17583-50-5Relevant articles and documents
Synthesis of 1,3-dialkylimidazolium and 1,3-dialkylbenzimidazolium salts
Starikova,Dolgushin,Larina,Ushakov,Komarova,Lopyrev
, p. 1467 - 1470 (2003)
A number of N-alkylimidazoles and N-alkylbenzimidazoles were synthesized by reactions of imidazole and benzimidazole with alkyl halides. The reaction rate increases by a factor of 2 to 3 under conditions of microwave activation. Subsequent treatment of the resulting N-alkylazoles with alkyl halides afforded the corresponding 1,3-dialkylimidazolium and 1,3-dialkylbenzimidazolium halides.
Synthesis, crystal structure, and catalytic activity of bridged-bis(N-heterocyclic carbene) palladium(II) complexes in selective Mizoroki-Heck cross-coupling reactions
El Ali, Bassam,Fettouhi, Mohammed,Iali, Wissam,Mansour, Waseem,Suleiman, Rami
, (2021/08/09)
A series of three 1,3-propanediyl bridged bis(N-heterocyclic carbene)palladium(II) complexes (Pd-BNH1, Pd-BNH2, and Pd-BNH3), with + I effect order of the N-substituents of the ligand (isopropyl > benzyl > methoxyphenyl), was the subject of a spectroscopic, structural, computational and catalytic investigation. The bis(NHC)PdBr2 complexes were evaluated in Mizoroki-Heck coupling reactions of aryl bromides with styrene or acrylate derivatives and showed high catalytic efficiency to produce diarylethenes and cinnamic acid derivatives. The X-ray structure of the most active palladium complex Pd-BNH3 shows that the Pd(II) center is bonded to the two carbon atoms of the bis(N-heterocyclic carbene) and two bromide ligands in cis position, resulting in a distorted square planar geometry. The NMR data of Pd-BNH3 are consistent with a single chair-boat rigid conformer in solution with no dynamic behavior of the 8-membered ring palladacycle in the temperature range 25–120 °C. The catalytic activities of three Pd-bridged bis(NHC) complexes in the Mizoroki-Heck cross-coupling reactions were not found to have a direct correlation with +I effect order of the N-substituents of the ligand. However, a direct correlation was found between the DFT calculated absolute softness of the three complexes with their respective catalytic activity. The highest calculated softness, in the case of Pd-BNH3, is expected to favor the coordination steps of both the soft aryl bromides and alkenes in the Heck catalytic cycle.
Visible-light-induced aerobic oxidative desulfurization of 2-mercaptobenzimidazolesviaa sulfinyl radical
Deng, Guo-Jun,Fu, Mei,Huang, Huawen,Ji, Xiaochen,Li, Yongtong
supporting information, p. 5594 - 5598 (2020/09/21)
A mild transition-metal-free non-toxic aerobic photoredox system was found to enable highly efficient desulfurization of 2-mercaptobenzimidazoles. This viable catalytic system includes Rose Bengal in a low catalyst loading as a photosensitizer and cheap, non-toxic NaCl in a catalytic amount as an additive, combined with an oxygen atmosphere. This protocol provides an important alternative access to a broad range of benzimidazole and deuterated benzimidazole products in generally high yields with good tolerance of various synthetically and pharmaceutically useful functionalities. The mechanistic studies reveal that both single electron transfer and energy transfer probably occur in the initial step and a sulfinyl radical intermediate is involved in the key desulfurization process.
Bis-benzimidazolium-palladium system catalyzed Suzuki-Miyaura coupling reaction of aryl bromides under mild conditions
Lin, Yi-Rang,Chiu, Chien-Cheng,Chiu, Huai-Tsu,Lee, Dong-Sheng,Lu, Ta-Jung
, (2017/10/05)
Bis-benzimidazolium salts were prepared successfully from commercially available and inexpensive o-phenylenediamine through a series of simple reactions. The bis-NHC-Pd complexes prepared in situ can catalyze Suzuki-Miyaura cross-coupling reaction under very mild conditions in aqueous media with excellent yields. The efficiency of this reaction is demonstrated by its compatibility with a range of functional groups. Di-ortho-substituted biaryls could be accomplished in 89–99% yields. Moreover, the rigorous exclusion of air or moisture is not required in these transformations.
