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

Wan, Zhengming; Ousman, Erena Farah; Παπαϊωάννου, Νικόλαος; Saiah, Eddine

doi:10.1016/j.tetlet.2011.05.146

Cited by 27 publications

(11 citation statements)

References 38 publications

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“…Our initial efforts to overcome this limitation by replacing the base used to a milder base (i.e. Nmethylmorpholine or pyridine) failed to improve the We have also utilized the reported method for the synthesis of two halogenated analogues of Boc-tyrosine derived benzimidazoles (20 and 21), and three N-Cbz protected amino acid derived benzimidazoles (22)(23)(24). Using these substrates, we demonstrated that both Boc and Cbz carbamates are tolerated.…”

Section: Resultsmentioning

confidence: 99%

An efficient one-pot conversion of carboxylic acids into benzimidazoles via an HBTU-promoted methodology

Barasa

Yoganathan

2018

RSC Adv.

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Section: Resultsmentioning

confidence: 99%

An efficient one-pot conversion of carboxylic acids into benzimidazoles via an HBTU-promoted methodology

Barasa

Yoganathan

2018

RSC Adv.

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“…BOP, also known as Castros reagent, is a phosphonium coupling agent used in peptide synthesis [101] . Wan et al ., employed BOP as desulfurizing agent to synthesize 2‐aminobenzimidazoles 151 from thioureas 150 by the treatment of various diphenyl thiourea derivatives 150 with BOP in MeCN and DBU as base (Scheme 30A) [102] . The electronic properties of substituents had no obvious effect on the yields of 2‐aminobenzimidazoles 151 .…”

Section: Non‐metal‐assisted Desulfurizationmentioning

confidence: 99%

“…The electronic properties of substituents had no obvious effect on the yields of 2‐aminobenzimidazoles 151 . Additionally, quinazoline 153 (Scheme 30B) [102] and 1,3,4‐oxadiazole 155 were synthesized by employing the same reaction condition (Scheme 30C) [103] …”

Section: Non‐metal‐assisted Desulfurizationmentioning

confidence: 99%

Cyclodesulfurization: An Enabling Protocol for Synthesis of Various Heterocycles

et al. 2021

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Heterocycles closely intertwine chemistry with biology reflecting the presence of nitrogen‐based heterocyclic ring structure in nearly 75 % of small‐molecule drugs. The number of reported strategies for the synthesis of several “privileged scaffolds” has expanded, amongst which, cyclodesulfurization of thioureas offers a quick access to highly substituted heterocycles, thereby playing a role of an excellent tool in organic syntheses of natural products and pharmaceutically active compounds. This comprehensive review emphasizes the applications of cyclodesulfurization as an integral synthetic step in the synthesis of nitrogen, oxygen and sulfur‐containing heterocycles. Furthermore, a survey of cyclodesulfurizing agents reported since 2000 is comprehensively reviewed and summarized.

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“…Consequently, the development of new strategies for the synthesis of fused heterocyclic systems is of prime importance. In the present study, the reaction of binucleophilic nitrogen system like o-phenylenediamine (1) with commercially available reagents was explored to build up seven-, six-, and five-membered heterocyclic systems [6][7][8][9][10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

o-Phenylenediamine as a Source of Fused Azole, Azine, and Diazepine Derivatives

et al. 2021

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A facile synthetic approach to diazepine and/or benzimidazole derivatives has been developed through the reaction of enamine [N 1 -(1-phenylethenyl)benzene-1,2-diamine] obtained from o-phenylenediamine and acetophenone. Its reaction with isophthaloyl chloride produced bis(1,5-benzodiazepinyl)benzene derivative via cyclization involving the nucleophilic enamino carbon atom, whereas the cyclocondensation with diethyl succinate occurred at the nucleophilic nitrogen atom to give bis-benzimidazole derivative. Depending on the conditions, the cyclization with carbon disulfide in DMSO afforded tricyclic 4-phenylimidazo[4,5,1-hi]indole-2(1H)-thione, while 4-phenyl-1,3-dihydro-2H-1,5-benzodiazepine-2-thione was formed in the presence of pyridine. Cyclocondensation of o-phenylenediamine with two equivalents of acetophenone in acid medium produced 3-phenyl-1-(1-phenylethenyl)-1,4-dihydroquinoxaline. N-(2-Aminophenyl)thiourea obtained from o-phenylenediamine and ammonium thiocyanate reacted with chloroacetyl chloride, diethyl malonate, carbon disulfide, and sodium nitrite in aqueous HCl to afford benzimidazole, thiadiazolobenzimidazole, and benzotriazole derivatives.

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

Cited by 27 publications

References 38 publications

An efficient one-pot conversion of carboxylic acids into benzimidazoles via an HBTU-promoted methodology

An efficient one-pot conversion of carboxylic acids into benzimidazoles via an HBTU-promoted methodology

Cyclodesulfurization: An Enabling Protocol for Synthesis of Various Heterocycles

o-Phenylenediamine as a Source of Fused Azole, Azine, and Diazepine Derivatives

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