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Upstream product

• 57159-81-6 2-(methylsulfonyl)-1H-benzo[d]imidazole 
• 106-47-8 4-chloro-aniline 
• 14223-48-4 p-chlorophenyl isoselenocyanate 
• 95-54-5 1,2-diamino-benzene 
• 1056477-06-5 2-bromocyclohexanone 
• 45964-97-4 1-(4-chlorophenyl)guanidine 
• 123375-81-5 N-(2-bromophenyl)guanidine 
• 637-87-6 1-Chloro-4-iodobenzene 
• 615-36-1 2-bromoaniline 
• 2131-55-7 4-Chlorophenyl isothiocyanate 
• 108-94-1 cyclohexanone 
• 4857-06-1 2-chloro-1H-benzoimidazole 
• 777097-91-3 N¹-(2-aminophenyl)-N²-(4-chlorophenyl)thiourea 

Relevant academic research and scientific papers

A practical synthesis of 2-(N-substituted)-aminobenzimidazoles utilizing CuCl-promoted intramolecular cyclization of N-(2-aminoaryl)thioureas

A practical protocol for synthesis of 2-(N-substituted)-aminobenzimidazoles was developed. N-(2-Aminoaryl)thioureas undergo a CuCl-promoted intramolecular cyclization to give the corresponding 2-(N-substituted amino)benzimidazoles in good to excellent isolated yields.

Copper-promoted one-pot approach: Synthesis of benzimidazoles

A facile, one-pot, and proficient method was developed for the production of various 2-arylaminobenzimidazoles. This methodology is based for the first time on a copper catalyst promoted domino C-N cross-coupling reaction for the generation of 2-arylaminobenzimidazoles. Mechanistic investigations revealed that the synthetic pathway involves a copper-based desulphurization/nucleophilic substitution and a subsequent domino intra and intermolecular C-N cross-coupling reactions. Some of the issues typically encountered during the synthesis of 2-arylaminobezimidazoles, including the use of expensive catalytic systems and the low reactivity of bromo precursors, were addressed using this newly developed copper-catalyzed method. The reaction procedure is simple, generally with excellent substrate tolerance, and provides good to high yields of the desired products.

Ultrasound-assisted synthesis of substituted 2-aminobenzimidazoles, 2-aminobenzoxazoles, and related heterocycles

A sonochemical method for the synthesis of 2-aminobenzimidazoles and 2-aminobenzoxazoles, as well as chiral aminooxazolines and a chiral substituted quinazolin-5-one is reported. Using the Ph3P–I2system in the presence of triethylami

A new NBS/oxone promoted one pot cascade synthesis of 2-aminobenzimidazoles/2-aminobenzoxazoles: A facile approach

A new strategy for the synthesis of 2-aminobenzimidazoles via a reaction of α-halogenated cyclohexanone with guanidine is reported. It provides a facile N-bromosuccinimide (NBS) mediated transition metal free, sustainable path for the synthesis of 2-substituted azoles. NBS along with the oxone promotes in situ halogenation of cyclohexanone, which in turn, when allowed to react with guanidine, afforded 2-aminobenzimidazoles (2-ABI). This eco-friendly protocol provides a competent laboratory synthesis method associated with significant advantages such as greater selectivity, cost-efficiency, mild reaction conditions, absence of chromatographic purification, clean reaction profile, and a simple work-up procedure to furnish high yields. The structures of all the synthesized compounds were confirmed on the basis of IR, 1H and 13C NMR, mass spectrometry, and elemental analyses data. In addition, we have also extended the scope of this strategy for obtaining 2-amino substituted benzoxazoles.

PROCESS FOR PREPARING 2-ARYLAMINO OR HETEROARYLAMINO SUBSTITUTED BENZIMIDAZOLE COMPOUNDS

The present invention is related to a process for preparing 2-arylamino or heteroarylamino substituted benzimidazole compounds.

Phosphonium-mediated cyclization of N-(2-aminophenyl)thioureas: Efficient synthesis of 2-aminobenzimidazoles

BOP efficiently promoted the phosphonium-mediated cyclization of thioureas, leading to a convenient synthesis of 2-aminobenzimidazoles. Compared to conventional methods, the reactions were complete at room temperature with times ranging from a few minutes

One-pot synthesis of five and six membered N, O, S-heterocycles using a ditribromide reagent

In a one-pot procedure, bromine less brominating reagent 1,1′-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) has been utilized as an efficient desulfurizing agent for the construction of a library of heterocycles containing N, O, and S starting from aryl/alkyl isothiocyanates. In this approach, aryl/alkyl isothiocyanate reacts with o-phenylenediamine (o-PD), o-aminophenol, and o-aminothiophenol to form their monothiourea which on desulfurization with EDPBT led to the formation of corresponding 2-aminobenzimidazoles, 2-aminobenzoxazoles, and 2-aminobenzothiazoles, respectively. An interesting regioselectivity was observed for unsymmetrical thiourea having a naphthyl moiety on the one side and an ortho amino or an ortho hydroxy phenyl group on the other side giving a completely different product which is mainly dependent on the nature of the nucleophiles (-OH or -NH 2). Further, the bis-thioureas resulted from the aliphatic 1,2-diamine with 2 equiv of aryl isothiocyanates on treatment with EDPBT gave imidazolidenecarbothioamides, whereas bis-thioureas resulted from aromatic 1,2-diamine yielded benzimidazoles with concurrent expulsion of an isothiocyanate unit. This method is simple and applied to various substrates which are amenable to bromination that reveals the desulfurizing ability of EDPBT predominating over its brominating ability. Finally, the spent reagent EDPDB can be recovered, regenerated, and reused without any loss of activity.

Novel synthesis of 2-aminobenzimidazoles from isoselenocyanates

An efficient one-pot procedure for the synthesis of 2-aminobenzimidazoles from isoselenocyanates and various substituted diamines is described. Precipitation of elemental selenium from the reaction mixture greatly simplifies the purification procedure and also allows it to be re-used for preparation of isoseleno?cyanates. A possible mechanism for the formation of 2-aminobenzimidazoles is proposed. Georg Thieme Verlag Stuttgart - New York.

Desulfurization mediated by hypervalent iodine(III): A novel strategy for the construction of heterocycles

The desulfurization ability of diacetoxyiodobenzene (DIB) has been explored in the preparation of isothiocyanates from the corresponding dithiocarbamate salts. The in situ generated isothiocyanates reacted with o-phenylenediamine and o-aminophenol to form monothioureas, which, on treatment with a further equivalent of DIB in one pot, gave benzimidazoles and aminobenzoxazoles, respectively. Aliphatic 1,2-diamines on reaction with 2 equiv. of isothiocyanate followed by treatment with DIB gave imidazolidenecarbothioamides, whereas the treatment of aromatic 1,2-diaminebis(thioureas) yielded benzimidazoles with the concurrent formation of isothiocyanate. The driving force for the formation of the latter is the aromatization of the product. The use of DIB makes these methods simpler and more efficient, giving high yields of the desired products in one pot. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

An efficient method to access 2-substituted benzimidazoles under solvent-free conditions

An expeditious method to access 2-substituted benzimidazoles was developed. Both aromatic (phenols, anilines, and thiophenols) and alkyl nucleophiles (amines and thiols) react with 2-methylsulfonyl benzimidazole under solvent-free conditions to generate a variety of 2-substituted benzimidazoles.