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With the rapid development of non-fullerene acceptors (NFAs), the power conversion efficiency (PCE) of organic solar cells (OSCs) is increasing. According to their different chemical structures, NFAs can initially be divided into two categories: small molecule acceptors (SMAs) and polymerized small molecule acceptors (PSMAs). Due to the strong absorption capacity and controllable energy levels, the PCE of devices based on SMAs has approached 20%. Compared with SMAs, PSMAs have advantages in stability and flexibility, and the PCE of PSMA-based devices has exceeded 18%. However, the higher synthesis cost and lower batch repeatability hinder its further development. Recently, the concept of giant molecule acceptors (GMAs) has been proposed. These materials have a clear molecular structure and are considered novel acceptor materials that combine the advantages of SMAs and PSMAs. Currently, the PCE of devices based on GMAs has exceeded 19%. In this review, we will introduce the latest developments in SMAs, PSMAs, and GMAs. Then, the advantages of GMAs and the relationship between their structure and performance will be analyzed. In the end, perspectives on the opportunities and challenges of these materials are provided, which could inspire further development of NFAs for advanced OSCs.
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AIM: Recent imaging studies have found significant abnormalities in the brain's functional or structural connectivity among patients with high myopia (HM), indicating a heightened risk of cognitive impairment and other behavioral changes. However, there is a lack of research on the topological characteristics and connectivity changes of the functional networks in HM patients. In this study, we employed graph theoretical analysis to investigate the topological structure and regional connectivity of the brain function network in HM patients. METHODS: We conducted rs-fMRI scans on 82 individuals with HM and 59 healthy controls (HC), ensuring that the two groups were matched for age and education level. Through graph theoretical analysis, we studied the topological structure of whole-brain functional networks among participants, exploring the topological properties and differences between the two groups. RESULTS: In the range of 0.05 to 0.50 of sparsity, both groups demonstrated a small-world architecture of the brain network. Compared to the control group, HM patients showed significantly lower values of normalized clustering coefficient (γ) (P = 0.0101) and small-worldness (σ) (P = 0.0168). Additionally, the HM group showed lower nodal centrality in the right Amygdala (P < 0.001, Bonferroni-corrected). Notably, there is an increase in functional connectivity (FC) between the saliency network (SN) and Sensorimotor Network (SMN) in the HM group, while the strength of FC between the basal ganglia is relatively weaker (P < 0.01). CONCLUSION: HM Patients exhibit reduced small-world characteristics in their brain networks, with significant drops in γ and σ values indicating weakened global interregional information transfer ability. Not only that, the topological properties of the amygdala nodes in HM patients significantly decline, indicating dysfunction within the brain network. In addition, there are abnormalities in the FC between the SN, SMN, and basal ganglia networks in HM patients, which is related to attention regulation, motor impairment, emotions, and cognitive performance. These findings may provide a new mechanism for central pathology in HM patients.
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Encéfalo , Imagen por Resonancia Magnética , Red Nerviosa , Humanos , Masculino , Femenino , Adulto , Imagen por Resonancia Magnética/métodos , Encéfalo/fisiopatología , Encéfalo/diagnóstico por imagen , Red Nerviosa/fisiopatología , Red Nerviosa/diagnóstico por imagen , Adulto Joven , Mapeo Encefálico/métodos , Miopía Degenerativa/fisiopatología , Descanso/fisiologíaRESUMEN
New adjuvants that trigger cellular immune responses are urgently needed for the effective development of cancer and virus vaccines. Motivated by recent discoveries that show activation of type I interferon (IFN-I) signaling boosts T cell immunity, this study proposes that targeting this pathway can be a strategic approach to identify novel vaccine adjuvants. Consequently, a comprehensive chemical screening of 6,800 small molecules is performed, which results in the discovery of the natural compound picrasidine S (PS) as an IFN-I inducer. Further analysis reveals that PS acts as a powerful adjuvant, significantly enhancing both humoral and cellular immune responses. At the molecular level, PS initiates the activation of the cGAS-IFN-I pathway, leading to an enhanced T cell response. PS vaccination notably increases the population of CD8+ central memory (TCM)-like cells and boosts the CD8+ T cell-mediated anti-tumor immune response. Thus, this study identifies PS as a promising candidate for developing vaccine adjuvants in cancer prevention.
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Adyuvantes Inmunológicos , Inmunidad Celular , Adyuvantes Inmunológicos/farmacología , Animales , Ratones , Inmunidad Celular/efectos de los fármacos , Inmunidad Celular/inmunología , Ratones Endogámicos C57BL , Nucleotidiltransferasas/inmunología , Nucleotidiltransferasas/metabolismo , Nucleotidiltransferasas/genética , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/efectos de los fármacos , Interferón Tipo I/inmunología , Humanos , Femenino , Modelos Animales de Enfermedad , Vacunas contra el Cáncer/inmunología , Vacunas contra el Cáncer/farmacologíaRESUMEN
The last few decades have witnessed the rapid development of organic solar cells (OSCs). High power conversion efficiencies (PCEs) of over 19% have been successfully achieved due to the emergence of fused-ring acceptors (FRAs). However, the high complexity and low yield for the material synthesis result in high production costs of FRAs, limiting the further commercial application of OSCs. In contrast, nonfused ring acceptors (NFRAs) with the merits of facile synthesis, high yield, and preferable stability can promote the development of low-cost OSCs. Currently, the PCEs of NFRAs-based OSCs have exceeded 17%, which is expected to reach efficiency comparable to that of the FRAs-based OSCs. This review describes the advantages of the recent advances in NFRAs, which emphasizes exploring how the chemical structures of NFRAs influence molecular conformation, aggregation, and packing modes. In addition, the further development of NFRA materials is prospected from molecular design, morphological control, and stability perspectives.
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Exonuclease III (Exo III) has been generally used as a double-stranded DNA (dsDNA)-specific exonuclease that does not degrade single-stranded DNA (ssDNA). Here, we demonstrate that Exo III at concentrations above 0.1 unit/µL can efficiently digest linear ssDNA. Moreover, the dsDNA specificity of Exo III is the foundation of many DNA target recycling amplification (TRA) assays. We demonstrate that with 0.3 and 0.5 unit/µL Exo III, the degradation of an ssDNA probe, free or fixed on a solid surface, was not discernibly different, regardless of the presence or absence of target ssDNA, indicating that Exo III concentration is critical in TRA assays. The study has expanded the Exo III substrate scope from dsDNA to both dsDNA and ssDNA, which will reshape its experimental applications.
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Técnicas Biosensibles , ADN de Cadena Simple , Exodesoxirribonucleasas , ADN/metabolismo , Límite de DetecciónRESUMEN
Rapid, sensitive, and accurate identification of pathogens is vital for preventing and controlling fish disease, reducing economic losses in aquaculture, and interrupting the spread of food-borne diseases in human populations. Herein, we proposed a hybridization chain reaction (HCR) cascaded dual-signal amplification platform for the ultrasensitive and specific detection of pathogenic microorganisms. A couple of specific primers for target bacterial 16S rRNAs were used to obtain amplified target single-stranded DNAs (AT-ssDNA). Then, AT-ssDNA initiated HCR amplification along with the opening of fluorophore (FAM) and a quencher (BHQ1) labeled hairpin reporter probe (H1), and the FAM fluorescence signal recovered. The proposed strategy could achieve a detection limit down to 0.31 CFU/mL for Staphylococcus aureus (S. aureus), 0.49 CFU/mL for Escherichia coli (E. coli) in buffer, and a linear range from 1 to 1 × 106 CFU/mL for S. aureus, 1 to 1 × 107 CFU/mL for E. coli. Furthermore, this platform enabled sensitive and precise detection of pathogenic microorganisms in complex samples such as fish blood and different organ tissues (large intestine, gallbladder, heart, liver, ren, gill, skin), which shows great potential in disease prevention and control in aquatic products.
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Técnicas Biosensibles , Escherichia coli , Animales , Humanos , Staphylococcus aureus/genética , Límite de Detección , Hibridación de Ácido Nucleico , Colorantes FluorescentesRESUMEN
Diabetic nephropathy (DN) is the predominant cause of end-stage renal disease globally. Diosgenin (DSG) has been reported to play a protective role in podocyte injury in DN. The present study aimed to explore the role of DSG in DN, as well as its mechanism of action in a high glucose (HG)-induced in vitro model of DN in podocytes. Cell viability, apoptosis, inflammatory response and insulin-stimulated glucose uptake were evaluated using Cell Counting Kit-8, TUNEL, ELISA and 2-deoxy-D-glucose assay, respectively. In addition, the expression of AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1)/NF-κB signaling-related proteins in podocyte cells was measured using western blotting. The results indicated that DSG enhanced the viability of podocytes after HG exposure, but inhibited inflammatory damage and attenuated insulin resistance. Moreover, DSG induced the activation of the AMPK/SIRT1/NF-κB signaling pathway. Furthermore, treatment with compound C, an inhibitor of AMPK, counteracted the protective effects of DSG on HG-induced podocyte cells. Therefore, DSG may be a potential therapeutic compound for the treatment of diabetic nephropathy.
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Background: Sphingosine kinase 1 (SPHK1) is a key enzyme that catalyzes the phosphorylation of sphingosine. Recent studies reported SPHK1 to be associated with renal cell carcinoma (RCC) progression by inducing targeted therapy resistance. However, the expression and the clinical significance of SPHK1 on RCC in those having received targeted therapy have not been elucidated. The present study explored the expression of SPHK1 in RCC tissues from targeted therapy recipients, the correlation of SPHK1 with clinicopathological parameters, and the effect of SPHK1 on RCC patient prognosis. Methods: Differential gene expression analysis of RCC treated with and without targeted therapy was performed. The correlations of SPHK1 expression with clinical parameters of RCC were examined. Gene set enrichment analysis (GSEA) was performed to clarify the potential role of SPHK1 associated with targeted therapy resistance. The value of SPHK1 as a diagnostic marker for RCC was also evaluated. The Kaplan-Meier method was applied to analyze the correlation between SPHK1 expression and patient survival rate by using the clinical data from patients with RCC. Results: Significant overexpression of SPHK1 was detected in RCC treated with targeted therapy. SPHK1 expression was closely correlated with RCC progression-related clinicopathological parameters. Therefore, elevated SPHK1 could effectively diagnose RCC and distinguish RCC with an advanced clinical stage and a high pathological grade. SPHK1 was associated with the stemness of RCC cells via the activation of the Wnt, Hedgehog, or Notch signaling pathways in targeted drug-treated or untreated RCC. Survival analysis of a large cohort of RCC samples indicated overexpression of SPHK1 to be inversely correlated with the overall and disease-free survival of patients with RCC. Conclusions: Our study indicated that SPHK1 associated with targeted therapy resistance could serve as a potential prognostic marker and a valuable biomarker of response to angiogenic agents in RCC.
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Diabetic encephalopathy (DE) is one of the major chronic complications of diabetes mellitus. This study aims to investigate the inhibitory effect of berberine (BBR) on the damage of PC12 cells induced by high glucose (HG). Differentiated PC12 cells were treated with different concentrations of glucose/BBR. The cell morphology, cell viability, lactate dehydrogenase (LDH) activity, apoptosis, oxidative stress (OS), mitochondrial structure, mitochondrial membrane potential (MMP), mitochondrial complex I-V activity, and adenosine triphosphate (ATP) levels were evaluated. The mRNA and protein levels of the Keap1/Nrf2/ARE pathway-related genes were assessed by RT-qPCR and Western blot. High-dose BBR and HG jointly treated-PC12 cells were treated with Nrf2-specific inhibitor ML385 to further verify whether Nrf2 was the target of BBR. The results showed that BBR inhibited cell damage, OS, and mitochondrial dysfunction induced by HG. The inhibitory effect of high BBR was more significant. The Keap1/Nrf2/ARE pathway was inhibited in PC12 cells induced by HG. BBR could activate the Keap1/Nrf2/ARE pathway, thus up-regulating the expression levels of antioxidant enzymes. ML385 antagonized the ameliorating effect of BBR on OS and mitochondrial dysfunction. The conclusion is that BBR can activate the Keap1/Nrf2/ARE pathway, upregulate the expression patterns of antioxidant enzymes, and reduce cell damage, OS, and mitochondrial dysfunction of PC12 cells induced by HG.
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Berberina , Ratas , Animales , Células PC12 , Berberina/farmacología , Berberina/metabolismo , Factor 2 Relacionado con NF-E2/genética , Antioxidantes/metabolismo , Proteína 1 Asociada A ECH Tipo Kelch/genética , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Transducción de Señal , Estrés Oxidativo , Glucosa/metabolismo , MitocondriasRESUMEN
This study investigates the therapeutic effect and the underlying mechanisms of ergothioneine (EGT) on the testicular damage caused by varicocele (VC) in vivo, in vitro, and in silico. This preclinical study combines a series of biological experiments and network pharmacology analyses. A total of 18 Sprague Dawley (SD) male rats were randomly and averagely divided into three groups: the sham-operated, VC model, and VC model with EGT treatment (VC + EGT) groups. The left renal vein of the VC model and the VC + EGT groups were half-ligated for 4 weeks. Meanwhile, the VC + EGT group was intragastrically administrated with EGT (10 mg/kg). GC1 and GC2 cells were exposed to H2 O2 with or without EGT treatment to re-verify the conclusion. The structure disorder of seminiferous tubules ameliorated the apoptosis decrease in the VC rats receiving EGT. EGT can also increase the sperm quality of the VC model rats (p < 0.05). The exposure to H2 O2 decreased proliferation and increased apoptosis of GC1 and GC2 cells, which was revisable by adding EGT to the plates (p < 0.05). The network pharmacology and molecular docking were conducted to explore the potential targets of EGT in VC, and HSP90AA1 was identified as the pivotal gene, which was validated by western blot, immunohistochemistry, and RT-qPCR both in vivo and in vitro (p < 0.05). Overall, EGT attenuates the testicular injury in the VC model both in vivo and in vitro by potentially potentiating the expression of HSP90AA1.
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Ergotioneína , Varicocele , Humanos , Ratas , Masculino , Animales , Ergotioneína/farmacología , Ratas Sprague-Dawley , Varicocele/tratamiento farmacológico , Varicocele/metabolismo , Simulación del Acoplamiento Molecular , Semen/metabolismo , Testículo/metabolismo , Proteínas HSP90 de Choque Térmico/metabolismo , Proteínas HSP90 de Choque Térmico/uso terapéuticoRESUMEN
MicroRNA (miRNA) play a vital role in the pathological development of many diseases. It is considered to be the diagnosis and potential biomarkers of prognosis. Herein, we proposed Bis-enzyme cascade Platform by combining T7 RNA polymerase and CRISPR-Cas12a (BPTC) for a miRNA detection. In the proposed BPTC, the RNA to DNA conversion ability of phi29 amplification and trans-cleavage of CRISPR-Cas12a are combined. The target miRNA can be amplified after binding to the recognizer ssDNA, and then transcribed the CRISPR-derived RNA (crRNA) by T7 RNA polymerase. The produced crRNA can thereby be assembled by CRISPR-Cas12a and recognized with its target dsDNA, thus triggered its trans-cleavage towards surrounding fluorescent reporters, labeled with a fluorophore and a corresponding quenching group. Based on the bis-enzyme cascade system, the biosensor shows highly sensitivity and excellent specificity. Moreover, this study provided a novel all-in-one detect strategy for miRNA and may open a new idea for the design of CRISR-Cas-based miRNA biosensing platforms.
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Técnicas Biosensibles , MicroARNs , Sistemas CRISPR-Cas , MicroARNs/genética , División del ADN , ADN de Cadena Simple , ADNRESUMEN
Purpose: We aimed to assess the efficacy of the Jiang Tang San Huang (JTSH) tablet for the treatment of patients with type 2 diabetes mellitus (T2DM). Methods: All data for this retrospective cohort study were acquired from the outpatient clinic database of our institution, and all enrolled patients received JTSH tablet for at least two months. Overall, 147 patients were included in the analysis. The primary outcome was patient-reported outcomes on the efficacy of the JTSH tablets using a questionnaire survey. Correlation analysis evaluated the duration of JTSH tablet administration and glycemic control in patients with T2DM. The secondary outcome measures included: changes in glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), 2-hour postprandial blood glucose, homeostasis model assessment of insulin resistance index (HOMA-IR) and homeostasis model assessment of ß-cell function (HOMA-ß) after 2 months of treatment with JTSH tablets. Results: Overall,120 patients (81.63%) reported a JTSH tablet treatment satisfaction score of ≥60 points, and believed that JTSH tablets had satisfactory hypoglycemic effects and could improve symptoms. The average duration of JTSH tablet treatment was 2.57±1.45 years. Overall, 111 patients achieved good blood glucose control, while 36 patients had poor glycemic control. Multivariate logistic regression model analysis showed that taking JTSH tablets for 1 year might reduce the risk of poor hypoglycemic effect by 17.00% (Risk ratio=0.830, 95% confidence interval:0.578, 1.021, P=0.066). Compared with the baseline data, the levels of HbA1c, FPG and HOMA-IR decreased significantly and HOMA-ß levels increased significantly (P<0.05). Conclusion: Good blood glucose control may be positively correlated with the duration of JTSH tablets administration. Patients with T2DM were satisfied with the anti-diabetic effects of JTSH tablets, which can significantly reduce blood glucose and insulin resistance, and improve the function of islet cells.
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Background: ACO1 and IREB2 are two homologous cytosolic regulatory proteins, which sense iron levels and change iron metabolism-linked molecules. These two genes were noticeably decreased in kidney renal clear cell carcinoma (KIRC), which confer poor survival. Meanwhile, there is a paucity of information about the mechanisms and clinical significance of ACO1 and IREB2 downregulation in renal cancers. Methods: The expression profiles of ACO1 and IREB2 were assessed using multiple public data sets via several bioinformatics platforms. Clinical and pathological information was utilized to stratify cohorts for comparison. Patient survival outcomes were evaluated using the Kaplan-Meier plotter, a meta-analysis tool. The correlations of ACO1 and IREB2 with ferroptosis were further evaluated in The Cancer Genome Atlas (TCGA)-KIRC database. Tumor immune infiltration was analyzed using the CIBERSORT, TIMER, and GEPIA data resources. ACO1 antagonist sodium oxalomalate (OMA) and IREB2 inhibitor sodium nitroprusside (SNP) was used to treat renal cancer ACHN cells together with sorafenib. Results: KIRC patients with low ACO1 or IREB2 contents exhibited a remarkably worse survival rate in contrast with those with high expression in Kaplan-Meier survival analyses. Meanwhile, ACO1 and IREB2 regulate autophagy-linked ferroptosis along with immune cell invasion in the tumor microenvironment in KIRC patients. Blocking the activation of these two genes by their inhibitors OMA and SNP ameliorated sorafenib-triggered cell death, supporting that ACO1 and IREB2 could be participated in its cytotoxic influence on renal cancer cells. Conclusion: ACO1 and IREB2 downregulation in renal cancers were correlated with cancer aggressiveness, cellular iron homeostasis, cytotoxic immune cell infiltration, and patient survival outcomes. Our research is integral to verify the possible significance of ACO1 and IREB2 contents as a powerful signature for targeted treatment or novel immunotherapy in clinical settings.
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CRISPR-Cas systems have been employed to detect a large variety of pathogenic microorganisms by simply changing the guide RNA sequence. However, these platforms usually rely on nucleic acid extraction and amplification to achieve good sensitivity. Herein, we developed a new platform for the highly specific and sensitive detection of live staphylococcus aureus (S. aureus) based on an Aptamer-based Cas14a1 Biosensor (ACasB), without the need for nucleic acid extraction or amplification. First, the S. aureus specific aptamer was hybrid with a blocker DNA. After the live S. aureus was added, the blocker can be released upon bacteria-aptamer binding. Finally, the released blocker can activate Cas14a1 protein by binding with the sgRNA to generate a change of fluorescent intensity. The ACasB indicates high specificity and sensitivity: it can directly distinguish 400 CFU/ml live S. aureus cells. Comparable to qPCR, the Cas14a1-aptamer biosensor can detect S. aureus with 100% accuracy in complex samples. Therefore, this ACasB for the on-site detection of live S. aureus can broaden its applications in food safety and environmental monitoring.
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Aptámeros de Nucleótidos , Técnicas Biosensibles , Infecciones Estafilocócicas , Aptámeros de Nucleótidos/química , ADN , Humanos , Infecciones Estafilocócicas/diagnóstico , Staphylococcus aureus/química , Staphylococcus aureus/genéticaRESUMEN
BACKGROUND: In bladder cancer, up to 70% of patients will relapse after resection within 5 years, in which the mechanism underlying the recurrence remains largely unclear. METHODS: Quantitative real-time PCR, western blot and immunohistochemistry were conducted. The assays of tumor sphere formation and tumor xenograft were further performed to assess the potential biological roles of ATF5 (activating transcription factor 5). Chromatin immunoprecipitation-qPCR and luciferase activity assays were carried out to explore the potential molecular mechanism. A two-tailed paired Student's t-test, χ2 test, Kaplan Meier and Cox regression analyses, and Spearman's rank correlation coefficients were used for statistical analyses. RESULTS: ATF5 is elevated in bladder urothelial cancer (BLCA) tissues, especially in recurrent BLCA, which confers a poor prognosis. Overexpressing ATF5 significantly enhanced, whereas silencing ATF5 inhibited, the capability of tumor sphere formation in bladder cancer cells. Mechanically, ATF5 could directly bind to and stimulate the promoter of DVL1 gene, resulting in activation of Wnt/ß-catenin pathway. CONCLUSIONS: This study provides a novel insight into a portion of the mechanism underlying high recurrence potential of BLCA, presenting ATF5 as a prognostic factor or potential therapeutic target for preventing recurrence in BLCA.
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We have successfully isolated and characterized the zinc carbamate complex (phen)Zn(OAc)(OC(=O)NHPh) (1; phen=1,10-phenanthroline), formed as an intermediate during the Zn(OAc)2 /phen-catalyzed synthesis of organic carbamates from CO2 , amines, and the reusable reactant Si(OMe)4 . Density functional theory calculations revealed that the direct reaction of 1 with Si(OMe)4 proceeds via a five-coordinate silicon intermediate, forming organic carbamates. Based on these results, the catalytic system was improved by using Si(OMe)4 as the reaction solvent and additives like KOMe and KF, which promote the formation of the five-coordinated silicon species. This sustainable and effective method can be used to synthesize various N-aryl and N-alkyl carbamates, including industrially important polyurethane raw materials, starting from CO2 under atmospheric pressure.
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AIMS: Liver hepatocellular carcinoma (LIHC) is the main manifestation of primary liver cancer, with low survival rate and poor prognosis. Medical decision-making process of LIHC is so complex that new biomarkers for diagnosis and prognosis have yet to be explored, this study aimed to identify the genes involved in the pathophysiology of LIHC and biomarkers that can be used to predict the prognosis of LIHC. METHODS: Six Gene Expression Omnibus (GEO) datasets selected from GEO were screened and integrated to find out the differential expression genes (DEGs) obtained from LIHC and normal hepatic tissues. The Gene Ontology and Kyoto Encyclopaedia of Genes and Genomes pathway enrichment analysis of DEGs was implemented by DAVID. The Protein-protein interaction network was performed via STRING. In addition, Cox regression model was used to construct a gene prognostic signature. RESULTS: We ascertained 10 hub genes, nine of them (CDK1, CDC20, CCNB1, Thymidylate synthetase, Nuclear division cycle80, NUF2, MAD2L1, CCNA2 and BIRC5) as biomarkers of progression in LIHC patients. We also build a six gene prognosis signature (SOCS2, GAS2L3, NLRP5, TAF3, UTP11 and GAGE2A), which can be implemented to predict over survival effectively. CONCLUSIONS: We revealed promising genes that may participate in the pathophysiology of LIHC, and found available biomarkers for LIHC prognosis prediction, which were significant for researchers to further understand the molecular basis of LIHC and direct the synthesis medicine of LIHC.
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Biomarcadores de Tumor/genética , Carcinoma Hepatocelular/genética , Perfilación de la Expresión Génica , Neoplasias Hepáticas/genética , Transcriptoma , Carcinoma Hepatocelular/mortalidad , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/terapia , Toma de Decisiones Clínicas , Biología Computacional , Bases de Datos Genéticas , Regulación Neoplásica de la Expresión Génica , Redes Reguladoras de Genes , Humanos , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/terapia , Análisis de Secuencia por Matrices de Oligonucleótidos , Valor Predictivo de las Pruebas , Pronóstico , Mapas de Interacción de ProteínasRESUMEN
A direct synthesis of carbamates from amines and carbon dioxide in the presence of Ti(OR)4 (R=nBu (1), Me (2), Et (3), nPr (4)) was investigated. Aniline was reacted with titanium n-butoxide (1) in the presence of carbon dioxide (5â MPa) to give the corresponding n-butyl N-phenylcarbamate (BPC) in nearly quantitative yield (99 %) within 20â min. Furthermore, 1 could be regenerated upon reaction with n-butanol during water removal. The recovered 1 could then be reused in a subsequent reaction.
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Several zinc salts were employed as catalysts for the synthesis of carbamates directly from aromatic amines, CO2 , and silicate esters. Zn(OAc)2 offered the best performance among the salts tested. The addition of an N-donor ligand such as 1,10-phenanthroline increased the yield. The best catalytic performance of Zn(OAc)2 can be explained by carboxylate-assisted proton activation. The interaction between the substrate and the catalyst can be observed by chemical shifts in 1 H and 15 Nâ NMR spectra. Isocyanate was a key intermediate, which was generated from amine and CO2 . Silicate ester was finally converted to siloxane, which was determined by 29 Siâ NMR. The commercially available catalyst system could be reused. The yield of isolated carbamate could reach up to 96 % with various substrates, and the catalytic reaction was amine-selective in the presence of other functional groups.