13105-53-8Relevant articles and documents
Polymer- and Carbon Nanotube-Supported Heterogeneous Catalysts for the Synthesis of Carbamates from Halides, Amines, and CO2
Krawczyk, Tomasz,Jasiak, Katarzyna,Kokolus, Aneta,Baj, Stefan
, p. 1163 - 1168 (2016)
Abstract: A series of tetraalkylammonium catalysts immobilized on polystyrene or carbon nanotubes were investigated in a reaction between alkyl halides, amines, and CO2. The yield of carbamates was up to 85?% at 100?°C and 1?MPa of CO2 after 3?h (first stage 25?°C, 1 h) in the presence of Cs2CO3 and DMF as a solvent. The best results were achieved in the case of large ammonium substituents (C4 and C6) in the catalyst, benzyl amine, and benzyl chloride as reagents. The catalysts retained their activity after at least five cycles when carefully dried between cycles. Both polymer and carbon nanotube supports were equally effective, but the latter were less prone to deactivation. Graphical Abstract: [Figure not available: see fulltext.]
Carbamate Synthesis Using a Shelf-Stable and Renewable C1 Reactant
Dobi, Zoltán,Reddy, B. Narendraprasad,Renders, Evelien,Van Raemdonck, Laurent,Mensch, Carl,De Smet, Gilles,Chen, Chen,Bheeter, Charles,Sergeyev, Sergey,Herrebout, Wouter A.,Maes, Bert U. W.
, p. 3103 - 3114 (2019/06/24)
4-Propylcatechol carbonate is a shelf-stable, renewable C1 reactant. It is easily prepared from renewable 4-propylcatechol (derived from wood) and dimethyl carbonate (derived from CO2) using a reactive distillation system. In this work, the 4-propylcatechol carbonate is used for the two-step synthesis of carbamates under mild reaction conditions. In the first step, 4-propylcatechol carbonate is treated with an alcohol at 50–80 °C in the presence of a Lewis acid catalyst, such as Zn(OAc)2?2 H2O. With liquid alcohols, no solvent is used and with solid alcohols 2-methyltetrahydrofuran is used as solvent. In the second step, the alkyl 2-hydroxy-propylphenyl carbonate intermediates obtained react with amines at room temperature in 2-methyltetrahydrofuran, forming the target carbamates and the byproduct 4-propylcatechol, which can be recycled into a carbonate reactant.
A facile protocol for N-Cbz protection of amines in PEG-600
Zhang, Chun Lin,Zhang, Dong Feng,Zhao, Hong Yi,Lin, Zi Yun,Huang, Hai Hong
experimental part, p. 789 - 792 (2012/08/08)
An efficient and eco-friendly protocol for the chemoselective N-benzyloxycarbonylation of amines was described. The reaction of amines with benzyl chloroformate (Cbz-Cl) in the presence of PEG-600 at room temperature afforded the corresponding N-Cbz derivatives in excellent yields. The method is applicable to the N-Cbz protection of aliphatic (acyclic and cyclic) and aromatic amines.
