Olgotrelvir, a dual inhibitor of SARS-CoV-2 Mpro and cathepsin L, as a standalone antiviral oral intervention candidate for COVID-19.

BACKGROUND: Oral antiviral drugs with improved antiviral potency and safety are needed to address current challenges in clinical practice for treatment of COVID-19, including the risks of rebound, drug-drug interactions, and emerging resistance. METHODS: Olgotrelvir (STI-1558) is designed as a next-generation antiviral targeting the SARS-CoV-2 main protease (Mpro), an essential enzyme for SARS-CoV-2 replication, and human cathepsin L (CTSL), a key enzyme for SARS-CoV-2 entry into host cells. FINDINGS: Olgotrelvir is a highly bioavailable oral prodrug that is converted in plasma to its active form, AC1115. The dual mechanism of action of olgotrelvir and AC1115 was confirmed by enzyme activity inhibition assays and co-crystal structures of AC1115 with SARS-CoV-2 Mpro and human CTSL. AC1115 displayed antiviral activity by inhibiting replication of all tested SARS-CoV-2 variants in cell culture systems. Olgotrelvir also inhibited viral entry into cells using SARS-CoV-2 Spike-mediated pseudotypes by inhibition of host CTSL. In the K18-hACE2 transgenic mouse model of SARS-CoV-2-mediated disease, olgotrelvir significantly reduced the virus load in the lungs, prevented body weight loss, and reduced cytokine release and lung pathologies. Olgotrelvir demonstrated potent activity against the nirmatrelvir-resistant Mpro E166 mutants. Olgotrelvir showed enhanced oral bioavailability in animal models and in humans with significant plasma exposure without ritonavir. In phase I studies (ClinicalTrials.gov: NCT05364840 and NCT05523739), olgotrelvir demonstrated a favorable safety profile and antiviral activity. CONCLUSIONS: Olgotrelvir is an oral inhibitor targeting Mpro and CTSL with high antiviral activity and plasma exposure and is a standalone treatment candidate for COVID-19. FUNDING: Funded by Sorrento Therapeutics.

[Effect of vitamin D binding protein gene polymorphism on susceptibility and prognosis of severe acute pancreatitis].

OBJECTIVE: To investigate the effect of vitamin D binding protein (DBP) gene polymorphism on susceptibility and prognosis of severe acute pancreatitis (SAP). METHODS: A prospective study was conducted. Eighty-three patients with SAP who were admitted to the department of general surgery of Tianjin Fifth Central Hospital from March 2018 to March 2021 were selected as the research objects, and 83 healthy people in the same period were selected as controls. Peripheral blood RNA was extracted and reverse transcribed into cDNA, and the genotype and allele frequency of DBP gene rs7041 locus were detected by fluorescence quantitative analyzer. Hardy-Weinberg equilibrium was used to test the genetic balance. On the day of admission, serum C-reactive protein (CRP) level was detected by scattering immunoturbidimetry, serum procalcitonin (PCT) level was detected by electrochemiluminescence, serum DBP level was detected by enzyme-linked immunosorbent assay (ELISA), and neutrophil to lymphocyte ratio (NLR) was calculated automatically by the instrument. The length of intensive care unit (ICU) stay, the length of hospital stay and prognosis during hospitalization of patients were statistically analyzed. Multivariate Logistic regression analysis was used to screen the influencing factors of SAP occurrence. RESULTS: The results of Hardy-Weinberg equilibrium test showed that the distribution of gene polymorphisms in the two groups of subjects conformed to the law of genetic equilibrium. The frequencies of TT genotype and T allele of DBP gene rs7041 locus in the patients of SAP group were significantly higher than those in the healthy control group [TT genotype: 34.94% (29/83) vs. 9.64% (8/83), T allele: 55.42% (92/166) vs. 38.55% (64/166), both P < 0.01], and the frequency of GT genotype was significantly lower than that in the healthy control group [40.96% (34/83) vs. 57.83% (48/83), P < 0.05]. There was no significant difference in the frequency of GG genotype between the healthy control group and SAP group [32.53% (27/83) vs. 24.10% (20/83), P > 0.05]. Further multivariate Logistic regression analysis showed that TT genotype [odds ratio (OR) = 2.831, 95% confidence interval (95%CI) was 1.582-5.067, P < 0.001] and T allele (OR = 2.533, 95%CI was 1.435-4.472, P < 0.001) of DBP gene rs7041 locus were independent risk factors for SAP in healthy people, while GT genotype was a protective factor for SAP (OR = 0.353, 95%CI was 0.143-0.868, P = 0.041). The levels of CRP, PCT, NLR and DBP in patients with TT genotype of DBP gene rs7041 locus were significantly higher than those in patients with GG/GT genotype on the day of admission in SAP group [CRP (mg/L): 43.25±13.25 vs. 31.86±12.83, PCT (µg/L): 1.53±0.24 vs. 1.21±0.20, NLR: 3.15±0.53 vs. 2.71±0.48, DBP (µg/L): 87.78±19.64 vs. 70.58±18.67, all P < 0.01]. The length of ICU stay in patients with TT genotype of DBP gene rs7041 locus in SAP group was significantly longer than that in patients with GG/GT genotype (days: 11.35±1.58 vs. 9.71±1.35, P < 0.01). The length of hospital stay of patients with TT genotype was longer than that of patients with GG/GT genotype (days: 23.41±3.64 vs. 23.17±3.57), and the in-hospital mortality was higher than that of patients with GG/GT genotype [34.48% (10/29) vs. 29.63% (16/54)], but the difference was not statistically significant (both P > 0.05). CONCLUSIONS: The risk of SAP was significantly increased in patients with TT genotype of rs7041 locus of DBP gene, and the mechanism may be related to the increase of DBP expression. And carrying the TT genotype will prolong the ICU hospitalization time of SAP patients, but the effect on prognosis is not obvious.

Novel hypoxia-related gene signature for predicting prognoses that correlate with the tumor immune microenvironment in NSCLC.

Background: Intratumoral hypoxia is widely associated with the development of malignancy, treatment resistance, and worse prognoses. The global influence of hypoxia-related genes (HRGs) on prognostic significance, tumor microenvironment characteristics, and therapeutic response is unclear in patients with non-small cell lung cancer (NSCLC). Method: RNA-seq and clinical data for NSCLC patients were derived from The Cancer Genome Atlas (TCGA) database, and a group of HRGs was obtained from the MSigDB. The differentially expressed HRGs were determined using the limma package; prognostic HRGs were identified via univariate Cox regression. Using the least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression, an optimized prognostic model consisting of nine HRGs was constructed. The prognostic model's capacity was evaluated by Kaplan‒Meier survival curve analysis and receiver operating characteristic (ROC) curve analysis in the TCGA (training set) and GEO (validation set) cohorts. Moreover, a potential biological pathway and immune infiltration differences were explained. Results: A prognostic model containing nine HRGs (STC2, ALDOA, MIF, LDHA, EXT1, PGM2, ENO3, INHA, and RORA) was developed. NSCLC patients were separated into two risk categories according to the risk score generated by the hypoxia model. The model-based risk score had better predictive power than the clinicopathological method. Patients in the high-risk category had poor recurrence-free survival in the TCGA (HR: 1.426; 95% CI: 0.997-2.042; p = 0.046) and GEO (HR: 2.4; 95% CI: 1.7-3.2; p < 0.0001) cohorts. The overall survival of the high-risk category was also inferior to that of the low-risk category in the TCGA (HR: 1.8; 95% CI: 1.5-2.2; p < 0.0001) and GEO (HR: 1.8; 95% CI: 1.4-2.3; p < 0.0001) cohorts. Additionally, we discovered a notable distinction in the enrichment of immune-related pathways, immune cell abundance, and immune checkpoint gene expression between the two subcategories. Conclusion: The proposed 9-HRG signature is a promising indicator for predicting NSCLC patient prognosis and may be potentially applicable in checkpoint therapy efficiency prediction.

The diagnostic role of CT, MRI/MRCP, PET/CT, EUS and DWI in the differentiation of benign and malignant IPMN: A meta-analysis.

PURPOSE: The objective of this study was to assess the diagnostic properties of computed tomography (CT), magnetic resonance imaging (MRI/MRCP) /Magnetic Resonance Cholangiopancreatography (MRCP), positron emission tomography/computed tomography (PET/CT), endoscopic ultrasound (EUS) and diffusion-weighted magnetic resonance imaging (DWI) in distinguishing benign and malignant intraductal papillary mucinous neoplasm (IPMN). MATERIALS AND METHODS: Eligible databases were searched for eligible studies, published through July 2020 on the diagnostic accuracy of these modalities. Diagnostic accuracy parameters, including sensitivity, specificity, diagnostic odds ratio (DOR), and summary receiver operating characteristic curves (SROC) were calculated. Meta-regression was performed to identify the source of heterogeneity. RESULTS: In total, 28 studies were included. Pooled sensitivities for CT, MRI/MRCP, PET/CT, EUS and DWI were 0.7, 0.76, 0.8, 0.6 and 0.72, respectively. Pooled specificities were 0.78, 0.83, 0.9, 0.8 and 0.97. The DORs were 8, 16, 35, 6 and 88. The areas under the curve (AUC) of SROC for CT, MRI/MRCP/MRCP, PET/CT, EUS and DW were 0.8, 0.87, 0.92, 0.79 and 0.82, respectively. CONCLUSION: PET/CT showed the highest AUC and the overall diagnostic accuracy results support the use of MRI/MRCP, PET/CT interchangeably as a first-line examination in the diagnosis of malignant IPMN. With regard to DWI, EUS and CT, each techniques have their advantages and supportive to MRI/MRCP.

Circular RNA hsa_circ_0102231 sponges miR-145 to promote non-small cell lung cancer cell proliferation by up-regulating the expression of RBBP4.

Circular RNAs (circRNAs) are important regulators in various cancers. Previous studies have found that hsa_circ_0102231 is an oncogene in lung adenocarcinoma. Here, we investigated its mechanism in the development of non-small cell lung cancer (NSCLC). We detected the levels of hsa_circ_0102231 in five NSCLC cell lines and one normal bronchial epithelium cell line. The interaction between hsa_circ_0102231 and miR-145 was predicted and confirmed by pull-down and luciferase assays. The nuclear mass separation assay and fluorescence in situ hybridization were used to detect the distribution of hsa_circ_0102231. Cell Counting Kit-8 and Transwell assays were used to assess the cell proliferative and invasive ability. Western blot and RT-qPCR, respectively, detected the protein and mRNA levels of RBBP4. The RBBP4 promoter activity was detected with a luciferase assay. We found that hsa_circ_0102231 level was higher in NSCLC cells. hsa_circ_0102231 is mainly localized to the cytoplasm. hsa_circ_0102231 promotes NSCLC cell proliferation and invasion by sponge for miR-145. miR-145 significantly decreases the RBBP4 promoter activity, and its mRNA and protein levels. RBBP4 is an oncogene to promote proliferation and invasion ability. Our findings suggest that hsa_circ_0102231 promotes proliferation and invasion by mediating the miR-145/RBBP4 axis in NSCLC, indicating that it might be a potential target for NSCLC treatment.

miR-424-3p Contributes to the Malignant Progression and Chemoresistance of Gastric Cancer.

BACKGROUND: Gastric cancer (GC) is one of the most common and lethal malignancies worldwide. Therefore, a better understanding of the mechanism of its malignant progression and chemoresistance will be helpful for the treatment of patients with GC. METHODS: The gene expression profiles downloaded from GEO database and the TargetScan Human were used to identify the key regulation model based on miRNA by bioinformatics analyses. The regulation of miRNA to target was clarified by luciferase assay, qPCR, and Western blotting. Then, the in vitro and in vivo experiments were further conducted by overexpression or knockdown of miRNA and/or target to examine the regulation effects and clarify the mechanism. RESULTS: In the present study, miR-424-3p was identified to be differentially expressed among normal gastric, GC, and chemoresistant GC tissues. Target analysis results indicated that ABCC2, a chemoresistance-related gene, was a regulated target of miR-424-3p. The in vitro and in vivo experiment results further demonstrated that miR-424-3p relied on ABCC2-induced chemoresistance to promote GC proliferation and metastasis. CONCLUSION: Overall, this study revealed that miR-424-3p contributed to the malignant progression and chemoresistance of GC. Thus, miR-424-3p could be a potential target for the treatment of GC.

miR-212 as potential biomarker suppresses the proliferation of gastric cancer via targeting SOX4.

BACKGROUND: Circulating microRNAs that post-transcriptionally regulate gene expressions have been reported as promising biomarkers in cancer monitoring. This study was to identify the potential role of circulating miR-212 in gastric cancer and whether it could serve as a novel biomarker for gastric cancer. METHODS: We detected the serum levels of miR-212 in 100 health people and 110 gastric cancer patients and analyzed the relationships of the serum level of miR-212 with gastric cancer. We detected the expression of miR-212 in human gastric mucosal epithelial cell line (GES-1) and human gastric cancer cell lines (NCI-N87 and SNU-16) using qRT-PCR. Then, we detected the role of 5-aza-deoxycytidine on the epigenetic regulation of miR-212 in human gastric cancer cell lines. Furthermore, luciferase reporter assay was used to detect binding activity of miR-212 on SOX4 mRNA, and their functions on the cell proliferation and apoptosis. RESULTS: The expression of miR-212 was higher in health people than that in gastric cancer patients, higher in gastric mucosal epithelial cell line than that in gastric cancer cells. miR-212 can be a circulating biomarker and an independent prognostic factor of gastric cancer. Moreover, miR-212 can directly regulate the 3'UTR of SOX4 mRNA to suppress p53 and Bax, resulting gastric cancer cells proliferation inhibition and apoptosis induction. CONCLUSION: Our study demonstrated that miR-212 was epigenetically downregulated in gastric cancer, and resulting low level of miR-212 can be a potential circulating biomarker and poor prognosis predicator of gastric cancer.

DERL3 functions as a tumor suppressor in gastric cancer.

BACKGROUND: Gastric cancer is a common malignant tumor in the clinic with a high mortality rate, ranking the first among malignant tumors of the digestive system. Early gastric cancer exhibits no specific clinical symptoms and signs, and most of the patients were diagnosed as advanced gastric cancer. The prognosis is poor, and the 5-year overall survival rate is still lower than 30%, seriously threatening people's life and health. However, the pathogenesis of gastric cancer is still unclear. METHODS: This study aimed to identify methylated differentially expressed genes in gastric cancer and to study the cellular functions and pathways that may be involved in its regulation, as well as the biological functions of key methylated differentially expressed genes. The gene expression data set and methylation data set of gastric cancer genes based on TCGA were analyzed to identify prognostic methylated genes. RESULTS: This study showed that the methylation of the DERL3 promoter was correlated with the clinical analysis of tumors. Further studies were conducted on genes co-expressed with DERL3, whose functions and pathways to inhibit gastric cancer were adaptive immune response, T cell activation, immune response-regulating pathway, cell surface on molecules, and natural killer cell-mediated cytotoxicity. Finally, cell proliferation assay, cell scratch assay, and cell invasion assay confirmed that DERL3 as a tumor suppressor gene inhibited the malignant evolution of gastric cancer. CONCLUSIONS: The analysis of key methylated differentially expressed genes helped elucidate the epigenetic regulation mechanism in the development of gastric cancer. DERL3, as a methylation biomarker, has a predictive and prognostic value in the accurate diagnosis and treatment of gastric cancer and provides potential targets for the precision treatment of gastric cancer. TRIAL REGISTRATION: Not applicable.

miR-876-5p suppresses breast cancer progression through targeting TFAP2A.

MicroRNAs (miRNAs) are widely expressed in human cells and closely associated with various types of cancer, including breast cancer. miR-876-5p has been indicated to participate in the tumorigenesis of certain types of cancer, such as hepatocellular carcinoma. Nevertheless, the roles of miR-876-5p in breast cancer remain unclear. In the present study, it was revealed that miR-876-5p expression levels were decreased in breast cancer cells compared with a normal cell line. miR-876-5p ectopic expression suppressed breast cancer cell proliferation and arrested progression of the cell cycle. In addition, miR-876-5p suppressed breast cancer cell migration and invasion. miR-876-5p was demonstrated to directly target transcription factor AP-2-α (TFAP2A) in breast cancer cells, and restoration of TFAP2A rescinded the suppressive role of miR-876-5p. In summary, the results from the present study provide evidence that miR-876-5p suppresses breast cancer progression by regulating cell proliferation, migration and invasion in a TFAP2A-dependent manner.

Prognostic significance of STIP1 expression in human cancer: A meta-analysis.

BACKGROUND: The prognostic significance of stress-induced protein 1 (STIP1) expression in human cancer has been explored in several studies, however, consensus has not been reached. This meta-analysis aimed to summarize the prognostic value of STIP1 expression in cancer. METHODS: Four common databases were searched to seek relevant studies. The meta-analysis was performed to explore the prognostic value of STIP1 expression in overall survival (OS) and clinicopathological parameters in cancer. RESULTS: Nine studies containing 1417 cancer patients were finally included into the meta-analysis. The results showed the prevalence of high STIP1 expression was 0.50 in patients with cancer. Compared to patients with low expression of STIP1, patients with high STIP1 expression tended to have shorter OS [hazard ratio (HR) = 2.15, 95% confidence interval (CI) = 1.68-2.76, P < 0.01]. The subgroup analysis also observed the association between high STIP1 expression and shorter OS in gastrointestinal cancer (HR = 2.02, 95%CI = 1.52-2.69, P < 0.01). The online database cross-validation containing 9502 patients also indicated high STIP1 expression predicted shorter OS (HR = 1.40, P < 0.01) and disease-free survival (DFS) (HR = 1.30, P < 0.01) compared with low STIP1 expression in cancer. Besides, high STIP1 expression was obviously related to earlier lymph node metastasis (P < 0.01) and more advanced clinical stage (P < 0.01) compared with low STIP1 expression in cancer. CONCLUSION: High STIP1 expression was significantly associated with shorter OS, earlier lymph node metastasis and more advanced clinical stage compared with low STIP1 expression in cancer. Therefore, STIP1 expression might be used as a prognostic biomarker for cancer treatment.

miR-519d-3p Inhibits Cell Proliferation and Invasion of Gastric Cancer by Downregulating B-Cell Lymphoma 6.

miR-519d inhibits cell growth, migration, and invasion, but its role in gastric cancer (GC) cells is obscure. We showed that miR-519d-3p was lowly expressed in GC tissues and was associated with the clinical stage and lymph node metastasis of GC tissues. We found that miR-519d-3p repressed cell proliferation and invasion of MGC803 cells and delayed the G1/S phase transition, resulting in decreased cyclin B1 and MMP2 and increased E-cadherin levels. Furthermore, miR-519d-3p targeted and downregulated B-cell lymphoma 6 (BCL6) expression. BCL6 overexpression partially abrogated the suppressive function of miR-519d in MGC803 cells. In conclusion, our study demonstrated that miR-519d-3p functions as a tumor suppressor by targeting and downregulating the expression of BCL6 in GC cells.

miR-320a serves as a negative regulator in the progression of gastric cancer by targeting RAB14.

Gastric cancer (GC) is one of the most common types of malignancy worldwide, with high morbidity and mortality rates. The dysregulation of microRNAs (miRs) has been found to be involved in the carcinogenesis of GC. The present study aimed to investigate the underlying association between GC and miR-320a. Analysis using reverse transcription quantitative polymerase chain reaction indicated that the expression of miR-320a was downregulated and the expression of RAB14 was upregulated in GC tissues and cells, compared with the corresponding controls. MTT, colony formation assays, and flow cytometric analyses were used to evaluate the effect of miR-320a on cell proliferation and the cell cycle. The ectopic expression of miR-320a using miR-320a mimics suppressed cell viability, inhibited G1/S transition, and induced apoptosis in AGS and MKN45 cells. In addition, RAB14 was identified as a direct target gene of miR-320a, according to the results of bioinformatics analysis and a luciferase reporter assay. Downregulation of RAB14 by RAB14-small interfering RNA inhibited the viability of GC cells, which was similar to the phenotype of miR-320a mimics. Furthermore, the reintroduction of RAB14 partially abrogated the miR-320a-mediated downregulation of RAB14 and rescued the miR-320a-induced effects on GC cell growth. These findings suggest a potential novel therapeutic target for the treatment of GC.

Theaflavins suppress tumor growth and metastasis via the blockage of the STAT3 pathway in hepatocellular carcinoma.

Theaflavins, the major black tea polyphenols, have been reported to exhibit promising antitumor activities in several human cancers. However, the role of theaflavins in hepatocellular carcinoma (HCC) is still unknown. In this study, we found that theaflavins could significantly inhibit proliferation, migration, and invasion, and induce apoptosis in HCC cells in vitro. Furthermore, we found that theaflavins inhibited the growth and metastasis of HCC in an orthotopic model and a lung metastasis model. Immunohistochemical analyses and terminal deoxynucleotidyl transferase dUTP nick end-labeling assays showed that theaflavins could suppress proliferation and induce apoptosis in vivo. Theaflavins also suppressed constitutive and inducible signal transducer and activator of transcription 3 (STAT3) phosphorylation. The downstream proteins regulated by STAT3, including the antiapoptotic proteins (Bcl-2 and Survivin) and the invasion-related proteins (MMP-2, MMP-9), were also downregulated after theaflavins treatment. Theaflavins induced apoptosis by activating the caspase pathway. Together, our results suggest that theaflavins suppress the growth and metastasis of human HCC through the blockage of the STAT3 pathway, and thus may act as potential therapeutic agents for HCC.

Aquatic toxicity of nanosilver colloids to different trophic organisms: contributions of particles and free silver ion.

The wide uses of nanosilver (nAg) have resulted in concerns regarding ecotoxicity to aquatic organisms. Some previous studies have found that the toxicity of nAg is due to the nanoparticles themselves, while others have found that ionic silver (Ag(+) ) released by nAg particles plays an important role. In the present study, the authors quantitatively evaluated the relative contribution of nAg particles and Ag(+) to the toxicity to three aquatic organisms of different trophic levels, including an algal species (Raphidocelis subcapitata), a cladoceran species (Chydorus sphaericus), and a freshwater fish larva (Danio rerio). A bare and a polyvinylpyrrolidone (PVP)-coated nAg as well as a monodispersed nAg with a dispersant (DIS-nAg) were examined. The toxicity of the nAg in the form of colloids decreased in the order DIS-nAg > PVP-nAg > Bare-nAg for all three trophic aquatic organisms (in terms of median effect concentration). The DIS-nAg had the highest and Bare-nAg the lowest concentration of free Ag(+) , implying that free Ag(+) cannot be neglected in explaining the toxicity of nAg colloids. Furthermore, the contribution of free Ag(+) to the toxicity of nAg colloids for R. subcapitata was the highest but for D. rerio the lowest, implying that the organisms tested have different accumulation abilities for Ag(+) or nAg particles.

A general and facile one-pot process of isothiocyanates from amines under aqueous conditions.

A general and facile one-pot protocol for the preparation of a broad range of alkyl and aryl isothiocyanates has been developed from their corresponding primary amines under aqueous conditions. This synthetic process involves an in situ generation of a dithiocarbamate salt from the amine substrate by reacting with CS(2) followed by elimination to form the isothiocyanate product with cyanuric acid as the desulfurylation reagent. The choice of solvent is of decisive importance for the successful formation of the dithiocarbamate salt particularly for highly electron-deficient substrates. This novel and economical method is suitable for scale-up activities.

Estrogenic activity of anthraquinone derivatives: in vitro and in silico studies.

Comprehension of the ligand-receptor interactions is a prerequisite for constructing mechanism based quantitative structure-activity relationship (QSAR) models on xenoestrogenic activity. Molecular docking was performed to simulate the interactions between anthraquinone derivative (AQs) molecules and the estrogen receptor alpha (ERalpha). Hydrogen bonding, hydrophobic, and pi-pi interactions were found to be the dominant interactions between AQs and the receptor, which implied the estrogenic activities of the compounds. The recombinant yeast-based assay was employed to determine the estrogenic activities of 20 AQs. On the basis of the observed interactions between the AQs and ERalpha, appropriate molecular structural parameters were computed to develop a QSAR model. The polarizability term, the binding energy, the average molecular polarizability, the most negative formal charge in the molecule, and the average of the negative potentials on the molecular surface were significant parameters explaining the estrogenicity. The developed QSAR model had good robustness, predictive ability, and mechanism interpretability. The interactions between the AQs and ERalpha and the partition ability of the AQs into the biophase are main factors governing the estrogenic activities. Moreover, the applicability domain of the model was described.

Electron-accepting potential of solvents determines photolysis rates of polycyclic aromatic hydrocarbons: experimental and density functional theory study.

Photochemical behaviour of polycyclic aromatic hydrocarbons (PAHs) is strongly dependent on the physical and chemical nature of the media in/on which they exist. To understand the media effects, the photolysis of phenanthrene (PHE) and benzo[a]pyrene (BaP) in several solvents was investigated. Distinct photolysis rate constants for PHE and BaP in the different solvents were observed. Some theoretical parameters reflecting the solvent properties were computed and employed to explain the solvent effects. Acetone competitively absorbed light with PHE and BaP, and the excited acetone molecules played different roles for the photodegradation of PHE and BaP. The photolysis rate constants of PHE and BaP in hexane, isopropanol, ethanol, methanol, acetonitrile and dichloromethane were observed to correlate with the electron-accepting potential of the solvent molecules. Absolute electronegativity of the solvents linearly correlated with the photolytic activity (log k) of the PAHs significantly. The results are important for better understanding the photodegradation mechanism of PAHs in different media.

Palladium-catalyzed benzylic addition of 2-methyl azaarenes to N-sulfonyl aldimines via C-H bond activation.

An efficient protocol for the generation of amines by palladium-catalyzed nucleophilic benzylic addition of 2-methyl-substituted azaarenes to N-sulfonyl aldimines under neutral conditions via C-H bond activation has been developed. This reaction represents a very efficient methodology for the synthesis of heterocycle-containing amines and thus opens a new way to access amines through C-H bond activation.