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Organic & Biomolecular Chemistry Jan 2023As a type of readily available small strained-ring heterocycle, -aziridines may undergo catalytic desymmetrizing transformations to empower the rapid construction of... (Review)
Review
As a type of readily available small strained-ring heterocycle, -aziridines may undergo catalytic desymmetrizing transformations to empower the rapid construction of diverse nitrogen-containing structures bearing contiguous stereocenters, which have great relevance in natural product synthesis, drug development and the design and synthesis of chiral catalysts/ligands for asymmetric catalysis. This review outlines the advances achieved in the catalytic asymmetric desymmetrization of aziridines and highlights some promising avenues for further work in this realm.
Topics: Stereoisomerism; Aziridines; Catalysis; Ligands
PubMed: 36508282
DOI: 10.1039/d2ob01935c -
International Journal of Molecular... May 2022Highly functionalized aziridines, including compounds with aromatic moieties, are attractive substrates both in synthetic and medical areas of chemistry. There is a... (Review)
Review
Highly functionalized aziridines, including compounds with aromatic moieties, are attractive substrates both in synthetic and medical areas of chemistry. There is a broad and interesting set of synthetic methods for reaching these compounds. Aziridination represents the most explored tool, but there are several other more specific, less well-known, but highly promising approaches. Therefore, the current review focuses on recently described or updated ways to obtain 3-arylated aziridines via different non-aziridination-based synthetic methods, reported mainly since 2000. The presented methods belong to two main directions of synthesis, namely, cyclization of open-chain substrates and rearrangement of other heterocycles. Cyclization of open-chain substrates includes the classic Gabriel-Cromwell type cyclization of halogenated substrates with amines, base-promoted cyclization of activated aminoalcohols (or its analogues), and the oxidative cyclization of β-dicarbonyls. Rearrangements of other heterocycles are presented as the Baldwin rearrangement of 4-isoxazolines, the cycloaddition of 1.3-dipoles or dienes to 2H-azirines, and the addition of C- and N-nucleophiles to the double bond of azirines.
Topics: Aziridines; Azirines; Carboxylic Acids; Cyclization; Ketones; Molecular Structure; Stereoisomerism
PubMed: 35682596
DOI: 10.3390/ijms23115919 -
Journal of Visualized Experiments : JoVE Jun 2022Nitrogen-containing heterocycle aziridines are synthetically very valuable for the preparation of azacyclic and acyclic molecules. However, it is very difficult and...
Nitrogen-containing heterocycle aziridines are synthetically very valuable for the preparation of azacyclic and acyclic molecules. However, it is very difficult and laborious to make aziridines in optically pure forms on a large scale to apply asymmetric synthesis of aza compounds. Fortunately, we successfully achieved both enantiomers (2R)- and (2S)-aziridine-2-carboxylates with the electron-donating α-methylbenzyl group at the ring nitrogen as non-activated aziridines. These starting aziridines have two distinct functional groups-highly reactive three-membered ring and versatile carboxylate. They are applicable in ring-opening or ring-transformation with aziridine and in functional group transformation to others from carboxylate. Both of these enantiomers were utilized in the preparation of biologically important amino acyclic and/or aza-heterocyclic compounds in an asymmetric manner. Specifically, this report describes the first expedient asymmetric synthesis of both enantiomers of 5, 6-dihydrouracil-type marine natural products biemamide B and D as potential TGF-β inhibitors. This synthesis consisted of regio- and the stereoselective ring-opening reaction of aziridine-2-carboxylate and subsequent formation of 4-aminoteterahydropyrimidine-2,4-dione. One more example in this protocol dealt a highly stereoselective Mukaiyama reaction of aziridine-2-carboxylate and silyl enol ether, following intramolecular aziridine ring-opening to provide easy and facile access to (-)-epiallo-isomuscarine.
Topics: Aza Compounds; Aziridines; Ethers; Nitrogen; Stereoisomerism
PubMed: 35758698
DOI: 10.3791/63705 -
The Journal of Allergy and Clinical... Mar 2022Allogeneic hematopoietic cell transplantation for hemophagocytic lymphohistiocytosis (HLH) disorders is associated with substantial morbidity and mortality.
BACKGROUND
Allogeneic hematopoietic cell transplantation for hemophagocytic lymphohistiocytosis (HLH) disorders is associated with substantial morbidity and mortality.
OBJECTIVE
The effect of conditioning regimen groups of varying intensity on outcomes after transplantation was examined to identify an optimal regimen or regimens for HLH disorders.
METHODS
We studied 261 patients with HLH disorders transplanted between 2005 and 2018. Risk factors for transplantation outcomes by conditioning regimen groups were studied by Cox regression models.
RESULTS
Four regimen groups were studied: (1) fludarabine (Flu) and melphalan (Mel) in 123 subjects; (2) Flu, Mel, and thiotepa (TT) in 28 subjects; (3) Flu and busulfan (Bu) in 14 subjects; and (4) Bu and cyclophosphamide (Cy) in 96 subjects. The day 100 incidence of veno-occlusive disease was lower with Flu/Mel (4%) and Flu/Mel/TT (0%) compared to Flu/Bu (14%) and Bu/Cy (22%) (P < .001). The 6-month incidence of viral infections was highest after Flu/Mel (72%) and Flu/Mel/TT (64%) compared to Flu/Bu (39%) and Bu/Cy (38%) (P < .001). Five-year event-free survival (alive and engrafted without additional cell product administration) was lower with Flu/Mel (44%) compared to Flu/Mel/TT (70%), Flu/Bu (79%), and Bu/Cy (61%) (P = .002). The corresponding 5-year overall survival values were 68%, 75%, 86%, and 64%, and did not differ by conditioning regimen (P = .19). Low event-free survival with Flu/Mel is attributed to high graft failure (42%) compared to Flu/Mel/TT (15%), Flu/Bu (7%), and Bu/Cy (18%) (P < .001).
CONCLUSIONS
Given the high rate of graft failure with Flu/Mel and the high rate of veno-occlusive disease with Bu/Cy and Flu/Bu, Flu/Mel/TT may be preferred for HLH disorders. Prospective studies are warranted.
Topics: Busulfan; Cyclophosphamide; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Lymphohistiocytosis, Hemophagocytic; Melphalan; Thiotepa; Transplantation Conditioning; Vidarabine
PubMed: 34375618
DOI: 10.1016/j.jaci.2021.07.031 -
Angewandte Chemie (International Ed. in... Jun 2023Aziridines are highly valued synthetic targets in organic and medicinal chemistry. The organocatalytic synthesis of such structures with broad substrate scope and good...
Aziridines are highly valued synthetic targets in organic and medicinal chemistry. The organocatalytic synthesis of such structures with broad substrate scope and good diastereoselectivity, however, is rare. Herein, we report a broadly applicable and diastereoselective synthetic method for the synthesis of trans-aziridines from imines and benzylic or alkyl halides utilizing sulfenate anions (PhSO ) as the catalyst. Substrates bearing heterocyclic aromatic groups, alkyl, and electron-rich and electron-poor aryl groups were shown to be compatible with this method (33 examples), giving good yields and high diastereoselectivities (trans : cis >20 : 1). Further functionalization of aziridines containing cyclopropyl or cyclobutyl groups was achieved through ring-opening reactions, with a cyclobutyl-substituted norephedrine derivative obtained through a four-step synthesis. We offer a mechanistic proposal involving reversible addition of the deprotonated benzyl sulfoxide to the imine to explain the high trans-diastereoselectivity.
Topics: Aziridines; Anions; Imines; Catalysis; Stereoisomerism
PubMed: 37068049
DOI: 10.1002/anie.202303069 -
National Science Review Oct 2023Aziridines derived from bioactive molecules may have unique pharmacological activities, making them useful in pharmacology (e.g. mitomycin C). Furthermore, the...
Aziridines derived from bioactive molecules may have unique pharmacological activities, making them useful in pharmacology (e.g. mitomycin C). Furthermore, the substitution of the epoxide moiety in epothilone B with aziridine, an analog of epoxides, yielded a pronounced enhancement in its anticancer efficacy. Thus, there is interest in developing novel synthetic technologies to produce aziridines from bioactive molecules. However, known methods usually require metal catalysts, stoichiometric oxidants and/or pre-functionalized amination reagents, causing difficulty in application. A practical approach without a metal catalyst and extra-oxidant for the aziridination of bioactive molecules is in demand, yet challenging. Herein, we report an electro-oxidative flow protocol that accomplishes an oxidant-free aziridination of natural products. This process is achieved by an oxidative sulfonamide/alkene cross-coupling, in which sulfonamide and alkene undergo simultaneous oxidation or alkene is oxidized preferentially. Further anticancer treatments in cell lines have demonstrated the pharmacological activities of these aziridines, supporting the potential of this method for drug discovery.
PubMed: 38059062
DOI: 10.1093/nsr/nwad187 -
Molecules (Basel, Switzerland) Feb 2019Small ring heterocycles, such as epoxides and aziridines, are present in several natural products and are also highly versatile building blocks, frequently involved in... (Review)
Review
Small ring heterocycles, such as epoxides and aziridines, are present in several natural products and are also highly versatile building blocks, frequently involved in the synthesis of numerous bioactive products and pharmaceuticals. Because of the potential for increased efficiency and selectivity, along with the advantages of environmentally benign synthetic procedures, multicomponent reactions (MCRs) have been explored in the synthesis and ring opening of these heterocyclic units. In this review, the recent advances in MCRs involving the synthesis and applications of epoxides and aziridines to the preparation of other heterocycles are discussed emphasizing the stereoselectivity of the reactions.
Topics: Aziridines; Biological Products; Epoxy Compounds; Green Chemistry Technology; Molecular Structure; Stereoisomerism
PubMed: 30754666
DOI: 10.3390/molecules24030630 -
Pediatric Blood & Cancer Jun 2021Appropriate high-dose chemotherapy (HDC) for high-risk neuroblastoma has not yet been established. In Japan, a unique HDC regimen that comprises two cycles of a total of...
BACKGROUND
Appropriate high-dose chemotherapy (HDC) for high-risk neuroblastoma has not yet been established. In Japan, a unique HDC regimen that comprises two cycles of a total of 800 mg/m of thiotepa and a total of 280 mg/m of melphalan is widely utilized.
METHODS
To evaluate the safety and efficacy of this thiotepa-melphalan high-dose therapy for high-risk neuroblastoma, we reviewed the medical records of 41 patients with high-risk neuroblastoma who underwent this regimen followed by autologous peripheral blood stem cell rescue between 2002 and 2012. MYCN-amplified high-risk neuroblastomas were observed in 23 patients. All patients underwent intensive multidrug induction chemotherapy, but none underwent anti-GD2 antibody immunotherapy. The primary tumor was resected at the adequate time point.
RESULTS
The median follow-up duration for living patients was 9.2 years (range 5.5-14.0 years). The 5-year event-free survival (EFS) and overall survival from treatment initiation were 41.5 ± 7.7% and 56.1 ± 7.8%, respectively. The 5-year EFS of MYCN-amplified high-risk neuroblastoma patients was 60.9 ± 10.2%, which was significantly superior compared with those with MYCN-nonamplified high-risk neuroblastoma (16.7 ± 8.8%; p < .001). MYCN amplification was the most favorable prognostic factor for EFS (hazard ratio = 0.29; 95% confidence interval = 0.12-0.66). Of the 41 patients, three died because of regimen-related toxicity (infection, n = 2; microangiopathy, n = 1).
CONCLUSION
The thiotepa-melphalan high-dose therapy with thiotepa and melphalan may be effective for high-risk neuroblastoma. However, this regimen is toxic and warrants special attention in clinical practice.
Topics: Antineoplastic Combined Chemotherapy Protocols; Disease-Free Survival; Humans; Infant; Melphalan; N-Myc Proto-Oncogene Protein; Neuroblastoma; Thiotepa; Transplantation, Autologous
PubMed: 33788375
DOI: 10.1002/pbc.28896 -
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