The Synthesis Of Oxazolidinones And Selective Synthesis Of Cyclic Di-or Trithiocarbonates Under Mild Conditions

In this paper,oxazolidinones were synthesized under different conditions using different substrates.On the other way,we studied the selective conversion of carbon disulfide under mild conditions.Oxazolidinone is an important heterocyclic compounds with many potential biological activities.However,a number of the existing methods for the participation of carbon dioxide in the synthesis of oxazolidinone have limitations such as poor selectivity,high temperature and high pressure.Therefore,it is urgent to find a method for the synthesis of oxazolidinones using atmospheric carbon dioxide in more convenient conditions.Herein,an three-component which atmospheric CO₂ with readily available dichloroethane and aromatic amine reacting toward oxazolidinones catalyzed effective by in-situ N-heterocyclic carbenes?NHC?was developed.The reaction occurred in good to excellent yields with good generality and wide functional group tolerance.The catalytic system is not sensitive to air and moisture,and high yield of oxazolidinone was achieved even with about 0.3 atm of pressure of carbon dioxide.The catalyst can be recycled for at least 3 times without obvious loss of catalytic activity.The protocol is also effective to making six-membered and seven-membered products when dichloropropane and dichlorobutane were employed.Then,a convenient and effective method which synthesizing 3-aryl-2-oxazolidinones from cyclic carbonates and aryl amines was found.The reaction used hydrogen bond donor adenine as the catalyst in the presence of Et₃N without organic solvent.The protocol is suitable for the wide scope of substrates.The products were obtained in good to excellent yields under the optimal conditions,even in steric hindered cases.In contrast to carbon dioxide,the research on the cycloaddition of epoxides with its isoelectronic heterocumulene carbon disulfide is very limited.One of the main challenges in this transformation is to control the chemoselectivity.In the thesis a simple and convenient method toward selective synthesis of oxathiolanes or trithiocarbonates from epoxides and CS₂ has been developed.The reaction used NHC/LiCl?LiBr?as catalyst without other organic solvent.This catalytic system exhibits excellent activity and selectivity in cycloaddition reactions of carbon disulfide to terminal epoxides.