A convenient method for the synthesis of 2-amino substituted aza-heterocycles from N,N′-disubstituted thioureas using TsCl/NaOH
摘要:
p-Toluenesulfonyl chloride (TsCl)/NaOH has been introduced as reagent combination for the synthesis of 2-amino-oxa- or 2-amino-thiazolidines from N-(2-hydroxyethyl)-thioureas, but its general application in heterocycle synthesis has not been investigated. In this paper the convenient and efficient synthesis of a variety of 2-amino-substituted 1-aza 3-(aza, oxo or thio) heterocycles of different substitution and ring sizes is described. The application of polymer-supported TsCl facilitates work-up and renders the reaction conditions very suitable for parallel or robot synthesis. (C) 2004 Elsevier Ltd. All rights reserved.
Cobalt-Catalyzed Oxidative Isocyanide Insertion to Amine-Based Bisnucleophiles: Diverse Synthesis of Substituted 2-Aminobenzimidazoles, 2-Aminobenzothiazoles, and 2-Aminobenzoxazoles
作者:Tong-Hao Zhu、Shun-Yi Wang、Gao-Nan Wang、Shun-Jun Ji
DOI:10.1002/chem.201300239
日期:2013.5.3
Cobalt catalysis: Synthesis of substituted 2‐aminobenzimidazoles, 2‐aminobenzothiazoles, and 2‐aminobenzoxazoles was achieved by using cobalt(II) acetate catalyzed isocyanideinsertion to o‐diaminobenzene, 2‐aminobenzenethiol, and 2‐aminophenol derivatives in 1,4‐dioxane (see scheme). It was found that the reaction proceeded efficiently to give the desired products in up to 95 % isolated yields by
The direct N-alkylation of 2-aminoimidazoles to give the corresponding 2-(N-alkylamino)imidazoles was accomplished using alcohols as alkylating agents in the presence of a [Cp*IrCl2]2/K2CO3system. The iridium-catalyzed regioselective reaction is simple, efficient, general, and environmentally benign.
Cobalt‐Catalyzed Aerobic Oxidative Cyclization of 2‐Aminoanilines with Isonitriles: Facile Access to 2‐Aminobenzimidazoles
作者:Jiaqi Liu、Sarah Morgan、Jessica M. Hoover
DOI:10.1002/cctc.201902011
日期:2020.3.6
A ligand‐ and additive‐free aerobiccobalt‐catalyzed synthesis of 2‐aminobenzimidazoles from 2‐aminoanilines was developed. A variety of aminoanilines and isonitriles undergo efficient coupling to furnish substituted 2‐aminobenzimidazoles in moderate to excellent yields. This protocol enables efficient access to the unsubstituted 2‐aminobenzimidazoles.
BOP efficiently promoted the phosphonium-mediated cyclization of thioureas, leading to a convenient synthesis of 2-aminobenzimidazoles. Compared to conventional methods, the reactions were complete at room temperature with times ranging from a few minutes to 1 h in near quantitative yields. This method is also applicable to the synthesis of more challenging structures such as 2-akylaminobenzimidazoles
作者:James J. Perkins、Amy E. Zartman、Robert S. Meissner
DOI:10.1016/s0040-4039(98)02592-1
日期:1999.2
A general and highly convenient procedure for the synthesis of 2-(alkylamino)benzimidazoles has been developed and a variety of analogs have been efficiently prepared. Included is a dipeptide mimetic in which the guanidine group of an arginine residue has been replaced with a 2-aminobenzimidazole.