3652-93-5Relevant academic research and scientific papers
Aryl-substituted dimethylbenzimidazolines as effective reductants of photoinduced electron transfer reactions
Hasegawa, Eietsu,Ohta, Taku,Tsuji, Shiori,Mori, Kazuma,Uchida, Ken,Miura, Tomoaki,Ikoma, Tadaaki,Tayama, Eiji,Iwamoto, Hajime,Takizawa, Shin-Ya,Murata, Shigeru
, p. 5494 - 5505 (2015/08/03)
Photoinduced electron transfer (PET) reactions promoted by 2-aryl substituted 1,3-dimethylbenzimidazolines (Ar-DMBIH) were investigated. Excited states of Ar-DMBIH, formed by irradiation using light above 360 nm, initiate PET reductions of various organic substrates, including transformations of epoxy ketones to aldols, free radical rearrangements such as the Dowd-Beckwith ring-expansion and 5-exo hexenyl cyclization, deprotection of N-sulfonyl-indols, and allylation of acyl formates. In these processes, Ar-DMBIH possessing 1-naphthyl, 2-naphthyl, 1-pyrenyl and 9-anthryl substituents formally act as two electron and one proton donors while the hydroxynaphthyl substituted derivative serves as a two electron and two proton donor. On the basis of the results of absorption spectroscopy studies, cyclic voltammetry and DFT calculation, a mechanistic sequence for these reduction reactions is proposed that involves initial photoexcitation of the aryl chromophore of the Ar-DMBIH followed by single electron transfer (SET) to the organic substrate to generate the radical cation of benzimidazoline and the radical anion of the substrate.
Contrastive photoreduction pathways of benzophenones governed by regiospecific deprotonation of imidazoline radical cations and additive effects
Hasegawa, Eietsu,Seida, Takayuki,Chiba, Naoki,Takahashi, Tomoya,Ikeda, Hiroshi
, p. 9632 - 9635 (2007/10/03)
In the photoreaction of benzophenones with 1,3-dimethyl-2- phenylbenzimidazoline (DMPBI), benzhydrols were major products. Addition of H2O accelerated the reaction with no change in the product distribution, while AcOH, PhOH, and metal salts such as LiClO4 and Mg(ClO4)2 were effective additives to produce benzpinacols. In contrast, benzpinacols were exclusively formed regardless of the solvent and the additive in the reactions with 2-(o-hydroxyphenyl)-1,3- dimethylbenzimidazoline (o-HPDMBI). These observations are consistent with the hypothesis that DMPBI.+ donates a proton at the C2 position to the benzophenone ketyl radicals while o-HPDMBI.+ donates a phenol proton.
2-Hydroxyphenyl-1,3-dimethylbenzimidazolines. Formal two hydrogen atom-donors for photoinduced electron transfer reactions
Hasegawa, Eietsu,Chiba, Naoki,Takahashi, Tomoya,Takizawa, Shinya,Kitayama, Takashi,Suzuki, Toshio
, p. 18 - 19 (2007/10/03)
Both 2-(2′-hydroxyphenyl)-1,3-dimethylbenzimidazoline and 2-(4′-hydroxyphenyl)-1,3-dimethylbenzimidazoline were found to act as formal two hydrogen atom-donors for photoinduced electron transfer reactions of epoxy ketones and other carbonyl compounds.
Formal Transfers of Hydride from Carbon-Hydrogen Bonds. Thermolysis of 2,3-dihydro-2-(2-hydroxyphenyl)-1,3-dimethyl-1H-benzimidazole
Montgrain, France,Ramos, Socorro M.,Wuest, James D.
, p. 1489 - 1492 (2007/10/02)
In 2,3-dihydro-2-(2-hydroxyphenyl)-1,3-dimethyl-1H-benzimidazole (3), the acidic hydrogen of a phenolic oxygen-hydrogen bond is near a carbon-hydrogen bond activated as a donor of hydride by two adjacent lone pairs in a dihydro aromatic ring.This juxtapos
Synthesis and Autoxidation of 1,3-Dialkyl-2-arylbenzimidazolines
Reddy, A. Pandu Ranga,Veeranagaiah, V.,Ratnam, C. V.
, p. 367 - 371 (2007/10/02)
During the attempted studies of the elimination reactions of 1,3-dimethyl-(I, R = CH3)- and 1,3-diethyl-(I, R = C2H5)-2-arylbenzimidazolines, a novel rearrangement has been observed to take place resulting in substituted amides by autoxidative ring-opening.
