2725-46-4Relevant articles and documents
From Phenylhydrazone to 1H-1,2,4-Triazoles via Nitrification, Reduction and Cyclization
Hao, Liqiang,Wang, Guodong,Sun, Jian,Xu, Jun,Li, Hongshuang,Duan, Guiyun,Xia, Chengcai,Zhang, Pengfei
, p. 1657 - 1662 (2020/03/19)
Herein we report an annulation of phenylhydrazone via a tandem nitrification, reduction, cyclization protocol employing cobalt nitrate and 1,2-dichloroethane to produce substituted 1H-1,2,4-triazoles. Notably, 1,2-dichloroethane serves both the solvent and a hydrogen source for transfer hydrogenation. This methodology works under mild conditions, providing a direct approach for the synthesis of 1H-1,2,4-triazoles. (Figure presented.).
Palladium-catalysed dehydrogenative generation of imines from amines. A nature-inspired route to indoles via cross-couplings of amines with arylhydrazines
Taddei, Maurizio,Mura, Manuel G.,Rajam?ki, Suvi,De Luca, Lidia,Porcheddu, Andrea
, p. 3002 - 3013 (2014/03/21)
H-substituted imines are elusive compounds formed when aldehydes or ketones are mixed with ammonia. However, this class of molecules can be prepared through selective removal of a hydrogen molecule from a primary amine using a transition metal catalyst. This biomimetic transformation, previously employed for the N-alkylation of anilines, is applied here to a domino preparation of differently substituted indoles from aliphatic primary amines and arylhydrazines. Several different linear and branched aliphatic primary amines are oxidized with reusable palladium on charcoal to the corresponding primary imines entrapped as arylhydrazones that can be isolated as such. Arylhydrazones can be further converted into N-alkylindole derivatives via an acid-mediated indolisation reaction. The one-pot domino hydrogen transfer Fischer indole synthesis under heterogeneous catalysis is also possible, giving access to diverse substituted indoles, including NH indoles obtained after deprotection of the corresponding benzyl compounds. The truly heterogeneous nature of the catalyst was demonstrated by recycling the catalyst in the same reaction, and in other palladium-catalysed transformations.
Copper-mediated synthesis of substituted 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles via C-H functionalization/C-N/C-O bond formation
Guru, Murali Mohan,Ali, Md Ashif,Punniyamurthy, Tharmalingam
, p. 5295 - 5308 (2011/08/05)
An efficient method for the transformation of N-benzyl bisarylhydrazones and bisaryloxime ethers to functionalized 2-aryl-N-benzylbenzimidazoles and 2-arylbenzoxazoles is described. The protocol involves a copper(II)-mediated cascade C-H functionalization/C-N/C-O bond formation under neutral conditions. Substrates having either electron-donating or -withdrawing substituents undergo the cyclization to afford the target heterocycles at moderate temperature.
