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1.
J Org Chem ; 87(9): 6426-6431, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35439001

RESUMO

An intramolecular formal [3+2] cycloaddition of activated aziridines and epoxides with electron-deficient alkene has been developed for the general and efficient construction of bridged aza- and oxa-[n.2.1] (n = 3 or 4) skeletons. This strategy can be efficiently promoted by lithium iodide. To demonstrate its potential, the intramolecular formal [3+2] cycloaddition was used to access the important intermediate of homoepiboxidine.


Assuntos
Alcenos , Aziridinas , Catálise , Reação de Cicloadição , Elétrons , Compostos de Epóxi , Esqueleto
2.
Org Lett ; 24(14): 2655-2659, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-35377668

RESUMO

Copper catalyzed regioselective and stereospecific coupling between aziridines and in situ generated pyridine Grignard reagents is reported. This method provides ß-pyridylethylamines with diverse structures and functionalities from aziridines and iodopyridines. ß-Pyridylethylamines are potential scaffolds for the synthesis of biologically active compounds often found in pharmaceuticals. The synthesis of challenging chiral dihydroazaindoles was also achieved through mild one-pot reaction conditions via aziridine opening followed by nucleophilic cyclization.


Assuntos
Aziridinas , Cobre , Aziridinas/química , Catálise , Cobre/química , Estrutura Molecular , Estereoisomerismo
3.
Org Lett ; 24(15): 2783-2787, 2022 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-35394290

RESUMO

A palladium catalyzed directing group assisted cross-coupling of aliphatic aziridines with indole, indoline, tetrahydroquinoline, and aniline has been developed to furnish the corresponding ß-arylethylamine derivatives. The substrate scope was very general, and the protocol was also tolerated in the presence of various external additives. Control experiments suggested that the C-H cleavage step is the rate-determining step.


Assuntos
Aziridinas , Triptaminas , Catálise , Indóis , Paládio
4.
J Am Chem Soc ; 144(11): 4739-4745, 2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35258294

RESUMO

We report enantioselective one-carbon ring expansion of aziridines to make azetidines as a new-to-nature activity of engineered "carbene transferase" enzymes. A laboratory-evolved variant of cytochrome P450BM3, P411-AzetS, not only exerts unparalleled stereocontrol (99:1 er) over a [1,2]-Stevens rearrangement but also overrides the inherent reactivity of aziridinium ylides, cheletropic extrusion of olefins, to perform a [1,2]-Stevens rearrangement. By controlling the fate of the highly reactive aziridinium ylide intermediates, these evolvable biocatalysts promote a transformation which cannot currently be performed using other catalyst classes.


Assuntos
Azetidinas , Aziridinas , Carbono , Catálise , Estereoisomerismo
5.
Molecules ; 27(6)2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35335129

RESUMO

A short synthetic route to stereoselective access to C-glycosyl-aminoethyl sulfide derivatives has been developed through the reaction of tributhyltin derivatives of glycals with aziridinecarboaldehyde and the regioselective ring opening of a chiral aziridine with thiophenol. The absolute configurations of the resulting diastereoisomers were determined by 1H NMR spectroscopy.


Assuntos
Aziridinas , Aziridinas/química , Estereoisomerismo , Sulfetos
6.
Chem Commun (Camb) ; 58(23): 3767-3770, 2022 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-35234243

RESUMO

An unprecedented synthetic strategy is devised to generate ß-aminoboronic acids from aziridines via a sequential process involving 1,2-iodoamine formation and radical borylation under light irradiation. A variety of aziridines including multiply substituted aziridines have been successfully employed as synthetic precursors, expanding their synthetic utility compared to previous methods. Mechanistic studies suggest that the boron source plays a unique role in the borylation step, and in the formation of haloamine intermediates.


Assuntos
Aziridinas , Boro
7.
J Org Chem ; 87(5): 3751-3757, 2022 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-35171590

RESUMO

The first direct general method for N-Me aziridination of electron-deficient olefins, enones, is described using N-methyl-O-tosylhydroxylamine as the aminating agent in the presence of a Cu(OTf)2 catalyst. The aziridination of vinyl ketones, hitherto unknown for N-Me as well as N-H, has been achieved efficiently. The open-flask reaction is stereospecific, operationally simple, and additive-free. It also efficiently affords N-H aziridinated products under a similar reaction condition.


Assuntos
Aziridinas , Alcenos , Catálise , Cetonas , Estrutura Molecular
8.
Chemistry ; 28(16): e202200060, 2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35133031

RESUMO

We report a method for the synthesis of chiral vicinal chloroamines via asymmetric protonation of catalytically generated prochiral chloroenamines using chiral Brønsted acids. The process is highly enantioselective, with the origin of asymmetry and catalyst substituent effects elucidated by DFT calculations. We show the utility of the method as an approach to the synthesis of a broad range of heterocycle-substituted aziridines by treatment of the chloroamines with base in a one-pot process, as well as the utility of the process to allow access to vicinal diamines.


Assuntos
Aziridinas , Catálise , Cloraminas , Ciclização , Estereoisomerismo
9.
Chem Commun (Camb) ; 58(22): 3681-3684, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35226000

RESUMO

A straightforward synthesis of aryl aziridines is reported from readily available azides and alkenes and using technical solvents in the presence of air. This methodology does not require any additives and the obtained compounds can be employed in ring-opening and ring-expansion reactions.


Assuntos
Aziridinas , Alcenos , Azidas , Reação de Cicloadição , Estrutura Molecular , Estereoisomerismo
10.
J Hazard Mater ; 425: 127995, 2022 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-34906875

RESUMO

Uranium extraction from natural seawater and wastewater are quintessential requirements to supply uninterrupted carbon-free nuclear energy and to prevent potential radiochemical and toxicological effects, respectively. Owing to the complexity and low-concentration uranium of these water samples, the design and synthesis of sorbent materials for uranium extraction with meaningful efficiencies remains a grand challenge. Herein, we reported a novel three-dimensional bifunctional network of hyperbranched poly(amidoxime-ethyleneimine) (PAO-h-PEI) using PEI as the skeleton material via cyanoethylation, crosslinking and then amidoximation. As a result of the synergistic supramolecular strategy, the PAO-h-PEI membrane achieved a remarkable adsorption capacity of 985.7 mg/g for aqueous uranium solution, which was 2.5 folds that of the monofunctional h-PEI membrane (387.6 mg/g). The PAO-h-PEI membrane also exhibited good selectivity towards uranium in the presence of various metal ions, high-content salt, and natural organic matter as well as common anions. According to the XPS and FTIR results, the utilization of amines as the second ligand enhanced uranyl binding by providing additional coordination sites or by interacting with oxime to force N-OH dissociation. The good reusability (adsorption rate of 93% after six adsorption-desorption cycles) and satisfactory adsorption performance in extracting low-concentration uranium in real seawater demonstrate its practicability.


Assuntos
Aziridinas , Urânio , Adsorção , Oximas , Água do Mar , Águas Residuárias
11.
Org Lett ; 24(2): 501-505, 2022 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-34967220

RESUMO

We report that the treatment of unsymmetrical 2,3-disubstituted aziridines with TiCl4 yields ß-phenethylamine products via the intermediacy of a phenonium ion. Derivatization of the products obtained via this method is demonstrated. Computational analysis of the reaction pathway provides insight into the reaction mechanism, including the selectivity of the phenonium opening.


Assuntos
Aziridinas
12.
J Org Chem ; 86(24): 17762-17773, 2021 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-34852456

RESUMO

Boroxinate complexes of VAPOL and VANOL are a chiral anionic platform that can serve as a versatile staging arena for asymmetric catalysis. The structural underpinning of the platform is a chiral polyborate core that covalently links together alcohols (or phenols) and vaulted biaryl ligands. The polyborate platform is assembled in situ by the substrate of the reaction, and thus a multiplex of chiral catalysts can be rapidly assembled from various alcohols (or phenols) and bis-phenol ligands for screening of catalyst activity. In the present study, variations in the steric and electronic properties of the phenol/alcohol component of the boroxinate catalyst are probed to reveal their effects on the asymmetric induction in the catalytic asymmetric aziridination reaction. A Hammett study is consistent with a mechanism in which the two substrates are hydrogen-bonded to the boroxinate core in the enantiogenic step. The results of the Hammett study are supported by a computational study in which it is found that the H-O distance of the protonated imine hydrogen bonded to the anionic boroxinate core decreases with an increase in the electron releasing ability of the phenol unit incorporated into the boroxinate. The results are not consistent with a mechanism in which the boroxinate catalyst functions as a Lewis acid and activates the imine by a Lewis acid/Lewis base interaction.


Assuntos
Aziridinas , Ânions , Catálise , Eletrônica , Estereoisomerismo
13.
Int J Mol Sci ; 22(23)2021 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-34884949

RESUMO

N,N-Dimethylaziridine-2-carboxamides react with organolithium reagents yielding 2-aziridinylketones. The reaction with one equivalent of organolithium compound is selective to amide carbonyl at a low (-78 °C) temperature. These ketones, in reaction with organolithium reagents, give symmetrical and unsymmetrical aziridinyl carbinols. The usage of excess phenyllithium may serve as a special N-Boc-protecting group cleavage method for acid-sensitive substrates.


Assuntos
Aziridinas/química , Cetonas/química , Lítio/química , Metanol/química , Estrutura Molecular , Compostos Organometálicos/química , Estereoisomerismo
14.
J Am Chem Soc ; 143(45): 19149-19159, 2021 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-34748699

RESUMO

The development of the first intermolecular Rh2(II)-catalyzed aziridination of olefins using anilines as nonactivated N atom precursors and an iodine(III) reagent as the stoichiometric oxidant is reported. This reaction requires the transfer of an N-aryl nitrene fragment from the iminoiodinane intermediate to a Rh2(II) carboxylate catalyst; in the absence of a catalyst only diaryldiazene formation was observed. This N-aryl aziridination is general and can be successfully realized by using as little as 1 equiv of the olefin. Di-, tri-, and tetrasubstituted cyclic or acylic olefins can be employed as substrates, and a range of aniline and heteroarylamine N atom precursors are tolerated. The Rh2(II)-catalyzed N atom transfer to the olefin is stereospecific as well as chemo- and diastereoselective to produce the N-aryl aziridine as the only amination product. Because the chemistry of nonactivated N-aryl aziridines is underexplored, the reactivity of N-aryl aziridines was explored toward a range of nucleophiles to stereoselectively access privileged 1,2-stereodiads unavailable from epoxides, and removal of the N-2,4-dinitrophenyl group was demonstrated to show that functionalized primary amines can be constructed.


Assuntos
Alcenos/química , Aziridinas/síntese química , Compostos de Anilina/química , Catálise , Ciclização , Oxirredução , Ródio/química
15.
Molecules ; 26(20)2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34684715

RESUMO

Aziridine derivatives involved in nucleophilic ring-opening reactions have attracted great interest, since they allow the preparation of biologically active molecules. A chemoselective and mild procedure to convert a peptide cysteine residue into lanthionine via S-alkylation on aziridine substrates is presented in this paper. The procedure relies on a post-synthetic protocol promoted by molecular sieves to prepare lanthionine-containing peptides and is assisted by microwave irradiation. In addition, it represents a valuable alternative to the stepwise approach, in which the lanthionine precursor is incorporated into peptides as a building block.


Assuntos
Alanina/análogos & derivados , Aziridinas/química , Cromatografia em Gel/métodos , Sulfetos/química , Alanina/química , Alquilação , Catálise , Cromatografia Líquida , Cisteína/química , Calefação , Micro-Ondas , Estrutura Molecular , Peptídeos/química
16.
Org Lett ; 23(20): 7916-7920, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34609884

RESUMO

Ring opening reactions of meso-aziridines generate chiral amine derivatives where the control of stereochemistry is possible through enantioselective catalysis. We report the use of a diphosphine-palladium(II) catalyst for the highly enantioselective desymmetrization of N-acylaziridines with indoles. The ß-tryptamine products are isolated in moderate to high yield across a range of indole and aziridine substitution patterns. The synthetic utility of ß-tryptamine products is demonstrated by conversion to the brominated pyrroloindoline derivative.


Assuntos
Aziridinas/química , Indóis/química , Paládio/química , Catálise , Halogenação , Estrutura Molecular , Estereoisomerismo
17.
Int J Mol Sci ; 22(18)2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34576025

RESUMO

Aziridination reactions represent a powerful tool in aziridine synthesis. Significant progress has been achieved in this field in the last decades, whereas highly functionalized aziridines including 3-arylated aziridine-2-carbonyl compounds play an important role in both medical and synthetic chemistry. For the reasons listed, in the current review we have focused on the ways to obtain 3-arylated aziridines and on the recent advances (mainly since the year 2000) in the methodology of the synthesis of these compounds via aziridination.


Assuntos
Aziridinas/química , Cetonas/química , Aziridinas/síntese química , Ácidos Carboxílicos/química , Iminas/química , Estrutura Molecular , Estereoisomerismo
18.
Carbohydr Res ; 509: 108430, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34488002

RESUMO

N-sugar substituted chiral aziridines were synthesized via Gabriel-Cromwell reaction. Novel pure diastereomers of aziridine derivatives (4 diastereomers) were readily obtained in high yields and their structures were confirmed by means of 1H NMR, 13C NMR, FT-IR, Mass and optical rotations. This is, to the best of our knowledge, the unique example of N-sugar aziridine synthesis. Diastereomeric effects for prostate (PC3) and cervix (HeLa) cancers were screened and it has been observed that the epimers bearing the same sugars showed different results against PC3 and HeLa cancer cells. The novel sugar aziridines were investigated as promising prodrug candidates for prostate cancer (PC3) therapy. Moreover, the drug likeness calculations (Lipinski's rule, physicochemical properties, lipophilicity, solubility, pharmacokinetics and bioavailability radar) have indicated that the sugar aziridines can be good candidates as oral drugs.


Assuntos
Aziridinas
19.
Molecules ; 26(14)2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34299540

RESUMO

Several phosphorus-substituted N-acylated cyanoaziridines 2 and N-carbamoylated cyanoziridines 5 were prepared in good to high yields. N-Acylated cyanoaziridines 2 were used, after ring expansion, in an efficient synthesis of oxazoline derivative 3a and in a completely regio-controlled reaction in the presence of NaI. Conversely, N-carbamoyl cyanoaziridines 5 reacted with NaI to obtain a regioisomeric mixture of 2-aminocyanooxazolines 7. Mild acidic conditions can be used for the isomerization of N-thiocarbamoyl cyanoaziridine 6a into a 2-aminocyanothiazoline derivative 8a by using BF3·OEt2 as a Lewis acid. Likewise, a one pot reaction of NH-cyanoaziridines 1 with isocyanates obtained 2-iminocyanooxazolidines 9 regioselectively. This synthetic methodology involves the addition of isocyanates to starting cyanoaziridines to obtain N-carbamoyl cyanoaziridines 5, which after the ring opening, reacts with a second equivalent of isocyanate to give the final 2-imino cyanooxazolidines 9. In addition, the cytotoxic effect on the cell lines derived from human lung adenocarcinoma (A549) was also screened. 2-Iminooxazolidines 9 exhibited moderate activity against the A549 cell line in vitro. Furthermore, a selectivity towards cancer cells (A549) over non-malignant cells (MCR-5) was detected.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Aziridinas/síntese química , Aziridinas/farmacologia , Proliferação de Células/efeitos dos fármacos , Fósforo/farmacologia , Células A549 , Adenocarcinoma de Pulmão/tratamento farmacológico , Fenômenos Bioquímicos/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Estrutura Molecular
20.
Chem Commun (Camb) ; 57(56): 6915-6918, 2021 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-34152343

RESUMO

Described here is the first stereoselective synthesis of highly functionalized chloroalkene dipeptide isosteres containing an α,α-disubstituted amino acid (ααAA). This synthesis requires the construction of a quaternary carbon center, and this challenge was overcome by the Aza-Darzens condensation of ketimine with α,α-dichloroenolate, producing 2-chloroaziridines with quaternary carbon centers including spirocyclic motifs, which are valuable for the previously elusive synthesis of various ααAA-containing chloroalkene isosteres.


Assuntos
Aminoácidos/síntese química , Hidrocarbonetos Clorados/síntese química , Peptidomiméticos/síntese química , Aziridinas/síntese química , Estereoisomerismo
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