- The dilemma between acid and base catalysis in the synthesis of benzimidazole from: O -phenylenediamine and carbon dioxide
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The tandem synthesis of benzimidazole and other azoles can be achived by the N-formylation of ortho-substituted anilines followed by a cyclization reaction. However, CO2-based N-formylations with hydrosilane reducing agents are base catalyzed whereas the cyclization reaction is acid catalyzed. The mismatch in catalytic conditions means that only one of the steps can be catalyzed in a single pot reaction. While the N-formylation reaction is frequently the target of catalyst development, the cyclization reaction requires comparably much harsher reaction conditions. Identification of these difficulties lead us to the development of a one-pot, two-step synthesis of benzimidazole under mild reaction conditions employing acid catalysts.
- Hulla, Martin,Nussbaum, Simon,Bonnin, Alexy R.,Dyson, Paul J.
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supporting information
p. 13089 - 13092
(2019/11/11)
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- Heteropolyanion-based sulfated ionic liquid catalyzed formamides synthesis by grindstone chemistry
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A novel heteropolyanion-based sulfated ionic liquid (HIL-[Ch-OSO 3H]3W12PO40) was prepared by pairing sulfate functionalized cholinium cation [N,N,N-trimethyl-2-(sulfooxy) ethanaminium] with catalytically active phosphotungstic acid anion (W 12PO403-). It was characterized by 1H NMR, FT-IR, EDX, XRD, TGA and elemental analysis. Catalytic activity of thus prepared HIL was studied in N-formylation of amines under solvent-free grinding condition. The methodology provided cleaner conversion over shorter reaction time with high turnover frequency (TOF) and chemoselectivity.
- Satasia, Shailesh P.,Kalaria, Piyush N.,Raval, Dipak K.
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- Phototransformation of benzimidazole and thiabendazole inside cucurbit[8]uril
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The phototransformation of benzimidazole (BZ) and of the benzimidazole pesticide thiabendazole (TBZ) was investigated in aqueous solution in the absence and presence of the supramolecular host cucurbit[8]uril (CB8). ESI-MS and NMR reveal that both compoun
- Smitka, Jaroslav,Lemos, Americo,Porel, Mintu,Jockusch, Steffen,Belderrain, Tomas R.,Tesarova, Eva,Da Silva, Jose P.
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p. 310 - 315
(2014/02/14)
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