485324-10-5Relevant academic research and scientific papers
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.
A highly active catalyst supported molecular sieves-NaHCO3 mixture for the selective and advantageous N-monoalkylation of amines
Das, Asish R.,Medda, Arunima,Singha, Raghunath,Guchhait, Nikhil
experimental part, p. 841 - 848 (2010/06/01)
Amines are mono-N-alkylated by alkylmesylates in the presence of catalyst supported molecular sieves-NaHCO3 mixture in a regioselective, chemoselective and non-toxic process. Observed chemoselectivity is supported by 'DFT'.
Radical-induced formation of some siloles and diazasiloles
Ding, Bangwei,Teng, Zhu,Keese, Reinhart
, p. 8906 - 8910 (2007/10/03)
The Bu3Sn radical-induced reaction of o-iodobenzylvinylsilanes and o-iodoallylsilanes leads to cyclic products in yields of 40-60%. These regioselective cyclizations occur with high preference for a 5-exo and a 7-endo mode with a 6-exo mode being absent. An example for ring closure via a 7-exo mode is described.
