Free Amino Group Transfer via α-Amination of Native Carbonyls.

We report herein a straightforward transfer of a free amino group (NH2 ) from a commercially available nitrogen source to unfunctionalized, native carbonyls (amides and ketones) resulting in direct α-amination. Primary α-amino carbonyls are readily produced under mild conditions, further enabling diverse in situ functionalization reactions-including peptide coupling and Pictet-Spengler cyclization-that capitalize on the presence of the unprotected primary amine.

Prognostic and functional roles of EIF4G1 in lung squamous cell carcinoma.

Eukaryotic translation initiation factor 4 gamma 1 (EIF4G1) is highly expressed in many cancers and affects their occurrence and development. However, the effect of EIF4G1 on the prognosis, biological function and the relevant mechanism in lung squamous cell carcinoma (LSCC) is unclear. Through clinical cases, Cox's proportional hazard model and Kaplan-Meier plotter survival analysis, we find the expression levels of EIF4G1 are dependent on age and clinical stage, high expression of EIF4G1 could be used to predict the overall survival of LSCC patients. LSCC cell line NCI-H1703, NCI-H226 and SK-MES-1infected with EIF4G1 siRNA are used to detect the function of EIF4G1 with cell proliferation and tumorigenesis in vivo and vitro. The data show that EIF4G1 promotes tumor cell proliferation and the G1/S transition of cell cycle in LSCC, then the biological function of LSCC is effected by the AKT/mTOR pathway. Above all, these results have demonstrated that EIF4G1 promotes LSCC cell proliferation and may represent an indicator of prognosis in LSCC.

Inhibition of HIST1H2AB suppresses the proliferation of lung adenocarcinoma.

BACKGROUND: Lung adenocarcinoma is one of the common causes of cancer-related deaths worldwide. Histone cluster 1 H2A family member b (HIST1H2AB) is a member of the histone H2A family. Bioinformatic analyses have revealed that HIST1H2AB is highly expressed in some cancers and might be an oncogene. However, information on the function of HIST1H2AB in lung adenocarcinoma is limited. METHODS: The expression of HIST1H2AB was analyzed in normal lung, lung adenocarcinoma and paracancerous tissues from The Cancer Genome Atlas (TCGA) database and immunohistochemistry staining. It was further verified in the relative cell lines using real-time quantitative polymerase chain reaction (RT-qPCR). When the adenocarcinoma cells lines (A549 and H1299) were successfully transfected with shHIST1H2AB or an empty plasmid packaged into a lentivirus, cell proliferation was detected using Celigo fluorescence cell-counting, colony formation and annexin V-allophycocyanin assays. Twenty nude mice were subcutaneously injected with A549 cells transfected with shHIST1H2AB or empty plasmid; the tumor size was recorded on day 25 and then measured every 3 days thereafter. The final tumor weight was measured on day 37. Significantly differentially expressed genes were analyzed using a human gene expression array. Furthermore, the potentially relevant genes were verified using RT-qPCR and western blotting. RESULTS: HIST1H2AB was highly expressed in lung adenocarcinoma tissues from TCGA database and immunohistochemistry staining. Similar results were seen in the lung adenocarcinoma cells. When the cells were successfully transfected with shHIST1H2AB or an empty plasmid, downregulation of HIST1H2AB inhibited the growth and promoted the apoptosis of lung adenocarcinoma cells. The xenograft results suggested that HIST1H2AB downregulation delayed tumor growth and reduced tumor weight. Moreover, interferon signaling pathway and four genes (HMGB1, FOXM1, F2RL1 and SLC4A7) might be regulated by HIST1H2AB in the development of lung adenocarcinoma as indicated through gene expression array, RT-qPCR and western blotting analyses. CONCLUSIONS: HIST1H2AB acts as an oncogenic protein and HIST1H2AB inhibition suppresses the proliferation of lung adenocarcinoma cells. It may be a novel target for lung adenocarcinoma therapy.

Direct Synthesis of α-Amino Acid Derivatives by Hydrative Amination of Alkynes.

α-Amino acid derivatives are key components of the molecules of life. The synthesis of α-amino carbonyl/carboxyl compounds is a contemporary challenge in organic synthesis. Herein, we report a practical method for the preparation of α-amino acid derivatives via direct hydrative amination of activated alkynes under mild conditions, relying on sulfinamides as the nitrogen source. Computational studies suggest that the reaction is enabled by a new type of sulfonium [2,3]-sigmatropic rearrangement.

Challenges and Breakthroughs in Selective Amide Activation.

In contrast to ketones and carboxylic esters, amides are classically seen as comparatively unreactive members of the carbonyl family, owing to their unique structural and electronic features. However, recent decades have seen the emergence of research programmes focused on the selective activation of amides under mild conditions. In the past four years, this area has continued to rapidly develop, with new advances coming in at a fast pace. Several novel activation strategies have been demonstrated as effective tools for selective amide activation, enabling transformations that are at once synthetically useful and mechanistically intriguing. This Minireview comprises recent advances in the field, highlighting new trends and breakthroughs in what could be called a new age of amide activation.

Prognostic Model and Nomogram Construction and Validation With an Autophagy-Related Gene Signature in Low-Grade Gliomas.

Background : Autophagy plays a vital role in cancer development. However, the prognostic value of autophagy-related genes (ARGs) in low-grade gliomas (LGG) is unclear. This research aimed to investigate whether ARGs correlated with overall survival (OS) in LGG patients. Methods: RNA-sequencing data were obtained from The Cancer Genome Atlas (TCGA) TARGET GTEx database. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis of ARGs were performed by the "clusterprofile" R package. Cox regression with the wald χ2 test was employed to identify prognostic significant ARGs. Next, the receiver operator characteristic curves were established to evaluate the feasibility of risk score ( riskscore = h 0 ( t ) exp ( ∑ j = 1 n Coef j × X j ) ) and other clinical risk factors to predict prognosis. A nomogram was constructed. Correlations between clinical features and ARGs were further verified by a t-test or Kruskal-Wallis test. In addition, the correlations between autophagy and immune cells were assessed through the single-sample gene set enrichment analysis (ssGSEA) and tumor immune estimation resource database. Last, the prediction model was verified by LGG data downloaded from the Chinese Glioma Genome Atlas (CGGA) database. Results: Overall, 35 DE-ARGs were identified. Functional enrichment analysis showed that these genes were mainly related to oxidative stress and regulation of autophagy. Nine ARGs (BAX, BIRC5, CFLAR, DIRAS3, GRID2, MAPK9, MYC, PTK6, and TP53) were significantly associated with OS. Age (Hazard ratio (HR) = 1.063, 95% CI: 1.046-1.080), grade (HR = 3.412, 95% CI: 2.164-5.379), histological type (HR = 0.556, 95% CI: 0.346-0.893), and risk score (HR = 1.135, 95% CI: 1.104-1.167) were independent prognostic risk factors (all p < 0.05). In addition, BIRC5, CFLAR, DIRAS3, TP53, and risk scores were found to correlate significantly with age and tumor grade (all p < 0.05). Immune cell enrichment analysis demonstrated that the types of immune cells and their expression levels in the high-risk group were significantly different from those in the low-risk group (all p < 0.05). A prognostic nomogram was constructed to predict 1-, 3-, and 5-year survival, and the prognostic value of sorted ARGs were verified in the CGGA database and clinical samples. Conclusion: Our findings suggest that the 9 DE-ARGs' risk score model could serve as diagnostic and prognostic biomarkers. The prognostic nomograms could be useful for individualized survival prediction and improved treatment strategies.

Selective chlorination of iminosydnones for fast release of amide, sulfonamide and urea-containing drugs.

Herein, we describe a methodology for iminosydnone chlorination and we demonstrate the high beneficial effect of this modification on the reactivity of these mesoionic dipoles in strain-promoted cycloaddition reactions. Exploiting their reaction with cyclooctynes, we used these new iminosydnones for bioorthogonal release of amide, urea and sulfonamide containing drugs. Notably, drugs containing a terminal amide function were released for the first time with good kinetic constants.

Deployment of Sulfinimines in Charge-Accelerated Sulfonium Rearrangement Enables a Surrogate Asymmetric Mannich Reaction.

ß-Amino acid derivatives are key structural elements in synthetic and biological chemistry. Despite being a hallmark method for their preparation, the direct Mannich reaction encounters significant challenges when carboxylic acid derivatives are employed. Indeed, not only is chemoselective enolate formation a pitfall (particularly with carboxamides), but most importantly the inability to reliably access α-tertiary amines through an enolate/ketimine coupling is an unsolved problem of this century-old reaction. Herein, we report a strategy enabling the first direct coupling of carboxamides with ketimines for the diastereo- and enantioselective synthesis of ß-amino amides. This conceptually novel approach hinges on the innovative deployment of enantiopure sulfinimines in sulfonium rearrangements, and at once solves the problems of chemoselectivity, reactivity, and (relative and absolute) stereoselectivity of the Mannich process. In-depth computational studies explain the observed, unexpected (dia)stereoselectivity and showcase the key role of intramolecular interactions, including London dispersion, for the accurate description of the reaction mechanism.

Challenges and Breakthroughs in Selective Amide Activation.

In contrast to ketones and carboxylic esters, amides are classically seen as comparatively unreactive members of the carbonyl family, owing to their unique structural and electronic features. However, recent decades have seen the emergence of research programmes focused on the selective activation of amides under mild conditions. In the past four years, this area has continued to rapidly develop, with new advances coming in at a fast pace. Several novel activation strategies have been demonstrated as effective tools for selective amide activation, enabling transformations that are at once synthetically useful and mechanistically intriguing. This Minireview comprises recent advances in the field, highlighting new trends and breakthroughs in what could be called a new age of amide activation.

Direct Carbon Isotope Exchange of Pharmaceuticals via Reversible Decyanation.

The incorporation of carbon-14 allows tracking of organic molecules and provides vital knowledge on their fate. This information is critical in pharmaceutical development, crop science, and human food safety evaluation. Herein, a transition-metal-catalyzed procedure enabling carbon isotope exchange on aromatic nitriles is described. By utilizing the radiolabeled precursor Zn([14C]CN)2, this protocol allows the insertion of the desired carbon tag without the need for structural modifications, in a single step. By reducing synthetic costs and limiting the generation of radioactive waste, this procedure will facilitate the labeling of nitrile containing drugs and accelerate 14C-based ADME studies supporting drug development.

Profiles of autophagy-related genes in esophageal adenocarcinoma.

BACKGROUND: Several studies have demonstrated autophagy was involved in the process of esophageal adenocarcinoma (EAC). The aim of this study was to explore autophagy-related genes (ARGs) correlated with overall survival (OS) in EAC patients. METHODS: Expressions of ARGs in EAC and normal samples were downloaded from TCGA database. GO and KEGG enrichment analyses were used to investigate the ARGs bioinformatics functions. Univariate and multivariate cox regressions were performed to identify prognostic ARGs and the independent risk factors. ROC curve was established to evaluate the feasibility to predict the prognosis. Finally, the correlations between ARGs and clinical features were further explored. In addition, significantly different ARGs were verified in EAC specimens and normal esophageal mucosal tissues. RESULTS: Thirty significantly different ARGs were selected from EAC and normal tissues. Functional enrichments showed these ARGs were mainly related apoptosis. Multivariate cox regression analyses demonstrated eight ARGs were significantly associated with OS. Among these eight genes, BECN1 (HR = 0.321, P = 0.046), DAPK1 (HR = 0.636, P = 0.025) and CAPN1 (HR = 0.395, P = 0.004) played protective roles in survival. Gender (HR = 0.225, P = 0.032), stage (HR = 5.841, P = 0.008) and risk score (HR = 1.131, P < 0.001) were independent prognostic risk factors. ROC curves showed better efficacy to predict survival using the risk score. Additionally, we found BECN1, DAPK1, VAMP7 and SIRT1 genes were correlated significantly with survival status, gender, primary tumor and tumor stage (all P < 0.05). The experimental results confirmed the BIRC5 was overexpressed and the ITPR1, PRKN were downregulated in the EAC tissues compared with the normal esophageal mucosal tissues (all P < 0.05). CONCLUSION: Our findings suggested that autophagy was involved in the process of EAC. Several ARGs probably could serve as diagnostic and prognostic biomarkers and may help facilitate therapeutic targets in EAC patients.

New Design of a Disulfurating Reagent: Facile and Straightforward Pathway to Unsymmetrical Disulfanes by Copper-Catalyzed Oxidative Cross-Coupling.

A novel reagent, which introduces two sulfur atoms in one step, was designed and used for the construction of diverse disulfanes by copper-catalyzed oxidative cross-coupling under mild reaction conditions. By applying this stable and readily prepared reagent, late-stage modification of pharmaceuticals and natural products can be achieved straightforward. The scaled-up experiments further indicated the practicality of this protocol. The pH value of the system plays a key role in achieving highly selective cleavage of the C-S bond instead of a S-S bond in the transformation.

Collective Synthesis of Phenanthridinone through C-H Activation Involving a Pd-Catalyzed Aryne Multicomponent Reaction.

A palladium-catalyzed multicomponent reaction (MCR) involving aryne, CO, and aniline is established for straightforward assembly of a phenanthridinone scaffold through C-H bond activation. Free combination with multiple kinds of readily available anilines and arynes is facilely achieved for phenanthridinone construction without prefunctionalization. Representative natural products were subsequently synthesized through this MCR strategy highly efficiently. Control experiments and interval NMR tracking revealed the mechanism, particularly the key role of CuF2 in determining the aryne-releasing rate from the precursor in this transformation.

Utility of Ligand Effect in Homogenous Gold Catalysis: Enabling Regiodivergent π-Bond-Activated Cyclization.

Comprehensive utilization of both electronic and steric properties of ligands in homogeneous gold catalysis is achieved in the regiodivergent intramolecular hydroarylation of alkynes. A flexible electron-deficient phosphite ligand, combined with the readily transformable directing group methoxyl amide, is attached to a cationic Au(I) center in three-coordinate mode, affording sterically hindered ortho-position cyclization. Meanwhile, para-position cyclization is exclusively achieved with the assistance of a rigid electron-abundant phosphine ligand-based Au(I) catalyst, in which ligands manifest the compensating effect for cyclization through steric hindrance and electronic properties. By combining gold with silver catalysts, tetrahydropyrroloquinolinones possessing a congested tricyclic structure are obtained via a proven Au/Ag relay catalytic process.

Sulfur Containing Scaffolds in Drugs: Synthesis and Application in Medicinal Chemistry.

The impact of the development of sulfur therapeutics is instrumental to the evolution of the pharmaceutical industry. Sulfur-derived functional groups can be found in a broad range of pharmaceuticals and natural products. For centuries, sulfur continues to maintain its status as the dominating heteroatom integrated into a set of 362 sulfur-containing FDA approved drugs (besides oxygen or nitrogen) through the present. Sulfonamides, thioethers, sulfones and Penicillin are the most common scaffolds in sulfur containing drugs, which are well studied both on synthesis and application during the past decades. In this review, these four moieties in pharmaceuticals and recent advances in the synthesis of the corresponding core scaffolds are presented.

Ligand Controlled Regiodivergent C1 Insertion on Arynes for Construction of Phenanthridinone and Acridone Alkaloids.

A palladium-catalyzed regiodivergent C1 insertion multicomponent reaction involving aryne, CO, and 2-iodoaniline is established to construct the scaffolds of phenanthridinone and acridone alkaloids. Regioselective control is achieved under the guidance of selective ligands. The phenanthridinones are solely obtained under ligand-free condition. In comparison, application of the electron-abundant bidentate ligand dppm afforded the acridones with high efficiency. The release rate of the aryne from the precursor assists the regioselectivity of insertion as well, which was revealed through interval NMR tracking. A plausible mechanism was suggested based on the control experiments. Representative natural products and two types of natural product analogues were synthesized divergently through this tunable method.

Transition-metal-free persulfuration to construct unsymmetrical disulfides and mechanistic study of the sulfur redox process.

A sulfur redox process has been developed between sulfinate and thiosulfate, which efficiently affords diverse unsymmetrical disulfides and provides a new method to modify pharmaceuticals and natural products without requiring an extra oxidant or reductant. Gram-scale investigation further demonstrates the practicality and application potential of this process. Isolated key intermediates and a series of control experiments afford an unusual process, which reveals the mechanism of comproportionation and the transition-metal-free sulfur redox process.

Unstrained carbon-carbon bond cleavage.

This Focus Review presents recent developments in the cleavage of C-C bonds in organic molecules. Significant progress in C-C activation, including the development of a variety of new synthetic strategies, has contributed to the development of this field over the past few decades. Transition-metal-mediated C-C bond cleavage has been shown to be a quite efficient process and several elegant metal-free methods have also recently been developed. Strained rings have been widely used in C-C cleavage transformations; however, unstrained C-C activation has increasingly caught the attention of organic researchers, which inspired us to clarify the developments in this field.