Direct conversion of alkyl halides into benzimidazoles using pyridine-N-oxide and 1,2-diaminobenzenes

Abstract

Benzimidazole heterocycles were obtained from halogenated compounds and aromatic 1,2-diamines. A mild oxidizing reagent such as pyridine N-oxide (PyO) is required to produce the benzimidazole core. The method is solvent free and provides products without the need for chromatography. Good yields, moderate reaction temperature, fast reaction rates are important advantages of this procedure.

Alkyl-1h-Benzo[d]imidazole Synthesis From Alkyl Bromides and 1,2-Benzenediamines by a Mild Domino Reaction

“…The novel one-pot domino sequence uses thermal heating conditions and does not require catalyst and solvent. The method allows the obtaining of the alkyl benzimidazoles in good yields, but the reaction time is longer than in the case of obtaining the aryl benzimidazoles [23,24]. The main advantages of the procedure are mild conditions, the operational simplicity, easy isolation of alkyl benzimidazole derivatives from reaction medium, and also simple work-up.…”

“…Previously, we developed a proceeding for obtaining 2arylbenzimidazoles in heterogeneous medium from benzylic halides and o-phenylenediamines [23,24]. In this line, starting from primary alkyl halides and 1,2-benzenediamine derivatives, we have extended the new method to obtain 2-alkyl-substituted benzimidazoles as well.…”

Alkyl-1h-Benzo[d]imidazole Synthesis From Alkyl Bromides and 1,2-Benzenediamines by a Mild Domino Reaction

“…The novel one-pot domino sequence uses thermal heating conditions and does not require catalyst and solvent. The method allows the obtaining of the alkyl benzimidazoles in good yields, but the reaction time is longer than in the case of obtaining the aryl benzimidazoles [23,24]. The main advantages of the procedure are mild conditions, the operational simplicity, easy isolation of alkyl benzimidazole derivatives from reaction medium, and also simple work-up.…”

“…Previously, we developed a proceeding for obtaining 2arylbenzimidazoles in heterogeneous medium from benzylic halides and o-phenylenediamines [23,24]. In this line, starting from primary alkyl halides and 1,2-benzenediamine derivatives, we have extended the new method to obtain 2-alkyl-substituted benzimidazoles as well.…”