Copper/iron controlled regioselective 1,2-carboazidation of 1,3-dienes with acetonitrile and azidotrimethylsilane

Carboazidation and diazidation were carried out on 1,3-diene compounds using TMSN3 as the azide source and MeCN as the cyanoalkylation reagent. This method exhibits excellent functional group tolerance, a broad substrate range, and a short reaction time, providing an effective pathway for synthesizing valuable azides. Our report introduces an unprecedented strategy for the carboazidation and diazidation of 1,3-dienes, with mechanism studies indicating that the reaction involves a radical pathway.

Design and Synthesis of Dual Galectin-3 and EGFR Inhibitors Against Liver Fibrosis

Liver fibrosis, mainly arising from chronic viral or metabolic liver diseases, is a significant global health concern. There is currently only one FDA-approved drug (Resmetirom) in the market to combat liver fibrosis. Both galectin-3 and epidermal growth factor receptor (EGFR) play important roles in liver fibrosis, while galectin-3 may interact with EGFR. Galectin-3 inhibitors, typically lactose or galactose derivatives may inhibit liver fibrosis. We hypothesized that targeting both galectin-3 and EGFR may have better effect against liver fibrosis. Here, EGFR inhibitor erlotinib was used in a series of designed galectin-3 inhibitors after hybridization with the pharmacophore structure in reported galectin-3 inhibitors to impede hepatic stellate cells (HSCs) activation by a typical method of click chemistry. Bioactivity test results showed that compound 29 suppressed TGF-β-induced upregulation of fibrotic markers (α-SMA, fibronectin-1, and collagen I). The preferred compound 29 displayed better binding to galectin-3 (KD=52.29 μM) and EGFR protein (KD=3.31 μM) by SPR assay. Further docking studies were performed to clarify the possible binding mode of compound 29 with galectin-3 and EGFR. Taken together, these results suggested that compound 29 could be a potential dual galectin-3 and EGFR inhibitor as leading compound for anti-liver fibrosis new drug development.

Acid Promoted Tetrafunctionalization of Terminal Alkynes: Geminal Diazidation and Dibromination

The synthesis of complex alkanes by the tetrafunctionalization of alkynes is limited and challenging. Herein, an unprecedented efficient geminal diazidation and dibromination of terminal alkynes is developed, which provides novel access to structurally diverse organic azides. The approach has exclusive chemo- and regioselectivity and features mild reaction conditions, good tolerance of various functional groups, and more crucially, no metal involved in the reaction, thereby benefiting the late-stage decoration of medicinal molecules. A mechanistic study showed that the current geminal diazidation and dibromination proceeds via a radical pathway.

Selective Azidooxygenation of Alkenes Enabled by Photo-induced Radical Transfer Using Aryl-λ3-azidoiodane Species

The photolytic radical-induced vicinal azidooxygenation of synthetically important and diverse functionalized substrates including unactivated alkenes is reported. The photoredox-catalyst/additive-free protocol enables intermolecular oxyazidation by simultaneously incorporating two new functionalities; C-O and C-N across the C=C double bond in a selective manner. Mechanistic investigations reveal the intermediacy of the azidyl radical facilitated via the photolysis of λ³-azidoiodane species and cascade proceeding to generate an active carbon-centered radical. The late-stage transformations of azido- and oxy-moieties were amply highlighted by assembling high-value drug analogs and bioactive skeletons.

Divergent functionalization of α,β-enones: catalyst-free access to β-azido ketones and β-amino α-diazo ketones

A simple and practical method for the azidation of β-fluoroalkyl α,β-unsaturated ketones to access a wide variety of fluorinated nitrogenous carbonyl compounds is developed. Different from existing precedents, neither a metallic nor an organic catalyst was involved in our strategy. Judicious choice of solvents allows for the modulation of the reaction outcomes, delivering β-azido ketones or β-amino α-diazo ketones. The reaction system features environmental friendliness, mild conditions, simplicity and excellent functional group tolerance.

Carrier-Free Nanoassembly of Curcumin-Erlotinib Conjugate for Cancer Targeted Therapy

Anticancer drug-loaded nanoparticles have been explored extensively to decrease side effects while improving their therapeutic efficacy. However, due to the low drug loading content, premature drug release, nonstandardized carrier structure, and difficulty in predicting the fate of the carrier, only a few nanomedicines have been approved for clincial use. Herein, a carrier-free nanoparticle based on the self-assembly of the curcumin-erlotinib conjugate (EPC) is developed. The EPC nanoassembly exhibits more potent cell killing, better antimigration, and anti-invasion effects for BxPC-3 pancreatic cancer cells than the combination of free curcumin and erlotinib. Furthermore, benefiting from both passive and active tumor targeting effect, EPC nanoassembly can effectively accumulate in the tumor tissue in a xenograft pancreatic tumor mouse model. Consequently, EPC effectively reduces the growth of pancreatic tumors and extends the median survival time of the tumor-bearing mice from 22 to 68 days. In addition, no systemic toxicity is detected in the mice receiving EPC treatment. Attributed to the uniformity of the curcumin-erlotinib conjugate and easiness of scaling up, it is expected that the EPC can be translated into a powerful tool in fighting against pancreatic cancer and other epidermal growth factor receptor positive cancers.

Visible-light activated metal catalyst-free vicinal diazidation of olefins with sulfonium iodate(i) species

An unprecedented visible-light inspired selective radical azidation of unactivated and diverse substituted vinylarenes with sulfonium iodate reagent has been realized. The intrinsic radical process triggered by light tolerated several synthetically useful functionalities enabling two new carbon-hetero bonds which display distinctive late-stage applications to biologically relevant scaffolds.

Copper-Catalyzed Ligand-Free Diazidation of Olefins with TMSN3 in CH3CN or in H2O

An environmentally benign, copper-catalyzed diazidation of a broad range of olefins, including vinylarenes, unactivated alkenes, allene, and dienes, under mild conditions with TMSN₃ (trimethylazidosilane) as azido source, has been developed. This reaction can be carried out in organic solvent or in aqueous solution where water is the sole solvent. The functional group compatibility of this reaction is good, which is proved by late-stage functionalizations of complex substrates.

Anti-cancer agents and reactive oxygen species modulators that target cancer cell metabolism

Traditionally the perspective on reactive oxygen species (ROS) has centered on the role they play as carcinogenic or cancer-causing radicals. Over the years, characterization and functional studies have revealed the complexity of ROS as signaling molecules that regulate various physiological cellular responses or whose levels are altered in various diseases. Cancer cells often maintain high basal level of ROS and are vulnerable to any further increase in ROS levels beyond a certain protective threshold. Consequently, ROS-modulation has emerged as an anticancer strategy with synthesis of various ROS-inducing or responsive agents that target cancer cells. Of note, an increased carbohydrate uptake and/or induction of death receptors of cancer cells was exploited to develop glycoconjugates that potentially induce cellular stress, ROS and apoptosis. This mini review highlights the development of compounds that target cancer cells by taking advantage of redox or metabolic alteration in cancer cells.

Synthesis and biological assay of erlotinib analogues and BSA-conjugated erlotinib analogue

A series of erlotinib analogues that have structural modification at 6,7-alkoxyl positions is efficiently synthesized. The in vitro anti-tumor activity of synthesized compounds is studied in two non-small cell lung cancer (NSCLC) cell lines (A549 and H1975). Among the synthesized compounds, the iodo compound 6 (ETN-6) exhibits higher anti-cancer activity compared to erlotinib. An efficient method is developed for the conjugation of erlotinib analogue-4, alcohol compound, with protein, bovine serum albumin (BSA), via succinic acid linker. The in vitro anti-tumor activity of the protein attached erlotinib analogue, 8 (ETN-4-Suc-BSA), showed stronger inhibitory activity in both A549 and H1975 NSCLC cell lines.