140381-66-4Relevant academic research and scientific papers
Metal-Free Synthesis of Polycyclic Quinazolinones Enabled by a (NH4)2S2O8-Promoted Intramolecular Oxidative Cyclization
Xie, Lijuan,Lu, Cong,Jing, Dong,Ou, Xinrui,Zheng, Ke
, p. 3649 - 3653 (2019)
An efficient metal-free, (NH4)2S2O8 mediated intramolecular oxidative cyclization for the construction of polycyclic heterocycles was disclosed. A series of polycyclic quinazolinone derivatives with good functional group tolerance were obtained in high yields. The natural products tryptanthrin and rutaecarpine, as well as their derivatives, were easily synthesized by this strategy. A preliminary mechanism study suggested the carbon-centered radical was involved in the catalytic cycle.
Redox condensation of o-halonitrobenzene with 1,2,3,4-tetrahydroisoquinoline: Involvement of an unexpected auto-catalyzed redox cascade
Nguyen,Ermolenko,Al-Mourabit
, p. 4914 - 4917 (2016)
A practical synthesis of fused benzimidazoles 5 has been developed by simply heating o-halonitrobenzenes 1 with tetrahydroisoquinolines 2. In this transformation, 2 played multiple roles as a building block, base and a double hydride donor in a cascade of uncatalyzed aromatic substitution, reduction of the nitro group, oxidation of the α-methylene group and condensation.
Synthesis of Spirooxindoles via the tert-Amino Effect
Ramakumar, Kinthada,Maji, Tapan,Partridge, James J.,Tunge, Jon A.
, p. 4014 - 4017 (2017)
A new method is developed for the synthesis of spirooxindoles from amines and isatins via C-H functionalization. The reaction leverages the tert-amino effect to form an enolate-iminium intermediate via [1,5]-hydride shift followed by cyclization. Interest
Organocatalytic cascade aldimine condensation/[1,6]-hydride transfer/Mannich-type cyclization: Sustainable access to indole-2,3-fused diazocanes
An, Xiao-De,Dong, Pei-Zhen,Liu, Rui-Bin,Qiu, Bin,Wang, Lin-Xuan,Xiao, Jian
supporting information, p. 8181 - 8186 (2021/11/01)
An unprecedented organocatalytic cascade aldimine condensation/[1,6]-hydride transfer/Mannich-type cyclization of indole-2-carbaldehydes with o-aminoanilines was developed to assemble polycyclic indole-2,3-fused diazocanes in one step. This novel methodol
Electrochemical Synthesis of Benzo[ d]imidazole via Intramolecular C(sp3)-H Amination
Li, An,Li, Caohui,Li, Lijun,Liu, Yu,Tang, Kewen,Yang, Tao,Yang, Zan,Zhou, Congshan
, (2022/01/03)
An electrochemical dehydrogenative amination for the synthesis of benzimidazoles was developed. This electrosynthesis method could address the limitations of the C(sp3)-H intramolecular amination synthesis reaction and provide novel access to obtain 1,2-disubstituted benzimidazoles without transition metals and oxidants. Under undivided electrolytic conditions, various benzimidazole derivatives could be synthesized, exhibiting functional group tolerance.
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.
An intramolecular C(sp3)-H imination using PhI-m CPBA
Bose, Anima,Maiti, Saikat,Sau, Sudip,Mal, Prasenjit
supporting information, p. 2066 - 2069 (2019/02/19)
Herein, a highly exothermic primary amine-polyvalent iodine reaction has been used successfully for selective functionalization of acidic C(sp3)-H groups for a dehydrogenative C-H imination reaction by 4H elimination. Overall, C(sp3)-H imination at 1,5 distances was readily done via organocatalysis using PhI (10 mol%)-mCPBA under ambient conditions.
Synthesis of benzimidazoles via iridium-catalyzed acceptorless dehydrogenative coupling
Sun, Xiang,Lv, Xiao-Hui,Ye, Lin-Miao,Hu, Yu,Chen, Yan-Yan,Zhang, Xue-Jing,Yan, Ming
supporting information, p. 7381 - 7383 (2015/07/15)
Iridium-catalyzed acceptorless dehydrogenative coupling of tertiary amines and arylamines has been developed. A number of benzimidazoles were prepared in good yields. An iridium-mediated C-H activation mechanism is suggested. This finding represents a novel strategy for the synthesis of benzimidazoles.
Synthesis of benzimidazoles via iridium-catalyzed acceptorless dehydrogenative coupling
Sun, Xiang,Lv, Xiao-Hui,Ye, Lin-Miao,Hu, Yu,Chen, Yan-Yan,Zhang, Xue-Jing,Yan, Ming
supporting information, p. 7381 - 7383 (2015/11/27)
Iridium-catalyzed acceptorless dehydrogenative coupling of tertiary amines and arylamines has been developed. A number of benzimidazoles were prepared in good yields. An iridium-mediated C-H activation mechanism is suggested. This finding represents a novel strategy for the synthesis of benzimidazoles.
Metal-free TEMPO-promoted C(sp3)-H amination to afford multisubstituted benzimidazoles
Xue, Ding,Long, Ya-Qiu
, p. 4727 - 4734 (2014/06/09)
An efficient TEMPO-air/cat. TEMPO-O2 oxidative protocol was developed to synthesize multisubstituted or fused tetracyclic benzimidazoles via a metal-free oxidative C-N coupling between the sp3 C-H and free N-H of readily available N1-benzyl/alkyl-1,2-phenylenediamines.
