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1.
Circulation ; 149(22): 1752-1769, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38348663

RESUMO

BACKGROUND: Vascular calcification, which is characterized by calcium deposition in arterial walls and the osteochondrogenic differentiation of vascular smooth muscle cells, is an actively regulated process that involves complex mechanisms. Vascular calcification is associated with increased cardiovascular adverse events. The role of 4-hydroxynonenal (4-HNE), which is the most abundant stable product of lipid peroxidation, in vascular calcification has been poorly investigated. METHODS: Serum was collected from patients with chronic kidney disease and controls, and the levels of 4-HNE and 8-iso-prostaglandin F2α were measured. Sections of coronary atherosclerotic plaques from donors were immunostained to analyze calcium deposition and 4-HNE. A total of 658 patients with coronary artery disease who received coronary computed tomography angiography were recruited to analyze the relationship between coronary calcification and the rs671 mutation in aldehyde dehydrogenase 2 (ALDH2). ALDH2 knockout (ALDH2-/-) mice, smooth muscle cell-specific ALDH2 knockout mice, ALDH2 transgenic mice, and their controls were used to establish vascular calcification models. Primary mouse aortic smooth muscle cells and human aortic smooth muscle cells were exposed to medium containing ß-glycerophosphate and CaCl2 to investigate cell calcification and the underlying molecular mechanisms. RESULTS: Elevated 4-HNE levels were observed in the serum of patients with chronic kidney disease and model mice and were detected in calcified artery sections by immunostaining. ALDH2 knockout or smooth muscle cell-specific ALDH2 knockout accelerated the development of vascular calcification in model mice, whereas overexpression or activation prevented mouse vascular calcification and the osteochondrogenic differentiation of vascular smooth muscle cells. In patients with coronary artery disease, patients with ALDH2 rs671 gene mutation developed more severe coronary calcification. 4-HNE promoted calcification of both mouse aortic smooth muscle cells and human aortic smooth muscle cells and their osteochondrogenic differentiation in vitro. 4-HNE increased the level of Runx2 (runt-related transcription factor-2), and the effect of 4-HNE on promoting vascular smooth muscle cell calcification was ablated when Runx2 was knocked down. Mutation of Runx2 at lysine 176 reduced its carbonylation and eliminated the 4-HNE-induced upregulation of Runx2. CONCLUSIONS: Our results suggest that 4-HNE increases Runx2 stabilization by directly carbonylating its K176 site and promotes vascular calcification. ALDH2 might be a potential target for the treatment of vascular calcification.


Assuntos
Aldeído-Desidrogenase Mitocondrial , Aldeídos , Subunidade alfa 1 de Fator de Ligação ao Core , Camundongos Knockout , Miócitos de Músculo Liso , Calcificação Vascular , Animais , Aldeídos/metabolismo , Calcificação Vascular/metabolismo , Calcificação Vascular/genética , Calcificação Vascular/patologia , Humanos , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Aldeído-Desidrogenase Mitocondrial/genética , Aldeído-Desidrogenase Mitocondrial/metabolismo , Camundongos , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Miócitos de Músculo Liso/efeitos dos fármacos , Masculino , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Feminino , Pessoa de Meia-Idade , Doença da Artéria Coronariana/metabolismo , Doença da Artéria Coronariana/genética , Doença da Artéria Coronariana/patologia , Células Cultivadas , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/patologia , Idoso
2.
Biochem Biophys Res Commun ; 723: 150169, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-38815487

RESUMO

Among the two Y RNAs in Deinococcus radiodurans, the functional properties of Yrn2 are still not known. Yrn2 although consists of a long stem-loop for Rsr binding, differs from Yrn1 in the effector binding site. An initial study on Yrn2 delineated it to be a UV-induced noncoding RNA. Apart from that Yrn2 has scarcely been investigated. In the current study, we identified Yrn2 as an γ-radiation induced Y RNA, which is also induced upon H2O2 and mitomycin treatment. Ectopically expressed Yrn2 appeared to be nontoxic to the cell growth. An overabundance of Yrn2 was found to ameliorate cell survival under oxidative stress through the detoxification of intracellular reactive oxygen species with a subsequent decrease in total protein carbonylation. A significant accumulation of intracellular Mn(II) with unaltered Fe(II) and Zn(II) with detected while Yrn2 is overabundant in the cells. This study identified the role of a novel Yrn2 under oxidative stress in D. radiodurans.


Assuntos
Deinococcus , Peróxido de Hidrogênio , Estresse Oxidativo , Deinococcus/metabolismo , Deinococcus/genética , Peróxido de Hidrogênio/metabolismo , Peróxido de Hidrogênio/farmacologia , RNA Bacteriano/metabolismo , RNA Bacteriano/genética , Espécies Reativas de Oxigênio/metabolismo , RNA não Traduzido/metabolismo , RNA não Traduzido/genética , Raios gama
3.
Appl Environ Microbiol ; 90(5): e0153823, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38587394

RESUMO

A plethora of gene regulatory mechanisms with eccentric attributes in Deinoccocus radiodurans confer it to possess a distinctive ability to survive under ionizing radiation. Among the many regulatory processes, small RNA (sRNA)-mediated regulation of gene expression is prevalent in bacteria but barely investigated in D. radiodurans. In the current study, we identified a novel sRNA, DrsS, through RNA-seq analysis in D. radiodurans cells while exposed to ionizing radiation. Initial sequence analysis for promoter identification revealed that drsS is potentially co-transcribed with sodA and dr_1280 from a single operon. Elimination of the drsS allele in D. radiodurans chromosome resulted in an impaired growth phenotype under γ-radiation. DrsS has also been found to be upregulated under oxidative and genotoxic stresses. Deletion of the drsS gene resulted in the depletion of intracellular concentration of both Mn2+ and Fe2+ by ~70% and 40%, respectively, with a concomitant increase in carbonylation of intracellular protein. Complementation of drsS gene in ΔdrsS cells helped revert its intracellular Mn2+ and Fe2+ concentration and alleviated carbonylation of intracellular proteins. Cells with deleted drsS gene exhibited higher sensitivity to oxidative stress than wild-type cells. Extrachromosomally expressed drsS in ΔdrsS cells retrieved its oxidative stress resistance properties by catalase-mediated detoxification of reactive oxygen species (ROS). In vitro binding assays indicated that DsrS directly interacts with the coding region of the katA transcript, thus possibly protecting it from cellular endonucleases in vivo. This study identified a novel small RNA DrsS and investigated its function under oxidative stress in D. radiodurans. IMPORTANCE: Deinococcus radiodurans possesses an idiosyncratic quality to survive under extreme ionizing radiation and, thus, has evolved with diverse mechanisms which promote the mending of intracellular damages caused by ionizing radiation. As sRNAs play a pivotal role in modulating gene expression to adapt to altered conditions and have been delineated to participate in almost all physiological processes, understanding the regulatory mechanism of sRNAs will unearth many pathways that lead to radioresistance in D. radiodurans. In that direction, DrsS has been identified to be a γ-radiation-induced sRNA, which is also induced by oxidative and genotoxic stresses. DrsS appeared to activate catalase under oxidative stress and detoxify intracellular ROS. This sRNA has also been shown to balance intracellular Mn(II) and Fe concentrations protecting intracellular proteins from carbonylation. This novel mechanism of DrsS identified in D. radiodurans adds substantially to our knowledge of how this bacterium exploits sRNA for its survival under stresses.


Assuntos
Proteínas de Bactérias , Deinococcus , Regulação Bacteriana da Expressão Gênica , RNA Bacteriano , Espécies Reativas de Oxigênio , Deinococcus/genética , Deinococcus/efeitos da radiação , Deinococcus/metabolismo , Espécies Reativas de Oxigênio/metabolismo , RNA Bacteriano/genética , RNA Bacteriano/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Radiação Ionizante , Pequeno RNA não Traduzido/genética , Pequeno RNA não Traduzido/metabolismo , Estresse Oxidativo , Raios gama
4.
Chemistry ; 30(9): e202303752, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38109037

RESUMO

Herein, a highly efficient five-step reaction sequence to BODIPYs is presented. The key step is the combination of transition metal-catalyzed in-situ generation of aldehydes and their subsequent organocatalytic activation to yield dipyrromethanes, which are further converted to the corresponding BODIPY. Classic syntheses towards BODIPYs have relied on aldehydes or acid chlorides, which are often not commercially available and rather sensitive to handle. The presented approach starts from readily available and stable alkenes or aryl-bromides, which allows to extend the range of readily available BODIPYs that can be tailored for their specific use. The synthesis of 55 derivatives with overall yields of up to 78 % demonstrates the wide applicability and advantages of the presented method.

5.
Chemistry ; 30(24): e202304056, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38379208

RESUMO

3-Indole-3-one is a key intermediate in the synthesis of many drugs and plays an important role in synthetic chemistry and biochemistry. A new method for synthesizing trifluoromethylated 3-indoleketones by Pd(0)-catalyzed carbonylation was introduced. In the absence of additives, 1-chloro-3,3,3-trifluoropropyl (an inexpensive and environmentally friendly synthetic block of trifluoromethyl) reacts with indole and carbon monoxide to generate trifluoromethylindole ketones with good yields, regioselectivity, and chemical selectivity; furthermore, the products exhibit strong resistance to basic functional groups, such as alkynes, aldehydes, and esters. In addition to the conversion of indole compounds into corresponding products, pyrrole and heteroindole may be suitable for corresponding chemical transformations. This study provides a synthetic method for the further construction of trifluoromethylated 3-indole ketones.

6.
Chemistry ; : e202401658, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38890146

RESUMO

A new nickel catalyzed cross-electrophile coupling for accessing γ-lactams (isoindolinones) as well as γ-lactones (isobenzofuranones) via carbonylation with CO2 is documented. The protocol exploits the synergistic role of redox-active Ni(II) complexes and AlCl3 as a CO2 activator/oxygen scavenger, leading to the formation of a wide range of cyclic amides and esters (28 examples) in good to high yields (up to 87%). A dedicated computational investigation revealed the multiple roles played by AlCl3. In particular, the simultaneous transient protection of the pendant amino group of the starting reagents and the formation of the electrophilically activated CO2-AlCl3 adduct are shown to concur in paving the way for an energetically favorable mechanistic pathway.

7.
Artigo em Inglês | MEDLINE | ID: mdl-38981979

RESUMO

Hormone therapy (HT) has been reported to reduce protein carbonylation (PC) in postmenopausal women, in whom fibrinolysis is impaired. We investigated whether PC affects fibrinolysis and if HT modulates this effect. We enrolled 150 women aged 55.5 ± 4.7 years in a randomized interventional open-label study, including 50 on standard oral HT, 50 on ultra-low-dose HT, and 50 controls. PC, along with global fibrinolysis (clot lysis time, CLT), fibrinolysis proteins, and prothrombotic markers were determined at baseline and at 24 weeks. Patients with the baseline top quartile PC (> 2.07 nM/mg protein) had 10.3% longer CLT, higher activity (but not antigen) of TAFI (+ 19.9%) and PAI-1 (+ 68.1%) compared to the remainder. No differences were observed in thrombin generation, factor VIII, plasminogen or α2-antiplasmin. On-treatment PC decreased by 16.4% (p < 0.0001), without differences related to the type of HT, compared to baseline and by 30% compared to controls, in whom PC and fibrinolysis markers remained unchanged. Patients with PC > 2.07 nM/mg had shortened CLT during HT compared to baseline, along with lower PAI-1 (-69%) and TAFI (-26%) activity. In this subgroup CLT was 5.8% shorter compared to controls with the highest PC. In postmenopausal women with increased PC, HT was accompanied by PC reduction and faster clot lysis together with decreased PAI-1 and TAFI activity.

8.
Artigo em Inglês | MEDLINE | ID: mdl-38965130

RESUMO

INTRODUCTION: Plasma protein carbonylation that reflects oxidative stress has been demonstrated to be associated with the prothrombotic fibrin clot phenotype. However, the role of protein carbonyls (PC) in predicting ischemic stroke in atrial fibrillation (AF) is largely unknown. This study aimed to investigate whether PC increase the risk of stroke in anticoagulated AF patients during follow-up. METHODS: In 243 AF patients on anticoagulation (median age 69 years; median CHA2DS2-VASc of 4), we measured plasma PC using the assay by Becatti, along with plasma clot permeability (Ks), clot lysis time (CLT), thrombin generation, and fibrinolytic proteins, including plasminogen activator inhibitor type 1 (PAI-1) and thrombin activatable fibrinolysis inhibitor (TAFI). Ischemic stroke, major bleeding, and mortality were recorded during a median follow-up of 53 months. RESULTS: Plasma PC levels (median, 3.16 [2.54-3.99] nM/mg protein) at baseline showed positive associations with age (P < 0.001), CHA2DS2-VASc (P = 0.003), and N-terminal B-type natriuretic peptide (P = 0.001), but not with type of AF or comorbidities except for heart failure (P = 0.007). PC levels were correlated with CLT (r = 0.342, P < 0.001), endogenous thrombin potential (r = 0.217, P = 0.001) and weakly with Ks (r = -0.145, P = 0.024), but not with fibrinogen, PAI-1, or TAFI levels. Stroke was recorded in 20 patients (1.9%/year), who had at baseline 36% higher PC levels (P < 0.001). Elevated PC (P = 0.003) at baseline were independently associated with stroke risk. CONCLUSION: Our findings suggest that in patients with AF enhanced protein carbonylation is associated with increased "residual" risk of stroke despite anticoagulation, which is at least in part due to unfavorably altered fibrin clot phenotype.

9.
J Labelled Comp Radiopharm ; 67(6): 245-249, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38124264

RESUMO

AZD4747 is a KRASG12C inhibitor recently shown to cross the non-human primate blood-brain barrier efficiently. In the current study, a GMP-compliant production of [11C]AZD4747 was developed to enable PET studies in human subjects. The validated procedure afforded [11C]AZD4747 as an injectable solution in good radioactivity yield (1656 ± 532 MBq), excellent radiochemical purity (100%), and a molar activity of 77 ± 13 GBq/µmol at the end of the synthesis, which took 46 ± 1 min from the end of the bombardment. Quality control on the final product was performed satisfactorily and met all acceptance criteria.


Assuntos
Radioisótopos de Carbono , Proteínas Proto-Oncogênicas p21(ras) , Radioisótopos de Carbono/química , Proteínas Proto-Oncogênicas p21(ras)/antagonistas & inibidores , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Radioquímica , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/farmacocinética , Humanos
10.
J Environ Manage ; 351: 119990, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38183952

RESUMO

Leachate, an effluent produced during solid waste decomposition, interacts directly with soil, mainly in dumpsite areas. Studies on terrestrial animal exposure to leachate are, however, lacking. Plants are the most frequently studied organisms, while animal studies, especially earthworms, are limited. Nevertheless, ecotoxicological assessments involving earthworms are crucial due to their role in soil health and ecosystem maintenance, which are paramount in understanding potential terrestrial ecosystem leachate effects. In this context, this study aimed to evaluate behavioral effects, sublethal cytotoxicity and antioxidant system alterations in Eisenia andrei earthworms chronically exposed to leachate from a closed dumpsite. Cytotoxicity was determined by coelomocyte density, viability and cell typing, while antioxidant system alterations were assessed through superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), reduced glutathione (GSH) and metallothionein (MT) determinations. Malondialdehyde (MDA) and protein carbonylation (PTC) levels were also determined as oxidative effect markers. Finally, the Biomarker Response Index (BRI) was assessed, aiming to quantitatively integrate the results of the investigated endpoints and establish a biological health state (BHS) for each leachate concentration. Leachate exposure led to leak responses at concentrations of up to 50%, but attraction at higher concentrations. Decreased cell density (28%) was observed after 48 days and reduced viability (50%), after 14 days of leachate exposure. The observed cell typing changes indicate anti-inflammatory immune system effects. Leachate exposure led to several antioxidant system alterations, increasing SOD (2-6 %), CAT (5-35 %) and GST (5-70 %) activities and GSH (7-37%) and MT (3-67%) levels. Earthworm antioxidant defenses were, however, able to prevent lipid peroxidation, which decreased (11-37%) following leachate exposure to concentrations above 12.5%, and PTC, which increased at 42 days (26%) and reduced at 56 days (12 %). This is the first PTC assessment in leachate-exposed earthworms. The increased carbonylation levels observed after 42 days alongside MDA decreases highlight the need for further research employing oxidative effect biomarkers other than MDA. Finally, an integrated approach employing the BRI was carried out, revealing mild initial changes evolving to moderate to major effects at the highest leachate exposure concentration, with an effect attenuation detected at the end of the experiment. In this sense, this study brings forth a significant novelty, employing a biomarker previously not assessed in earthworms, demonstrating an oxidative effect, alongside the use of the BRI as an integrative tool for the endpoints applied in this assessment.


Assuntos
Oligoquetos , Poluentes do Solo , Animais , Antioxidantes/metabolismo , Oligoquetos/metabolismo , Estresse Oxidativo , Ecossistema , Poluentes do Solo/toxicidade , Poluentes do Solo/metabolismo , Superóxido Dismutase/metabolismo , Solo , Biomarcadores/metabolismo
11.
Molecules ; 29(4)2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38398602

RESUMO

The use of gaseous CO in Pd-catalyzed carbonylative quinolone synthesis presents challenges related to safety and precise pressure control. In response, a streamlined non-gaseous synthesis of 4-quinolone compounds has been developed. This study introduces a tunable CO-releasing system utilizing Fe(CO)5 activated by a dual-base system of piperazine and triethylamine. This alternative liquid CO resource facilitates the palladium-catalyzed carbonylative C-C coupling and subsequent intramolecular cyclization. By tuning the tandem kinetics of carbonylation and cyclization, this non-gaseous method achieves the successful synthesis of 22 distinct 4-quinolones with excellent yields. This is achieved through the three-component condensation of sub-stoichiometric amounts of Fe(CO)5 with 2-iodoaniline and terminal alkynes. Operando mechanistic studies have revealed a novel CO transfer mechanism that facilitates homogeneous carbonylative cyclization, distinguishing this method from traditional techniques. In addition to addressing safety concerns, this approach also provides precise control over selectivity, with significant implications for pharmaceutical research and the efficient synthesis of pharmaceutical and bioactive compounds.

12.
Molecules ; 29(7)2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38611790

RESUMO

In this study, pyrazole tartrate (Pya·DL) and tartaric acid (DL) complexed with cobalt-iron bimetallic modified hydrogen-type mordenite (HMOR) were prepared using the ion exchange method. The results demonstrate that the stability of the dimethyl ether (DME) carbonylation reaction to methyl acetate (MA) was significantly improved after the introduction of Pya·DL to HMOR. The Co∙Fe∙DL-Pya·DL-HMOR (0.8) sample exhibited sustainable stability within 400 h DME carbonylation, exhibiting a DME conversion rate of about 70% and MA selectivity of above 99%. Through modification with the DL-complexed cobalt-iron bimetal, the dispersion of cobalt-iron was greatly enhanced, leading to the formation of new metal Lewis acidic sites (LAS) and thus a significant improvement in catalysis activity. Pya·DL effectively eliminated non-framework aluminum in HMOR, enlarged its pore size, and created channels for carbon deposition diffusion, thereby preventing carbon accumulation and pore blockage. Additionally, Pya·DL shielded the Bronsted acid sites (BAS) in the 12 MR channel, effectively suppressing the side reactions of carbon deposition and reducing the formation of hard carbon deposits. These improvements collectively contribute to the enhanced stability of the DME carbonylation reaction.

13.
Molecules ; 29(9)2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38731490

RESUMO

The zeolite-catalyzed conversion of DME into chemicals is considered environmentally friendly in industry. The periodic density functional theory, statistical thermodynamics, and the transition state theory are used to study some possible parallel reactions about the hydrogen-bonded DME over zeolite ferrierite. The following are the key findings: (1) the charge separation probably leads to the conversion of a hydrogen-bonded DME into a dimethyl oxonium ion (i.e., DMO+ or (CH3)2OH+) with a positive charge of about 0.804 e; (2) the methylation of DME, CH3OH, H2O, and CO by DMO+ at the T2O6 site of zeolite ferrierite shows the different activated internal energy (∆E≠) ranging from 18.47 to 30.06 kcal/mol, implying the strong methylation ability of DMO+; (3) H-abstraction by DMO+ is about 3.94-15.53 or 6.57-18.16 kcal/mol higher than DMO+ methylation in the activation internal energy; (4) six DMO+-mediated reactions are more likely to occur due to the lower barriers, compared to the experimental barrier (i.e., 39.87 kcal/mol) for methyl acetate synthesis; (5) active intermediates, such as (CH3)3O+, (CH3)2OH+, CH3CO+, CH3OH2+, and CH2=OH+, are expected to appear; (6) DMO+ is slightly weaker than the well-known surface methoxy species (ZO-CH3) in methylation; and (7) the methylated activity declines in the order of DME, CH3OH, H2O, and CO, with corresponding rate constants at 463.15 K of about 3.4 × 104, 1.1 × 102, 0.18, and 8.2 × 10-2 s-1, respectively.

14.
Angew Chem Int Ed Engl ; 63(2): e202313714, 2024 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-37988191

RESUMO

An unprecedented regiodivergent palladium-catalyzed carbonylation of aromatic alkenes has been developed. Utilizing commercially available Pd(CH3 CN)2 Cl2 in the presence of 1,1'-ferrocenediyl-bis(tert-butyl(pyridin-2-yl)phosphine) ligand L8 diverse selenoesters are obtained in a straightforward manner. Key to success for the control of the regioselectivity of the carbonylation step is the concentration of the acidic co-catalyst. This general protocol features wide functional group compatibility and good regioselectivity. Mechanistic studies suggest that the presence of stoichiometric amounts of acid changes the properties and coordination mode of the ligand leading to reversed regioselectivity.

15.
Angew Chem Int Ed Engl ; : e202410597, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38986016

RESUMO

The development of all kinds of covalent drugs had a major impact on the improvement of the human health system. Covalent binding to target proteins is achieved by so-called electrophilic warheads, which are incorporated in the respective drug molecule. In the last decade, specifically acrylamides emerged as attractive warheads in covalent drug design. Herein, a straightforward palladium-catalyzed hydroaminocarbonylation of acetylene has been developed, allowing a modular and diverse synthesis of bio-active acrylamides. This general protocol features high atom efficiency, wide functional group compatibility, high chemoselectivity and proceeds additive free under mild reaction conditions. The synthetic utility of this protocol is showcased in the synthesis of ibrutinib, osimertinib, and other bio-active compound derivatives.

16.
Angew Chem Int Ed Engl ; : e202403917, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38818640

RESUMO

Although dearomative functionalizations enable the direct conversion of flat aromatics into precious three-dimensional architectures, the case for simple arenes remains largely underdeveloped owing to the high aromatic stabilization energy. We herein report a dearomative sequential addition of two nucleophiles to arene π-bonds through umpolung of chromium-arene complexes. This mode enables divergent dearomative carbonylation reactions of benzene derivatives by tolerating various nucleophiles in combination with alcohols or amines under CO-gas-free conditions, thus providing modular access to functionalized esters or amides. The tunable synthesis of 1,3- or 1,4-cyclohexadienes as well as the construction of carbon quaternary centers further highlight the versatility of this dearomatization. Diverse late-stage modifications and derivatizations towards synthetically challenging and bioactive molecules reveal the synthetic utility. A possible mechanism was proposed based on control experiments and intermediate tracking.

17.
Angew Chem Int Ed Engl ; 63(10): e202318803, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38205884

RESUMO

Transition metal-catalyzed enantioselective C-H carbonylation with carbon monoxide, an essential and easily available C1 feedstock, remains challenging. Here, we disclosed an unprecedented enantioselective C-H carbonylation catalyzed by inexpensive and readily available cobalt(II) salt. The reactions proceed efficiently through desymmetrization, kinetic resolution, and parallel kinetic resolution, affording a broad range of chiral isoindolinones in good yields with excellent enantioselectivities (up to 92 % yield and 99 % ee). The synthetic potential of this method was demonstrated by asymmetric synthesis of biological active compounds, such as (S)-PD172938 and (S)-Pazinaclone. The resulting chiral isoindolinones also serve as chiral ligands in cobalt-catalyzed enantioselective C-H annulation with alkynes to construct phosphorus stereocenter.

18.
Angew Chem Int Ed Engl ; 63(8): e202318257, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38116921

RESUMO

Multicomponent reactions, particularly those entailing four or more reagents, have presented a longstanding challenge due to the inherent complexities associated with balancing reactivity, selectivity, and compatibility. In this study, we describe a palladium-catalyzed multi-component fluoroalkylative carbonylation of 1,3-enynes. A series of products featuring three active functional groups-allene, fluoroalkyl, and carboxyl, were efficiently and selectively integrated in a single chemical operation. Furthermore, more intricate fluoroalkyl-substituted pyrimidinones can be constructed by simply altering the 1,3-bisnucleophilic reagent. This approach also provides a valuable strategy for the late-stage modification of naturally occurring molecules and concise construction of diverse cyclic compounds.

19.
Angew Chem Int Ed Engl ; 63(23): e202403674, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38647344

RESUMO

The construction of carbonyl compounds via carbonylation reactions using safe CO sources remains a long-standing challenge to synthetic chemists. Herein, we propose a catalyst cascade Scheme in which CO2 is used as a CO surrogate in the carbonylation of benzyl chlorides. Our approach is based on the cooperation between two coexisting catalytic cycles: the CO2-to-CO electroreduction cycle promoted by [Fe(TPP)Cl] (TPP=meso-tetraphenylporphyrin) and an electrochemical carbonylation cycle catalyzed by [Ni(bpy)Br2] (2,2'-bipyridine). As a proof of concept, this protocol allows for the synthesis of symmetric ketones from good to excellent yields in an undivided cell with non-sacrificial electrodes. The reaction can be directly scaled up to gram-scale and operates effectively at a CO2 concentration of 10 %, demonstrating its robustness. Our mechanistic studies based on cyclic voltammetry, IR spectroelectrochemistry and Density Functional Theory calculations suggest a synergistic effect between the two catalysts. The CO produced from CO2 reduction is key in the formation of the [Ni(bpy)(CO)2], which is proposed as the catalytic intermediate responsible for the C-C bond formation in the carbonylation steps.

20.
Angew Chem Int Ed Engl ; : e202410967, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39007709

RESUMO

A Pd-catalyzed asymmetric isomerization-hydroamidocarbonylation of amide-containing alkenes was developed, affording a variety of chiral a-alkyl succinimides in moderate to good yields with high enantioselectivities. The key to success was introducing bulky 1-adamentyl P-substitution and 2,3,5,6-tetramethoxyphenyl group into the rigid P-chirogenic bisphosphine ligand to create stronger steric hinderance and deeper catalytic pocket. By this approach, regio- or stereo-convergent synthesis of enantiomeric succinimides from the mixture of olefin isomers was achieved.

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