Discovery of a potent Gilteritinib-based FLT3-PROTAC degrader for the treatment of Acute myeloid leukemia.

Fms-like tyrosine receptor kinase 3 (FLT3) proteolysis targeting chimeras (PROTACs) emerge as a promising approach to overcome the limitations of FLT3 inhibitors, while the development of orally bioavailable FLT3-PROTACs faces great challenges. Here, we report the rational design and evaluation of a series of Gilteritinib-based FLT3-PROTACs. Among them, B3-2 exhibited the strongest antiproliferative activity against FLT3-ITD mutant AML cells, and significantly induced FLT3-ITD protein degradation. Mechanistic investigations demonstrated that B3-2 induced FLT3-ITD degradation in a ubiquitin-proteasome-dependent manner. More importantly, B3-2 exhibited an oral bioavailability of 5.65%, and oral administration of B3-2 showed good antitumor activity in MV-4-11 xenograft models. Furthermore, B3-2 showed strong antiproliferative activity against FLT3 resistant mutations, highlighting its potential in overcoming drug resistance.

Blocking potential metabolic sites on NAT to improve its safety profile while retaining the pharmacological profile.

The number of opioid-related overdose deaths and individuals that have suffered from opioid use disorders have significantly increased over the last 30 years. FDA approved maintenance therapies to treat opioid use disorder may successfully curb drug craving and prevent relapse but harbor adverse effects that reduce patient compliance. This has created a need for new chemical entities with improved patient experience. Previously our group reported a novel lead compound, NAT, a mu-opioid receptor antagonist that potently antagonized the antinociception of morphine and showed significant blood-brain barrier permeability. However, NAT belongs to thiophene containing compounds which are known structural alerts for potential oxidative metabolism. To overcome this, 15 NAT derivatives with various substituents at the 5'-position of the thiophene ring were designed and their structure-activity relationships were studied. These derivatives were characterized for their binding affinity, selectivity, and functional activity at the mu opioid receptor and assessed for their ability to antagonize the antinociceptive effects of morphine in vivo. Compound 12 showed retention of the basic pharmacological attributes of NAT while improving the withdrawal effects that were experienced in opioid-dependent mice. Further studies will be conducted to fully characterize compound 12 to examine whether it would serve as a new lead for opioid use disorder treatment and management.

Discovery of 2-Amide-3-methylester Thiophenes that Target SARS-CoV-2 Mac1 and Repress Coronavirus Replication, Validating Mac1 as an Antiviral Target.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has made it clear that further development of antiviral therapies will be needed. Here, we describe small-molecule inhibitors for SARS-CoV-2 Mac1, which counters ADP-ribosylation-mediated innate immune responses. Three high-throughput screening hits had the same 2-amide-3-methylester thiophene scaffold. We studied the compound binding mode using X-ray crystallography, allowing us to design analogues. Compound 27 (MDOLL-0229) had an IC50 of 2.1 µM and was selective for CoV Mac1 proteins after profiling for activity against a panel of viral and human proteins. The improved potency allowed testing of its effect on virus replication, and indeed, 27 inhibited replication of both murine hepatitis virus (MHV) prototypes CoV and SARS-CoV-2. Sequencing of a drug-resistant MHV identified mutations in Mac1, further demonstrating the specificity of 27. Compound 27 is the first Mac1-targeted small molecule demonstrated to inhibit coronavirus replication in a cell model.

Structure-Guided Discovery and Preclinical Assessment of Novel (Thiophen-3-yl)aminopyrimidine Derivatives as Potent ERK1/2 Inhibitors.

The RAS-RAF-MEK-ERK signaling cascade is abnormally activated in various tumors, playing a crucial role in mediating tumor progression. As the key component at the terminal stage of this cascade, ERK1/2 emerges as a potential antitumor target and offers a promising therapeutic strategy for tumors harboring BRAF or RAS mutations. Here, we identified 36c with a (thiophen-3-yl)aminopyrimidine scaffold as a potent ERK1/2 inhibitor through structure-guided optimization for hit 18. In preclinical studies, 36c showed powerful ERK1/2 inhibitory activities (ERK1/2 IC50 = 0.11/0.08 nM) and potent antitumor efficacy both in vitro and in vivo against triple-negative breast cancer and colorectal cancer models harboring BRAF and RAS mutations. 36c could directly inhibit ERK1/2, significantly block the phosphorylation expression of their downstream substrates p90RSK and c-Myc, and induce cell apoptosis and incomplete autophagy-related cell death. Taken together, this work provides a promising ERK1/2 lead compound for multiple tumor-treatment drug discovery.

Chemoenzymatic total synthesis of rotigotine via IRED-catalyzed reductive amination.

A short and chemoenzymatic synthesis of rotigotine using an IR-36-M5 mutant is reported. Focusing on the residues that directly contact the 2-tetralone moiety, we applied structure-guided semi-rational design to obtain a double-mutant F260W/M147Y, which showed a good isolated yield and S-stereoselectivity >99% toward 2-aminotetralin synthesis. Furthermore, the utility of this biocatalytic protocol was successfully demonstrated in the enantioselective synthesis of rotigotine via enzymatic reductive amination as the key step.

Discovery of novel thiophene-3-carboxamide derivatives as potential VEGFR-2 inhibitors with anti-angiogenic properties.

VEGFR-2 is an attractive target for the development of anti-tumor drugs and plays a crucial role in tumor angiogenesis. This study reports a series of novel thiophene-3-carboxamide derivatives based on PAN-90806 as VEGFR-2 inhibitors, among which compound 14d exhibits excellent anti-proliferative activity against HCT116, MCF7, PC3, and A549 cell lines, and has effective VEGFR-2 inhibitory activity with an IC50 value of 191.1 nM. Additionally, CETSA results indicated that VEGFR-2 was a relevant target of compound 14d in the cell lines, and compound 14d could also inhibit VEGFR-2 protein phosphorylation in A549 cell line. Furthermore, compound 14d inhibited colony formation, cell migration, and HUVECs tube formation in a dose-dependent manner. The mechanism by which 14d induced cancer cell death involves blocking the cell cycle, increasing ROS production, inducing apoptosis, and dose-dependently reducing the levels of phosphorylated ERK and MEK. Molecular docking and molecular dynamics simulations had shown that compound 14d could stably bind to the active site of VEGFR-2. These results confirmed that compound 14d might be a promising lead compound for anti-angiogenesis.

A decade's overview of 2-aminothiophenes and their fused analogs as promising anticancer agents.

Over the past decades, cancer has been a challenging domain for medicinal chemists as it is an international health concern. In association, small molecules such as 2-aminothiophenes and their derivatives showed significant antitumor activity through variable modes of action. Therefore, this article aims to review the advances regarding these core scaffolds over the past 10 years, where 2-aminothiophenes and their fused analogs are classified and discussed according to their biological activity and mode of action, in the interest of boosting new design pathways for medicinal chemists to develop targeted antitumor candidates.

Anti-proliferative, Morphological and Molecular Docking Studies of New Thiophene Derivatives and their Strategy in Ionic Liquids Immobilized Reactions.

BACKGROUND: A number of research were conducted on the pyran and thiophene derivatives, which were attributed to have a wide range of biological activities, including anti-plasmodial, as well as acting as caspase, hepatitis C and cancer inhibitors. OBJECTIVE: The multicomponent reactions of the 5-acetyl-2-amino-4-(phenylamino)-thiophene-3-carbonitrile produced biologically active target molecules like pyran and their fused derivatives. Comparison between regular catalytic multi-component reactions and solvent-free ionic liquids immobilized multicomponent was studied. METHODS: The multicomponent reactions in this work were carried out not only under the reflux conditions using triethylamine as a catalyst but also in solvent-free ionic liquids immobilized magnetic nanoparticles (MNPs) catalysts. RESULTS: Through this work, thirty-one new compounds were synthesized and characterized and were evaluated toward the six cancer cell lines, namely A549, HT-29, MKN-45, U87MG, and SMMC-7721 and H460. The most active compounds were further screened toward seventeen cancer cell lines classified according to the disease. In addition, the effect of compound 11e on the A549 cell line was selected to make further morphological changes in the cell line. The Molecular docking studies of 11e and 11f were carried and promising results were obtained. CONCLUSION: The synthesis of heterocyclic compounds derived from thiophene derivatives has been receiving significant attention. After a detailed optimizing study, it has been found that the solvent-free ionic liquids immobilized multi-component syntheses afforded a high yield of compounds, opening a greener procedure for this synthetically relevant transformation. Many of the synthesized compounds can be considered anticancer agents, enhancing further studies.

Development of Selective Phosphatidylinositol 5-Phosphate 4-Kinase γ Inhibitors with a Non-ATP-competitive, Allosteric Binding Mode.

Phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) are emerging as attractive therapeutic targets in diseases, such as cancer, immunological disorders, and neurodegeneration, owing to their central role in regulating cell signaling pathways that are either dysfunctional or can be modulated to promote cell survival. Different modes of binding may enhance inhibitor selectivity and reduce off-target effects in cells. Here, we describe efforts to improve the physicochemical properties of the selective PI5P4Kγ inhibitor, NIH-12848 (1). These improvements enabled the demonstration that this chemotype engages PI5P4Kγ in intact cells and that compounds from this series do not inhibit PI5P4Kα or PI5P4Kß. Furthermore, the first X-ray structure of PI5P4Kγ bound to an inhibitor has been determined with this chemotype, confirming an allosteric binding mode. An exemplar from this chemical series adopted two distinct modes of inhibition, including through binding to a putative lipid interaction site which is 18 Å from the ATP pocket.

Synthesis of High Performance Thiophene-Aromatic Polyesters from Bio-Sourced Organic Acids and Polysaccharide-Derived Diol: Characterization and Degradability Studies.

In this work, the feasibility of replacing petroleum-based poly(ethylene terephthalate) (PET) with fully bio-based copolyesters derived from dimethyl 2,5-thiophenedicarboxylate (DMTD), dimethyl 2,5-dimethoxyterephthalate (DMDMT), and polysaccharide-derived 1,6-hexanediol (HDO) was investigated. A systematic study of structure-property relationship revealed that the properties of these poly(thiophene-aromatic) copolyesters (PHS(20-90)) can be tailored by varying the ratio of diester monomers in the reaction, whereby an increase in DMTD content noticeably shortened the reaction time in the transesterification step due to its higher reactivity as compared with DMDMT. The copolyesters had weight-average molar masses (Mw) between 27,500 and 38,800 g/mol, and dispersity D of 2.0-2.5. The different polarity and stability of heterocyclic DMTD provided an efficient mean to tailor the crystallization ability of the copolyesters, which in turn affected the thermal and mechanical performance. The glass transition temperature (Tg) could be tuned from 70-100 °C, while the tensile strength was in a range of 23-80 MPa. The obtained results confirmed that the co-monomers were successfully inserted into the copolyester chains. As compared with commercial poly(ethylene terephthalate), the copolyesters displayed not only enhanced susceptibility to hydrolysis, but also appreciable biodegradability by lipases, with weight losses of up to 16% by weight after 28 weeks of incubation.

Synthesis and Evaluation of Structurally Diverse C-2-Substituted Thienopyrimidine-Based Inhibitors of the Human Geranylgeranyl Pyrophosphate Synthase.

Novel analogues of C-2-substituted thienopyrimidine-based bisphosphonates (C2-ThP-BPs) are described that are potent inhibitors of the human geranylgeranyl pyrophosphate synthase (hGGPPS). Members of this class of compounds induce target-selective apoptosis of multiple myeloma (MM) cells and exhibit antimyeloma activity in vivo. A key structural element of these inhibitors is a linker moiety that connects their (((2-phenylthieno[2,3-d]pyrimidin-4-yl)amino)methylene)bisphosphonic acid core to various side chains. The structural diversity of this linker moiety, as well as the side chains attached to it, was investigated and found to significantly impact the toxicity of these compounds in MM cells. The most potent inhibitor identified was evaluated in mouse and rat for liver toxicity and systemic exposure, respectively, providing further optimism for the potential value of such compounds as human therapeutics.

Design, synthesis, and biological activity evaluation of 2-(benzo[b]thiophen-2-yl)-4-phenyl-4,5-dihydrooxazole derivatives as broad-spectrum antifungal agents.

To discover antifungal compounds with broad-spectrum and stable metabolism, a series of 2-(benzo[b]thiophen-2-yl)-4-phenyl-4,5-dihydrooxazole derivatives was designed and synthesized. Compounds A30-A34 exhibited excellent broad-spectrum antifungal activity against Candida albicans with MIC values in the range of 0.03-0.5 µg/mL, and against Cryptococcus neoformans and Aspergillus fumigatus with MIC values in the range of 0.25-2 µg/mL. In addition, compounds A31 and A33 showed high metabolic stability in human liver microsomes in vitro, with the half-life of 80.5 min and 69.4 min, respectively. Moreover, compounds A31 and A33 showed weak or almost no inhibitory effect on the CYP3A4 and CYP2D6. The pharmacokinetic evaluation in SD rats showed that compound A31 had suitable pharmacokinetic properties and was worthy of further study.

Synthesis and cytotoxicity evaluation of alpha beta unsaturated carboxylic acids of thiophene analogs by using polymer supported microwave-assisted method.

α- ß unsaturated carboxylic acids containing a heterocyclic moiety is one of the most potent class of bioactive compounds whose speedy generation through novel synthetic techniques has become an enigma for the synthetic chemists. This research project demonstrates a novel method for the synthesis of these compounds using polymer-supported microwave-assisted methodology carried out through one-pot multicomponent reaction. Both soluble and insoluble polymers have been used and their results are comprehensively analyzed. Moreover, the compounds are characterized through spectral analysis like FTIR, GC-MASS, 1HNMR Spectroscopy. The cytotoxicity of synthesized compounds is evaluated through MTT assay using HEPG 2 cells.

Analogs of TIQ-A as inhibitors of human mono-ADP-ribosylating PARPs.

The scaffold of TIQ-A, a previously known inhibitor of human poly-ADP-ribosyltransferase PARP1, was utilized to develop inhibitors against human mono-ADP-ribosyltransferases through structure-guided design and activity profiling. By supplementing the TIQ-A scaffold with small structural changes, based on a PARP10 inhibitor OUL35, selectivity changed from poly-ADP-ribosyltransferases towards mono-ADP-ribosyltransferases. Binding modes of analogs were experimentally verified by determining complex crystal structures with mono-ADP-ribosyltransferase PARP15 and with poly-ADP-ribosyltransferase TNKS2. The best analogs of the study achieved 10-20-fold selectivity towards mono-ADP-ribosyltransferases PARP10 and PARP15 while maintaining micromolar potencies. The work demonstrates a route to differentiate compound selectivity between mono- and poly-ribosyltransferases of the human ARTD family.

Nanoscale Covalent Organic Frameworks with Donor-Acceptor Structures as Highly Efficient Light-Responsive Oxidase-like Mimics for Colorimetric Detection of Glutathione.

Although organic artificial enzymes have been reported as biomimetic oxidation catalysts and are widely used for colorimetric biosensors, developing organic artificial enzymes with high enzymatic activity is still a challenge. Two-dimensional (2D) covalent organic frameworks (COFs) have shown superior potential in biocatalysts because of their periodic π-π arrays, tunable pore size and structure, large surface area, and thermal stability. The interconnection of electron acceptor and donor building blocks in the 2D conjugated COF skeleton can lead to narrower band gaps and efficient charge separation and transportation and thus is helpful to improve catalytic activity. Herein, a donor-acceptor 2D COF was synthesized using tetrakis(4-aminophenyl)pyrene (Py) as an electron donor and thieno[3,2-b]thiophene-2,5-dicarbaldehyde (TT) as an electron acceptor. Under visible light irradiation, the donor-acceptor 2D COF exhibited superior enzymatic catalytic activity, which could catalyze the oxidation of chromogenic substrates such as 3,3',5,5'-tetramethylbenzidine (TMB) by the formation of superoxide radicals and holes. Based on the above property, the photoactivated donor-acceptor 2D COF with enzyme-like catalytic properties was designed as a robust colorimetric probe for cheap, highly sensitive, and rapid colorimetric detection of glutathione (GSH); the corresponding linear range of GSH was 0.4-60 µM, and the limit of detection was 0.225 µM. This study not only presents the construction of COF-based light-activated nanozymes for environmentally friendly colorimetric detection of GSH but also provides a smart strategy for improving nanozyme activity.

Design, synthesis and biological evaluation of novel (E)-2-benzylidene-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)hydrazine-1-carboxamide derivatives as α-glucosidase inhibitors.

In this present study, a series of novel (E)-2-benzylidene-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)hydrazine-1-carboxamide derivatives against α-glucosidase were designed and synthesized, and their biological activities were evaluated in vitro and in vivo. Most of the designed analogues exhibited better inhibitory activity than the marketed acarbose, especially the most potent compound 7 with an IC50 value of 9.26 ± 1.84 µM. The direct binding of 7 and 8 with α-glucosidase was confirmed by fluorescence quenching experiments, and the kinetic and molecular docking studies revealed that 7 and 8 inhibited α-glucosidase in a non-competitive manner. Cytotoxicity bioassay indicated compounds 7 and 8 were non-toxic towards LO2 and HepG2 at 100 µM. Furthermore, both compounds were demonstrated to have in vivo hypoglycemic activity by reducing the blood glucose levels in sucrose-treated rats.

Discovery of imidazo[1,2-a]pyridine-thiophene derivatives as FLT3 and FLT3 mutants inhibitors for acute myeloid leukemia through structure-based optimization of an NEK2 inhibitor.

FMS-like tyrosine kinase 3 (FLT3) with an internal tandem duplication (ITD) mutation has been validated as a driver lesion and a therapeutic target for acute myeloid leukemia (AML). Currently, several potent small-molecule FLT3 kinase inhibitors are being evaluated or have completed evaluation in clinical trials. However, many of these inhibitors are challenged by the secondary mutations on kinase domain, especially the point mutations at the activation loop (D835) and gatekeeper residue (F691). To overcome the resistance challenge, we identified a novel series of imidazo[1,2-a]pyridine-thiophene derivatives from a NIMA-related kinase 2 (NEK2) kinase inhibitor CMP3a, which retained inhibitory activities on FTL3-ITDD835V and FLT3-ITDF691L. Through this study, we identified the imidazo[1,2-a]pyridine-thiophene derivatives as type-I inhibitors of FLT3. Moreover, we observed compound 5o as an inhibitor displaying equal anti-proliferative activities against FLT3-ITD, FTL3-ITDD835Y and FLT3-ITDF691L driven acute myeloid leukemia (AML) cell lines. Meanwhile, the apoptotic effects of compound supported its mechanism of anti-proliferative action. These results indicate that the imidazo[1,2-a]pyridine-thiophene scaffold is promising for targeting acquired resistance caused by FLT3 secondary mutations and compound 5o is an interesting lead in this direction.

Redox-Neutral Vicinal Difunctionalization of Five-Membered Heteroarenes with Dual Electrophiles.

A new reaction mode of palladium/norbornene (Pd/NBE) cooperative catalysis is reported involving the selective coupling of two different carbon-based electrophiles for vicinal double C-H functionalization of five-membered heteroarenes in a site-selective and redox-neutral manner. The key is to use alkynyl bromides as the second electrophile, which allows vicinal difunctionalization of a wide range of heteroarenes including pyrroles, thiophenes and furans at their C4 and C5 positions. One- or two-step tetrafunctionalizations of simple pyrrole and thiophene have also been realized. The C2-substituted NBEs prove most effective in these reactions, and the mechanistic exploration discloses the origin of the high selectivity of this transformation. Synthetic utility of this method has been exemplified in the concise preparations of thiophene-containing organic materials and a protein kinase inhibitor analogue. Preliminary success has also been achieved in a direct annulation event, using a tethered ketone as the second electrophile.

Synthesis and antischistosomal activity of linker- and thiophene-modified biaryl alkyl carboxylic acid derivatives.

Schistosomiasis is a neglected tropical disease caused by blood flukes of the genus Schistosoma and causes severe morbidity in infected patients. In 2018, 290.8 million people required treatment, and 200,000 deaths are reported per year. Treatment of this disease depends on a single drug, praziquantel (PZQ). However, in the past few years, reduced sensitivity of the parasites toward PZQ has been reported. Therefore, there is an urgent need for new drugs against this disease. In the past few years, we have focused on a new substance class called biaryl alkyl carboxylic acid derivatives, which showed promising antischistosomal activity in vitro. Structure-activity relationship (SAR) studies of the carboxylic acid moiety led to three promising carboxylic amides (morpholine, thiomorpholine, and methyl sulfonyl piperazine) with an antischistosomal activity down to 10 µM (morpholine derivative) and no cytotoxicity up to 100 µM. Here, we show our continued work on this substance class. We investigated, in extended SAR studies, whether modification of the linker and the thiophene ring could improve the antischistosomal activity. We found that the exchange of the alkyl linker by a pentadienyl or benzyl linker was tolerated and led to similar antischistosomal effects, whereas the exchange of the thiophene ring was not tolerated. Our data suggest that the thiophene ring is important for the antischistosomal activity of this compound class.

Benzothiophene derivatives as selective estrogen receptor covalent antagonists: Design, synthesis and anti-ERα activities.

Estrogen receptor α emerged as a well validated therapeutic target of breast cancer for decades. However, approximately 50% of patients who initially responding to standard-of-care (SoC), such as undergo therapy of Tamoxifen, generally inevitably progress to an endocrine-resistance ER+ phenotype. Recently, selective estrogen receptor covalent antagonists (SERCAs) targeted to ERα have been demonstrated as a therapeutic alternative. In the present study, series of novel 6-OH-benzothiophene (BT) derivatives targeting ERα and deriving from Raloxifene were designed, synthesized, and biologically evaluated as covalent antagonists. Driven by the antiproliferative efficacy in ER+ breast cancer cells, our chemical optimization finally led to compound 19d that with potent antagonistic activity in ER+ tumor cells while without agonistic activity in endometrial cells. Moreover, the docking simulation was carried out to elucidate the binding mode, revealing 19d as an antagonist and covalently binding to the cysteine residue at the 530 position of ER helix H11.