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1.
Crit Rev Food Sci Nutr ; : 1-18, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38384235

RESUMO

The cultured meat technology has developed rapidly in recent years, but there are still many technical challenges that hinder the large-scale production and commercialization of cultured meat. Firstly, it is necessary to lay the foundation for cultured meat production by obtaining seed cells and maintaining stable cell functions. Next, technologies such as bioreactors are used to expand the scale of cell culture, and three-dimensional culture technologies such as scaffold culture or 3D printing are used to construct the three-dimensional structure of cultured meat. At the same time, it can reduce production costs by developing serum-free medium suitable for cultured meat. Finally, the edible quality of cultured meat is improved by evaluating food safety and sensory flavor, and combining ethical and consumer acceptability issues. Therefore, this review fully demonstrates the current development status and existing technical challenges of the cultured meat production technology with regard to the key points described above, in order to provide research ideas for the industrial production of cultured meat.

2.
Front Oncol ; 13: 1241357, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37916161

RESUMO

Gastrointestinal cancer is a common malignancy with high mortality and poor prognosis. Therefore, developing novel effective markers and therapeutic targets for gastrointestinal cancer is currently a challenging and popular topic in oncology research. Accumulating studies have reported that N6-methyladenosine is the most abundant epigenetic modification in eukaryotes. N6-methyladenosine plays an essential role in regulating RNA expression and metabolism, including splicing, translation, stability, decay, and transport. FTO, the earliest demethylase discovered to maintain the balance of N6-adenosine methylation, is abnormally expressed in many tumors. In this review, we discuss the molecular structure and substrate selectivity of FTO. we focus on the role of FTO in gastrointestinal tumor proliferation, migration, invasion, apoptosis, autophagy, immune microenvironment, and its molecular mechanisms. We also discuss its potential in the treatment of gastrointestinal cancers.

3.
Front Oncol ; 13: 1223857, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37655111

RESUMO

Objectives: The advanced gastric adenocarcinoma (GAC) patients (stage III/IV) with surgery may have inconsistent prognoses due to different demographic and clinicopathological factors. In this retrospective study, we developed clinical prediction models for estimating the overall survival (OS) and cancer-specific survival (CSS) in advanced GAC patients with surgery. Methods: A retrospective analysis was conducted using the Surveillance, Epidemiology, and End Results (SEER) database. The total population from 2004 to 2015 was divided into four levels according to age, of which 179 were younger than 45 years old, 695 were 45-59 years old, 1064 were 60-74 years old, and 708 were older than 75 years old. There were 1,712 men and 934 women. Univariate and multivariate Cox regression analyses were performed to identify prognostic factors for OS and CSS. Nomograms were constructed to predict the 1-, 3-, and 5-year OS and CSS. The models' calibration and discrimination efficiency were validated. Discrimination and accuracy were evaluated using the consistency index, area under the receiver operating characteristic curve, and calibration plots; and clinical usefulness was assessed using decision curve analysis. Cross-validation was also conducted to evaluate the accuracy and stability of the models. Prognostic factors identified by Cox regression were analyzed using Kaplan-Meier survival analysis. Results: A total of 2,646 patients were included in our OS study. Age, primary site, differentiation grade, AJCC 6th_TNM stage, chemotherapy, radiotherapy, and number of regional nodes examined were identified as prognostic factors for OS in advanced GAC patients with surgery (P < 0.05). A total of 2,369 patients were included in our CSS study. Age, primary site, differentiation grade, AJCC 6th_TNM stage, chemotherapy, radiotherapy, and number of regional nodes examined were identified as risk factors for CSS in these patients (P < 0.05). These factors were used to construct the nomogram to predict the 1-, 3-, and 5-year OS and CSS of advanced GAC patients with surgery. The consistency index and area under the receiver operating characteristic curve demonstrated that the models effectively differentiated between events and nonevents. The calibration plots for 1-, 3-, and 5-year OS and CSS probability showed good consistence between the predicted and the actual events. The decision curve analysis indicated that the nomogram had higher clinical predictive value and more significant net gain than AJCC 6th_TNM stage in predicting OS and CSS of advanced GAC patients with surgery. Cross-validation also revealed good accuracy and stability of the models. Conclusion: The developed predictive models provided available prognostic estimates for advanced GAC patients with surgery. Our findings suggested that both OS and CSS can benefit from chemotherapy or radiotherapy in these patients.

4.
Foods ; 12(14)2023 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-37509774

RESUMO

Cultured meat is one of the meat substitutes produced through tissue engineering and other technologies. Large-scale cell culture is the key for cultured meat products to enter the market. Therefore, this study is aimed to explore the effect of long-term passage in vitro on smooth muscle cells (SMCs) and the effect of transforming growth factor-ß1 (TGF-ß1) on SMCs in the late passage. Multiple passages lead to the decline of the proliferation rate of SMCs in the proliferation stage and the differentiation ability in the differentiation stage. Transcriptome results showed that the ECM pathway and aging-related signaling pathways were significantly up-regulated in the late passage period. TGF-ß1 did not promote SMCs of late passage proliferation at the proliferation stage but promoted the gene and protein expression of collagen as the main protein of the extracellular matrix proteins at the differentiation stage. In addition, proteomic analysis revealed that TGF-ß1 promoted the expression of cell adhesion molecules which activate the Hippo signaling pathway and the HIF-1 signaling pathway and further promoted the production of collagen-containing extracellular matrix proteins. This could provide ideas for large-scale production of cultured meat products using SMCs.

5.
Nanoscale Adv ; 5(7): 2118, 2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36998668

RESUMO

[This corrects the article DOI: 10.1039/D3NA00025G.].

6.
Nanoscale Adv ; 5(6): 1559-1573, 2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36926563

RESUMO

The development of new technologies has led to an explosion of data, while the computation ability of traditional computers is approaching its upper limit. The dominant system architecture is the von Neumann architecture, with the processing and storage units working independently. The data migrate between them via buses, reducing computing speed and increasing energy loss. Research is underway to increase computing power, such as developing new chips and adopting new system architectures. Computing-in-memory (CIM) technology allows data to be computed directly on the memory, changing the current computation-centric architecture and designing a new storage-centric architecture. Resistive random access memory (RRAM) is one of the advanced memories which has appeared in recent years. RRAM can change its resistance with electrical signals at both ends, and the state will be preserved after power-down. It has potential in logic computing, neural networks, brain-like computing, and fused technology of sense-storage-computing. These advanced technologies promise to break the performance bottleneck of traditional architectures and dramatically increase computing power. This paper introduces the basic concepts of computing-in-memory technology and the principle and applications of RRAM and finally gives a conclusion about these new technologies.

7.
Dalton Trans ; 51(38): 14639-14645, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36093644

RESUMO

Semi-hydrogenation usually requires an effective catalyst to ensure selectivity, especially when reducible groups coexist in a molecule. Pd is widely used in the semi-hydrogenation of alkynes to synthesize alkenes, but the selectivity control is still challenging. Herein, we design a catalyst with a semi-encapsulated PdRh alloy heterojunction in a carbon layer for the selective semi-hydrogenation of 3-nitrophenylacetylene (3-NPA). Benefiting from the presence of a PdRh alloy heterojunction and a semi-encapsulated structure, the catalyst delivers good selectivity and maintains high activity. In addition, the carbon shell can ensure the stability of the catalyst and prolong the service life. This study provides ideas for the rational design of a catalyst to achieve a selective hydrogenation reaction for practical applications.

8.
Front Oncol ; 12: 918778, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35814382

RESUMO

Aldehyde dehydrogenases 1 family member A1(ALDH1A1) gene codes a cytoplasmic enzyme and shows vital physiological and pathophysiological functions in many areas. ALDH1A1 plays important roles in various diseases, especially in cancers. We reviewed and summarized representative correlative studies and found that ALDH1A1 could induce cancers via the maintenance of cancer stem cell properties, modification of metabolism, promotion of DNA repair. ALDH1A1 expression is regulated by several epigenetic processes. ALDH1A1 also acted as a tumor suppressor in certain cancers. The detoxification of ALDH1A1 often causes chemotherapy failure. Currently, ALDH1A1-targeted therapy is widely used in cancer treatment, but the mechanism by which ALDH1A1 regulates cancer development is not fully understood. This review will provide insight into the status of ALDH1A1 research and new viewpoint for cancer therapy.

9.
Clin. transl. oncol. (Print) ; 24(6): 1100-1114, junio 2022.
Artigo em Inglês | IBECS | ID: ibc-203809

RESUMO

PurposeEsophageal squamous cell carcinoma (ESCC) is a malignant tumor with high heterogeneity. Research on molecular mechanisms involved in the process of tumor origination and progression is extremely limited to investigating mechanisms of molecular typing for ESCC.MethodsAfter comprehensively analyzing the gene expression profiles in The Cancer Genome Atlas and Gene Expression Omnibus databases, we identified four immunotypes of ESCC (referred to as C1–C4) based on the gene sets of 28 immune cell subpopulations. The discrepancies in prognostic value, clinical features, drug sensitivity, and tumor components between the immunotypes were individually analyzed.ResultsThe ranking of immune infiltration is C1 > C4 > C3 > C2. These subtypes are characterized by high and low expression of immune checkpoint proteins, enrichment and insufficiency of immune-related pathways, and differential distribution of immune cell subgroups. Poorer survival was observed in the C1 subtype, which we hypothesized could be caused by an immunosuppressive cell population. Fortunately, C1’s susceptibility to anti-PD-1 therapy offers hope for patients with poor prognosis in advanced stages. On the other hand, C4 is sensitive to docetaxel, which may offer novel treatment strategies for ESCC in the future. It is worth noting that immunophenotyping is tightly bound to the abundance of stromal components and stem cells, which could explain the tumor immune escape to some extent. Ultimately, determination of hub genes based on the C1 subtypes provides a reference for the discovery of immunotarget drugs against ESCC.ConclusionThe identification of immunophenotypes in our study provides new therapeutic strategies for patients with ESCC.


Assuntos
Humanos , Biomarcadores Tumorais/genética , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/patologia , Regulação Neoplásica da Expressão Gênica , Microambiente Tumoral , Prognóstico
10.
Artigo em Inglês | MEDLINE | ID: mdl-35457441

RESUMO

Previous research suggests that heavy metals may be associated with increased susceptibility to Helicobacter pylori infection. This study investigated the effect of heavy metal exposure (Pb and Cd) on tooth loss and H. pylori infection in a Chinese rural population, who live near a mining and smelting area. Blood samples were collected from the study participants to estimate the lead (Pb) and cadmium (Cd) exposure levels. H. pylori infection was analyzed using the 14C-urea breath test, and the number of missing teeth (MT), filled teeth (FT), and missing or filled teeth (MFT) were counted by conducting a physical examination. Regression analysis was used to assess the difference between H. pylori-positive and -negative individuals in the MT, FT, and MFT groups, adjusting for confounders. The H. pylori infection prevalence was higher in individuals in the high Cd or high Pb groups than that in the low Cd or low Pb groups (p < 0.05). In addition, greater numbers of FT and MFT were observed in individuals in the high Pb group than those in the low Pb group (p < 0.05). We further found 8.7% (95% CI, 2.8−23.8%, p = 0.017) of the effect of the high BPb level on H. pylori infection risk could be statistically explained by FT using amediation analyses in adjusted models, and 6.8% (95% CI, 1.6−24.8%, p = 0.066) by MFT. Furthermore, FT and MFT were significantly associated with increased risk for H. pylori infection (odds ratio (OR) = 4.938, 95% confidence interval (CI): 1.125−21.671; OR = 3.602, 95% CI: 1.218−10.648, respectively). Pb and Cd exposure may be associated with tooth loss and increased susceptibility to H. pylori infection, and tooth loss may be an independent risk factor for H. pylori infection.


Assuntos
Distinções e Prêmios , Infecções por Helicobacter , Helicobacter pylori , Perda de Dente , Testes Respiratórios , Cádmio , China/epidemiologia , Infecções por Helicobacter/complicações , Humanos , Chumbo , População Rural , Perda de Dente/complicações , Perda de Dente/epidemiologia
11.
Small ; 18(18): e2200439, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35355393

RESUMO

The intercrystalline interfaces have been proven vital in heterostructure catalysts. However, it is still challenging to generate specified heterointerfaces and to make clear the mechanism of a reaction on the interface. Herein, this work proposes a strategy of Fe-catalyzed cascade formation of heterointerfaces for comprehending the hydrogen evolution reaction (HER). In the pure solid-phase reaction system, Fe catalyzes the in situ conversion of MoO2 to MoC and then Mo2 C, and the consecutive formation leaves lavish intercrystalline interfaces of MoO2 -MoC (in Fe-MoO2 /MoC@NC) or MoC-Mo2 C (in Fe-MoC/ß-Mo2 C@NC), which contribute to HER activity. The improved HER activity on the interface leads to further checking of the mechanism with density functional theory calculation. The computation results reveal that the electroreduction (Volmer step) produced H* prefers to be adsorbed on Mo2 C; then two pathways are proposed for the HER on the interface of MoC-Mo2 C, including the single-molecular adsorption pathway (Rideal mechanism) and the bimolecular adsorption pathway (Langmuir-Hinshelwood mechanism). The calculation results further show that the former is favorable, and the reaction on the MoC-Mo2 C heterointerface significantly lowers the energy barriers of the rate-determining steps.


Assuntos
Hidrogênio , Ferro , Catálise , Hidrogênio/química , Molibdênio/química
12.
ACS Appl Mater Interfaces ; 14(6): 7949-7961, 2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-35130694

RESUMO

Cascade reactions take advantage of step-saving and facile operation for obtaining chemicals. Herein, catalytic hydrogenation of nitroarene coupled condensation with ß-diketone to afford ß-ketoenamines is achieved by an integrated nanocatalyst, Pd-e@UiO-66. The catalyst has the structure of an acid-rich metal-organic framework (MOF), UiO-66-encapsulated electron-rich Pd nanoparticles, and it reconciles the electron-effect contradiction of cascade catalytic reactions: catalytic hydrogenation requires an electron-rich catalyst, while condensation requires electron-deficient Lewis acid sites. The catalyst showed good activity, high chemoselectivity, and universal applicability for the synthesis of ß-ketoenamines using nitroarenes. More than 30 ß-ketoenamines have been successfully prepared with up to 99% yield via the methodology of relay catalysis. The catalyst exhibited excellent stability to maintain its catalytic performance for more than five cycles. Furthermore, we conducted an in-depth exploration of the reaction mechanism with theoretical calculations.

13.
Clin Transl Oncol ; 24(6): 1100-1114, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35098447

RESUMO

PURPOSE: Esophageal squamous cell carcinoma (ESCC) is a malignant tumor with high heterogeneity. Research on molecular mechanisms involved in the process of tumor origination and progression is extremely limited to investigating mechanisms of molecular typing for ESCC. METHODS: After comprehensively analyzing the gene expression profiles in The Cancer Genome Atlas and Gene Expression Omnibus databases, we identified four immunotypes of ESCC (referred to as C1-C4) based on the gene sets of 28 immune cell subpopulations. The discrepancies in prognostic value, clinical features, drug sensitivity, and tumor components between the immunotypes were individually analyzed. RESULTS: The ranking of immune infiltration is C1 > C4 > C3 > C2. These subtypes are characterized by high and low expression of immune checkpoint proteins, enrichment and insufficiency of immune-related pathways, and differential distribution of immune cell subgroups. Poorer survival was observed in the C1 subtype, which we hypothesized could be caused by an immunosuppressive cell population. Fortunately, C1's susceptibility to anti-PD-1 therapy offers hope for patients with poor prognosis in advanced stages. On the other hand, C4 is sensitive to docetaxel, which may offer novel treatment strategies for ESCC in the future. It is worth noting that immunophenotyping is tightly bound to the abundance of stromal components and stem cells, which could explain the tumor immune escape to some extent. Ultimately, determination of hub genes based on the C1 subtypes provides a reference for the discovery of immunotarget drugs against ESCC. CONCLUSION: The identification of immunophenotypes in our study provides new therapeutic strategies for patients with ESCC.


Assuntos
Neoplasias Esofágicas , Carcinoma de Células Escamosas do Esôfago , Biomarcadores Tumorais/genética , Neoplasias Esofágicas/patologia , Carcinoma de Células Escamosas do Esôfago/genética , Carcinoma de Células Escamosas do Esôfago/patologia , Regulação Neoplásica da Expressão Gênica , Humanos , Imunofenotipagem , Prognóstico , Microambiente Tumoral
14.
Int J Mol Med ; 49(3)2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35014673

RESUMO

Following the publication of the above article, an interested reader drew to the author's attention that Fig. 4 contained a duplication error, which arose during the assembly of the figure; specifically, the upper-left panel in Fig. 4, showing the result of the 'Control in 12 h' experiment, was inadvertently repeated with the 'Control in 48 h' panel. The corrected version of Fig. 4, showing the correct data for the 'Control in 12 h' experiment, is shown below. The authors can confirm that this error does not change either the interpretation or the original conclusions of this study. The authors are grateful to the Editor of International Journal of Molecular Medicine for granting them the opportunity to publish the Corrigendum, and all the authors agree with this correction. Furthermore, the authors apologize to the readership for any inconvenience caused. [the original article was published in International Journal of Molecular Medicine 32: 93­100, 2013; DOI: 10.3892/ijmm.2013.1376].

15.
Cancer Epidemiol Biomarkers Prev ; 31(3): 625-632, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35027436

RESUMO

BACKGROUND: A lack of research on the association of trefoil factors (TFF) with gastric cancer and premalignant lesions (PML) in the general population is an important obstacle to the application of TFFs for gastric cancer screening. We aimed to analyze the association of TFFs with gastric cancer and PMLs in a general population. METHODS: We evaluated 3,986 adults residing in Wuwei, China. We collected baseline characteristics and gastric cancer risk factors, including TFFs, endoscopic diagnosis, and pathologic information. Three logistic regression models were generated to analyze the association between TFFs and gastric cancer, as well as PMLs. Adjusted odds ratio (OR) and 95% confidence intervals (95% CI) were calculated to determine the strength of association. RESULTS: Compared with pepsinogen (PG) and anti-Helicobacter pylori immunoglobulin G antibody (Hp-IgG), TFFs had significant association with gastric cancer and PMLs after adjusting for biomarkers and risk factors (P < 0.05). The ORs (95% CI) for TFF1 (1.67; 1.27-2.20), TFF2 (2.66; 2.01-3.51), and TFF3 (1.32; 1.00-1.74) were larger than the ORs for PGI (0.79; 0.61-1.03), PGI/II (1.00; 0.76-1.31), and Hp-IgG (0.99; 0.73-1.35) in the gastric cancer group. In the intestinal metaplasia (IM) group, not only the TFF3 serum level was the highest, but also the OR (1.92; 1.64-2.25) was the highest. CONCLUSIONS: TFFs were associated with risk of gastric cancer and PMLs. IMPACT: Serum TFFs can improve the screening of high-risk populations for gastric cancer.


Assuntos
Helicobacter pylori , Neoplasias Gástricas , Fatores Trefoil , Adulto , Estudos de Coortes , Estudos Transversais , Humanos , Imunoglobulina G , Pepsinogênio A , Peptídeos , Fator Trefoil-2 , Fator Trefoil-3
16.
J Org Chem ; 87(6): 3885-3894, 2022 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-34028276

RESUMO

Herein, we report an efficient method for the chemical generation of 1O2 by treatment of H2O2 with AIBX, a highly water-soluble, bench-stable, recyclable hypervalent iodine(V) reagent developed by our group. The generation of 1O2 was confirmed by the following results: (1) capture of 1O2 with the sodium salt of anthracene-9,10-bis(ethanesulfonate) produced the corresponding endoperoxide and (2) TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy) produced by the oxidation of 2,2,6,6-tetramethylpiperidine with 1O2 generated using the AIBX/H2O2 system was detected by electron spin resonance spectroscopy. To illustrate the potential utility of this method for organic synthesis, we used the AIBX/H2O2 system to perform typical reactions of 1O2: [2 + 2]/[4 + 2] cycloadditions, Schenck ene reactions, and heteroatom oxidation reactions, which afforded the corresponding products in high yields. Moreover, we used the method to synthesize the antimalarial drug artemisinin. Finally, we demonstrated that AIBX could be regenerated after the reaction by means of a workup involving extraction and removal of water to obtain a precursor of AIBX, which could then be re-oxidized.


Assuntos
Iodo , Oxigênio Singlete , Artemisininas , Peróxido de Hidrogênio , Indicadores e Reagentes , Iodetos , Iodo/química , Oxirredução , Oxigênio/química , Oxigênio Singlete/química , Água
17.
Front Microbiol ; 13: 1024155, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36713177

RESUMO

Several risk factors have been identified for the development of gastric adenocarcinoma (GAC), where the control group was usually a healthy population. However, it is unclear at what stage known risk factor exert their influence toward the progression to cancer. Based on the Wuwei Cohort, we enrolled 1,739 patients with chronic non-atrophic gastritis (no-CAG), 3,409 patients with chronic atrophic gastritis (CAG), 1,757 patients with intestinal metaplasia (IM), 2,239 patients with low-grade dysplasia (LGD), and 182 patients with high-grade dysplasia (HGD) or GAC to assess the risk factors between each two consecutive stages from no-CAG to GAC/HGD using adjusted logistic regression. We found that different groups of risk factors were associated with different stages. Age, occupation of farmer, low annual family income, Helicobacter pylori (H. pylori) infection, drinking, eating hot food, histories of gastritis and peptic ulcer were associated with the development of CAG. Age, illiteracy, H. pylori infection, smoking, eating hot food, eating quickly, and histories of gastritis and gallbladder diseases were associated with the progression to IM from CAG. Male, occupation of farmer and history of peptic ulcer were associated with the development of LGD from IM. Age, male and polyp history appeared to be risk factors associated with the development of GAC/HGD from LGD. In conclusion, it seems that most risk factors function more as a set of switches that initiated the GAC carcinogenesis. H. Pylori eradication and control of other risk factors should be conducted before IM to decrease the incidence of GAC.

18.
Nat Commun ; 12(1): 6194, 2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34702832

RESUMO

The product selectivity in catalytic hydrogenation of nitriles is strongly correlated with the structure of the catalyst. In this work, two types of atomically dispersed Pd species stabilized on the defect-rich nanodiamond-graphene (ND@G) hybrid support: single Pd atoms (Pd1/ND@G) and fully exposed Pd clusters with average three Pd atoms (Pdn/ND@G), were fabricated. The two catalysts show distinct difference in the catalytic transfer hydrogenation of nitriles. The Pd1/ND@G catalyst preferentially generates secondary amines (Turnover frequency (TOF@333 K 709 h-1, selectivity >98%), while the Pdn/ND@G catalyst exhibits high selectivity towards primary amines (TOF@313 K 543 h-1, selectivity >98%) under mild reaction conditions. Detailed characterizations and density functional theory (DFT) calculations show that the structure of atomically dispersed Pd catalysts governs the dissociative adsorption pattern of H2 and also the hydrogenation pathway of the benzylideneimine (BI) intermediate, resulting in different product selectivity over Pd1/ND@G and Pdn/ND@G, respectively. The structure-performance relationship established over atomically dispersed Pd catalysts provides valuable insights for designing catalysts with tunable selectivity.

19.
Angew Chem Int Ed Engl ; 60(45): 24171-24178, 2021 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-34523779

RESUMO

Herein, we report a new strategy for carbon-carbon bond scission and intramolecular ring expansion fluorination of unactivated cyclopropanes, which was accomplished with a new hypervalent fluoroiodane(III) reagent 1. This novel method delivers medicinally relevant 4-fully substituted fluoropiperidines in moderate to high yields with excellent regio- and diastereoselectivity. Reagent 1, which has an N-acetylbenziodazole framework, was readily synthesized via three steps in 76 % overall yield and was characterized by NMR spectroscopy and X-ray crystallography. Owing to the presence of a secondary I⋅⋅⋅O bonding interaction between the λ3 -iodane atom and the carbonyl oxygen of the acetyl group of the N-acetylbenziodazole framework, 1 has excellent stability and can be stored at ambient temperature for 6 months without any detectable decomposition. Density functional theory calculations and experimental studies showed that the reaction proceeds via a carbocation intermediate that readily combines with a fluoride ion to generate the product.

20.
Chemistry ; 27(3): 1080-1087, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33146415

RESUMO

A novel armor-type composite of metal-organic framework (MOF)-encapsulated CoCu nanoparticles with a Fe3 O4 core (Fe3 O4 @SiO2 -NH2 -CoCu@UiO-66) has been designed and synthesized by the half-way injection method, which successfully serves as an efficient and recyclable catalyst for the selective transfer hydrogenation. In this half-way injection approach, the pre-synthetic Fe3 O4 @SiO2 -NH2 -CoCu was injected into the UiO-66 precursor solution halfway through the MOF budding period. The formed MOF armor could play a role of providing significant additional catalytic sites besides CoCu nanoparticles, protecting CoCu nanoparticles, and improving the catalyst stability, thus facilitating the selective transfer hydrogenation of nitrobenzaldehydes into corresponding nitrobenzyl alcohols in high selectivity (99 %) and conversion (99 %) rather than nitro group reduction products. Notably, this method achieves the precise assembly of a MOF-encapsulated composite, and the ingenious combination of MOF and nanoparticles exhibits excellent catalytic performance in the selective hydrogen transfer reaction, implementing a "1+1>2" strategy in catalysis.

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