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1.
J Mech Behav Biomed Mater ; 137: 105539, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36343522

RESUMO

PURPOSE: The effect of hydroxyapatite (HAp) coating layer on mechanical and optical properties at bonding interface of high-performance polymers (HPPs) used in computer-aided design (CAD)/computer-aided manufacture (CAM) technology was investigated in this in vitro study. MATERIALS AND METHODS: Two hundred-twenty specimens were divided into two material groups (n = 110): polyetheretherketone (PEEK, KERA® starPEEK) and polyetherketoneketone (PEKK, Pekkton® ivory). For mechanical testing, each group was divided into five surface pretreatment subgroups and a control group (n = 10): HAp coating (1%,3%, 5%, and 10% concentrations) and sandblasting with 110-µm Al2O3 particles. For optical testing, each group was divided into five subgroups (n = 10): HAp coating (1%, 3%, 5%, and 10% concentrations) and control. The effects of the HAp coating on the optical changes and shear bond strength (SBS) of the specimens were investigated. Data was statistically analyzed by one-way ANOVA and Tukey's post-hoc test. Failure modes and surface properties of the specimens were examined by scanning electron microscopy (SEM) and coupled electron dispersive spectroscopy (EDS). RESULTS: Average translucency and color change values increased with increasing HAp coating concentration in HPPs. As a result of the data, statistically significant differences were observed in terms of the effect of the HAp coating on SBS of HPPs (p < 0.05). Failure modes were examined, and mixed failure mode was observed. CONCLUSION: HAp coating can contribute to the improvement of both the optical properties and bond strength of the HPPs to resin composite. CLINICAL SIGNIFICANCE: Adhesion and color problems of high performance polymers are still under discussion. In order to solve these problems, generally focused on surface modifications of these polymers, but the effect of the HAp coating has not been investigated.


Assuntos
Colagem Dentária , Durapatita , Cimentos de Resina/química , Teste de Materiais , Resistência ao Cisalhamento , Polímeros , Propriedades de Superfície , Resinas Compostas/química , Cetonas , Polietilenoglicóis , Microscopia Eletrônica de Varredura
2.
Food Chem ; 404(Pt A): 134554, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36252373

RESUMO

Heating of either 3,5-heptadien-2-one or 2,6-heptanedione in the presence of ammonia produced 2,6-dimethylpyridine, and also 3-methylcyclohex-2-en-1-one for the second ketone. When phenolics were present, inhibition of pyridine formation was only observed in mixtures of 3,5-heptadien-2-one and resorcinol. This inhibition was due to the formation of ketone-resorcinol adducts, which were isolated and identified by nuclear magnetic resonance (NMR) and mass spectrometry (MS) as 2,4-dimethyl-5,6-dihydro-4H-2,6-methanobenzo[d][1,3]dioxocin-9-ol and 1-(7-hydroxy-4-methylchroman-2-yl)propan-2-one. The other assayed phenolics increased pyridine formation. This increase was mainly observed in the presence of oxygen, at slightly basic pH values, depended on time, temperature, and the phenolic concentration, and had an activation energy of 56.8 kJ/mol for the formation of 2,6-dimethylpyridine from 2,6-heptanedione in the presence of orcinol. This increase was a consequence of the promotion by phenolics of a required aromatization step in the pyridine formation pathway. This phenolic function needs to be considered when phenolics are added to food products.


Assuntos
Cetonas , Fenol , Fenóis/química , Resorcinóis , Piridinas/química
3.
J Environ Sci (China) ; 124: 860-874, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36182189

RESUMO

Particulate matter (PM2.5) samples were collected in the vicinity of an industrial chemical pole and analysed for organic and elemental carbon (OC and EC), 47 trace elements and around 150 organic constituents. On average, OC and EC accounted for 25.2% and 11.4% of the PM2.5 mass, respectively. Organic compounds comprised polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, anhydrosugars, phenolics, aromatic ketones, glycerol derivatives, aliphatic alcohols, sterols, and carboxyl groups, including aromatic, carboxylic and dicarboxylic acids. Enrichment factors > 100 were obtained for Pb, Cd, Zn, Cu, Sn, B, Se, Bi, Sb and Mo, showing the contribution of industrial emissions and nearby major roads. Principal component analysis revealed that vehicle, industrial and biomass burning emissions accounted for 66%, 11% and 9%, respectively, of the total PM2.5-bound PAHs. Some of the detected organic constituents are likely associated with plasticiser ingredients and thermal stabilisers used in the manufacture of PVC and other plastics in the industrial complex. Photooxidation products of both anthropogenic (e.g., toluene) and biogenic (e.g., isoprene and pinenes) precursors were also observed. It was estimated that biomass burning accounted for 13.8% of the PM2.5 concentrations and that secondary OC represented 37.6% of the total OC. The lifetime cancer risk from inhalation exposure to PM2.5-bound PAHs was found to be negligible, but it exceeded the threshold of 10-6 for metal(loi)s, mainly due to Cr and As.


Assuntos
Poluentes Atmosféricos , Hidrocarbonetos Policíclicos Aromáticos , Oligoelementos , Poluentes Atmosféricos/análise , Álcoois , Cádmio/análise , Carbono/análise , Ácidos Dicarboxílicos/análise , Monitoramento Ambiental , Cetonas , Chumbo/análise , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Cloreto de Polivinila/análise , Estações do Ano , Esteróis/análise , Tolueno/análise , Oligoelementos/análise , Emissões de Veículos/análise
4.
Food Chem ; 401: 134126, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36088714

RESUMO

To clarify the role of Acetobacter sp. in fermented noni juice, the physiochemical properties, main active ingredients and volatile constituents were comprehensively analyzed. The sugar content and acidity tended to be stable after 12 days of fermentation. Acetobacter sp. had no significant influence on major active ingredients of products. The headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) were performed to describe the characteristic flavor profiles during fermentation. A total of 55 flavor compounds were screened with odour threshold and Kruskal-Wallis p < 0.05. Among them, 14 different biomarkers were selected with Variable Importance in Projection (VIP) greater than 1. The concentrations of ketones and aldehydes increased significantly, mainly contributing to the floral, fruit and green features. The content of hexanoic acid, octanoic acid and butanoic acid as the main source of peculiar odor were significantly reduced, indicating Acetobacter sp. could improve the unpleasant odor of fermented noni juice.


Assuntos
Acetobacter , Morinda , Odorantes , Ácido Butírico , Cromatografia Gasosa-Espectrometria de Massas , Frutas/química , Açúcares/análise , Aldeídos/análise , Cetonas/análise
5.
Food Chem ; 401: 134122, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36096003

RESUMO

To prepare pumpkin juice (PJ) rich in coenzyme Q10, this study analyzed the chemical composition, antioxidant activity, and gut microbiota of pumpkin juice fermented by Rhodobacter sphaeroides (RPJ). The number of viable bacteria in the juice reached 2.8 × 108 CFU/mL; the fermentation process mainly consumed glucose and sucrose; the total sugar content was reduced, ß-carotene was reduced, and a new antioxidant substance, coenzyme Q10, appeared at a content of 12.345 mg/L; levels of volatile alcohols, esters, and ketones significantly increased; and antioxidation ability improved, particularly the ferric ion reducing antioxidant power activity. The gut microbiota of mice shifted by increasing Lactobacillus and Bifidobacterium and protected the gut barrier by reducing Proteobacteria after 48 h of fermentation. Pumpkin juice fermented by Rhodobacter sphaeroides not only produces bioactive substances with antioxidant capacity but can also regulate the gut microbiota of mice.


Assuntos
Cucurbita , Microbioma Gastrointestinal , Rhodobacter sphaeroides , Camundongos , Animais , Antioxidantes/química , Sucos de Frutas e Vegetais , beta Caroteno , Açúcares , Glucose , Sacarose , Cetonas
6.
J Phys Chem Lett ; 13(47): 11023-11028, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36413431

RESUMO

Fatty acid photodecarboxylase is a newly identified blue-light driven photoenzyme that catalyzes decarboxylation of fatty acids. The catalytic reaction involves a transient anionic semiquinone of flavin cofactor (FAD•-) as an intermediate, but photochemical properties of this anionic radical are largely unknown. Here, we have anaerobically produced the wild-type FAP in the FAD•- state and conducted femtosecond-resolved fluorescence and absorption measurements. We have observed the multiphasic deactivation dynamics of excited states on multiple time scales from a few picoseconds even to a few nanoseconds through conical intersections between various electronic states. Interestingly, the nanosecond components can only be observed from higher electronic excited states. Our results show the complexity of the energy landscapes of various excited states and rule out the occurrence of electron or proton transfer with nearby residue(s) in the active site.


Assuntos
Ácidos Graxos , Flavina-Adenina Dinucleotídeo , Ânions , Cetonas , Catálise
7.
Cells ; 11(22)2022 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-36429071

RESUMO

Accumulating evidence indicates that the APOA1 binding protein (AIBP)-a secreted protein-plays a profound role in lipid metabolism. Interestingly, AIBP also functions as an NAD(P)H-hydrate epimerase to catalyze the interconversion of NAD(P)H hydrate [NAD(P)HX] epimers and is renamed as NAXE. Thus, we call it NAXE hereafter. We investigated its role in NAD(P)H-involved metabolism in murine cardiomyocytes, focusing on the metabolism of hexose, lipids, and amino acids as well as mitochondrial redox function. Unbiased metabolite profiling of cardiac tissue shows that NAXE knockout markedly upregulates the ketone body 3-hydroxybutyric acid (3-HB) and increases or trends increasing lipid-associated metabolites cholesterol, α-linolenic acid and deoxycholic acid. Paralleling greater ketone levels, ChemRICH analysis of the NAXE-regulated metabolites shows reduced abundance of hexose despite similar glucose levels in control and NAXE-deficient blood. NAXE knockout reduces cardiac lactic acid but has no effect on the content of other NAD(P)H-regulated metabolites, including those associated with glucose metabolism, the pentose phosphate pathway, or Krebs cycle flux. Although NAXE is present in mitochondria, it has no apparent effect on mitochondrial oxidative phosphorylation. Instead, we detected more metabolites that can potentially improve cardiac function (3-HB, adenosine, and α-linolenic acid) in the Naxe-/- heart; these mice also perform better in aerobic exercise. Our data reveal a new role of NAXE in cardiac ketone and lipid metabolism.


Assuntos
Cetonas , NAD , Animais , Camundongos , Ácido alfa-Linolênico , NAD/metabolismo , Racemases e Epimerases , Respiração Celular
8.
Chem Commun (Camb) ; 58(95): 13202-13205, 2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36353925

RESUMO

A silver-catalysed oxidative sp2 C-H alkylation of N-heteroarenes with ketone-derived 2,3-dihydroquinazolinones at room temperature is developed. The combination of a metal catalyst and perdisulfate oxidant promotes the rarely explored thermal activation of pre-aromatic 2,3-dihydroquinazolinone to generate an alkyl radical, supported by mechanistic studies. In addition to the broad scope, good functionality tolerance, late stage functionalization of APIs, and synthesis of a novel Papaverine analogue, the utilization of an N-heteroarene C-H bond and ketone as a non-trivial alkyl radical source represents the salient feature of this method.


Assuntos
Cetonas , Metais , Catálise , Alquilação , Oxirredução , Estresse Oxidativo
9.
J Am Chem Soc ; 144(45): 20672-20679, 2022 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-36318611

RESUMO

Amidines are a ubiquitous class of bioactive compounds found in a wide variety of natural products; thus, efficient strategies for their preparation are in great demand. Specifically, their common structural core decorated with three substituents sets amidines as perfect candidates for multicomponent synthesis. Herein, we present a highly modular metal-free multicomponent strategy for the synthesis of sulfonyl amidines. This work was focused on selecting readily accessible reagents to facilitate the in situ formation of enamines by the addition of amines to ketones. These components were coupled with azides to provide a broad reaction scope with respect to all three coupling partners. Aromatic and aliphatic amines and ketones were tolerated under our reaction conditions. Likewise, the presence of a methyl group on the ketone was critical to reactivity, which was leveraged for the design of a highly regioselective reaction with aliphatic ketones. A biologically active compound was successfully synthesized in one step, demonstrating the practical utility of our methodology. Finally, the postulated mechanism was investigated and supported both experimentally and by means of a multivariate statistical model.


Assuntos
Amidinas , Azidas , Azidas/química , Amidinas/química , Aminas/química , Cetonas/química , Cobre/química , Metais , Metadona
10.
J Am Chem Soc ; 144(46): 21103-21115, 2022 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-36346612

RESUMO

Alcohol oxidation is an important class of reaction that is traditionally performed under harsh conditions and most often requires the use of organometallic compounds or transition metal complexes as catalysts. Here, we introduce a new electrochemical synthetic method, referred to as reductive oxidation, in which alcohol oxidation is initiated by the redox-mediated electrocatalytic reduction of peroxydisulfate to generate the highly oxidizing sulfate radical anion. Thus, and counter-intuitively, alcohol oxidation occurs as a result of an electrochemical reduction reaction. This approach provides a selective synthetic route for the oxidation of alcohols carried out under mild conditions to aldehydes, ketones, and carboxylic acids with up to 99% conversion yields. First-principles density functional theory calculations, ab initio molecular dynamics simulations, cyclic voltammetry, and finite difference simulations are presented that support and provide additional insights into the S2O82--mediated oxidation of benzyl alcohol to benzaldehyde.


Assuntos
Álcoois , Cetonas , Álcoois/química , Oxirredução , Cetonas/química , Catálise , Aldeídos/química
11.
ACS Appl Mater Interfaces ; 14(47): 52579-52598, 2022 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-36380598

RESUMO

Patients suffering diabetic bone defects still need some new and effective strategies to achieve enhanced prognostic effects. Although medical implants are the common treatment of bone defects, the excessive oxidative stress and high risk of bacterial infection in diabetes mellitus lead to a higher risk of implant failure. To improve the healing ability of diabetic bone defects, herein, polyetheretherketone (PEEK) was modified through a developed layer-by-layer (LBL) construction strategy to obtain multifunctional PEEK (SP@(TA-GS/PF)*3) by the assembly of tannic acid (TA), gentamicin sulfate (GS) and Pluronic F127 (PF127) on the basis of prepared porous PEEK through sulfonation (SPEEK). The prepared SP@(TA-GS/PF)*3 exhibited sustained antimicrobial activity and enhanced the differentiation of osteoblast (MC3T3-E1) for needed osteogenesis. Moreover, SP@(TA-GS/PF)*3 scavenged excessive oxidative stress to promote the growth of H2O2 damaged HUVEC with enhanced secretion of VEGF for neovascularization. In addition, the remarkable in vivo outcomes of angiogenesis and osseointegration were revealed by the subcutaneous implant model and bone tissue implant model in diabetic rats, respectively. The in vitro and in vivo results demonstrated that modified PEEK with multifunction can be an attractive tool for enhancing bone integration under diabetic conditions, underpinning the clinical application potential of modified implants for diabetic osseointegration.


Assuntos
Antioxidantes , Diabetes Mellitus Experimental , Ratos , Animais , Antioxidantes/farmacologia , Peróxido de Hidrogênio/farmacologia , Diabetes Mellitus Experimental/tratamento farmacológico , Benzofenonas/farmacologia , Cetonas/farmacologia , Polietilenoglicóis/farmacologia , Osseointegração , Osteogênese , Osso e Ossos , Antibacterianos/farmacologia , Propriedades de Superfície
12.
Front Public Health ; 10: 1003591, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36419987

RESUMO

Background: To reduce the costs and financial burden in the ACLR treatment, we compare the early clinical outcomes and Magnetic Resonance Imaging (MRI) results of Delta Medical's PEEK (polyether ether ketone) interference screw and EndoButton with those of Smith & Nephew's PEEK interference screw and EndoButton in patients with arthroscopic anterior cruciate ligament reconstruction. Methods: A total of 104 patients in five different medical centers were randomly allocated into two groups: 1: Delta Medical's PEEK interference screw and EndoButton (53 patients); 2: Smith & Nephew's PEEK interference screw and EndoButton (51 patients). The modified Lysholm knee score, the laxity examination, and clinical and functional range of motion were evaluated at 3 and 6 months postoperatively. The clinical effective rate was calculated and classified as excellent and good at 6 months postoperatively. MRI examinations were performed at 3 and 6 months postoperatively to determine the healing process. Computerized tomography (CT) was performed at 2 weeks and 3 months postoperatively to evaluate the complications. Results: Significant improvements in knee function and functional scores were observed in both groups after surgery regardless of the fixation materials applied (P < 0.05). No differences were observed in the functional scores and range of motion. The assessments of Lysholm knee scores at 3 and 6 months produced no statistical differences (both P > 0.05). The clinical effective rate revealed no difference between the groups at 6 months postoperatively (non-inferiority analysis P = 0.0220). The differences of laxity examination between the groups were not statistically significant (Fisher's test, P = 0.6139, 0.2004, respectively). No significant differences in the functional range of motion were found at each follow-up time-point (P > 0.05). No major intra- or postoperative complications, such as infection, and vessel or nerve injury were observed. Conclusions: Knee function and functional scores were improved after ACLR in both groups, regardless of the PEEK interference screw and EndoButton applied. The difference in functional scores and range of motion were not significant in groups 1 and 2. Delta Medical's PEEK interference screw and EndoButton had a non-inferiority effect compared to Smith & Nephew's PEEK interference screw and EndoButton. Delta Medical's PEEK interference screw and EndoButton were suitable for arthroscopic ACLR.


Assuntos
Reconstrução do Ligamento Cruzado Anterior , Cetonas , Humanos , Estudos Prospectivos , Polietilenoglicóis , Parafusos Ósseos
13.
PLoS One ; 17(11): e0277184, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36409721

RESUMO

In this study, two different feeds were treated to produce hydrocarbons: (1) reagent-grade acetone, and (2) mixed ketones obtained from lignocellulosic biomass via the carboxylate platform. Acetone and mixed ketones underwent catalytic self-condensation over HZSM-5. For acetone, HZSM-5(80) was used, and the experiments were conducted in two sets: (1) vary temperature (305-415°C) at P = 101 kPa (abs) and weight hourly space velocity (WHSV) = 1.3 h-1; (2) vary WHSV (1.3-7.9 h-1) at T = 350 and 415°C, and P = 101 kPa (abs). For acetone over HZSM-5(280), the experiments were conducted in two sets: (1) vary WHSV (1.3-6.5 h-1) at T = 415°C, and P = 101 kPa (abs); and (2) vary WHSV (1.3-11.8 h-1) at P = 790 kPa (abs) and T = 415°C. For mixed ketones, HZSM-5(280) was used at WHSV = 1.9 h-1, T = 430-590°C, and P = 101 kPa (abs). For acetone at higher temperatures, the conversion was 100% and the liquid products were aromatics centered on C8. At low temperatures, conversion was less and the carbon liquid distribution was centered on C9 (mainly mesitylene). For mixed ketones, catalyst deactivation was higher causing product concentrations to change over time, and the highest conversion reached was 40%.


Assuntos
Acetona , Cetonas , Hidrocarbonetos , Catálise , Biomassa
14.
Int J Nanomedicine ; 17: 5327-5338, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36411765

RESUMO

Introduction: Polyetheretherketone (PEEK) has good biosafety and chemical stability for bone repair. However, PEEK is biologically inert and cannot promote bone apposition. This study investigated whether graphene-modified PEEK (G-PEEK) could improve cell adhesion and osteogenic differentiation. Methods: G-PEEK was prepared by melted blending and was characterized. In vitro, the biocompatibility of G-PPEK and the ability to promote cell adhesion and osteogenic differentiation in rabbit bone marrow mesenchymal stem cells (rBMSCs) were examined using live and dead cell double staining, the cell counting kit-8 (CCK-8) assay, immunofluorescence and quantitative real-time PCR (qRT‒PCR). An in vivo rabbit extra-articular graft-to-bone healing model was established. At 4 and 12 weeks after surgery, CT analysis and histological evaluation were performed. Results: In vitro, G-PEEK significantly improved the adhesion and proliferation of rBMSCs, with good biocompatibility. In vivo, G-PEEK promoted new bone formation at the site of the bone defect. Conclusion: G-PEEK showed excellent osteogenesis performance, which promises new applications in implant materials.


Assuntos
Grafite , Osteogênese , Animais , Coelhos , Adesão Celular , Grafite/química , Polímeros , Cetonas/farmacologia , Cetonas/química , Polietilenoglicóis/química
15.
J Org Chem ; 87(22): 15634-15643, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36322913

RESUMO

The natural product armeniaspirol possesses a unique spirocyclic N,O-ketal in an α,ß-dichloro-α,ß-unsaturated lactam scaffold that has proved challenging to synthesize. Herein, we characterize the oxidative chlorination of pyrrole-2-carboxylate derivatives that rapidly generates this scaffold. The scope of this oxidation was extended to a series of esters and amides. Pyrrole-2-ketones could not be converted into the lactam due to an oxidative fragmentation. This result was unexpected since chloro-armeniaspirol has been synthesized via oxidative chlorination of a pyrrole-2-ketone. Examination of this successful oxidation showed that the desired scaffold was accessed due to intramolecular trapping from the neighboring free phenol, preventing fragmentation. Using the product of methyl N-methyl pyrrole-2-carboxylate oxidation 7b, we attempted to access the natural product armeniaspirol 2; however, an unanticipated Lewis acid-mediated rearrangement led to formation of a constitutional isomer, pseudoarmeniaspirol A 1. A small panel of pseudoarmeniaspirol analogues was synthesized and evaluated for antibiotic activity, inhibition of the targets of armeniaspirol, ClpXP and ClpYQ, and protonophore activity. While pseudoarmeniaspirol shows antibiotic activity, it does not target ClpXP or ClpYQ and has less protonophore activity than the natural product.


Assuntos
Produtos Biológicos , Ácidos de Lewis , Pirróis , Cetonas , Antibacterianos , Lactamas
16.
J Org Chem ; 87(22): 15031-15041, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36325975

RESUMO

An example of asymmetric Steglich-type rearrangement of enol lactones is reported. This highly enantioselective acyl transfer reaction is catalyzed by chiral isothiourea at ambient temperature and provides a useful synthetic approach to access enantioenriched spirotricyclic ß,ß'-diketones from a broad range of indanone or tetralone-derived lactones. Preliminary mechanistic studies suggest the initial formation of an N-acylated iminium cation intermediate that induces a following facial selective condensation.


Assuntos
Cetonas , Lactonas , Estereoisomerismo , Catálise
17.
J Org Chem ; 87(22): 15101-15113, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36349364

RESUMO

Precise control of the chemoselectivity of the halogenation of a substrate equipped with multiple nucleophilic sites is highly demanding and challenging. Most reported chlorinations of methyl ketones show poor compatibility or even exclusive selectivity toward electron-rich arene, olefin, and alkyne residues. This is attributed to the direct or in situ employment of electrophilic Cl2/Cl+ species. Here, we reported that, even bearing those competitive residues, methyl ketones can still undergo dichlorination to afford α,α-dichloroketones in a chemo-specific manner. Enabled by the I2-dimethyl sulfoxide catalytic system, in which hydrochloric acid only acts as a nucleophilic Cl- donor, this straightforward dichlorination reaction is safe and operator-friendly and has high atomic economy, giving access to structurally diverse α,α-dichloroketones in good yields and with good functional-group tolerance.


Assuntos
Dimetil Sulfóxido , Cetonas , Cetonas/química , Acetona , Catálise , Halogenação
18.
J Org Chem ; 87(22): 15403-15414, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36350139

RESUMO

N-alkylation of amines is an important catalytic reaction in synthetic chemistry. Herein, we report a simple strategy for the N-alkylation of 2-aminopyridines with 1,2-diketones using BF3·OEt2 as a catalyst. The reaction proceeds under aerobic conditions, leading to the formation of a diverse range of substituted secondary amines in good to excellent yields. A close inspection of the mechanistic pathway using various spectroscopic techniques and the computational study revealed that the reaction proceeds through the formation of an iminium-keto intermediate with the liberation of CO2.


Assuntos
Aminas , Aminopiridinas , Catálise , Alquilação , Aminas/química , Cetonas
19.
BMC Oral Health ; 22(1): 484, 2022 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-36368972

RESUMO

BACKGROUND: The data on polyetheretherketone (PEEK) influence on the peri-implant soft tissues in clinical settings are deficient. The aims of this pilot study were to analyze and compare soft tissues' response to PEEK and titanium (Ti) healing abutments (HA) by means of histological and immunohistochemical analyses. METHODS: A total of 22 implants with PEEK or Ti HA were placed in 11 patients, applying the "split-mouth" study design. Three months later, soft tissue specimens were harvested from 20 implants for histology in order to qualitatively detect the inflammatory cells' presence, to semi-qualitatively analyze the inflammation intensity and to assess the inflammatory responses type by immunohistochemical analysis using LCA, CD3, CD20 and CD68 antibodies. RESULTS: Epithelial infiltrate followed by an intensive inflammation in sub-epithelium was observed in 100% around PEEK HA. A number of LCA+ and CD 68+ cells was significantly higher in PEEK comparing to Ti group (p = 0.001 and p = 0.020, respectively), while CD 20+ and CD3+ counted cells were found in a significantly higher amount in Ti than in PEEK group (p = 0.006 and p = 0.010, respectively). CONCLUSION: PEEK HA seems to evoke the more intense tissue inflammatory response demonstrated predominantly by histocytes' and plasmacytes' activation, while Ti HA triggers the inflammatory reaction of lower intensity, dominantly mediated by B-cells. TRIAL REGISTRATION: The study registered at ClinicalTrials.gov (NCT04436939).


Assuntos
Implantes Dentários , Humanos , Implantes Dentários/efeitos adversos , Titânio , Projetos Piloto , Dente Suporte , Cetonas , Polietilenoglicóis , Inflamação
20.
Org Biomol Chem ; 20(45): 8952-8961, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36326093

RESUMO

We report a strategy for the direct synthesis of 3-organylselanylthiochromones and 3-organylselanylchromones via the radical cyclization reaction between alkynyl aryl ketones containing an ortho-thiopropyl/methoxy group and diorganyl diselenides promoted by Oxone®. This method allows the construction and seleno-functionalization of thiochromones and chromones using Oxone® as a stable and non-hazardous oxidizing agent in the presence of CH3CN at 82 °C. These reactions tolerate a variety of substituents, and allowed the synthesis of twenty-one new 3-organylselanylthiochromones and selanylchromones in good to excellent yields (55-95%). Additionally, the developed method proved to be suitable for scale up (3.0 mmol, 80%), and the synthetic usefulness of the prepared compounds was demonstrated in the oxidation of 2-phenyl-3-(phenylselanyl)-4H-thiochromen-4-one.


Assuntos
Cromonas , Cetonas , Ciclização , Catálise
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