- NOVEL ONE-POT HOMOGENEOUS PROCESS FOR THE LARGE SCALE MANUFACTURE OF 2-SUBSTITUTED BENZIMIDAZOLES
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2-substituted benzimidazoles and methods of preparing the same are disclosed. The compositions may include a compound or salt thereof, an acid, and a polar aprotic solvent. The compositions may be used to inhibit corrosion of a metal surface in contact with an aqueous system, and provide enhanced protection against corrosion of metals in the aqueous system.
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Paragraph 0147; 0148
(2019/05/24)
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- Synthesis and in vitro antifungal evaluation of benzoimidazolyl-piperazinyl-phenylmethanone derivatives
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Benzimidazole and piperazines are the important pharmacophores in the structures of many antifungal compounds. Further, the phenylmethanone are also a unique class of compounds whose antifungal profile is not much exploited. So to exploit their antifungal potential we have selected these three combinations and framed the novel parent structure for our research work. In this study a novel series of benzimidazoles derivatives was synthesized by microwave irradiation and characterized by 1H NMR, 13C NMR, Infra Red (IR), and Mass Spectroscopy (MS), and by elemental analysis. The screening of compound for in vitro (turbidimetric method) antifungal activity against C.albicans revealed activity in many of the compounds as comparable to that of ketoconazole.
- Kankate, Rani S.,Gide, Parag S.,Belsare, Deepak P.
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p. 1855 - 1863
(2015/04/22)
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- BENZAZOLE DERIVATIVES AS HISTAMINE H4 RECEPTOR LIGANDS
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The present patent application concerns new Iigands of the H4-receptor of formula (I), their process of preparation and their therapeutic use.
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Page/Page column 63
(2012/04/17)
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- Benzazole derivatives as histamine H4 receptor ligands
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The present patent application concerns new ligands of the H4-receptor of formula (I), their process of preparation and their therapeutic use.
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Page/Page column 29
(2012/05/20)
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- The synthesis, characterization and optical properties of novel pyrido[1,2-a]benzimidazole derivatives
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A series of novel, substituted, pyrido[1,2-a]benzimidazole derivatives were synthesized using a novel tandem annulation reaction between 2-acylbenzimidazole derivatives and 4-bromobut-2-enoic esters under mild conditions. The compounds were characterized using IR, 1H NMR, 13C NMR and HRMS; the crystal structure of 2,7,8-trimethyl-3- ethoxycarbonyl-4-phenylpyrido[1,2-a]benzimidazole was determined as orthorhombic. The absorbance and fluorescence spectra of the pyrido[1,2-a]benzimidazoles were measured in dichloromethane; an intense absorption maxima was observed at 250 nm and emission maxima were noted at 460 nm. The absorption spectra and fluorescence characteristics of the pyrido[1,2-a]benzimidazole derivatives revealed that a phenyl and a methyl group attached to the pyrido[1,2-a]benzimidazole ring markedly influenced maximum emission.
- Ge, Yan Qing,Jia, Jiong,Yang, He,Tao, Xu Tang,Wang, Jian Wu
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scheme or table
p. 344 - 349
(2011/06/11)
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- Boric acid-catalyzed direct condensation of carboxylic acids with benzene-1,2-diamine into benzimidazoles
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The applicability of boric acid catalysis for the direct condensation of carboxylic acids with benzene-1,2-diamine to give 2-substituted benzimidazoles was investigated. It was found that catalytic amounts (5-10 mol-%) of boric acid efficiently promote the cyclocondensation of aliphatic carboxylic acids in refluxing toluene. In addition, the relatively neutral conditions allow the use of acid-sensitive substrates and give rise to specific transformations and selectivities that are not observed with some classical methods. Benzoic acids were found to be less reactive than aliphatic acids and thus require refluxing xylene for better efficiency. Phenylboronic acid was found to be inactive as a catalyst due to its rapid consumption by condensation with benzene-1,2-diamine to give a 2-phenylbenzodiazaborole. Copyright
- Maras, Nenad,Kocevar, Marijan
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experimental part
p. 1860 - 1874
(2011/12/02)
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- Studies on synthesis of 2-acetylbenzimidazole and related benzimidazole derivatives
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Condensation of o-phenylenediamine (1) with propanoic acid under Phillips' conditions gives 2-ethylbenzimidazole (2). Attempts to oxidise 2 to 2-acetylbenzimidazole (3) using H2O2, SeO2, KMnO4/acetone were unsuccessful. Condensation of 2 with benzaldehyde yields 2-(α-methylstyryl)benzimidazole (4) which on oxidation with KMnO4 gives benzimidazole-2-carboxylic acid (5) as the sole product. Reaction of 1 with pyruvic acid results in 3-methylbenzo-1H-dihydropyrazine-2-one (7) rather than 3 as the major product. Treatment of 1 with formic acid gives the known compound benzimidazole (9) which with acetic anhydride in the presence of NaOAc does not yield 3. Reaction of 1 with lactic acid under Phillips' conditions gives 2-(α-hydroxyethyl)benzimidazole (10) which on oxidation with acid dichromate, however, yields 3. Studies on syntheses and spectral properties of related benzimidazoles are reported.
- Ramaiah,Grossert,Hooper,Dubey,Ramanatham
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p. 140 - 144
(2007/10/03)
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- A New Synthetic Method for the 2-Substitution of N-Unsubstituted Benzimidazoles: Formaldehyde as a Versatile Protecting Agent for Heterocyclic NH
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N-Unsubstituted benzimidazoles 1 are readily converted in a one-pot sequence into 2-substituted derivatives 2 with good overall yields.N-Protection with formaldehyde and lithiation with lithium N,N-diisopropylamide (LDA), n-butyllithium, or tert-butyllithium gives the dilithiohemiaminals 6, which readily react with a range of electrophiles at the 2-carbon.The 2-substituted 1-(lithioxymethyl)benzimidazoles 7 undergo smooth acid-catalyzed dehydroxymethylation under mild conditions to give N-unsubstituted 2-substituted benzimidazoles 2.
- Katritzky, Alan R.,Akutagawa, Kunihiko
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p. 2949 - 2952
(2007/10/02)
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- Practicable Syntheses of 2-Hydroxymethyl-substituted Benzimidazoles and 2-Formylbenzimidazole
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N-Protection of benzimidazole by a diethoxymethyl group, as in , allows exclusive lithiation at the 2-position.This protected anion can be made to react with various electrophiles (e. g. ketones, aldehydes) to yield the corresponding 2-hydroxymethylbenzimidazoles (1).Facile deprotection occurs with acid.Two practicable syntheses of 2-formylbenzimidazole are also described and an indirect route to benzimidazole-2-alcohols is discussed.
- Ooi, Hong Chin,Suschitzky, Hans
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p. 2871 - 2876
(2007/10/02)
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