24340-87-2Relevant academic research and scientific papers
1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric o-Phenylenediamine Substrates
Foss, Frank W.,Palacios, Philip M.,Pierce, Brad S.,Thapa, Pawan,Tran, Tam
, p. 1991 - 2009 (2020/03/13)
Benzimidazoles are common in nature, medicines, and materials. Numerous strategies for preparing 2-arylbenzimidazoles exist. In this work, 1,2-disubstituted benzimidazoles were prepared from various mono- and disubstituted ortho-phenylenediamines (OPD) by iron-catalyzed oxidative coupling. Specifically, O2 and FeCl3·6H2O catalyzed the cross-dehydrogenative coupling and aromatization of diarylmethyl and dialkyl benzimidazole precursors. N,N′-Disubstituted-OPD substrates were significantly more reactive than their N,N-disubstituted isomers, which appears to be relative to their propensity for complexation and charge transfer with Fe3+. The reaction also converted N-monosubstituted OPD substrates to 2-substituted benzimidazoles; however, electron-poor substrates produce 1,2-disubstituted benzimidazoles by intermolecular imino-transfer. Kinetic, reagent, and spectroscopic (UV-vis and EPR) studies suggest a mechanism involving metal-substrate complexation, charge transfer, and aerobic turnover, involving high-valent Fe(IV) intermediates. Overall, comparative strategies for the relatively sustainable and efficient synthesis of 1,2-disubstituted benzimidazoles are demonstrated.
Microwave-assisted synthesis of polysubstituted benzimidazoles by heterogeneous Pd-catalyzed oxidative C-H activation of tertiary amines
De Luca, Lidia,Porcheddu, Andrea
supporting information; scheme or table, p. 5791 - 5795 (2011/11/06)
Tertiary amines can be used in place of aldehydes and carboxylic derivatives as partners in the synthesis of benzimidazoles. Dehydrogenative amine activation under heterogeneous catalysis was developed for the direct transformation of tertiary amines into benzimidazoles. Good yields and efficient recovery and recycling of the catalyst are some of the advantages of this new methodology, which shows that a simple alkene is used as the overall oxidative agent. Enhanced reaction rates were observed by using focused microwave heating.
Poly(1,1-bis(dialkylamino)propan-1,3-diyl)s; Conformationally-controlled oligomers bearing electroactive groups
Alder, Roger W.,Hyland, Niall P.,Jeffery, John C.,Riis-Johannessen, Thomas,Riley, D. Jason
supporting information; experimental part, p. 2704 - 2715 (2009/09/07)
The design of polymers with repeating [C(NR2)2CH 2CH2] units which may simultaneously provide conformational control and contain repeating electroactive centres is discussed; (NR2)2 groups would be ideally provided by ortho-phenylenediamine derivatives, with 1,8-diaminonaphthalenes as alternatives. Oligomers containing 1,8-bis(methylamino)naphthalenes, up to the hexamer, were obtained by condensation of oligomers of CH3[COCH 2CH2]nCOCH3 with 1,8-bis(methylamino)naphthalene, but attempts to prepare related oligomers from 1,2-bis(alkylamino)benzenes were unsuccessful, as only terminal ketone groups could be converted to aminals. Evidence for a strong preference for all-anti conformations of the main chain in the naphthalenediamine oligomers is provided by ring current effects on 1H NMR shifts, and by X-ray structures, which also provide evidence of intercalation in the solid state. Electrochemical studies of these oligomers show irreversible oxidation of oligomers in solution, but oxidation of longer oligomers leads to the deposition of a reddish-pink insoluble material which shows two reversible oxidation waves. Possible interpretation of these results is discussed. The Royal Society of Chemistry 2009.
One-Electron Oxidation and Triphenylmethylation of Benzimidazolines by the Triphenylmethyl Cation
Morkovnik, A. S.,Suslov, A. N.,Klimov, E. S.,Morkovnik, Z. S.,Okhlobystin, O. Yu.
, p. 847 - 852 (2007/10/03)
With triphenylmethyl perchlorate (tetrafluoroborate) 1,2,2,3-tetrasubstituted benzimidazolines undergo electrophilic triphenylation at position 5.In further reaction with the electrophilic agent the obtained 5-triphenylmethylbenzimidazolines are converted into radical-cations.They undergo a similar transformation during the action of silver perchlorate and molecular oxygen.The results from investigation of the radicalcations by ESR and PMR are given.
Synthesis and Autoxidation of 1,3-Dialkyl-2-arylbenzimidazolines
Reddy, A. Pandu Ranga,Veeranagaiah, V.,Ratnam, C. V.
, p. 367 - 371 (2007/10/02)
During the attempted studies of the elimination reactions of 1,3-dimethyl-(I, R = CH3)- and 1,3-diethyl-(I, R = C2H5)-2-arylbenzimidazolines, a novel rearrangement has been observed to take place resulting in substituted amides by autoxidative ring-opening.
