Desulfurization Strategy in the Construction of Azoles Possessing Additional Nitrogen, Oxygen or Sulfur using a Copper(I) Catalyst

Guin, Srimanta; Rout, Saroj Kumar; Gogoi, Anupal; Nandi, Shyamapada; Ghara, Krishna Kanta; Patel, Bhisma K.

doi:10.1002/adsc.201200408

Cited by 55 publications

(34 citation statements)

References 88 publications

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“…Based on these experimental investigations and the available literature [37,[40][41][42][43][44][45][46][47][48][49][50], the mechanism for the formation of the final product 2-phenylaminobenzimidazole is very much similar to the mechanism reported for cobalt catalysis [37] (see supporting information Scheme S1).…”

Section: (4) (5)supporting

confidence: 66%

Copper-Promoted One-Pot Approach: Synthesis of Benzimidazoles

et al. 2020

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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.

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Section: (4) (5)supporting

confidence: 66%

Copper-Promoted One-Pot Approach: Synthesis of Benzimidazoles

et al. 2020

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“…Cobalt can co‐ordinate with thiourea and followed by removal of protons to afford intermediate R via intermediates P and Q . The intermediate R may react with 2‐iodoaniline to provide 2‐iodophenyl guanidine A along with by‐products CoS and poly sulphide via desulphurization/substitution . Oxidative addition of A with cobalt complex can lead to the formation of a which can undergo intramolecular C‐N cyclised product B using base via intermediate b .…”

Section: Figurementioning

confidence: 99%

Synthesis of Benzimidazoles via Domino Intra and Intermolecular C‐N Cross‐Coupling Reaction

2018

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The synthesis of aminobenzimidazoles has been demonstrated under mild reaction conditions using cobalt catalyst in one pot reaction. This methodology involved domino intra and intermolecular C-N cross-coupling reaction. In addition, functional group tolerance has been also explored.Benzimidazoles [1][2][3][4][5][6][7][8][9][10] and 2-aminobenzimidazoles [11][12][13][14][15][16][17][18][19][20][21] are very powerful compounds because of their applications in therapeutic [22][23] and biological sciences ( Figure 1). [24][25] These compounds were used as neuropeptide YY1 receptor antagonist, [26] N-methyl-D-aspartate (NMDA) antagonist, [27] factor Xa(FXa) inhibitor, [28] poly(ADP-ribose)polymerase (PARP) inhibitor [29] and non-peptide thrombin inhibitor. [30] In addition, these compounds show anti-inflammatory, antimicrobial and antibacterial activities. [31] Apart from that, these compounds can also be used for the synthesis of dyes and high-temperature resistance polymers. [32] Therefore, the construction of benzimidazole derivatives were developed by many researchers via both traditional methods [33][34][35] and C-N cross-coupling reactions using various transition metals such as Cu, [36][37][38][39][40] Pd, [41][42][43] Co, [44] Zn, [45][46][47] and Ru. [48] In this connection, we would like to demonstrate the methodology for the synthesis of benzimidazoles from thiourea in one pot reaction via desulphurization/substitution/domino C-N cross-coupling reaction using cobalt source as catalyst under mild reaction conditions.

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“…Then, reaction of A with Cu(OTf) 2 probably leads to the formation of Cu II species B with the aid of base, which should induce intermolecular nucleophilic addition to generate intermediate C . Subsequently, further deprotonation and the departure of CuS6d provides Cu II –metallacycle D , which is followed by ligand oxidation by Cu II to give desired thiadiazole 2 as well as a reduced copper species; the reduced copper species is oxidized to Cu II .…”

Section: Resultsmentioning

confidence: 99%