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1.
Allergy ; 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-38993131

RESUMO

BACKGROUND: A combination of proton-pump inhibitors (PPI) and topical steroids (TS) is used to treat children with eosinophilic esophagitis (EoE). However, a subset of children do not respond to this combination therapy. We aimed to identify the esophageal transcriptional, cell composition, and microbial differences between the non-responders (EoE-PPI-TSnr; n = 7) and responders (EoE-PPI-TSr; n = 7) to the combination therapy for EoE and controls (n = 9) using metatranscriptomics. METHODS: Differential gene expression analysis was used to identify transcriptional differences, validated using the EoE diagnostic panel (EDP). Deconvolution analysis was performed to identify differences in their cell type composition. Microbiome analysis was conducted from esophageal biopsies RNAseq data, and microbial abundance was correlated with esophageal gene expression. RESULTS: In all, 3164 upregulated and 3154 downregulated genes distinguished EoE-PPI-TSnr from EoE-PPI-TSr. Eosinophilic inflammatory response, cytokine signaling, and collagen formation pathways were significantly upregulated in EoE-PPI-TSnr. There was a 56% overlap in dysregulated genes between EoE-PPI-TSnr and EDP, with a perfect agreement in the directionality of modulation. Eosinophils, dendritic cells (DCs), immature DCs, megakaryocytic-erythroid progenitors, and T helper type 1 cells were significantly higher in EoE-PPI-TSnr. There was no significant difference in microbiome diversity. The relative abundance of Fusobacterium sp. and Acinetobacter sp. notably differed in EoE-PPI-TSnr and correlated with the key pathways. CONCLUSION: Our results provide critical insights into the molecular, cellular, and microbial factors associated with the lack of response to PPI and TS combination therapy in children with EoE. This study advances our understanding of the pathobiology of EoE while guiding personalized treatment strategies.

2.
Oral Oncol ; 156: 106926, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38959641

RESUMO

Surgery forms the backbone of treatment for most locoregional or advanced oral cavity squamous cell carcinoma. Unfortunately, infectious complications (including orocutaneous fistulas) are common following such extensive surgery and can afflict over half of patients. These complications can lead to delays in adjuvant treatment, prolonged hospitalization, reconstructive failure, and decreased quality of life. The frequency and morbidity associated with infectious complications has led to the search for pre-disposing risk factors; and, several have been identified, including both patient (e.g. diabetes) and surgical (e.g. operative time) factors. However, these findings are inconsistently reproduced, and risk factor modification has had a limited impact on rates of infectious complications. This is striking given that the likely contaminant-the oral microbiome-is a well-studied microbial reservoir. Because many oral cavity cancer surgeries involve violation of oral mucosa and the spillage of the oral microbiome into normally sterile areas (e.g. the neck), variance in oral microbiome composition and function could underly differences in infectious complications. The goal of this perspective is to highlight 1) this knowledge gap and 2) opportunities for studies in this domain. The implication of this line of thought is that the identification of oral microbial dysbiosis in patients undergoing surgery for oral cavity cancer could lead to targeted pre-operative therapeutic interventions, decreased infectious complications, and improved patient outcomes.


Assuntos
Microbiota , Neoplasias Bucais , Humanos , Neoplasias Bucais/cirurgia , Neoplasias Bucais/microbiologia , Boca/microbiologia , Infecção da Ferida Cirúrgica/microbiologia , Infecção da Ferida Cirúrgica/etiologia , Complicações Pós-Operatórias/microbiologia , Fatores de Risco
3.
Pediatr Neurol ; 157: 57-69, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38878674

RESUMO

INTRODUCTION: Addressing the need to uniformly classify arteriopathies among patients with arterial ischemic stroke (AIS) due to tubercular meningitis (TBM), we used the Childhood AIS Standardised Classification and Diagnostic Evaluation (CASCADE) criteria. METHODS: This tri-centric prospective study included children aged 0.5-12 years with TBM and AIS. Magnetic resonance angiographies (MRAs) were done during admission and repeated 3 and 12 months after discharge. Arteriopathies were classified according to the primary CASCADE criteria. We used the modified Pediatric Alberta Stroke Programme Early Computed Tomography Score as an ordinal measure of infarct volume. The severity of arteriopathies was graded using the focal cerebral arteriopathy severity score (FCASS). The final outcomes were measured at the 12-month follow-up visit using the Pediatric Stroke Outcome Measure (PSOM). RESULTS: Out of 55 patients, 64% had MRA-evidenced arteriopathies and 84% had multiple infarcts. The middle cerebral (46%) and internal carotid arteries (22%) were most commonly affected. The basal ganglia (70%) and the cerebral cortex (61%) were most commonly infarcted. CASCADE categories included 3b (40%), 1d (38%), 2b (16%), 2c (5%), progressive (32%), and stable (44%) arteriopathies. Younger age, hypertrophic pachymeningitis, cortical infarcts, recurrent strokes, progressive arteriopathies, EEG abnormalities, and mortality were significantly higher among patients with MRA-proven arteriopathies. Patients with progressive arteriopathies had a significantly higher prevalence of hypertrophic pachymeningitis, cortical infarcts, and recurrent strokes. FCASS correlated positively with outcomes measured by the Pediatric Stroke Outcome Measure and modified Pediatric Alberta Stroke Programme Early Computed Tomography Score. CONCLUSION: The CASCADE classification clarified the arteriopathy patterns, enabling us to correlate them with the characteristics of the infarcts. FCASS is useful to grade the arteriopathy severity and progression in TBM.


Assuntos
AVC Isquêmico , Tuberculose Meníngea , Humanos , Tuberculose Meníngea/complicações , Tuberculose Meníngea/diagnóstico por imagem , Pré-Escolar , Masculino , Criança , Feminino , Índia , AVC Isquêmico/diagnóstico por imagem , AVC Isquêmico/complicações , Lactente , Estudos Prospectivos , Angiografia por Ressonância Magnética , Doenças Arteriais Intracranianas/diagnóstico por imagem , Doenças Arteriais Intracranianas/complicações , Índice de Gravidade de Doença , Seguimentos
4.
Angew Chem Int Ed Engl ; : e202410954, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38900650

RESUMO

The 2,2-difluoroethyl group is an important lipophilic hydrogen bond donor in medicinal chemistry, but its incorporation into small molecules is often challenging. Herein, we demonstrate electrophilic 2,2-difluoroethylation of thiol, amine and alcohol nucleophiles with a hypervalent iodine reagent, (2,2-difluoro-ethyl)(aryl)iodonium triflate, via a proposed ligand coupling mechanism. This transformation offers a complementary strategy to existing 2,2-difluoroethylation methods and allows access to a wide range of 2,2-difluoroethylated nucleophiles, including the drugs Captopril, Normorphine and Mefloquine.

5.
J Food Prot ; 87(6): 100279, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38631421

RESUMO

A simple new, rapid, sensitive, and cost-effective HPLC-PDA method was developed and validated for the determination of tetracycline (TC), oxytetracycline (OTC), and ciprofloxacin (CIP) simultaneously. Chromatographic separations were carried out using a reversed-phase Shim-pack GIS C18 column (4.60 × 250.00 mm; 5.00 µm) at 30°C. Oxalic acid (0.05 M), acetonitrile, and methanol were used as mobile phase under gradient elution conditions at the flow rate of 1.50 mL min-1. Detection wavelength was set at 330 nm. An aliquot of 20.00 µL solution was injected, and three drugs were eluted within 7.39 ± 0.05 min. As per ICH guidelines linearity, recovery, accuracy, precision, selectivity, specificity, sensitivity, stability, column efficiency, system suitability, and robustness were determined for the validation of the proposed method. Calibration curves were linear over a studied concentration range of 8.00 µg mL-1 with a correlation coefficient (r) of 0.999 for all drugs. Relative standard deviation (RSD) for intra- and interday precision was found less than 2.87% and 3.22%, respectively, indicating the method to be reproducible. The proposed method has been suitably applied for the estimation of TC, OTC, and CIP in pharmaceutical formulation and milk samples collected from local market in Bangladesh. Among 15 milk samples analyzed, most of the cases (more than 50%) TC, OTC, and CIP were detected above maximum residue levels (MRLs) though no significant toxicological effect on the health of consumers in the study area was identified.


Assuntos
Antibacterianos , Leite , Leite/química , Cromatografia Líquida de Alta Pressão , Animais , Antibacterianos/análise , Bovinos , Medição de Risco , Contaminação de Alimentos/análise , Humanos , Reprodutibilidade dos Testes , Oxitetraciclina/análise
6.
J Chem Phys ; 160(1)2024 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-38174794

RESUMO

Ultraviolet and vacuum ultraviolet photo-absorption spectra of azido (-N3)-based energetic plasticizer, bis(1,3-diazido-prop-2-yl)-malonate (abbreviated as BDAzPM), in the gas phase is recorded at room temperature and in the photon energy range of 5.5-9.9 eV using a synchrotron radiation source. Complementary computational results obtained using the time-dependent density functional theory document the vertical transition energies and oscillator strengths. Comparison of the simulated spectra with the experimental absorption spectrum of BDAzPM reveals that the early part of the absorption spectrum of BDAzPM is of pure valence excitation character, whereas the later intense part of the absorption spectrum is dominated by mixed Rydberg and valence electronic excitations.

7.
Otolaryngol Head Neck Surg ; 170(3): 977-980, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37933740

RESUMO

The objective of this study was to characterize mucosal microbial shifts in patients with acute laryngeal injury (ALgI) after intubation. This cross-sectional study included 20 patients with ALgI who underwent early endoscopic intervention with tissue culture, 20 patients with idiopathic subglottic stenosis (iSGS) who underwent tissue culture during the routine endoscopic intervention, and 3 control patients who underwent mucosal swab culture. 70% of the ALgI patients had a positive culture compared to 5% of the iSGS patients and none of the controls. The most identified microbes isolated from ALgI patients included Staphylococcus species in 30% and Streptococcus species in 25%. The high rate of pathologic bacterial infiltration into postintubation laryngeal wounds supports efforts to reduce bacterial colonization of endotracheal tubes and highlights the role of culture-directed antibiotic therapy as a part of early intervention to improve outcomes for patients with ALgI.


Assuntos
Doenças da Laringe , Laringoestenose , Microbiota , Humanos , Estudos Transversais , Doenças da Laringe/etiologia , Laringoestenose/etiologia , Intubação Intratraqueal/efeitos adversos
8.
Chemistry ; 30(6): e202303337, 2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-37987541

RESUMO

A photocatalytic domain of doubly decarboxylative Csp 2 -Csp 2 cross coupling reaction is disclosed. Merging iridium and palladium photocatalysis manifested carbon-carbon bonds in a tandem dual-radical pathway. Present catalytic platform efficiently cross-coupled α, ß-unsaturated acids and α-keto acids to afford a variety of α, ß-unsaturated ketones with excellent (E)-selectivity and functional group tolerance. Mechanistically, photocatalyst implicated through reductive quenching cycle whereas cross coupling proceeded over one electron oxidative pallado-cycle.

9.
Food Addit Contam Part B Surveill ; 17(1): 77-86, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38152026

RESUMO

The concentrations of manganese, iron, copper, lead, nickel, cadmium, arsenic, copper and mercury were determined in 10 cultured fish species, which were collected from local markets of Chittagong, Bangladesh, in June 2021. Measurements were performed by atomic absorption spectrophotometry, after acid digestion of the samples. In some cases, the concentration of the investigated elements was more than the maximum limit set by the WHO. Although the concentration of toxic elements in fishes was relatively high in some species, no health risk has been identified in comparison to the estimated daily intake and the maximum limit. Calculated hazard indices were below 1, which indicates the investigated fish would not cause human health risks. Carcinogenic risk indices for Cr, As, and Cu in all species were considered to be significant.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Animais , Humanos , Metais Pesados/análise , Cobre , Bangladesh , Contaminação de Alimentos/análise , Cádmio/análise , Medição de Risco , Peixes , Monitoramento Ambiental , Poluentes Químicos da Água/análise
11.
Environ Technol ; : 1-18, 2023 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-38158754

RESUMO

Low molecular weight organic acids (LMWOAs) are common in rhizospheric soil and may impede the interaction between phosphate and metals. Thus, studying how phosphate compounds impact metal immobilization in rhizospheric soil using LMWOAs is crucial. An incubation experiment examined the effects of NaH2PO4 (a P compound) (3%), various concentrations of citric acid (CA), and combinations of P and CA, on soil cadmium (Cd), lead (Pb), and zinc (Zn) immobilization using the European Community Bureau of Reference (BCR) sequential extraction method, CaCl2 extraction method, zeta potential, fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The P, low CA (2 mmol kg-1 soil) (CA2), and P-CA2 treatments reduced acid-soluble and CaCl2-extractable Cd, Pb, and Zn, indicating metal immobilization, with the P-CA2 treatment being the most effective. High CA (>5-20 mmol kg-1 soil) or a P with high CA reversed prior patterns, suggesting metal mobilization. The zeta potential study indicated that when pH increased, treatments became more negative, notably P-CA2 followed by P, suggesting that electrostatic adsorption was the predominant metal immobilization mechanism, especially in P-CA2. XRD tests, however, showed that the P treatment alone produced Cd phosphate, pyromorphite, and hopeite, indicating that sorption and precipitation were the main metal immobilization processes in the P treatment alone. In conclusion, P-CA2 was found to be the most efficient metal immobilization and redistribution treatment for contaminated soils. Rhizospheric CA may alter Cd, Pb, and Zn mineral stability. Therefore, when treating Cd, Pb, and Zn-contaminated soils with a P compound, CA should be addressed.

12.
J Pediatr Pharmacol Ther ; 28(6): 504-508, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38130344

RESUMO

OBJECTIVE: Proton pump inhibitors (PPIs) are commonly used to manage children with upper gastrointestinal symptoms and without a formal diagnosis. We investigated the effect of PPIs on esophageal mucosal transcriptome and active microbiota in children with normal esophagi. Furthermore, we examined whether the differences in host esophageal mucosal gene expression were driven by an underlying esophageal epithelial cell type composition. METHODS: Using metatranscriptomics, the host transcriptional and active microbial profiles were captured from 17 esophageal biopsy samples (PPI naïve [PPI-], n = 7; PPI exposed [PPI+], n = 10) collected from children without any endoscopic and histologic abnormalities in their esophagus (normal esophagus). Deconvolution computational analysis was performed with xCell to assess if the observed epithelial gene expression changes were related to the cell type composition in the esophageal samples. RESULTS: The median (IQR) age of our cohort was 14 years (12-16) with female (63%) preponderance. Both groups were similar in terms of their demographics and clinical features. Compared with PPI-, the PPI+ had upregulation of 27 genes including the MUC genes. The cell type composition was similar between the PPI- and PPI+ groups. Prevotella sp and Streptococcus sp were abundant in PPI+ group. CONCLUSIONS: In children with normal esophagus, PPI exposure can be associated with upregulation of esophageal mucosal homeostasis and epithelial cell function genes in a cell-type independent manner, and an altered esophageal microbiome. Additional studies are warranted to validate our findings and to investigate the causal effect of PPIs on the normal esophageal epithelium and microbial communities.

13.
J Cyst Fibros ; 2023 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-37953184

RESUMO

BACKGROUND: The nutritional status of children with cystic fibrosis (CF), as assessed by their body mass index percentile (BMIp), is a critical determinant of long-term health outcomes. While the intestinal microbiome plays an important role in nutrition, little is known regarding the relationship of the microbiome and BMIp in children with CF. METHODS: Pediatric patients (< 18 years old) with CF and healthy comparison patients (HCs) were enrolled in the study and stool samples obtained. BMIp was categorized as Green Zone (BMIp > 50th), Yellow Zone (BMIp 25th-49th) and Red Zone (BMIp < 25th). Intestinal microbiome assessment was performed via 16S rRNA gene sequencing; microbial richness, diversity, and differential species abundance were assessed. RESULTS: Stool samples were collected from 107 children with CF and 50 age-matched HCs. Compared to HCs, children with CF were found to have lower bacterial richness, alpha-diversity, and a different microbial composition. When evaluating them by their BMIp color zone, richness and alpha-diversity were lowest in those in the Red Zone. In addition, an unclassified amplicon sequence variant (ASV) of Blautia, a known butyrate-producing anaerobe, was of lowest abundance in children in the Red Zone. CONCLUSION: Children with CF have a dysbiotic intestinal microbiome with specific changes that accompany changes in BMIp. Longitudinal assessments of the microbiome and its metabolic activities over time are needed to better understand how improvements in the microbiome may improve nutrition and enhance long-term survival in children with CF.

14.
Ann Indian Acad Neurol ; 26(5): 678-689, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38022439

RESUMO

Introduction: Hypertrophic pachymeningitis (HP) is a treatable, rare inflammatory disease, either primary or secondary to systemic causes. Aims: To characterize the etiology, clinical manifestations, and treatment outcomes of HP patients and determine the factors influencing the radiological resolution of the pachymeningeal enhancement and recurrence of symptoms within the follow-up period. Materials and Methods: We collected data for this prospective observational study between March 1, 2021 and May 31, 2022, at the Bangur Institute of Neurosciences, Kolkata, and the patients were followed for a 6-month period. Demographic, clinical, laboratory, and treatment-related data were collected. A univariate logistic regression model was used for comparison between patients with and without radiological resolution of pachymeningitis and between patients with and without symptom recurrence. Results: Among 44 patients, the male: female ratio was 1.2:1. The median age at disease onset was 35.5 (28.5-49.5) years. The etiologies were idiopathic (56.8%), tuberculosis (22.8%), immunoglobulin G subtype 4 (IgG4) disease (9.2%), other infections (6.8%), and neoplastic (4.4%). Headache was the most common presentation (95.4%), followed by cranial neuropathies (68.2%). Optic and oculomotor neuropathies were the most common. In terms of radiological features, 27.27, 29.54, and 43.18% of patients had diffuse, focal regular, and focal irregular enhancement, respectively. Temporal (50%), followed by cavernous sinus (38.63%) enhancement, was the most common. Recurrence occurred in 36 and 50% of idiopathic and IgG4-related HP cases, respectively. Mycophenolate mofetil was added to their steroid regimen with no further recurrences. Conclusion: The cohort had a marked absence of (antineutrophil cytoplasmic antibodies) ANCA-associated HP. The severity of clinical manifestations or distribution of pachymeningitis did not differ significantly among the etiological groups. The presence of idiopathic etiology and focal regular enhancement had a significantly higher chance of radiological resolution. The response to therapy was satisfactory. Recurrence was significantly related to shorter steroid courses (

15.
J Org Chem ; 88(21): 14847-14859, 2023 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-37867455

RESUMO

Herein, we report metal- and photocatalyst-free room-temperature amidation for α-ketoamide synthesis from feedstock phenacyl bromides and amines using molecular oxygen as an oxidant as well as a source of oxygen in the amide segment. Visible light-mediated base-promoted one-pot sequential C-N/C═N/C═O bond formation takes place in a tandem manner to afford the desired product. Functional group tolerance (benzylic alcohol, keto, cyano, nitro, halo, etc.), a broad substrate scope, and gram-scale synthesis make this synthetic methodology more attractive. We have observed that electron-rich aromatic amines, aliphatic amines, and phenacyl bromide derivatives proceeded the present transformation with marginally superior reactivity in comparison to electron-deficient aromatic amines and phenacyl bromide derivatives. Moreover, several control experiments, in situ isolation of secondary amine and imine as key intermediates, and 18O-labeling experiments provide complete insight into the mechanism of the tandem pathway.

16.
Chem Sci ; 14(38): 10467-10470, 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37799986

RESUMO

The synthesis and Cu/Pd-catalyzed arylboration of 1-silyl-1,3-cyclohexadiene is described. This diene is significant as it allows for synthesis of polyfunctional cyclohexane/enes. To achieve high levels of diastereoselectivity, the use of a pyridylidene Cu-complex was employed. In addition, through the use of a chiral catalyst, an enantioselective reaction was possible. Due to the presence of the silyl and boron substituents, the products can be easily diversified into a range of valuable cyclohexane/ene products.

17.
Nat Aging ; 3(9): 1091-1106, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37580394

RESUMO

Dietary restriction promotes longevity in several species via autophagy activation. However, changes to lysosomes underlying this effect remain unclear. Here using the nematode Caenorhabditis elegans, we show that the induction of autophagic tubular lysosomes (TLs), which occurs upon dietary restriction or mechanistic target of rapamycin inhibition, is a critical event linking reduced food intake to lifespan extension. We find that starvation induces TLs not only in affected individuals but also in well-fed descendants, and the presence of gut TLs in well-fed progeny is predictive of enhanced lifespan. Furthermore, we demonstrate that expression of Drosophila small VCP-interacting protein, a TL activator in flies, artificially induces TLs in well-fed worms and improves C. elegans health in old age. These findings identify TLs as a new class of lysosomes that couples starvation to healthy aging.


Assuntos
Proteínas de Caenorhabditis elegans , Envelhecimento Saudável , Inanição , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Inanição/metabolismo , Lisossomos/metabolismo
18.
J Phys Chem A ; 127(33): 6892-6901, 2023 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-37614172

RESUMO

We present a theoretical study on the occurrence of excited-state proton transfer in an aggregated structure of 2-(benzo[d]thiazol-2-yl)-6-methoxyphenol (TMP) exclusively in water among polar solvents, as reported in a recent experiment (Bhattacharyya, A. New J. Chem. 2019, 43, 15087). Our extensive investigation of the TMP monomer and dimer implementing density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods, in three different solvents, namely, water, methanol, and dimethyl sulfoxide (DMSO), with explicit inclusion of solvent molecules demonstrated the existence of both enol and keto forms of the TMP dimer in the excited state, but only in water; this confirmed the experimental emission spectra completely and simultaneously validated the aggregation-induced emission phenomenon. Further analysis of various parameters such as potential energy scan (PES) of the hydroxyl (O-H) bond involved in hydrogen bonding, frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP), and infrared (IR) stretching frequencies of both the monomer and dimer forms of TMP in different solvents clearly indicated the geometry of the dimer, with the arrangement of the solvent molecules to be the sole reason for the excited-state charge transfer. The bridging alignment of water molecules in between the stacked units of the TMP dimer results in intermolecular interactions, ultimately leading to intermolecular proton transfer in the excited state.

19.
Int J Biol Macromol ; 251: 126189, 2023 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-37586624

RESUMO

Self-structure induction in a single stranded polyriboadenylic acid [poly (rA)] is an auspicious physiological phenomenon which switches off protein production in tumor cells. In the present study, the self-structure induction process in poly (rA) moiety was thoroughly investigated using various steady state and time resolved techniques. Optical melting pattern directly evidenced the formation of self-structured assembly in single stranded poly (rA) upon complexation with quinacrine. Further, UV-absorption spectroscopic studies revealed that quinacrine binds to poly (rA) in co-operative fashion and the indication of intercalative mode of binding first came out with the involvement of around two base pairs of poly (rA) in the complexation. Experimental observations established the unconventional or non-classical intercalation of quinacrine molecule inside self-structured duplex poly (rA) moiety. This complexation was accompanied with negative enthalpy change and positive entropy change; suggesting strong van der Waals and the H-bonding interactions as the major governing forces in the complexation. Moreover, ionic strength dependent binding study established that the non-polyelectrolytic forces were the dominating forces. Further, the photo physical behavior of QN was authenticated using time dependent density functional theory (TDDFT) where both the ground and excited states were exploited.

20.
Chemistry ; 29(61): e202301637, 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37551730

RESUMO

The involvement of nitroalkenes instead of minimal one alkyne motif for (E)-1,3-enynes synthesis through a palladium catalyzed stereoselective bond forming pathway at room temperature is presented. Implication of nitro group as a sacrificial directing group, formation of magical alkyne on a newly developed Csp 3 -Csp 3 bond with initial palladium-MBH adduct make this methodology distinctive. This protocol features an unprecedented sequential acetate addition, carbon-carbon bond formation, isomerization of double bond and nitromethane degradation in a tandem catalytic walk via dancing hybridization. Mechanistic understanding through identification of intermediates and computational calculations furnishes complete insight into the tandem catalytic pathway. Broad substrates scope and functional groups tolerance make this synthetic methodology magnificent and dynamic. This represents the first example of stereoselective 1,3-enyne synthesis exclusively from alkene substrates by introducing the concept of sacrificial directing group.

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