326800-64-0Relevant academic research and scientific papers
Microwave-Assisted Electrostatically Enhanced Phenol-Catalyzed Synthesis of Oxazolidinones
Rostami, Ali,Ebrahimi, Amirhossein,Sakhaee, Nader,Golmohammadi, Farhad,Al-Harrasi, Ahmed
, p. 40 - 55 (2021/10/20)
An electrostatically enhanced phenol is utilized as a straightforward, sustainable, and potent one-component organocatalyst for the atom-economic transformation of epoxides to oxazolidinones under microwave irradiation. Integrating a positively charged center into phenols over a modular one-step preparation gives rise to a bifunctional system with improved acidity and activity, competent in rapid assembly of epoxides and isocyanates under microwave irradiation in a short reaction time (20-60 min). A careful assessment of the efficacy of various positively charged phenols and anilines and the impact of several factors, such as catalyst loading, temperature, and the kind of nucleophile, on catalytic reactivity were examined. Under neat conditions, this one-component catalytic platform was exploited to prepare more than 40 examples of oxazolidinones from a variety of aryl- and alkyl-substituted epoxides and isocyanates within minutes, where up to 96% yield and high degree of selectivity were attained. DFT calculations to achieve reaction barriers for different catalytic routes were conducted to provide mechanistic understanding and corroborated the experimental findings in which concurrent epoxide ring-opening and isocyanate incorporation were proposed.
Squaramide–Quaternary Ammonium Salt as an Effective Binary Organocatalytic System for Oxazolidinone Synthesis from Isocyanates and Epoxides
Rostami, Ali,Ebrahimi, Amirhossein,Husband, John,Anwar, Muhammad Usman,Csuk, Rene,Al-Harrasi, Ahmed
, p. 1881 - 1895 (2020/03/13)
Squaramide–quaternary ammonium salt is illustrated as a simple, tunable, and competent metal-free binary catalytic platform for the atom-economic conversion of epoxides and isocyanates into oxazolidinones. Although, various metal catalysts have been employed for the title reaction, application of organocatalysis is scarce. At first, a rational survey of catalytic activity of several air-stable and architecturally distinct squaramides was undertaken. Thereafter, the impact on catalytic capability of different parameters, such as temperature, catalyst loading, and nature of nucleophiles, was examined. This binary organocatalytic system for the oxazolidinone synthesis, composed of a squaramide entity along with a suitable halide anion, was applied to the challenging conversion of a plethora of alkyl- and aryl-substituted epoxides– including disubstituted and enantioenriched ones– and isocyanates into the corresponding oxazolidinones in high-to-excellent yields. The time-dependent formation of oxazolidinone from epoxide and isocyanate was monitored by FTIR-ATR and 1H NMR spectroscopy and the scalability of this process was also described. In light of 1H NMR experiment, a hydrogen-bonding/anion-binding mechanism was proposed wherein the nucleophilic ring-opening operation, and oxo- and carbamate-anions stabilization occur cooperatively towards isocyanate fixation.
A Multicomponent Approach to Oxazolidinone Synthesis Catalyzed by Rare-Earth Metal Amides
Zhou, Meixia,Zheng, Xizhou,Wang, Yaorong,Yuan, Dan,Yao, Yingming
, p. 5783 - 5787 (2019/04/14)
Three-component reaction of epoxides, amines, and dimethyl carbonate catalyzed by rare-earth metal amides has been developed to synthesize oxazolidinones. 47 examples of 3,5-disubstituted oxazolidinones were prepared in 13–97 % yields. This is a simple and most practical method which employs easily available substrates and catalysts, and is applicable to a wide range of aromatic and aliphatic amines, as well as mono-substituted epoxides. Scope of disubstituted epoxides is rather limited, which requires further study. Preliminary mechanistic study reveals two possible reaction pathways through intermediates of β-amino alcohols or amides.
A Multicomponent Route to Functionalized Amides and Oxazolidinones
McPherson, Christopher G.,Cooper, Alasdair K.,Bubliauskas, Andrius,Mulrainey, Paul,Jamieson, Craig,Watson, Allan J. B.
supporting information, p. 6736 - 6739 (2017/12/26)
An organobase-mediated multicomponent reaction of unactivated esters, epoxides, and amines is reported, furnishing functionalized amide derivatives. A wide range of substrates are tolerated under the reaction conditions, including chiral epoxides, which react with no erosion of enantiopurity. Facile modification of the method through replacing the ester derivative with dimethyl carbonate enables access to the corresponding oxazolidinone derivatives.
Quaternary ammonium bromide functionalized polyethylene glycol: A highly efficient and recyclable catalyst for selective synthesis of 5-aryl-2-oxazolidinones from carbon dioxide and aziridines under solvent-free conditions
Du, Ya,Wu, Ying,Liu, An-Hua,He, Liang-Nian
, p. 4709 - 4712 (2008/09/21)
(Chemical Equation Presented) A quaternary ammonium bromide covalently bound to polyethylene glycol (PEG, MW = 6000), i.e., PEG6000- (NBu3Br)2, was found to be an efficient and recyclable catalyst for the cycloaddition reaction of aziridines to CO2 under mild conditions without utilization of additional organic solvents or cocatalysts. As a result, 5-aryl-2-oxazolidinone was obtained in high yield with excellent regioselectivity. The catalyst worked well for a wide variety of 1-alkyl-2-arylaziridines. Besides, the catalyst could be recovered by centrifugation and reused without significant loss of catalytic activity and selectivity.
