1850-13-1Relevant academic research and scientific papers
Dynamic 1H NMR study of the barrier to rotation about the C-N bond in primary carbamates and its solvent dependence
Modarresi-Alam, Ali Reza,Najafi, Parisa,Rostamizadeh, Mohsen,Keykha, Hossein,Bijanzadeh, Hamid-Reza,Kleinpeter, Erich
, p. 2208 - 2211 (2007)
The dynamic 1H NMR study of some primary carbamates in the solvents CDCl3 and CD3COCD3 between 183 and 298 K is reported. The free energies of activation, thus obtained (12.4 to 14.3 kcal mol-1), were attributed to the conformational isomerization about the N-C bond. These barriers to rotation show solvent dependence in contrast to the tertiary analogues and are lower in free energy by ca. 2-3 kcal mol-1.
Triazinetriamine-derived porous organic polymer-supported copper nanoparticles (Cu-NPs@TzTa-POP): an efficient catalyst for the synthesis of: N -methylated products via CO2fixation and primary carbamates from alcohols and urea
Haque, Najirul,Biswas, Surajit,Basu, Priyanka,Haque Biswas, Imdadul,Khatun, Resmin,Khan, Aslam,Islam, Sk Manirul
supporting information, p. 15446 - 15458 (2020/10/22)
In recent times, carbon dioxide fixation has received much attention for its potential application as an abundant C1 source and a range of important fine chemicals can be manufactured via this fixation. Here, a copper nanoparticle-decorated porous organic polymer-based (Cu-NPs@TzTa-POP) material was prepared by a simple in situ process. The catalyst was characterized by various techniques such as UV-vis spectra, FTIR spectra, HR-TEM, PXRD, N2 adsorption-desorption, TG-DTA, XPS, and AAS analysis. The synthesized heterogeneous catalyst showed excellent activity in an atmospheric carbon dioxide fixation reaction to produce N-methylated products from aromatic/heterocyclic amines in the presence of polymethyl-hydrosiloxane (PMHS) as the reducing agent at 80 °C within 12 h of the reaction. Through this catalytic N-methylation reaction, we obtained 98% yield of the product with turnover frequency ranging from 18 to 42 h-1. The catalyst is also very stable for the formation of primary carbamates from alcohols using the eco-friendly carbonylating agent, urea. Diverse alcohols (such as benzylic alcohols, phenols, heterocyclic alcohols, as well as aliphatic alcohols) showed much acceptance to this catalytic reaction and produced moderate to excellent yields of the respective carbamate products under ambient reaction conditions. Moreover, Cu-NPs@TzTa-POP is effortlessly recyclable and reusable without the extensive loss of active copper metal centres for many catalytic rounds (up to six catalytic rounds were examined).
Superparamagnetic Fe3O4 Nanoparticles in a Deep Eutectic Solvent: An Efficient and Recyclable Catalytic System for the Synthesis of Primary Carbamates and Monosubstituted Ureas
Inaloo, Iman Dindarloo,Majnooni, Sahar,Esmaeilpour, Mohsen
, p. 3481 - 3488 (2018/07/29)
Superparamagnetic Fe3O4 nanoparticles were used to synthesize various primary carbamates as well as monosubstituted and N,N-disubstituted ureas. This efficient phosgene-free process used urea as an eco-friendly carbonyl source in the presence of a biocompatible deep eutectic solvent (DES) to provide an inexpensive and attractive route that afforded the products in moderate to excellent yields. The employed DES serves both a catalytic role and as the green reaction medium. The magnetic nanocatalyst and DES can been reused several times without a significant loss of activity.
4-Dodecylbenzenesulfonic acid (DBSA) promoted solvent-free diversity-oriented synthesis of primary carbamates, S-thiocarbamates and ureas
Sardarian, Ali Reza,Inaloo, Iman Dindarloo
, p. 76626 - 76641 (2015/09/22)
A simple and highly efficient solvent-free method for the conversion of alcohols, phenols, thiols and amines to primary carbamates, S-thiocarbamates and ureas in the presence of 4-dodecylbenzenesulfonic acid (DBSA) as a cheap and green Bronsted acid reagent has been described. All products were obtained in good to excellent yields and characterized using FT-IR, 1H- and 13C-NMR, MS and CHNS techniques.
Silica supported perchloric acid (HClO4-SiO2): an efficient reagent for the preparation of primary carbamates under solvent-free conditions
Modarresi-Alam, Ali Reza,Khamooshi, Ferydoon,Nasrollahzadeh, Mahmoud,Amirazizi, Homeyra Alsadat
, p. 8723 - 8726 (2008/02/11)
The synthesis of primary carbamates from structurally diverse compounds containing a hydroxyl group has been performed in high yields and purity, and without any epimerization under solvent-free conditions using HClO4-SiO2 as a mild, convenient, and effective reagent. The procedure is operationally simple, efficient, and environmentally benign.
Unprecedented observation of sulfonamides in the transesterification of N-unsubstituted carbamates with sulfonyl chlorides
Dauvergne, Jér?me,Wellington, Kevin,Chibale, Kelly
, p. 43 - 47 (2007/10/03)
Sulfonamides have been identified as by-products in the base-mediated transesterification of N-unsubstituted carbamates with sulfonyl chlorides to give the corresponding sulfonates. A proposed mechanism and the synthesis of hindered 2,6-disubstituted arylsulfonates via this method are also reported.
