Synthesis Of Oxazolidinones Research Articles

CuxOy Incorporated COF: A Potential Reusable Catalyst for the Synthesis of α‐Hydroxy Ketones and Oxazolidinones Under Atmospheric CO2 Pressure and Solvent‐Free Conditions

AbstractIn this present work, a newly designed metal‐oxide nanoparticle incorporated Covalent organic framework (COF), CuxOy@TFP‐ODA has been successfully synthesized and used for the effective synthesis of Oxazolidinones and a‐hydroxy ketones under mild conditions utilizing CO2. Initially, imine‐linked 2D COF, TFP‐ODA was synthesized by simple solvothermal method followed by the embedment of copper oxide nanoparticles (NPs) into the skeleton of the as‐synthesized COF. Different characterization techniques were employed to establish the physical and chemical characteristics of both CuxOy@TFP‐ODA and TFP‐ODA COF materials. To study the catalytic efficiency of the highly porous CuxOy@TFP‐ODA, three components coupling reaction involving primary amine, propargyl alcohol and CO2 to synthesize a series of 2‐Oxazolidinone and synthesis of α‐hydroxy ketones using CO2 as a Co‐catalyst were carried out over the as‐prepared catalyst under green and sustainable conditions which illustrated excellent yields and selectivity of the corresponding products. The synthesized catalyst was proved to be completely heterogeneous and especially, the catalyst material demonstrated significant potential for reuse across several catalytic cycles.

Non‐Reductive CO2 Valorization into Oxazolidinones via Cycloaddition to Aziridines: A Personal Insight

AbstractThis perspective discusses bibliography data that has been published since 2018 on the synthesis of oxazolidinones by reacting corresponding aziridines with CO2. The versatility and viability of various procedures have been analyzed by considering the variety of tested substrates as well as experimental conditions and catalytic systems used. Collected data highlights that the reaction can be effectively promoted by several homogeneous and heterogeneous catalytic systems that have been optimized in order to conjugate the process sustainability and productivity with convenient procedural costs.

A Ni‐Based Metal‐Organic Framework with Polarizing Traits for Efficient Heterogeneous Catalysis in the Sustainable Synthesis of Oxazolidinones

A Ni‐Based Metal‐Organic Framework with Polarizing Traits for Efficient Heterogeneous Catalysis in the Sustainable Synthesis of Oxazolidinones

Metal Acetylacetonates as Robust Catalysts for the Synthesis of Oxazolidinone from CO2 and Aziridine Under Atmospheric Pressure

Metal Acetylacetonates as Robust Catalysts for the Synthesis of Oxazolidinone from CO2 and Aziridine Under Atmospheric Pressure

A Mechanistic Insight on CuI‐Catalyzed Synthesis of Oxazolidinones through a Four‐Component Reaction

AbstractIn this contribution, we describe a straightforward and efficient synthesis of oxazolidin‐2‐ones through a Cu(I)‐catalyzed four‐component coupling of amines, aldehydes, terminal alkynes, and CO2 via carboxylative cyclization of propargylamine intermediates. This strategy enables the selective synthesis of a variety of (Z)‐5‐alkylidene‐oxazolidin‐2‐ones substituted in positions 3, 4 and 5 of the heterocyclic core with a variety of functional groups, well‐tolerated in terms of scope. A mechanistic study was carried out monitoring the process in solution by different techniques (operando FTIR, multi‐nuclear NMR), with the aim of identifying the intermediates, both organic compounds and Cu(I) coordination complexes, which showed the plausible multi‐metallic nature of the catalytic intermediates (identified by X‐ray diffraction analyses on monocrystal).

Magnesium-porphyrin as an efficient photocatalyst for the transformation of CO2 to cyclic carbonates and oxazolidinones under ambient conditions

Herein, we report an efficient and simple photocatalytic system based on Mg-porphyrin for the synthesis of cyclic carbonates and oxazolidinones. As this reaction uses non-toxic, renewable, and widely available CO2, it promotes sustainability.

Continuous Synthesis of Carbamates from CO2 and Amines.

We present a novel approach for the continuous preparation of carbamates. The simple yet fast synthetic route relies on directly utilizing carbon dioxide and, in contrast with the literature-known methods, only employs 1,8-diazabicyclo[5.4.0]undec-7-ene as an additive. The applicable amines' diversity offers considerable flexibility to the synthetic protocol. Additionally, the continuous method's applicability significantly decreases the reaction time typically required for CO2-based carbamate synthesis and allows for straightforward and precise gas introduction. The mild reaction conditions and omission of the need for column chromatography render the process less time-demanding and environmentally more benign, providing the desired compounds in yields of 45 to 92%. Moreover, the modified procedure can potentially be applied in the selective synthesis of oxazolidinones from aziridines.

AgNPs Embedded in Porous Polymeric Framework: A Reusable Catalytic System for the Synthesis of α-Alkylidene Cyclic Carbonates and Oxazolidinones via Chemical Fixation of CO2

AgNPs Embedded in Porous Polymeric Framework: A Reusable Catalytic System for the Synthesis of α-Alkylidene Cyclic Carbonates and Oxazolidinones via Chemical Fixation of CO2

B−N Coordinated Phenanthroimidazole‐Based Zinc‐Salen as a Photocatalyst for the Synthesis of Oxazolidinones using Carbon Dioxide as a C1 Source under Mild Reaction Conditions

AbstractCycloaddition of carbon dioxide (CO2) with aziridine catalyzed by a zinc‐salen having B−N coordinated phenanthroimidazole motif as a photocatalyst (1), at 1 bar CO2 pressure and room temperature under solvent free condition is presented. The photocatalyst exhibited excellent selectivity and tolerates a variety of substituted aziridines, and successfully produces the corresponding oxazolidinones at mild conditions.magnified image

Electrocatalytic three-component reactions: synthesis of tellurium-containing oxazolidinone for anticancer agents

A new synthetic method involving electrochemical catalysis were used to synthesize various tellurium-containing oxazolidinones which showed better antitumor activity compared to other oxazolidinones.

Synthesis of polysubstituted oxazolidinones via regioselective addition of azonaphthalenes

A series of novel and synthetically challenging oxazolidinone compounds were synthesized through a regioselective radical addition of azonaphthalenes.

Construction of hierarchically chiral metal–organic frameworks for fast and mild asymmetric catalysis

Here, CMOF(ASP) is synthesized as a chiral Zr-fumarate framework functionalized with l-aspartate for highly efficient catalysis of ring opening and nitroaldol reactions and asymmetric synthesis of oxazolidinone in mild and green conditions.

Protonated Porphyrins: Bifunctional Catalysts for the Metal-Free Synthesis of N-Alkyl-Oxazolidinones.

The protonation of commercially available porphyrin ligands yields a class of bifunctional catalysts able to promote the synthesis of N-alkyl oxazolidinones by CO2 cycloaddition to corresponding aziridines. The catalytic system does not require the presence of any Lewis base or additive, and shows interesting features both in terms of cost effectiveness and eco-compatibility. The metal-free methodology is active even with a low catalytic loading of 1 % mol, and the chemical stability of the protonated porphyrin allowed it to be recycled three times without any decrease in performance. In addition, a DFT study was performed in order to suggest how a simple protonated porphyrin can mediate CO2 cycloaddition to aziridines to yield oxazolidinones.

A metal-free porphyrin heterogenised onto SBA-15 silica: A performant material for the CO2 cycloaddition to epoxides and aziridines

The covalently heterogenisation of a free-base porphyrin on SBA-15 silica yielded TPPH2@SBA-15 (TPPH2 = tetraphenyl porphyrin), which was very efficient to promote the CO2 cycloaddition to three-membered rings. The TPPH2@SBA-15/TBAX-based catalytic procedure was very general, as revealed by excellent activities registered in the reaction of CO2 with epoxides, N-alkyl and N-aryl aziridines, forming cyclic carbonates, N-alkyl and N-aryl oxazolidinones, respectively. It is worth noting that this is the first example of the heterogeneously catalysed synthesis of N-aryl oxazolidinones from corresponding N-aryl aziridines. The scale-up of the methodology highlighted that catalytic performances of all the three investigated reactions were maintained also working at a gram-scale to pave the way for future developments of the procedure. In addition, the recycle of TPPH2@SBA–15 for several consecutive reactions was efficient and observed catalytic activities were very similar to those registered in the presence of a fresh material. All the acquired data indicated an excellent sustainability of the catalytic protocol to envisage upcoming practical applications.

N-Alkyl Carbamoylimidazoles as Isocyanate Equivalents: Exploration of the Reaction Scope for the Synthesis of Ureas, Hydantoins, Carbamates, Thiocarbamates, and Oxazolidinones.

The reaction of the HCl or trifluoroacetic acid salts of primary amines with carbonyldiimidazole (CDI) is shown to be a preparatively useful method for forming monosubstituted carbamoylimidazoles (28 examples) without the formation of symmetrical urea side products. The utility of these air- and water-stable crystalline carbamoylimidazole reagents was demonstrated by their reactions as blocked or masked isocyanate equivalents. Reaction with various classes of nucleophiles provides access to useful functional groups including ureas, carbamates, thiocarbamates, hydantoins, and oxazolidinones. A parallel synthesis library of 30 ureas was generated by the reaction of 6× carbamoylimidazole intermediates with 5× amines and triethylamine. The unsymmetrical urea-containing natural products macaurea A and pygmaniline A were also prepared in good yields (95% over four steps and 79% over three steps, respectively) using this approach. The reaction of carbamoylimidazoles with amino acid methyl esters followed by microwave irradiation in aqueous media gives hydantoins in high yields, further demonstrating the ability of carbamoylimidazoles as isocyanate surrogates. Three hydantoin-containing natural products including macahydantoin D and meyeniihydantoin A were prepared in nearly quantitative yields from proline methyl ester and carbamoylimidazoles. The reaction of carbamoylimidazoles with alcohols and thiols under basic conditions affords carbamates and thiocarbamates, respectively, in good yields. Lastly, a method for the preparation of chiral oxazolidinone heterocycles from chiral epoxy alcohols is demonstrated using a double displacement approach. The reactions occur with high regio- and stereoselectivity (dr ≥ 15:1 by 1H NMR) via a domino attack of the corresponding alkoxides with carbamoylimidazoles followed by an intramolecular attack of the in situ generated urea anion at the proximal position of the epoxide group.

Catalytic Synthesis of Oxazolidinones from a Chitin-Derived Sugar Alcohol

Abstract Chitin is an abundant marine biomass that contains nitrogen atoms in its monomer units. Therefore, it is an attractive feedstock for the production of renewable organonitrogen compounds. The hydrolytic hydrogenation of chitin produces 2-acetamide-2-deoxysorbitol (ADS), which is a potential platform chemical in chitin-based biorefinery. In this work, we report the catalytic conversion of ADS to oxazolidinones named 2,3-OX and 1,2-OX. Of the two isomers, 2,3-OX possesses specific chirality suited for the application of antibiotic agents, naturally derived from ADS. This work demonstrates that a ubiquitous base catalyst, KHCO3, selectively gives 2,3-OX in 84% yield, 12 times more preferential than 1,2-OX under kinetic control. DFT calculations show that inner-molecular hydrogen bonds formed in the transition states specifically reduce the energy barrier for the 2,3-OX formation, thus giving this isomer selectively. We also found that the addition of boron compounds slightly shifts the selectivity towards 1,2-OX.

Synthesis of oxazolidinones from N-aryl-carbamate and epichlorohydrin under mild conditions

Synthesis of oxazolidinones from N-aryl-carbamate and epichlorohydrin under mild conditions

Rare-Earth-Metal-Complex-Catalyzed Hydroalkoxylation and Tandem Hydroalkoxylation/Cyclohydroamination of Isocyanates: Synthesis of Carbamates and Oxazolidinones.

Novel N,N,N-tridentate β-diketiminato rare-earth-metal dialkyl complexes LRE(CH2SiMe3)2 [RE = Y (1a), Gd (1b), Yb (1c), Lu (1d); L = MeC(NDipp)CHC(Me)N(CH2)2NC4H8, where Dipp = 2,6-iPr2C6H3] have been conveniently synthesized by one step from reactions of the rare-earth-metal trialkyl complexes RE(CH2SiMe3)3(THF)2 (THF = tetrahydrofuran) with a pyrrolidine-functionalized β-diketiminate HL, and their catalytic behaviors toward hydroalkoxylation and tandem hydroalkoxylation/cyclohydroamination of isocyanates have been described. These rare-earth-metal catalysts exhibited high efficiency in the hydroalkoxylation of isocyanates, providing a variety of N-alkyl and N-aryl carbamate derivatives under mild reaction conditions with a rather low catalyst loading (0.04 mol %). More significantly, they can promote a tandem hydroalkoxylation/cyclohydroamination reaction between terminal and internal propargylic alcohols with substituted arylisocyanates, leading to the efficient synthesis of methylene and (Z)-selective arylidene oxazolidinones in good-to-high yields via consecutive C-O and C-N bond formation. The stoichiometric reaction of 1a with p-tolylisocyanate generated an unusual dinuclear yttrium complex, {[η2-(4-MePhNCO)(CH2SiMe3)]Y[μ-η2:η1:η1-(4-MePhNCO)CC(Me)(NDipp)C(Me)N(CH2)2NC4H8]}2 (7a), with two different amidate units, which underwent an sp2 C-H bond activation of the β-diketiminato backbone, followed by the insertion of isocyanate.

Continuous organocatalytic flow synthesis of 2-substituted oxazolidinones using carbon dioxide

A catalytic continuous flow approach towards pharmaceutically relevant oxazolidinones has been developed using epoxy alcohols and CO2 as reagents, taking advantage of a stable, scalable and metal- and halide-free protocol.

Microwave-Assisted Electrostatically Enhanced Phenol-Catalyzed Synthesis of Oxazolidinones.

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.