- Palladium-catalyzed carbonylative cyclization of 2-(2-bromovinyl)benzimidazoles leading to pyrrolone-fused benzimidazoles
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2-(2-Bromovinyl)benzimidazoles are carbonylatively cyclized under carbon monoxide pressure in toluene in the presence of a catalytic amount of PdCl2 and PPh3 along with a base to give 1H-benzo[d]pyrrolo[1,2-a]imidazolones in good yields.
- Yang, Byeong Woo,Ho, Son Long,Lim, Ho-Jin,Cho, Chan Sik
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- Understanding the influence of geometric and electronic structure on the excited state dynamical and photoredox properties of perinone chromophores
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In this work, a series of eight similarly structured perinone chromophores were synthesized and photophysically characterized to elucidate the electronic and structural tunability of their excited state properties, including excited state redox potentials and fluorescence lifetimes/quantum yields. Despite their similar structure, these chromophores exhibited a broad range of visible absorption properties, quantum yields, and excited state lifetimes. In conjunction with static and time-resolved spectroscopies from the ultrafast to nanosecond time regimes, time-dependent computational modeling was used to correlate this behavior to the relationship between non-radiative decay and the energy-gap law. Additionally, the ground and excited state redox potentials were calculated and found to be tunable over a range of 1 V depending on the diamine or anhydride used in their synthesis (Ered* = 0.45-1.55 V;Eox* = ?0.88 to ?1.67 V), which is difficult to achieve with typical photoredox-active transition metal complexes. These diverse chromophores can be easily prepared, and with their range of photophysical tunability, will be valuable for future use in photofunctional applications.
- Castellano, Felix N.,Chakraborty, Arnab,Favale, Joseph M.,Garakyaraghi, Sofia,Palmer, Jonathan R.,Pemberton, Barry C.,Valchar, Mary Katharine,Wells, Kaylee A.,Yarnell, James E.
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p. 24200 - 24210
(2021/11/16)
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- 1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric o-Phenylenediamine Substrates
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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.
- Foss, Frank W.,Palacios, Philip M.,Pierce, Brad S.,Thapa, Pawan,Tran, Tam
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p. 1991 - 2009
(2020/03/13)
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- Imidazole spiro-containing compound and application thereof
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The invention relates to an imidazole spiro-containing compound and an application thereof. The compound has a structural general formula represented by chemical formula (1). The compound has the advantages of good stability, high luminous efficiency, long service life, and simplicity in synthesis.
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Paragraph 0207; 0209; 0211
(2020/02/20)
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- Cu(OAc)2-Mediated benzimidazole-directed C-H cyanation using 2-(4-methylpiperazin-1-yl)acetonitrile as the cyano source
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A new protocol for the Cu(OAc)2-mediated cyanation of arenes using benzimidazole as the directing group with 2-(4-methylpiperazin-1-yl)acetonitrile as the cyano source was developed. A series of cyano derivatives were facilely and conveniently obtained in moderate to good yields by using this method. The C-H activation catalytic system was originally applied to the C(sp2)-H cyanation of the aryl/heteroaryl to synthesize 2-(1H-benzo[d]imidazol-2-yl)aryl nitriles. There were 19 new compounds in the synthesized 20 cyanide products. In this reaction, 2-(4-methylpiperazin-1-yl)acetonitrile as the cyano source was originally employed in the C(sp2)-H cyanation of the arenes. In addition, a fluorescent material 5a was obtained by derivative reactions of the obtained cyanide product 3.
- Zhang, Tianyou,Qiao, Jingyi,Song, He,Xu, Feng,Liu, Xiaochong,Xu, Chunzhao,Ma, Junjie,Liu, Hao,Sun, Zhizhong,Chu, Wenyi
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p. 9084 - 9089
(2019/06/18)
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- The aminocarbonylation of 1,2-diiodoarenes with primary and secondary amines catalyzed by palladium complexes with imidazole ligands
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The efficient carbonylative cyclization of 1,2-diiodobenzene with different primary and secondary amines was performed using a palladium complex with an imidazole ligand, PdCl2(BIM)2, as a catalyst. In reactions performed at 1 atm of CO with primary amines, phthalimides were obtained as the only products with yields of up to 100% in 4 h. An even shorter time, 1 h, was sufficient to obtain the same products employing methyl-2-iodobenzoate as a substrate instead of 1,2-diiodobenzene. In an analogous reaction with secondary amines, 1,2-diiodobenzene was converted to three products, formed in amounts dependent on the reaction conditions. The presence of Pd NPs and soluble palladium intermediates indicated their participation in the catalytic reaction.
- Wójcik, Przemys?aw,Trzeciak, Anna M.
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- Substituted 2-formylbenzoic acids in the synthesis of 11H-isoindolo[2,1-a] benzimidazol-11-ones, 5H-isoindolo[2,1-a][3,1]benzoxazine-5,11(6aH)-diones, and 6,6a-dihydroisoindolo-[2,1-a]quinazoline-5,11-diones
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Optimal conditions were developed for the synthesis of 11H-isoindolo[2,1-a] benzimidazol-11-one, 5H-isoindolo[2,1-a][3,1]benzoxazine-5,11(6aH)-dione, and 6,6a-dihydroisoindolo[2,1-a]quinazoline-5,11-dione derivatives in the reaction of substituted 2-formylbenzoic acids with o-phenylenediamine, anthranilic acid, and anthranilamide, respectively. The bifolded structure of 6,6a- dihydroisoindolo-[1,2-a]quinazoline-5,11-dione was verified and investigated.
- Gromachevskaya,Fin'Ko,Butin,Pushkareva,Strelkov,Isakova,Krapivin
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p. 1331 - 1344
(2014/01/17)
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- Green synthesis of polycyclic benzimidazole derivatives and organic semiconductors
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Polycyclic benzimidazole derivatives, an important class of compounds in organic electronics and photovoltaics, were prepared using a solvent-free "green" process based on heating carboxylic acid anhydrides and arylene diamines in the presence of zinc acetate in the solid state. Products were isolated and purified directly by train sublimation of the crude reaction mixtures. The reaction conditions were optimized using various carboxylic acid anhydrides. Optical and electrochemical properties of these materials are also described.
- Mamada, Masashi,Perez-Bolivar, Cesar,Anzenbacher, Pavel
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scheme or table
p. 4882 - 4885
(2011/12/05)
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- Kinetic versus thermodynamic access to imidazoisoindolones, benzimidazoisoindolones, and [1,4]diazepinoisoindolones: Intramolecular nitrogen and π-aromatic trapping of N-acyliminium cation
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Efficient assembly of substituted imidazo[2,1-a]isoindolones I is reported from suitable α,β-diamine IV (or corresponding β-nitroamine) and phthalic anhydride (1) in a three- or four-step sequence in good yields. The key step of this methodology is based on an intramolecular α-aza- amidoalkylation of the N-acyliminium species. Furthermore, when R2 is an aromatic moiety a competing α-amidoalkylation took place and imidazo[2,1-a]isoindolones (or benzimidazo[2,1-a]isoindolones) I and/or isoindolo[1,4]benzodiazepines III were obtained under kinetic or thermodynamic control. The chemoselectivity of these transformations is also discussed.
- Cul, Armelle,Da?ch, Adam,Decroix, Bernard,Sanz, Gérard,Van Hijfte, Luc
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p. 11029 - 11039
(2007/10/03)
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- A new kinetic model for the acid-catalysed reactions of N-(2-aminophenyl)phthalamic acid in aqueous media
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The acid-catalysed breakdown of N-(2-aminophenyl)phthalamic acid has been studied in dilute aqueous acids in the pH range 0-6. The dominant reaction is the formation of N-(2-aminophenyl)phthalimide (between ~80 and ~100% yields in the pH range studied) and its subsequent rearrangement to 2-(2-carboxyphenyl)benzimidazole, occurring as consecutive pseudo-first-order processes. Anomalously, only a minor hydrolysis reaction is observed. A kinetic model for these processes has been constructed and rate constants and activation parameters evaluated. Mechanisms involving pre-equilibria to form the kinetically significant species have been proposed for the consecutive processes. The approach has been adapted to account for the observed kinetics of acid catalysed formation of benzimidazoles from o-aminoanilides.
- Perry, Christopher J.
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p. 977 - 982
(2007/10/03)
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- Spectroscopic Studies of Benzimidazole, Quinoxaline and Quinoline Derivatives.
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Four fused benzimidazoles, two quinoxalines and two fused quinoline derivatives were studied with respect to their MS, NMR and IR spectra.These compounds were chosen in order to compare the effect of the size of the hetero ring and the presence of C=N and C=O on their spectral behavior.
- Alkhathlan, Hamad Z.,Al-Lohedan, Hamad A.
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p. 201 - 220
(2007/10/02)
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- Synthesis and pharmacological evaluation of isoindolo[1,2-b]quinazolinone and isoindolo[2,1-a]benzimidazole derivatives related to the antitumor agent batracylin
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The synthesis and pharmacological activity of isoindolo[1,2-b]quinazolin- 12(10H)-ones and isoindolo[2,1-a]benzimidazoles related to batracylin are described. The acute toxicity of batracyclin has been associated with the formation of its N-acetyl metabolite which is a potent inducer of unscheduled DNA synthesis in rat hepatocytes. The desamino derivative and the 8-aza analog of batracylin retained the ability to inhibit topoisomerase II but did not induce unscheduled DNA synthesis. While less active than batracylin, these analogs were cytotoxic to CCRF CEM leukemia cells. The isoindolo[2,1- a]benzimidazole derivatives were inactive as topoisomerase II inhibitors and, in general, failed to exhibit comparable antitumor activity or to induce unscheduled DNA synthesis.
- Meegalla,Stevens,McQueen,Chen,Yu,Liu,Barrows,LaVoie
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p. 3434 - 3439
(2007/10/02)
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- APPLICATION OF PHOSPHORUS, ARSENIC AND ANTIMONY REAGENTS IN THE SYNTHESIS OF HETEROCYCLIC COMPOUNDS
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The ability of different reagents of the type R3XBr2, where R are various alkyl, alkoxide, phenyl, and phenoxide groups, and X is P, As and Sb, to promote an intramolecular cyclization of suitably substituted aromatic diamines has been investigated.The type of R group and X was found to have a great influence on the ability of these reagents to promote this type of cyclization.Best results were obtained when R=OMe and X=P. Key words: Phosphorus; arsenic; antimony; dibromotriphenylphosphorane; diamines; heterocycles.
- Alkhathlan, Hamad Z.,Al-Lohedan, Hamad A.
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p. 367 - 372
(2007/10/02)
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