2717-05-7Relevant articles and documents
Palladium-catalyzed carbonylative cyclization of 2-(2-bromovinyl)benzimidazoles leading to pyrrolone-fused benzimidazoles
Yang, Byeong Woo,Ho, Son Long,Lim, Ho-Jin,Cho, Chan Sik
, p. 83 - 87 (2016)
2-(2-Bromovinyl)benzimidazoles are carbonylatively cyclized under carbon monoxide pressure in toluene in the presence of a catalytic amount of PdCl2 and PPh3 along with a base to give 1H-benzo[d]pyrrolo[1,2-a]imidazolones in good yields.
1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric o-Phenylenediamine Substrates
Foss, Frank W.,Palacios, Philip M.,Pierce, Brad S.,Thapa, Pawan,Tran, Tam
, p. 1991 - 2009 (2020/03/13)
Benzimidazoles are common in nature, medicines, and materials. Numerous strategies for preparing 2-arylbenzimidazoles exist. In this work, 1,2-disubstituted benzimidazoles were prepared from various mono- and disubstituted ortho-phenylenediamines (OPD) by iron-catalyzed oxidative coupling. Specifically, O2 and FeCl3·6H2O catalyzed the cross-dehydrogenative coupling and aromatization of diarylmethyl and dialkyl benzimidazole precursors. N,N′-Disubstituted-OPD substrates were significantly more reactive than their N,N-disubstituted isomers, which appears to be relative to their propensity for complexation and charge transfer with Fe3+. The reaction also converted N-monosubstituted OPD substrates to 2-substituted benzimidazoles; however, electron-poor substrates produce 1,2-disubstituted benzimidazoles by intermolecular imino-transfer. Kinetic, reagent, and spectroscopic (UV-vis and EPR) studies suggest a mechanism involving metal-substrate complexation, charge transfer, and aerobic turnover, involving high-valent Fe(IV) intermediates. Overall, comparative strategies for the relatively sustainable and efficient synthesis of 1,2-disubstituted benzimidazoles are demonstrated.
Cu(OAc)2-Mediated benzimidazole-directed C-H cyanation using 2-(4-methylpiperazin-1-yl)acetonitrile as the cyano source
Zhang, Tianyou,Qiao, Jingyi,Song, He,Xu, Feng,Liu, Xiaochong,Xu, Chunzhao,Ma, Junjie,Liu, Hao,Sun, Zhizhong,Chu, Wenyi
, p. 9084 - 9089 (2019/06/18)
A new protocol for the Cu(OAc)2-mediated cyanation of arenes using benzimidazole as the directing group with 2-(4-methylpiperazin-1-yl)acetonitrile as the cyano source was developed. A series of cyano derivatives were facilely and conveniently obtained in moderate to good yields by using this method. The C-H activation catalytic system was originally applied to the C(sp2)-H cyanation of the aryl/heteroaryl to synthesize 2-(1H-benzo[d]imidazol-2-yl)aryl nitriles. There were 19 new compounds in the synthesized 20 cyanide products. In this reaction, 2-(4-methylpiperazin-1-yl)acetonitrile as the cyano source was originally employed in the C(sp2)-H cyanation of the arenes. In addition, a fluorescent material 5a was obtained by derivative reactions of the obtained cyanide product 3.
