18443-20-4Relevant academic research and scientific papers
Synthesis of Quinone Derivatives of Benzannelated Heterocycles with Bridgehead Nitrogen
Begunov,Sokolov,Filimonov
, p. 1383 - 1391 (2020/10/02)
Abstract: A facile synthesis of para-quinones derived from fused benzimidazoles with a bridgehead nitrogen atom was developed. The heterocyclic quinone core formed as a result of reductive cyclization of ortho-nitroarenes containing alicyclic and aromatic azaheterocycles. Functionalization of 1,2,3,4-tetrahydro- and pyrido[1,2-a]benzimidazoles via SEAr, condensation, and reduction reactions allowed synthesis of amino derivatives which were oxidized with KNO3 in H2SO4 to obtain novel heterocyclic quinones.
Electroreductive heterocyclization of ortho-piperidino substituted nitro(het)arenes
Begunov, Roman S.,Minyaev, Mikhail E.,Sakulina, Valeria O.,Saverina, Evgeniya A.,Sokolov, Alexandr A.,Syroeshkin, Mikhail A.
, p. 633 - 635 (2020/10/09)
Electrochemical reduction of ortho-piperidino substituted nitro(het)arenes in an undivided cell on a lead cathode in 8% HCl gave either 1,2,3,4-tetrahydropyrido[1,2-a]-benzimidazoles or 6,7,8,9-tetrahydropyrido[3′,2′:4,5]- imidazo[1,2-a]pyridines. The red
Formic acid as a sustainable and complementary reductant: An approach to fused benzimidazoles by molecular iodine-catalyzed reductive redox cyclization of: O -nitro- t -anilines
Nguyen,Ermolenko,Al-Mourabit
supporting information, p. 2966 - 2970 (2016/06/09)
Molecular iodine was found to be an excellent catalyst for reductive redox cyclization of o-nitro-t-anilines 1 into fused tricyclic or 1,2-disubtituted benzimidazoles 2. A range of functional groups such as halides (F, Cl, Br), methoxy, ester, trifluoromethyl, cyano, pyridine and even nitro groups were tolerated using formic acid as a clean, safe, user-friendly and complementary reductant. When iodine was used in a stoichiometric amount (50 mol%), the methodology allowed the direct synthesis of benzimidazole hydroiodides 2·HI in high yields by simple precipitation from the reaction mixture.
Metal-free construction of tricyclic or tetracyclic compounds - Acid-promoted synthesis of benzo[4,5]imidazo[2,1-a]isoindole and 1,2-dialkyl-2,3-dihydrobenzimidazoles
Chen, Jinying,Qu, Jinpeng,Zhang, Yuanqing,Chen, Yongxin,Liu, Na,Chen, Baohua
supporting information, p. 316 - 319 (2013/01/15)
An environmental friendly, efficient, and easy to operate strategy for synthesizing of benzo[4,5]imidazo[2,1-a]isoindole and 1,2-dialkyl-2,3- dihydrobenzimidazoles via acid-promoted coupling of dialdehyde and o-diaminobenzene under metal-free conditions is described. A series of products were generated in good yields under mild conditions.
Methine dyes
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, (2008/06/13)
The invention relates to a new class of pyrrolobenzimidazole, benzimidazoloisoquinoline and dipyrodinobenzodiimidazole in cyanine sensitizing dyes derived therefrom and their use in silver halide emulsions, and to methods for preparation of such new dyes.
