6528-76-3Relevant articles and documents
RESEARCH ON THE CHEMISTRY OF 2-HETARYLBENZIMIDAZOLES. 4. OXIDATION OF 1-METHYL-2-(5'-METHYL-2'-HETARYL)BENZIMIDAZOLES
El'chaninov, M. M.,Simonov, A. M.,Simkin, B. Ya.
, p. 833 - 835 (1982)
The methyl group in 1-methyl-2-(5'-methyl-2'-hetaryl)benzimidazoles (hetaryl = furyl and thienyl) was oxidized.It was found that a salt of a carboxylic acid, which in an acidic medium loses carbon dioxide to give 1-methyl-2-(2'-furyl)-benzimidazole, is formed when 1-methyl-2-(5'-methyl-2'-furyl)benzimidazole is treated with an aqueous solution of potassium permanganate.The carboxy derivative of thiophene is considerably more stable.Oxidation by means of selenium dioxide leads to the corresponding 5'-formyl derivative.The structures of the compounds obtained were confirmed by data from the IR and PMR spectra.
A dual biomimetic process for the selective aerobic oxidative coupling of primary amines using pyrogallol as a precatalyst. Isolation of the [5 + 2] cycloaddition redox intermediates
Deschamps, Patrick,Fleury, Maurice-Bernard,Hammad, Karim,Largeron, Martine
, p. 1894 - 1905 (2020/04/07)
A bioinspired organocatalytic cascade reaction mimicking both purpurogallin biosynthesis and copper amine oxidases (CuAOs) activity is described, at room temperature under ambient air, for the activation of the α-C-H bond of primary amines. The reaction sequence uses low-cost commercially available pyrogallol as a precatalyst which undergoes an in situ oxidative self-processing step, resulting in its conversion into natural purpurogallin, a [5 + 2] cycloaddition redox intermediate. This is further involved in the CuAOs-like transamination mechanism for producing, under single turnover, the active biomimetic organocatalyst which mediates the selective oxidative coupling of primary amines, including the non-activated substrates of CuAOs. Without any metal cocatalyst or additives, the protocol gives access to cross-coupled imines as well as 1,2-disubstituted benzimidazoles. The isolation of not easily accessible [5 + 2] cycloaddition redox intermediates provides direct and clear evidence for the proposed dual biomimetic process.
A Keggin heteropoly acid as an efficient catalyst for an expeditious, one-pot synthesis of 1-methyl-2-(hetero)arylbenzimidazoles
Chakrabarty, Manas,Mukherji, Ajanta,Mukherjee, Ratna,Arima, Shiho,Harigaya, Yoshihiro
, p. 5239 - 5242 (2008/02/08)
The Keggin heteropoly acid, silicotungstic acid, H4SiW12O40, has been demonstrated to be highly efficient for an expeditious, one-pot synthesis of 1-methyl-2-(hetero)arylbenzimidazoles from N-methyl-1,2-phenylenediamine and (hetero)aryl aldehydes in ethyl acetate at room temperature. The catalyst works equally well for N-phenyl-1,2-phenylenediamine.
