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Topics in Current Chemistry (Cham) Jan 2020The dramatic increase in atmospheric carbon dioxide (CO) concentrations has attracted human attention and many strategies about converting CO into high-value chemicals... (Review)
Review
The dramatic increase in atmospheric carbon dioxide (CO) concentrations has attracted human attention and many strategies about converting CO into high-value chemicals have been put forward. Metal-organic frameworks (MOFs), as a class of versatile materials, have been widely used in CO capture and chemical conversion, due to their unique porosity, multiple active centers and good stability and recyclability. Herein, we focused on the processes of chemical conversion of CO by MOFs-based catalysts, including the coupling reactions of epoxides, aziridines or alkyne molecules, CO hydrogenation, and other CO conversion reactions. The synthesized methods and high catalytic activity of MOFs-based materials were also analyzed systematically. Finally, a brief perspective on feasible strategies is presented to improve the catalytic activity of novel MOFs-based materials and explore the new CO conversion reactions.
Topics: Alkenes; Amines; Aziridines; Carbon Dioxide; Catalysis; Epoxy Compounds; Hydrogenation; Ionic Liquids; Metal-Organic Frameworks
PubMed: 31903506
DOI: 10.1007/s41061-019-0269-9 -
Chembiochem : a European Journal of... Jun 2024Only 0.016% of all known natural products contain an aziridine ring, but this unique structural feature imparts high reactivity and cytotoxicity to the compounds in...
Only 0.016% of all known natural products contain an aziridine ring, but this unique structural feature imparts high reactivity and cytotoxicity to the compounds in which it is found. Until 2021, no naturally occurring azirdine-forming enzymes had been identified. Since 2021, the biosynthetic enzymes for ~10% of known aziridine containing natural products have been identified and characterized. This article describes the recent advances in our understanding of enzyme-catalyzed aziridine formation in the context of historical means of azirdine formation through synthetic chemistry.
PubMed: 38830838
DOI: 10.1002/cbic.202400295 -
Energy & Fuels : An American Chemical... Apr 2023Carbon dioxide (CO) hydrates, which contain a relatively large amount of captured CO (almost 30 wt % of CO with the balance being water), represent a promising CO...
Carbon dioxide (CO) hydrates, which contain a relatively large amount of captured CO (almost 30 wt % of CO with the balance being water), represent a promising CO sequestration option for climate change mitigation. To facilitate CO storage via hydrates, using chemical additives during hydrate formation might help to expedite formation/growth rates, provided the additives do not reduce the storage capacity. Implementing atomistic molecular dynamics, we study the impact of aziridine, pyrrolidine, and tetrahydrofuran (THF) on the kinetics of CO hydrate growth/dissociation. Our simulations are validated via reproducing experimental data for CO and CO + THF hydrates at selected operating conditions. The simulated results show that both aziridine and pyrrolidine could perform as competent thermodynamic and kinetic promoters. Furthermore, aziridine seems to exceed pyrrolidine and THF in expediting the CO hydrate growth rates under the same conditions. Our analysis unveils direct correlations between the kinetics of CO hydrate growth and a combination of the free energy barrier for desorption of CO from the hydrate surface and the binding free energy of chemical additives adsorbed at the growing hydrate substrate. The detailed thermodynamic analysis conducted in both hydrate and aqueous phases reveals molecular-level mechanisms by which CO hydrate promoters are active, which could help to enable the implementation of CO sequestration in hydrate-bearing reservoirs.
PubMed: 37114945
DOI: 10.1021/acs.energyfuels.3c00472 -
Chemical Society Reviews Mar 2023Cyclic iron tetracarbenes are an emerging class of macrocyclic iron N-heterocyclic carbene (NHC) complexes. They can be considered as an organometallic compound class... (Review)
Review
Cyclic iron tetracarbenes are an emerging class of macrocyclic iron N-heterocyclic carbene (NHC) complexes. They can be considered as an organometallic compound class inspired by their heme analogs, however, their electronic properties differ, due to the very strong σ-donation of the four combined NHCs in equatorial coordination. The ligand framework of iron tetracarbenes can be readily modified, allowing fine-tuning of the structural and electronic properties of the complexes. The properties of iron tetracarbene complexes are discussed quantitatively and correlations are established. The electronic nature of the tetracarbene ligand allows the isolation of uncommon iron(III) and iron(IV) species and reveals a unique reactivity. Iron tetracarbenes are successfully applied in C-H activation, CO reduction, aziridination and epoxidation catalysis and mechanisms as well as decomposition pathways are described. This review will help researchers evaluate the structural and electronic properties of their complexes and target their catalyst properties through ligand design.
PubMed: 36852959
DOI: 10.1039/d2cs01064j -
Journal of the American Chemical Society Sep 2022Natural products containing an aziridine ring, such as mitomycin C and azinomycin B, exhibit antitumor activities by alkylating DNA via their aziridine rings; however,...
Natural products containing an aziridine ring, such as mitomycin C and azinomycin B, exhibit antitumor activities by alkylating DNA via their aziridine rings; however, the biosynthetic mechanisms underlying the formation of these rings have not yet been elucidated. We herein investigated the biosynthesis of vazabitide A, the structure of which is similar to that of azinomycin B, and demonstrated that Vzb10/11, with no similarities to known enzymes, catalyzed the formation of the aziridine ring via sulfate elimination. To elucidate the detailed reaction mechanism, crystallization of Vzb10/11 and the homologous enzyme, AziU3/U2, in the biosynthesis of azinomycin B was attempted, and the structure of AziU3/U2, which had a new protein fold overall, was successfully determined. The structural analysis revealed that these enzymes adjusted the dihedral angle between the amino group and the adjacent sulfate group of the substrate to almost 180° and enhanced the nucleophilicity of the C6-amino group temporarily, facilitating the S2-like reaction to form the aziridine ring. The present study reports for the first time the molecular basis for aziridine ring formation.
Topics: Aziridines; DNA; Mitomycin; Sulfates
PubMed: 35998388
DOI: 10.1021/jacs.2c07243 -
Chemistry (Weinheim An Der Bergstrasse,... Nov 2021Gaucher disease (GD) is a lysosomal storage disorder caused by inherited deficiencies in β-glucocerebrosidase (GBA). Current treatments require rapid disease diagnosis...
Gaucher disease (GD) is a lysosomal storage disorder caused by inherited deficiencies in β-glucocerebrosidase (GBA). Current treatments require rapid disease diagnosis and a means of monitoring therapeutic efficacy, both of which may be supported by the use of GBA-targeting activity-based probes (ABPs). Here, we report the synthesis and structural analysis of a range of cyclophellitol epoxide and aziridine inhibitors and ABPs for GBA. We demonstrate their covalent mechanism-based mode of action and uncover binding of the new N-functionalised aziridines to the ligand binding cleft. These inhibitors became scaffolds for the development of ABPs; the O6-fluorescent tags of which bind in an allosteric site at the dimer interface. Considering GBA's preference for O6- and N-functionalised reagents, a bi-functional aziridine ABP was synthesized as a potentially more powerful imaging agent. Whilst this ABP binds to two unique active site clefts of GBA, no further benefit in potency was achieved over our first generation ABPs. Nevertheless, such ABPs should serve useful in the study of GBA in relation to GD and inform the design of future probes.
Topics: Catalytic Domain; Fluorescent Dyes; Glucosylceramidase
PubMed: 34570911
DOI: 10.1002/chem.202102359 -
Polymers May 2022A novel drug delivery system based on chitosan nanofibers containing some steroidal derivatives was developed using an electrospinning process. Oxazolines and aziridines...
A novel drug delivery system based on chitosan nanofibers containing some steroidal derivatives was developed using an electrospinning process. Oxazolines and aziridines from the cholestane series of steroidal epoxides were successfully synthesized and characterized by elemental analysis, Fourier transforms infrared spectroscopy (FTIR), proton nuclear magnetic resonance (HNMR), and mass spectroscopy (MS). Steroidal-compound-loaded chitosan (ST-CH) nanofibers were fabricated using the electrospinning technique in the presence of polyvinylpyrrolidone (CH/PVP). The electrospun nanofibers were characterized by scanning electron microscopy (SEM). The swelling degree of the electrospun nanofibers and their steroidal compound release performance were studied as well. Furthermore, their antibacterial activity against gram-positive () and gram-negative bacteria () was evaluated. The experimental data revealed that identical and bead-free nanofiber mats loaded with 10 Wt. % of synthesized steroidal derivatives had been obtained. The FTIR spectrum proved that no change occurred in the chitosan structure during the electrospinning process. The synthesized nanofiber mats showed a high swelling degree and a burst release of steroidal compounds after 2 h doping in phosphate buffer saline. In addition, the electrospun nanofibers containing 3β-chloro-N-amido-5α-cholestano-aziridine and those containing 3β-acetoxy-N-amido-5α-cholestano-aziridine were the most active, with activity indices of 91 and 104% in the case of S. aureus and 52% and 61% in the case of , respectively. The release mechanism by CH/PVP of the drug samples was studied based on the charge density and diffusion controlled factors. The oxazoline derivatives release mechanism from CH/PVP was evaluated by applying the suppositions of the Ritger-Peppas kinetic model and by estimating the transport exponent; the latter revealed the involvement of the solvent diffusion and chain relaxation processes. Tailored steroidal loaded-chitosan (ST-CH) nanofibers are expected to be feasible and efficient drug delivery systems.
PubMed: 35631977
DOI: 10.3390/polym14102094 -
Blood Advances Jan 2024Allogeneic hematopoietic stem cell transplantation (HSCT) is highly effective for treating pediatric high-risk or relapsed acute lymphoblastic leukemia (ALL). For young...
Allogeneic hematopoietic stem cell transplantation (HSCT) is highly effective for treating pediatric high-risk or relapsed acute lymphoblastic leukemia (ALL). For young children, total body irradiation (TBI) is associated with severe late sequelae. In the FORUM study (NCT01949129), we assessed safety, event-free survival (EFS), and overall survival (OS) of 2 TBI-free conditioning regimens in children aged <4 years with ALL. Patients received fludarabine (Flu), thiotepa (Thio), and either busulfan (Bu) or treosulfan (Treo) before HSCT. From 2013 to 2021, 191 children received transplantation and were observed for ≥6 months (median follow-up: 3 years). The 3-year OS was 0.63 (95% confidence interval [95% CI], 0.52-0.72) and 0.76 (95% CI, 0.64-0.84) for Flu/Thio/Bu and Flu/Thio/Treo (P = .075), respectively. Three-year EFS was 0.52 (95% CI, 0.41-0.61) and 0.51 (95% CI, 0.39-0.62), respectively (P = .794). Cumulative incidence of nonrelapse mortality (NRM) and relapse at 3 years were 0.06 (95% CI, 0.02-0.12) vs 0.03 (95% CI: <0.01-0.09) (P = .406) and 0.42 (95% CI, 0.31-0.52) vs 0.45 (95% CI, 0.34-0.56) (P = .920), respectively. Grade >1 acute graft-versus-host disease (GVHD) occurred in 29% of patients receiving Flu/Thio/Bu and 17% of those receiving Flu/Thio/Treo (P = .049), whereas grade 3/4 occurred in 10% and 9%, respectively (P = .813). The 3-year incidence of chronic GVHD was 0.07 (95% CI, 0.03-0.13) vs 0.05 (95% CI, 0.02-0.11), respectively (P = .518). In conclusion, both chemotherapeutic conditioning regimens were well tolerated and NRM was low. However, relapse was the major cause of treatment failure. This trial was registered at www.clinicaltrials.gov as #NCT01949129.
Topics: Child; Child, Preschool; Humans; Busulfan; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Recurrence; Thiotepa; Transplantation Conditioning
PubMed: 37738088
DOI: 10.1182/bloodadvances.2023010591 -
RSC Advances Oct 2020Methyleneaziridines (MAs) are a special subset of aziridines featuring an exocyclic C-C double bond on the three-membered ring. They have found great potential in... (Review)
Review
Methyleneaziridines (MAs) are a special subset of aziridines featuring an exocyclic C-C double bond on the three-membered ring. They have found great potential in organic synthesis. In this review, the structural characterization of MAs, synthetic methods, chemical transformations and mechanisms, especially the advances achieved over the past decade are comprehensively summarized.
PubMed: 35518396
DOI: 10.1039/d0ra07663e -
RSC Advances Jun 2021Enantiopure aryl-sulfinamides are important chiral auxiliaries in the asymmetric synthesis of amines and their derivatives. Here, we provide an overview of... (Review)
Review
Enantiopure aryl-sulfinamides are important chiral auxiliaries in the asymmetric synthesis of amines and their derivatives. Here, we provide an overview of arylsulfinamide mediated asymmetric methods towards N-heterocycle synthesis. This methodology through sulfinylimines offers general access to structurally diverse piperidines, pyrrolidines, aziridines and their derivatives which represent the structural motif of many natural products and therapeutically important compounds. The review covers articles from 2006-2020 and we have categorized the review based on the ring size as 3-, 5-, and 6- membered heterocycles and their derivatives.
PubMed: 35479913
DOI: 10.1039/d1ra04099e