Discovery of 2-[1-(4-chlorophenyl)cyclopropyl]-3-hydroxy-8-(trifluoromethyl)quinoline-4-carboxylic acid (PSI-421), a P-selectin inhibitor with improved pharmacokinetic properties and oral efficacy in models of vascular injury

Total Synthesis of a PSGL-1 Glycopeptide Analogue for Targeted Inhibition of P-Selectin

The high affinity interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin is mediated by a multimotif glycosulfopeptide (GSP) recognition domain consisting of clustered tyrosine sulfates and a Core 2 O-glycan terminated with sialyl LewisX (C2-O-sLeX). These distinct GSP motifs are much more common than previously appreciated within a wide variety of functionally important domains involved in protein-protein interactions. However, despite the potential of GSPs to serve as tools for fundamental studies and prospects for drug discovery, their utility has been limited by the absence of chemical schemes for synthesis on scale. Herein, we report the total synthesis of GSnP-6, an analogue of the N-terminal domain of PSGL-1, and potent inhibitor of P-selectin. An efficient, scalable, hydrogenolysis-free synthesis of C2-O-sLeX-Thr-COOH was identified by both convergent and orthogonal one-pot assembly, which afforded this crucial building block, ready for direct use in solid phase peptide synthesis (SPPS). C2-O-sLeX-Thr-COOH was synthesized in 10 steps with an overall yield of 23% from the 4-O,5-N oxazolidinone thiosialoside donor. This synthesis represents an 80-fold improvement in reaction yield as compared to prior reports, achieving the first gram scale synthesis of SPPS ready C2-O-sLeX-Thr-COOH and enabling the scalable synthesis of GSnP-6 for preclinical evaluation. Significantly, we established that GSnP-6 displays dose-dependent inhibition of venous thrombosis in vivo and inhibits vaso-occlusive events in a human sickle cell disease equivalent microvasculature-on-a-chip system. The insights gained in formulating this design strategy can be broadly applied to the synthesis of a wide variety of biologically important oligosaccharides and O-glycan bearing glycopeptides.

The roles of P-selectin in cancer cachexia

P-selectin, a cell adhesion molecule of the selectin family, is expressed on the surface of activated endothelial cells (ECs) and platelets. Binding of P-selectin to P-selectin glycoprotein ligand-1 (PSGL-1) supports the leukocytes capture and rolling on stimulated ECs and increases the aggregation of leukocytes and activated platelets. Cancer cachexia is a systemic inflammation disorder characterized by metabolic disturbances, reduced body weight, loss of appetite, fat depletion, and progressive muscle atrophy. Cachexia status is associated with increased pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), which activates ECs to release P-selectin. Single-nucleotide polymorphisms (SNPs) loci of P-selectin encoding gene SELP are associated with higher level of plasma P-selectin and increase the susceptibility to cachexia in cancer patients. Elevated P-selectin expression has been observed in the hypothalamus, liver, and gastrocnemius muscle in animal models with cancer cachexia. Increased P-selectin may cause excessive inflammatory processes, muscle atrophy, and blood hypercoagulation, thus facilitating the development of cancer cachexia. In this review, physiological functions of P-selectin and its potential roles in cancer cachexia have been summarized. We also discuss the therapeutic potential of P-selectin inhibitors for the treatment of cancer cachexia.

N-Trifluoromethyl Succinimide as a New Reagent for Direct C-H Trifluoromethylation of Free Anilines

N-trifluoromethylsuccinimide (NTFS) as a new trifluoromethylation reagent was designed and prepared via Ag-CF₃ , and applied to the direct trifluoromethylation of free aniline, and a series of trifluoromethyl products were obtained with good yields. The practicability of the protocol was verified by a gram-level experiment and the synthesis of the antiasthmatic drug Mabuterol. In addition, a possible radical mechanism was proposed and verified by related experiments. The protocol provided a new solution for C-H trifluoromethylation of free anilines.

Convenient synthesis, characterization and biological evaluation of novel 1-phenylcyclopropane carboxamide derivatives

Small, strained ring molecules of phenylcyclopropane carboxamide have rigid, defined conformations and unique electronic properties. For these reasons many groups, seek to use these subunits to form biologically active compounds. Herein we report a generally applicable approach for preparing a small cyclopropane ring containing 1-phenylcyclopropane carboxamide derivatives to a wide range of the different aromatic compounds by α-alkylation of 2-phenyl acetonitrile derivatives with 1, 2-dibromo ethane in good yields followed by the conversion of cyano group to acid group by the reaction with concentrated hydrochloric acid. This obtained acid derivative undergoes acid amine coupling with various Methyl 2-(aminophenoxy)acetate to form 1-Phenylcyclopropane Carboxamide. These compounds possess distinct effective inhibition on the proliferation of U937, pro-monocytic, human myeloid leukaemia cell line while these compounds did not show cytotoxic activity on these cells. The structure-activity relationships of these compounds are discussed.

A PSGL-1 glycomimetic reduces thrombus burden without affecting hemostasis

Events mediated by the P-selectin/PSGL-1 pathway play a critical role in the initiation and propagation of venous thrombosis by facilitating the accumulation of leukocytes and platelets within the growing thrombus. Activated platelets and endothelium express P-selectin, which binds P-selectin glycoprotein ligand-1 (PSGL-1) that is expressed on the surface of all leukocytes. We developed a pegylated glycomimetic of the N terminus of PSGL-1, PEG40-GSnP-6 (P-G6), which proved to be a highly potent P-selectin inhibitor with a favorable pharmacokinetic profile for clinical translation. P-G6 inhibits human and mouse platelet-monocyte and platelet-neutrophil aggregation in vitro and blocks microcirculatory platelet-leukocyte interactions in vivo. Administration of P-G6 reduces thrombus formation in a nonocclusive model of deep vein thrombosis with a commensurate reduction in leukocyte accumulation, but without disruption of hemostasis. P-G6 potently inhibits the P-selectin/PSGL-1 pathway and represents a promising drug candidate for the prevention of venous thrombosis without increased bleeding risk.

Nanoparticles of a New Small-Molecule P-Selectin Inhibitor Attenuate Thrombosis, Inflammation, and Tumor Growth in Two Animal Models

Purpose

To assess whether the newly designed small-molecule oral P-selectin inhibitor 3S-1,2,3,4-tetrahydro-β-carboline-3-methyl aspartyl ester (THCMA) as a nanomedicine enhances antithrombosis, anti-inflammation, and antitumor activity more than the clinical trial drug PSI-697.

Methods

THCMA was designed as an amphiphile containing pharmacophores of PSI-697. Its nanofeatures were explored with TEM, SEM, Tyndall effect, ζ-potential, FT-ICR-MS, and NOESY 2D ¹H NMR. The P-selectin inhibitory effect of THCMA was demonstrated with molecular docking, ultraviolet (UV) spectra, and competitive ELISA. In vivo and in vitro assays — anti-arterial thrombosis, anti–venous thrombosis, anti-inflammation, antitumor growth, anti–platelet aggregation, rat-tail bleeding time, anticoagulation index, soluble P-selectin (sP-selectin) expression, and serum TNFα expression — were performed to explore bioactivity and potential mechanisms. Water solubility of THCMA was measured using UV-absorption spectra.

Results

THCMA self-assembled into nanorings of approximately 100 nm in diameter. Its water solubility was about 1,030-fold that of PSI-697. THCMA exhibited more potent P-selectin inhibitory effect than PSI-697. The oral efficacy of THCMA was 100-fold that of PSI-697 in inhibiting arterial and venous thrombosis and tenfold in inhibiting inflammation. THCMA inhibited thrombosis at a dose that produces no coagulation disorders and no bleeding risk. THCMA exhibited enhanced antitumor activity over PSI-697 without systemic chemotherapy toxicity. THCMA significantly inhibited platelet aggregation in vitro and downregulated the expression levels of serum sP-selectin and TNFα in vivo.

Conclusion

A new small-molecule P-selectin inhibitor, THCMA, has been successfully designed as a nanomedicine with largely enhanced oral efficacy compared to the clinical trial drug PSI-697, and thus might be developed for the oral treatment of arterial thrombosis, venous thrombosis, inflammation, and cancer-associated thrombosis.

Potential antibacterial and antifungal activities of novel sulfamidophosphonate derivatives bearing the quinoline or quinolone moiety

A series of new α‐sulfamidophosphonate/sulfonamidophosphonate (4a–n) and cyclosulfamidophosphonate (5a–d) derivatives containing the quinoline or quinolone moiety was designed and synthesized via Kabachnik–Fields reaction in the presence of ionic liquid under ultrasound irradiation. This efficient methodology provides new 1,2,5‐thiadiazolidine‐1,1‐dioxide derivatives 5a–d in one step and optimal conditions. The molecular structures of the novel compounds 4a–n and 5a–d were confirmed using various spectroscopic methods. All these compounds were evaluated for their in vitro antibacterial activity against Gram‐negative (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853) and Gram‐positive (Staphylococcus aureus ATCC 27923) bacteria, in addition to three clinical strains (E. coli 1, P. aeruginosa 1, and S. aureus 1). Most of the tested compounds showed more potent inhibitory activities against both Gram‐positive and ‐negative bacteria compared with the sulfamethoxazole reference. The following compounds, 4n, 4f, 4g, 4m, 4l, 4d, and 4e, are the most active sulfamidophosphonate derivatives. Furthermore, these molecules gave interesting zones of inhibition varying between 28 and 49 mm, against all tested bacterial strains, with a low minimum inhibitory concentration (MIC) value ranging from 0.125 to 8 μg/ml. All the synthesized derivatives were also evaluated for their in vitro antifungal activity against Fusarium oxyporum f. sp. lycopersici and Alternaria sp. The results revealed that all the synthesized compounds exhibited excellent antifungal inhibition and the compounds 4f, 4g, 4m, and 4i were the most potent derivatives with MIC values ranging from 0.25 to 1 µg/ml against the two tested fungal strains. The strongest inhibition of bacteria and fungi strains was detected by the effect of quinolone and sulfamide moieties.

Copper-Catalyzed ortho-Functionalization of Quinoline N-Oxides with Vinyl Arenes

An efficient copper-catalyzed regioselective C-H alkenylation and borylative alkylation of quinoline N-oxides with vinyl arenes in the presence of pinacol diborane has been developed. The reaction proceeds through the borylcupration of the vinyl arenes followed by nucleophilic attack of the resulting alkyl copper species to the quinoline N-oxides. Benzoquinone and KO^t Bu were identified as the necessary additives at the second step of the reaction that are crucial for the success of the reaction. A wide range of C2-functionalizaed quinolines were obtained with good functional group tolerance, which may find utilities in pharmaceuticals and synthetic chemistry.

Photoredox-Catalyzed Enantioselective α-Deuteration of Azaarenes with D2O

The site-specific incorporation of deuterium (D) into small molecules is frequently used to access isotopically labeled compounds with broad utility in many research areas, such as drug development, mechanistic studies, and NMR analyses. Nevertheless, the deuteration of a stereocenter in an enantioselective manner, which could slow the metabolism and improve the bioavailability of bioactive molecules, remains challenging owing to the lack of established catalytic methods. Here, we report an asymmetric α-deuteration strategy for azaarenes with inexpensive D₂O as the deuterium source. A cooperative visible light-driven photoredox and chiral Brønsted acid–catalyzed system using a Hantzsch ester as the terminal reductant has been developed, which enables racemic α-chloro-azaarenes and prochiral azaarene-substituted ketones to experience a single-electron reduction–enantioselective deuteration process. The transition metal-free method provides important chiral α-deuterated azaarenes in satisfactory yields with good to excellent enantioselectivities (up to 99% ee) and substantial deuterium incorporation.

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Enantioselective deuteration enabled by photoredox asymmetric catalysis

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D₂O as the deuterium source

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Azaarenes with a deuterated stereocenter

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Transition-metal-free catalyst system

C5-Regioselective C-H fluorination of 8-aminoquinoline amides and sulfonamides with Selectfluor under metal-free conditions

A novel and efficient regioselective C-H fluorination of 8-aminoquinoline amides and sulfonamides at the C5 position was achieved. Using Selectfluor as a "F" reagent and HOAc as an additive, the reaction proceeds smoothly via a radical pathway. This method features metal-free conditions, a broad substrate scope and operational simplicity.

Phase Transition Nanoparticles as Multimodality Contrast Agents for the Detection of Thrombi and for Targeting Thrombolysis: in Vitro and in Vivo Experiments

Thrombotic disease is extremely harmful to human health, and early detection and treatment can improve the prognosis and reduce mortality. Multimodal molecular imaging can provide abundant information about thrombi, but to date, few studies have used multimodal and multifunctional nanoparticles (NPs) for thrombus detection and for targeting thrombolysis. In this study, phase transition multimodal and multifunctional NPs (EWVDV-Fe-Ink-PFH NPs) were constructed for the first time using a three-step emulsification and carbodiimide method, and the physical and chemical properties of the NPs were investigated. The targeting abilities of the NPs and multimodal imaging, that is, photoacoustic, magnetic resonance, and ultrasound imaging, were successfully achieved in vitro and in vivo. The ability of the EWVDV peptide on the NPs to effectively target the P-selectin of thrombi was confirmed by multimodal imaging and pathology, and the penetration depths of the NPs into the thrombi were far deeper than the previously reported depths. Moreover, a perfluorohexane (PFH) phase transition induced by low-intensity focused ultrasound irradiation enabled the EWVDV-Fe-Ink-PFH NPs to cause thrombolysis in vitro. In summary, EWVDV-Fe-Ink-PFH NPs are a theranostic contrast agent that will provide a simple, effective, and noninvasive approach for the diagnosis and treatment of thrombosis.

Novel ureidopropanamide based N-formyl peptide receptor 2 (FPR2) agonists with potential application for central nervous system disorders characterized by neuroinflammation

Formyl peptide receptor2 (FPR2) is a G-protein coupled receptor that plays critical roles in inflammatory reactions. FPR2-specific interaction can be possibly used to facilitate the resolution of pathological inflammatory responses by enhancing endogenous anti-inflammation systems. Starting from our lead agonist 5, we designed new ureidopropanamides derivatives able to activate FPR2 in transfected cells and human neutrophils. The new FPR2 agonists showed good stability towards oxidative metabolism in vitro. Moreover, selected compounds showed anti-inflammatory properties in LPS-stimulated rat primary microglial cells. (S)-3-(4-Cyanophenyl)-N-[[1-(3-chloro-4-fluorophenyl)cyclopropyl]methyl]-2-[3-(4-fluorophenyl)ureido]propanamide ((S)-17) emerged as prospective pharmacological tool to study the effects of FPR2 activation in the central nervous system (CNS) being able to reduce IL-1β and TNF-α levels in LPS-stimulated microglial cells and showing good permeation rate in hCMEC/D3 cells, an in vitro model of blood brain barrier. These results are very promising and can open new therapeutic perspectives in the treatment of CNS disorders characterized by neuroinflammation.

Targeting P-selectin glycoprotein ligand-1/P-selectin interactions as a novel therapy for metabolic syndrome

Obesity-induced insulin resistance and metabolic syndrome continue to pose an important public health challenge worldwide as they significantly increase the risk of type 2 diabetes and atherosclerotic cardiovascular disease. Advances in the pathophysiologic understanding of this process has identified that chronic inflammation plays a pivotal role. In this regard, given that both animal models and human studies have demonstrated that the interaction of P-selectin glycoprotein ligand-1 (PSGL-1) with P-selectin is not only critical for normal immune response but also is upregulated in the setting of metabolic syndrome, PSGL-1/P-selectin interactions provide a novel target for preventing and treating resultant disease. Current approaches of interfering with PSGL-1/P-selectin interactions include targeted antibodies, recombinant immunoglobulins that competitively bind P-selectin, and synthetic molecular therapies. Experimental models as well as clinical trials assessing the role of these modalities in a variety of diseases have continued to contribute to the understanding of PSGL-1/P-selectin interactions and have demonstrated the difficulty in creating clinically relevant therapeutics. Most recently, however, computational simulations have further enhanced our understanding of the structural features of PSGL-1 and related glycomimetics, which are responsible for high-affinity selectin interactions. Leveraging these insights for the design of next generation agents has thus led to development of a promising synthetic method for generating PSGL-1 glycosulfopeptide mimetics for the treatment of metabolic syndrome.

Organoiodine reagent-promoted intermolecular oxidative amination: synthesis of cyclopropyl spirooxindoles

An organoiodine-promoted intramolecular direct oxidative C(sp²)–N cross-coupling reaction was developed for the preparation of cyclopropyl spirooxindoles from readily available secondary cyclopropyl carboxamides.

IQCA-TASS: a nano-scaled P-selectin inhibitor capable of targeting thrombus and releasing IQCA/TARGD(S)S in vivo

Thrombosis is a serious threat to human health worldwide. Tetrahydroisoquinoline-3-carboxylic acid (IQCA) is an antithrombotic agent, while Thr-Ala-Arg-Gly-Asp(Ser)-Ser (TASS) can target thrombus.

Design, Synthesis and Antibacterial Evaluation of Some New 2-Phenyl-quinoline-4-carboxylic Acid Derivatives

A series of new 2-phenyl-quinoline-4-carboxylic acid derivatives was synthesized starting from aniline, 2-nitrobenzaldehyde, pyruvic acid followed by Doebner reaction, amidation, reduction, acylation and amination. All of the newly-synthesized compounds were characterized by ¹H-NMR, ¹³C-NMR and HRMS. The antibacterial activities of these compounds against Gram-negative (Escherichia coli, Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis), as well as one strain of methicillin-resistant Staphylococcus aureus (MRSA) bacteria were evaluated by the agar diffusion method (zone of inhibition) and a broth dilution method (minimum inhibitory concentration (MIC)), and their structure-activity relationships were obtained and discussed. The results revealed that some compounds displayed good antibacterial activity against Staphylococcus aureus, and Compounds 5a₄ and 5a₇ showed the best inhibition with an MIC value of 64 μg/mL against Staphylococcus aureus and with an MIC value of 128 μg/mL against Escherichia coli, respectively. The results of the MTT assay illustrated the low cytotoxicity of Compound 5a₄.

Glycopeptide analogues of PSGL-1 inhibit P-selectin in vitro and in vivo

Blockade of P-selectin/PSGL-1 interactions holds significant potential for treatment of disorders of innate immunity, thrombosis, and cancer. Current inhibitors remain limited due to low binding affinity or by the recognized disadvantages inherent to chronic administration of antibody therapeutics. Here we report an efficient approach for generating glycosulfopeptide mimics of N-terminal PSGL-1 through development of a stereoselective route for multi-gram scale synthesis of the C2 O-glycan building block and replacement of hydrolytically labile tyrosine sulfates with isosteric sulfonate analogs. Library screening afforded a compound of exceptional stability, GSnP-6, that binds to human P-selectin with nanomolar affinity (K_d ~ 22 nM). Molecular dynamics simulation defines the origin of this affinity in terms of a number of critical structural contributions. GSnP-6 potently blocks P-selectin/PSGL-1 interactions in vitro and in vivo and represents a promising candidate for the treatment of diseases driven by acute and chronic inflammation.

Visible-light-promoted radical C-H trifluoromethylation of free anilines

The trifluoromethyl-substituted anilines are biologically active compounds and useful building blocks. In this communication, we have developed the first visible-light-induced radical trifluoromethylation of free anilines with the commercially available and easily handled Togni reagent at room temperature. The resulting products were successfully transformed into a variety of valuable fluorine-containing molecules and heterocyclic compounds. This protocol provides an economical and powerful route to trifluoromethylated free anilines.

Palladium-catalyzed trifluoromethylation of aromatic C-H bond directed by an acetamino group

The first palladium-catalyzed ortho-trifluoromethylation of the aromatic C-H bond directed by an acetamino group is reported. This method provides an efficient and green approach to synthesize the highly biological potential key structure of ortho-CF(3) acetanilides and anilines.