894693-94-8Relevant articles and documents
Enzyme- and ruthenium-catalyzed dynamic kinetic resolution involving cascade alkoxycarbonylations for asymmetric synthesis of 5-Substituted N-Aryloxazolidinones
Zhang, Yang,Xie, Sheng,Yan, Mingdi,Ramstr?m, Olof
, p. 138 - 144 (2019/04/10)
Asymmetric synthesis of N-aryloxazolidinones via dynamic kinetic resolution was developed. A ruthenium-based catalyst was used in the racemization of β-anilino alcohols, while Candida antarctica lipase B (CAL-B) was applied for two selective alkoxycarbony
Catalytic metallodendrimers grafted on mesoporous polymethacrylate beads for the regioselective synthesis of β-amino alcohols under solvent-free conditions
Tiwari, Richa,H. Daware, Sachdeo,Kale, Sandeep B.
, p. 42526 - 42535 (2015/05/20)
A new series of dendritic structures was grafted on epoxy activated mesoporous polymethacrylate beads (Sepabeads EB-EP-400). Grafting with the dendritic structures was followed by loading of metal termini to the chelating groups to form metallodendrimer-g
The reaction of primary aromatic amines with alkylene carbonates for the selective synthesis of bis-N-(2-hydroxy)alkylanilines: The catalytic effect of phosphonium-based ionic liquids
Selva, Maurizio,Fabris, Massimo,Lucchini, Vittorio,Perosa, Alvise,Noe, Marco
scheme or table, p. 5187 - 5198 (2010/12/25)
At T ≥ 140 °C, different primary aromatic amines (pX-C 6H4NH2; X = H, OCH3, CH3, Cl) react with both ethylene- and propylene-carbonates to yield a chemoselective N-alkylation process: bis-N-(2-hydroxyalkyl)anilines [pX-C 6H4N(CH2CH(R)OH)2; R = H, CH 3] are the major products and the competitive formation of carbamates is substantially ruled out. At 140 °C, under solventless conditions, the model reaction of aniline with ethylene carbonate goes to completion by simply mixing stoichiometric amounts of the reagents. However, a class of phosphonium ionic liquids (PILs) such as tetraalkylphosphonium halides and tosylates turn out to be active organocatalysts for both aniline and other primary aromatic amines. A kinetic analysis monitored by 13C NMR spectroscopy, shows that bromide exchanged PILs are the most efficient systems, able to impart a more than 8-fold acceleration to the reaction. The reactions of propylene carbonate take place at a higher temperature than those of ethylene carbonate, and only in the presence of PIL catalysts. A mechanism based on the Lewis acidity of tetraalkylphosphonium cations and the nucleophilicity of halide anions has been proposed to account for both the reaction chemoselectivity and the function of the catalysts.
