nanoparticles yielding 2-aminobenzothiazoles. This methodology provides easy access to aminobenzothiazoles utilising even the ortho âCl and âF substrates. The catalyst is recyclable several times without loss of substantial activity. Other remarkable features include the wide range of functional group tolerance, absence of chromatographic purification (for ortho âI and âBr substrates) and providing moderate to excellent yield of the products under mild conditions, thus rendering the methodology as a highly eco-friendly alternative to the existing methods.