Microwave-Assisted Improved Synthesis of Oxazolidin-2-ones, Oxazolidine-2-thiones and Thiazolidine-2-thione Chiral Auxiliaries

Abstract

A microwave assisted method for the synthesis of some typical 4-substituted oxazolidinone chiral auxiliaries used in asymmetric synthesis is reported in this work. Under these conditions, treatment of (S)-phenylalaninol, (S)-phenylglycinol, (S)-valinol and (1S, 2R)-norephedrine with ethyl carbonate or carbon disulfide under the appropriate and specific microwave reaction conditions, led to an efficient synthesis of some oxazolidin-2-ones, oxazolidine-2-thiones and thiazolidine-2-thiones. The methodology reported in this paper provides these chiral auxiliaries with improved yields and a remarkable reduction on the reaction times, particularly in the case of thiazolidine-2-thiones, as compared with the conventional methods. All the auxiliaries prepared here show spectroscopic data in full agreement with those previously reported in the literature.

Design, Synthesis and Evaluation of Novel Trichloromethyl Dichlorophenyl Triazole Derivatives as Potential Safener

“…The preparation of compounds 4a – 4u were conducted as the method reported by references [27,28,29,30,31]. Substituted o -aminophenol (27 mmol) was added to a stirred solution of DMSO (40 mL) and K 2 CO 3 (7.5 g, 54 mmol) of substituted dibromoethane (27 mmol) or (CH 2 Cl 2 , 41 mmol for 4p – 4q ) at reflux.…”

One-pot synthesis of oxazolidinones and five-membered cyclic carbonates from epoxides and chlorosulfonyl isocyanate: theoretical evidence for an asynchronous concerted pathway

“…Therefore, numerous synthetic approaches have been developed to date for the preparation of oxazolidinones and fivemembered cyclic carbonates of various structures. The most well-known strategies for the synthesis of oxazolidinones are the reaction of an amino alcohol with phosgene [5,22], the carbonylation reaction of β-amino alcohols with CO 2 or dialkyl carbonates [23][24][25][26][27], the multicomponent reaction of rare-earth metal amides [28], the reaction of CO 2 with propargylamines or aziridines [29,30] and the cycloaddition reaction of epoxides with isocyanates [31,32]. On the other hand, for the synthesis of five-membered cyclic carbonates, the cycloaddition of CO 2 to epoxides, the reaction with the metal complexes or catalysts, and the reaction of a diol with toxic phosgene are the most common processes [16,17,[33][34][35][36].…”

One-Pot Synthesis of Oxazolidinones and Five-Membered Cyclic Carbonates from Epoxides and Chlorosulfonyl isocyanate: Theoretical Evidence for the Asynchronous Concerted Pathway

“…Therefore, numerous synthetic approaches have been developed to date for the preparation of oxazolidinones and five-membered cyclic carbonates in various structures. The most wellknown strategies for the synthesis of oxazolidinones are the reaction of an amino alcohol with phosgene [5,22], carbonylation reaction of β-amino alcohols with CO2 or dialkyl carbonates [23][24][25][26][27], multicomponent reaction by rare-earth metal amides [28], reaction of CO2 with propargylamines or aziridines [29,30] and cycloaddition reaction of epoxides with isocyanates [31,32]. On the other hand, for synthesis of five membered cyclic carbonates, the cycloaddition of CO2 to epoxides, the reaction with the metal complexes or catalysts, and the reaction of a diol with toxic phosgene are the most common processes [16,17,[33][34][35][36].…”