One-Pot Total Synthesis of Evodiamine and Its Analogues through a Continuous Biscyclization Reaction

Advances in the self-organized total synthesis of natural products

Natural product total synthesis has trailblazed in the era of multistep synthesis. The strategic application of existing synthetic methodologies and the stepwise construction that revolves around newly developed, tailored key steps, are two basic tactics in the principle of classic retrosynthetic analysis. However, a new synthetic model, termed self-organized total synthesis, has emerged in recent years, enabling the rapid creation of specific natural products by a one-pot reaction. Distinct from conventional analysis associated with certain bond disconnections, the design of self-organized total synthesis focuses on seeking a series of self-organized reaction sequences which can be integrated compatibly under a uniform condition, therefore allowing the entire sequence to proceed in one pot, and most importantly, starting from commercially available feedstocks or biomass materials. Whilst dauntingly challenging, this synthetic strategy is more consistent with the biogenetic pathway of natural products compared with conventional counterparts, and will hopefully provide the shortest synthesis for such natural products. Through this rational analysis, one-pot total synthesis is no longer in the way of serendipity but can be precisely designed and manipulated. In this review, we account for the definition, delimitation, and categorization of self-organized total synthesis and then elucidate a comprehensive understanding of this synthetic strategy based on our intensive explorations. We also highlight the contributions of other research groups in this growing field and anticipate that it will give rise to advancing new methodologies, as well as new concepts within organic synthesis.

Evodiamine: A Extremely Potential Drug Development Candidate of Alkaloids from Evodia rutaecarpa

Evodiamine (EVO) is a tryptamine indole alkaloid and the main active ingredient in Evodia rutaecarpa. In recent years, the antitumor, cardioprotective, anti-inflammatory, and anti-Alzheimer's disease effects of EVO have been reported. EVO exerts antitumor effects by inhibiting tumor cell activity and proliferation, blocking the cell cycle, promoting apoptosis and autophagy, and inhibiting the formation of the tumor microvasculature. However, EVO has poor solubility and low bioavailability. Several derivatives with high antitumor activity have been discovered through the structural optimization of EVO, and new drug delivery systems have been developed to improve the solubility and bioavailability of EVO. Current research found that EVO could have toxic effects, such as hepatotoxicity, nephrotoxicity, and cardiac toxicity. This article reviews the pharmacological activity, derivatives, drug delivery systems, toxicity, and pharmacokinetics of EVO and provides research ideas and references for its further in-depth development and clinical applications.

Evo312: An Evodiamine Analog and Novel PKCβI Inhibitor with Potent Antitumor Activity in Gemcitabine-Resistant Pancreatic Cancer

As an obstinate cancer pancreatic cancer (PC) poses a major challenge due to limited treatment options which include resection surgery, radiation therapy, and gemcitabine-based chemotherapy. In cancer cells, protein kinase C βI (PKCβI) participates in diverse cellular processes, including cell proliferation, invasion, and apoptotic pathways. In the present study, we created a scaffold to develop PKCβI inhibitors using evodiamine-based synthetic molecules. Among the candidate inhibitors, Evo312 exhibited the highest antiproliferative efficacy against PC cells, PANC-1, and acquired gemcitabine-resistant PC cells, PANC-GR. Additionally, Evo312 robustly inhibited PKCβI activity. Mechanistically, Evo312 effectively suppressed the upregulation of PKCβI protein expression, leading to the induction of cell cycle arrest and apoptosis in PANC-GR cells. Furthermore, Evo312 exerted an antitumor activity in a PANC-GR cell-implanted xenograft mouse model. These findings position Evo312 as a promising lead compound for overcoming gemcitabine resistance in PC through novel mechanisms.

Synthesis of bioactive evodiamine and rutaecarpine analogues under ball milling conditions

Mechanochemical reactions achieved by processes such as milling and grinding are promising alternatives to traditional solution-based chemistry. This approach not only eliminates the need for large amounts of solvents, thereby reducing waste generation, but also finds applications in chemical and materials synthesis. The focus of this study is on the synthesis of quinazolinone derivatives by ball milling, in particular evodiamine and rutaecarpine analogues. These compounds are of interest due to their diverse bioactivities, including potential anticancer properties. The study examines the reactions carried out under ball milling conditions, emphasizing their efficiency in terms of shorter reaction times and reduced environmental impact compared to conventional methods. The ball milling reaction of evodiamine and rutaecarpine analogues resulted in yields of 63-78% and 22-61%, respectively. In addition, these compounds were tested for their cytotoxic activity, and evodiamine exhibited an IC50 of 0.75 ± 0.04 μg mL-1 against the Ca9-22 cell line. At its core, this research represents a new means to synthesise these compounds, providing a more environmentally friendly and sustainable alternative to traditional approaches.

N(14)-substituted evodiamine derivatives as dual topoisomerase 1/tubulin-Inhibiting anti-gastrointestinal tumor agents

Gastrointestinal tumor is an important factor threatening human health. Natural product-based drug discovery is a popular paradigm for expanding the chemical space and identifying new molecular entities that ameliorate human disease. Evodiamine-inspired medicinal chemistry presents therapeutic potential for treating tumors in different tissues via multi-target inhibition. Here, by focusing on the discovery of anti-gastrointestinal tumor drugs, a series of N(14) alkyl-substituted evodiamine derivatives were designed and synthesized. The structure-activity relationship studies culminated in the identification of the N(14)-propyl-substituted evodiamine analog 6b, which showed low nanomolar inhibitory activity against MGC-803 (IC₅₀ = 0.09 μM) and RKO (IC₅₀ = 0.2 μM) cell lines. Moreover, compound 6b was effective in inducing apoptosis, arresting the cell cycle in the G2/M phase, and inhibiting migration and invasion of MGC-803 and RKO cell lines in a dose-dependent manner in vitro. Further antitumor mechanism studies revealed that compound 6b significantly inhibited topoisomerase 1 (inhibition rate of 58.3% at 50 μM) and tubulin polymerization (IC₅₀ = 5.69 μM). Overall, compound 6b represents a promising dual topoisomerase 1/tubulin-targeting lead structure for the treatment of gastrointestinal tumor.

An A-ring substituted evodiamine derivative with potent anticancer activity against human non-small cell lung cancer cells by targeting heat shock protein 70

The heat shock protein (HSP) system is essential for the conformational stability and function of several proteins. Therefore, the development of efficacious HSP-targeting anticancer agents with minimal toxicity is required. We previously demonstrated that evodiamine is an anticancer agent that targets HSP70 in non-small cell lung cancer (NSCLC) cells. In this study, we synthesized a series of evodiamine derivatives with improved efficacy and limited toxicity. Among the 14 evodiamine derivatives, EV408 (10-hydroxy-14-methyl-8,13,13b,14-tetrahydroindolo [2',3':3,4]pyrido[2,1-b]quinazolin-5(7H)-one) exhibited the most potent inhibitory effects on viability and colony formation under anchorage-dependent and -independent culture conditions in various human NSCLC cells, including those that are chemoresistant, by inducing apoptosis. In addition, EV408 suppressed the cancer stem-like cell (CSC) population of NSCLC cells and the expression of stemness-associated markers. Mechanistically, EV408 inhibited HSP70 function by directly binding and destabilizing the HSP70 protein. Furthermore, EV408 significantly inhibited the growth of NSCLC cell line tumor xenografts without overt toxicity. Additionally, EV408 had a negligible effect on the viability of normal cells. These results suggest the potential of EV408 as an efficacious HSP70-targeting evodiamine derivative with limited toxicity that inhibits both non-CSC and CSC populations in NSCLC.

Synthesis of pyrimidine-containing alkaloids

This review deals with the synthesis of naturally occurring alkaloids containing partially or completely saturated pyrimidine nuclei. The interest in these compounds is associated with their structural diversity, high biological activity and toxicity. The review is divided into four parts, each of which describes a number of synthetic methodologies toward structurally different naturally occurring alkaloids containing saturated cyclic six-membered amidine, guanidine, aminal and urea (thiourea) moieties, respectively. The development of various synthetic strategies for the preparation of these compounds has remarkably increased during the past few decades. This is primarily due to the fact that some of these compounds are isolated only in limited quantities, which makes it practically impossible to study their full structural characteristics and biological activity.

The Synthesis, Structural Modification and Mode of Anticancer Action of Evodiamine: a review

BACKGROUND

Finding novel antitumor reagents from naturally occurring alkaloids is a widely accepted strategy. Evodiamine, a tryptamine indole alkaloid isolated from Evodia rutaecarpa, has a wide range of biological activities, such as antitumor, anti-inflammation, and anti-bacteria. Hence, research works on the structural modification of evodiamine will facilitate the discovery of new antitumor drugs.

OBJECTIVE

The recent advances in the synthesis of evodiamine, and studies on the drug design, biological activities, and structure-activity-relationships of its derivatives, published in patents and primary literatures, are reviewed in this paper.

METHODS

The literatures, including patents and follow-up research papers from 2015 to 2020, related to evodiamine is searched in the Scifinder, PubMed, Espacenet, China National Knowledge Infrastructure (CNKI), and Wanfang databases. The key words are evodiamine, synthesis, modification, anticancer, mechanism.

RESULTS

The synthesis of evodiamine are summarized. Then, structural modifications of evodiamine are described, and the possible modes of actions are discussed.

CONCLUSION

Evodiamine has a 6/5/6/6/6 ring system, and the structural modifications are focused on ring A, D, E, C5, N-13, and N-14. Some compounds show promising anticancer potentials and warrant further study.

Discovery of Novel Polycyclic Heterocyclic Derivatives from Evodiamine for the Potential Treatment of Triple-Negative Breast Cancer

Evodiamine (Evo) is a quinazolinocarboline alkaloid found in Evodia rutaecarpa and exhibits moderate antiproliferative activity. Herein, we report using a scaffold-hopping approach to identify a series of novel polycyclic heterocyclic derivatives based on Evo as the topoisomerase I (Top1) inhibitor for the treatment of triple-negative breast cancer (TNBC), which is an aggressive subtype of breast cancer with limited treatment options. The most potent compound 7f inhibited cell growth in a human breast carcinoma cell line (MDA-MB-231) with an IC₅₀ value of 0.36 μM. Further studies revealed that Top1 was the target of 7f, which directly induced irreversible Top1-DNA covalent complex formation or induced an oxidative DNA lesion through an indirect mechanism mediated by reactive oxygen species. More importantly, in vivo studies showed that 7f exhibited potent antitumor activity in a TNBC-patient-derived tumor xenograft model. These results suggest that compound 7f deserves further investigation as a promising candidate for the treatment of TNBC.

Design, synthesis and bioactivity evaluation of novel evodiamine derivatives with excellent potency against gastric cancer

Gastric cancer represents a significant health burden worldwide. Previously, inspired by the traditional Chinese medicine Wu-Chu-Yu to treat the spleen and stomach system for thousands of years, we identified N14-phenyl substituted evodiamine derivatives as potential antitumor agents with favorable inhibition on Top1. Herein, structural optimization and structure-activity relationship studies (SARs) led us to discovering a highly active evodiamine derivative compound 6t against gastric cancer. Further anti-tumor mechanism studies revealed that compound 6t played as the inhibition of topoisomerase 1 (Top1), effectively induced apoptosis, obviously arrested the cell cycle at the G2/M phase, and significantly inhibited the migration and invasion of SGC-7901 and MGC-803 cell lines in a dose-dependent manner. Moreover, the compound 6t was low toxicity in vivo and exhibited excellent anti-tumor activity (TGI = 70.12%) in the MGC-803 xenograft models. In summary, compound 6t represents a promising candidate as a potential chemotherapeutic agent against gastric cancer.

Natural STAT3 inhibitors: A mini perspective

Signal transducer and activator of transcription 3 (STAT3) plays pivotal role in several cellular processes such as cell proliferation and survival and has been found to be aberrantly activated in many cancers. STAT3 is largely believed to be one of the key oncogenes and crucial therapeutic targets. Much research has suggested the leading mechanisms for regulating the STAT3 pathway and its role in promoting tumorigenesis. Therefore, intensive efforts have been devoted to develop potent STAT3 inhibitors and several of them are currently undergoing clinical trials. Nevertheless, many natural products were identified as STAT3 inhibitors but attract less attention compared to the small molecule counterpart. In this review, the development of natural STAT3 inhibitors with an emphasis on their biological profile and chemical synthesis are detailed. The current state of STAT3 inhibitors and the future directions and opportunities for STAT3 inhibitor are discussed.

Palladium-Catalyzed Formal (5 + 6) Cycloaddition of Vinylethylene Carbonates with Isatoic Anhydrides for the Synthesis of Medium-Sized N,O-Containing Heterocycles

Under the reaction conditions of Pd(PPh₃)₄ (2.5 mol %) and PPh₃ (10 mol %) in EtOAc at 60 °C, the formal (5 + 6) cycloaddition of vinylethylene carbonates with isatoic anhydrides proceeded smoothly and furnished medium-sized N,O-containing heterocycles in reasonable chemical yields. The chemical structures of the title products were clearly identified by X-ray diffraction analysis.

Recent Advances in the Synthesis of β-Carboline Alkaloids

β-Carboline alkaloids are a remarkable family of natural and synthetic indole-containing heterocyclic compounds and they are widely distributed in nature. Recently, these alkaloids have been in the focus of interest, thanks to their diverse biological activities. Their pharmacological activity makes them desirable as sedative, anxiolytic, hypnotic, anticonvulsant, antitumor, antiviral, antiparasitic or antimicrobial drug candidates. The growing potential inherent in them encourages many researchers to address the challenges of the synthesis of natural products containing complex β-carboline frameworks. In this review, we describe the recent developments in the synthesis of β-carboline alkaloids and closely related derivatives through selected examples from the last 5 years. The focus is on the key steps with improved procedures and synthetic approaches. Furthermore the pharmacological potential of the alkaloids is also highlighted.

Evodiamine inhibits both stem cell and non-stem-cell populations in human cancer cells by targeting heat shock protein 70

Rationale: Cancer stem cells (CSCs) are known to cause tumor recurrence and drug resistance. The heat shock protein (HSP) system plays a major role in preserving expression and function of numerous oncoproteins, including those involved in the CSC activities. We explored novel anticancer drugs, especially those targeting HSP components required for the functional role of CSCs.

Methods: Investigation of the role of the HSP system in CSCs and screening of a natural product chemical library were performed by utilizing cancer cell lines, primary cultures of patient-derived xenografts (PDXs), and their putative CSC subpopulations (i.e., those grown under sphere-forming conditions, stably transfected with reporter vectors carrying NANOG or POUSF1 promoters, or carrying high ALDH activity) in vitro and PDX and Kras^G12D/+-driven tumor models in vivo. Regulation of the HSP system was investigated by immunoprecipitation, drug affinity responsive target stability assay, binding experiments using ATP-agarose beads and biotinylated drug, and docking analysis.

Results: The HSP system was activated in CSCs via transcriptional upregulation of the HSP system components, especially HSP70. Evodiamine (Evo) was identified to induce apoptosis in both CSC and bulk non-CSC populations in human lung, colon, and breast cancer cells and their sublines with chemoresistance. Evo administration decreased the multiplicity, volume, and load of lung tumors in Kras^G12D/+ transgenic mice and the growth of cancer cell line- and PDX-derived tumors without detectable toxicity. Mechanistically, Evo disrupted the HSP system by binding the N-terminal ATP-binding pocket of HSP70 and causing its ubiquitin-mediated degradation.

Conclusions: Our findings illustrate HSP70 as a potential target for eliminating CSCs and Evo as an effective HSP70-targeting anticancer drug eradicating both CSCs and non-CSCs with a minimal toxicity.

[4 + 2]-Annulation of Prop-2-ynylsulfonium Salts and Isatoic Anhydrides: Access to 3-Methylthio-4-quinolones

An unparalleled [4 + 2]-annulation of prop-2-ynylsulfonium salts with isatoic anhydrides was developed, affording a series of 4-quinolones with a alkylthio group in medium to good yields under mild conditions. In this reaction type, the prop-2-ynylsulfonium salt serves as a C2 synthon and sulfide does not act as a leaving group, providing facile access to organosulfur compounds. The resulting quinolone products could be further transformed to a diverse range of synthetically useful compounds.

Role of Indole Scaffolds as Pharmacophores in the Development of Anti-Lung Cancer Agents

Lung cancer is the leading cause of death in men and women worldwide, affecting millions of people. Between the two types of lung cancers, non-small cell lung cancer (NSCLC) is more common than small cell lung cancer (SCLC). Besides surgery and radiotherapy, chemotherapy is the most important method of treatment for lung cancer. Indole scaffold is considered one of the most privileged scaffolds in heterocyclic chemistry. Indole may serve as an effective probe for the development of new drug candidates against challenging diseases, including lung cancer. In this review, we will focus on discussing the existing indole based pharmacophores in the clinical and pre-clinical stages of development against lung cancer, along with the synthesis of some of the selected anti-lung cancer drugs. Moreover, the basic mechanism of action underlying indole based anti-lung cancer treatment, such as protein kinase inhibition, histone deacetylase inhibition, DNA topoisomerase inhibition, and tubulin inhibition will also be discussed.

Palladium-Catalyzed Multistep Tandem Carbonylation/N-Dealkylation/Carbonylation Reaction: Access to Isatoic Anhydrides

A novel and efficient synthesis of isatoic anhydride derivatives was developed via palladium-catalyzed multistep tandem carbonylation/N-dealkylation/carbonylation reaction with alkyl as the leaving group and tertiary anilines as nitrogen nucleophiles. This approach features good functional group compatibility and readily available starting materials. Furthermore, it provided a convenient approach for the synthesis of biologically and medicinally useful evodiamine.

Synthesis of Piperidine Conjugated Dihydroquinazolin-4(1H)-ones and their Antiproliferative Activity, Molecular Docking Studies and DFT Calculations

Background:

Xanthatin, fluoropyrimidine and thienopyrimidine, pyrazolopyrimidine, pyrimidine carboxamides, and SKLB1002 are reported as VEGFR2 tyrosine kinase inhibitors. Recently, many studies related to different heterocycles conjugated with dihydroquinazolinones are known to have very good biological activities. In this study, we are intended to explore the cytotoxic studies of piperidine conjugated dihydroquinazolinones against colorectal/colon cancer cell lines and along with molecular docking studies and DFT calculations.

Methods:

The colorectal/colon cell lines HCT116 and A549 cell lines were treated with these compounds and cytotoxic activities were evaluated by MTT dye uptake method. We performed molecular modelling for compound 3d using the Auto Dock software. The binding of compound 3d with target proteins was studied with the collection of experimentally determined PDB database. Optimized geometry by DFT calculations was performed with B3LYP/6-31G (d) basis set.

Results:

Piperidine-conjugated dihydroquinazolinone analogues displayed anticancer activity. Particularly, the compound 3d with electron-withdrawing substituents on a phenyl ring showed significant cytotoxicity against HCT116 and A549 cell lines. Molecular docking studies proved that the compound 3d has good fitting by forming hydrogen bonds with amino acid residues at the active sites of VEGFR2. The HOMO, LUMO, their energies and UV visible spectrum were predicted using DFT calculations.

Conclusion:

Four piperidine-conjugated dihydroquinazolinones were synthesized and evaluated against colorectal and colon cancer cell lines. Compound 3d significantly inhibited the growth of HCT116 and A549. Molecular docking studies displayed good fitting of compound 3d by forming different H-bonds with the amino acid at the active sites of the VEGFR2 target. Using a theoretical approach, we optimized HOMO and LUMO plots for the compound 3d.

Facile access to evodiakine enabled by aerobic copper-catalyzed oxidative rearrangement

Oxidation as a fundamentally important method for the synthesis of complex structures is difficult to achieve in a selective manner. Evodiakine, a complex natural product possessing an unprecedented ring system (6/5/5/7/6), has a high oxidation state without a practical solution. Herein, we report the first synthesis of evodiakine via aerobic copper-catalyzed late-stage functionalization of evodiamine.

A concise synthesis and biological study of evodiamine and its analogues

Efficient access to evodiamine and its analogues is presented via Lewis acid catalysis. In this reaction, three chemical bonds and two heterocyclic-fused rings are constructed in one step.

Antiproliferative Effects of Alkaloid Evodiamine and Its Derivatives

Alkaloids, a category of natural products with ring structures and nitrogen atoms, include most U.S. Food and Drug Administration approved plant derived anti-cancer agents. Evodiamine is an alkaloid with attractive multitargeting antiproliferative activity. Its high content in the natural source ensures its adequate supply on the market and guarantees further medicinal study. To the best of our knowledge, there is no systematic review about the antiproliferative effects of evodiamine derivatives. Therefore, in this article the review of the antiproliferative activities of evodiamine will be updated. More importantly, the antiproliferative activities of structurally modified new analogues of evodiamine will be summarized for the first time.