Cycloaddition of Phenyltriazolinedione with Carbazole-Alkynes and Yne-Carbamates to Access Diazacyclobutenes

Previously, we described the synthesis of stable, bicyclic examples of the rather rare diazacyclobutene (DCB) motif by means of a cycloaddition between triazolinediones and electron-rich thiolated alkynes. Here, we report the investigation of the cycloaddition of triazolinediones with related electron-rich yne-carbamates and carbazole-alkynes. Bicyclic DCBs arising from yne-carbamates were isolated in 8-65% yield, while those arising from carbazole-alkynes were isolated in 28-59% yield. Mechanistic studies and characterization of isolable byproducts shed light on the underlying issues leading to poor to moderate yields.

Enhancing drug delivery with supramolecular amphiphilic macrocycle nanoparticles: selective targeting of CDK4/6 inhibitor palbociclib to melanoma

Drug delivery systems based on amphiphilic supramolecular macrocycles have garnered increased attention over the past two decades due to their ability to successfully formulate nanoparticles. Macrocyclic (MC) materials can self-assemble at lower concentrations without the need for surfactants and polymers, but surfactants are required to form and stabilize nanoparticles at higher concentrations. Using MCs to deliver both hydrophilic and hydrophobic guest molecules is advantageous. We developed two novel types of amphiphilic macrocycle nanoparticles (MC NPs) capable of delivering either Nile Red (NR) (a hydrophobic model) or Rhodamine B (RhB) (a hydrophilic model) fluorescent dyes. We extensively characterized the materials using various techniques to determine size, morphology, stability, hemolysis, fluorescence, loading efficiency (LE), and loading capacity (LC). We then loaded the CDK4/6 inhibitor Palbociclib (Palb) into both MC NPs using a solvent diffusion method. This yielded Palb-MC NPs in the size range of 65-90 nm. They exhibited high stability over time and in fetal bovine serum with negligible toxicity against erythrocytes. Cytotoxicity was minimal when tested against RAW macrophages, human fibroblast HDFn, and adipose stromal cells (ASCs) at higher concentrations of MC NPs. Cell viability studies were conducted with different concentrations of MC NPs, Palb-MC NPs, and free Palb against RAW macrophages, human U-87 GBM, and human M14 melanoma cell lines in vitro. Flow cytometry experiments revealed that blank MC NPs and Palb-MC NPs were selectively targeted to melanoma cells, resulting in cell death compared to the other two cell lines. Future work will focus on studying the biological effect of MC NPs including their binding affinity with molecules/receptors expressed on the M14 and other melanoma cell surfaces by molecular docking simulations. Subsequently, we will evaluate the MCs as a component of combination therapy in a murine melanoma model.

Enolase inhibitors as therapeutic leads for Naegleria fowleri infection

Infections with the pathogenic free-living amoebae Naegleria fowleri can lead to life-threatening illnesses including catastrophic primary amebic meningoencephalitis (PAM). Efficacious treatment options for these infections are lacking and the mortality rate remains >95% in the US. Glycolysis is very important for the infectious trophozoite lifecycle stage and inhibitors of glucose metabolism have been found to be toxic to the pathogen. Recently, human enolase 2 (ENO2) phosphonate inhibitors have been developed as lead agents to treat glioblastoma multiforme (GBM). These compounds, which cure GBM in a rodent model, are well-tolerated in mammals because enolase 1 (ENO1) is the predominant isoform used systemically. Here, we describe findings that demonstrate that these agents are potent inhibitors of N. fowleri ENO ( Nf ENO) and are lethal to amoebae. In particular, (1-hydroxy-2-oxopiperidin-3-yl) phosphonic acid (HEX) was a potent enzyme inhibitor (IC 50 value of 0.14 ± 0.04 µM) that was toxic to trophozoites (EC 50 value of 0.21 ± 0.02 µM) while the reported CC 50 was >300 µM. Molecular docking simulation revealed that HEX binds strongly to the active site of Nf ENO with a binding affinity of -8.6 kcal/mol. Metabolomic studies of parasites treated with HEX revealed a 4.5 to 78-fold accumulation of glycolytic intermediates upstream of Nf ENO. Last, nasal instillation of HEX increased longevity of amoebae-infected rodents. Two days after infection, animals were treated for 10 days with 3 mg/kg HEX, followed by one week of observation. At the conclusion of the experiment, eight of 12 HEX-treated animals remained alive (resulting in an indeterminable median survival time) while one of 12 vehicle-treated rodents remained, yielding a median survival time of 10.9 days. Brains of six of the eight survivors were positive for amoebae, suggesting the agent at the tested dose suppressed, but did not eliminate, infection. These findings suggest that HEX is a promising lead for the treatment of PAM.

Glucose metabolism in the pathogenic free-living amoebae: Tempting targets for treatment development

Pathogenic free-living amoebae (pFLA) are single-celled eukaryotes responsible for causing intractable infections with high morbidity and mortality in humans and animals. Current therapeutic approaches include cocktails of antibiotic, antifungal, and antimicrobial compounds. Unfortunately, the efficacy of these can be limited, driving the need for the discovery of new treatments. Pan anti-amebic agents would be ideal; however, identifying these agents has been a challenge, likely due to the limited evolutionary relatedness of the different pFLA. Here, we discuss the potential of targeting amoebae glucose metabolic pathways as the differences between pFLA and humans suggest specific inhibitors could be developed as leads for new therapeutics.

Enhancing Drug Delivery with Supramolecular Amphiphilic Macrocycle Nanoparticles: Selective Targeting of CDK4/6 Inhibitor Palbociclib to Melanoma

Drug delivery systems based on amphiphilic supramolecular macrocycles have garnered increased attention over the past two decades due to their ability to successfully formulate nanoparticles. Macrocyclic (MC) materials can self-assemble at lower concentrations without the need for surfactants and polymers, but surfactants are required to form and stabilize nanoparticles at higher concentrations. Using MCs to deliver both hydrophilic and hydrophobic guest molecules is advantageous. We developed two novel types of amphiphilic macrocycle nanoparticles (MC NPs) capable of delivering either Nile Red (NR) (a hydrophobic model) or Rhodamine B (RhB) (a hydrophilic model) fluorescent dyes. We extensively characterized the materials using various techniques to determine size, morphology, stability, hemolysis, fluorescence, loading efficiency (LE), and loading capacity (LC). We then loaded the CDK4/6 inhibitor Palbociclib (Palb) into both MC NPs using a solvent diffusion method. This yielded Palb-MC NPs in the size range of 65-90 nm. They exhibited high stability over time and in fetal bovine serum with negligible toxicity against erythrocytes. Cytotoxicity was minimal when tested against RAW macrophages, human fibroblast HDFn , and adipose stromal cells (ASCs) at higher concentrations of MC NPs. Cell viability studies were conducted with different concentrations of MC NPs, Palb-MC NPs, and free Palb against RAW macrophages, human U-87 GBM, and human M14 melanoma cell lines in vitro. Flow cytometry experiments revealed that blank MC NPs and Palb-MC NPs were selectively targeted to melanoma cells, resulting in cell death compared to the other two cell lines. Future work will focus on studying the biological effect of MC NPs including their binding affinity with molecules/receptors expressed on the M14 and other melanoma cell surface by molecular docking simulations. Subsequently, we will evaluate the MCs as a component of combination therapy in a murine melanoma model.

Graphical abstract

Enolase Inhibitors as Early Lead Therapeutics against Trypanosoma brucei

Glucose metabolism is critical for the African trypanosome, Trypanosoma brucei, serving as the lone source of ATP production for the bloodstream form (BSF) parasite in the glucose-rich environment of the host blood. Recently, phosphonate inhibitors of human enolase (ENO), the enzyme responsible for the interconversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP) in glycolysis or PEP to 2-PG in gluconeogenesis, have been developed for the treatment of glioblastoma multiforme (GBM). Here, we have tested these agents against T. brucei ENO (TbENO) and found the compounds to be potent enzyme inhibitors and trypanocides. For example, (1-hydroxy-2-oxopyrrolidin-3-yl) phosphonic acid (deoxy-SF2312) was a potent enzyme inhibitor (IC50 value of 0.60 ± 0.23 µM), while a six-membered ring-bearing phosphonate, (1-hydroxy-2-oxopiperidin-3-yl) phosphonic acid (HEX), was less potent (IC50 value of 2.1 ± 1.1 µM). An analog with a larger seven-membered ring, (1-hydroxy-2-oxoazepan-3-yl) phosphonic acid (HEPTA), was not active. Molecular docking simulations revealed that deoxy-SF2312 and HEX had binding affinities of -6.8 and -7.5 kcal/mol, respectively, while the larger HEPTA did not bind as well, with a binding of affinity of -4.8 kcal/mol. None of these compounds were toxic to BSF parasites; however, modification of enzyme-active phosphonates through the addition of pivaloyloxymethyl (POM) groups improved activity against T. brucei, with POM-modified (1,5-dihydroxy-2-oxopyrrolidin-3-yl) phosphonic acid (POMSF) and POMHEX having EC50 values of 0.45 ± 0.10 and 0.61 ± 0.08 µM, respectively. These findings suggest that HEX is a promising lead against T. brucei and that further development of prodrug HEX analogs is warranted.

Predicting Antioxidant Synergism via Artificial Intelligence and Benchtop Data

Lipid oxidation is a major issue affecting products containing unsaturated fatty acids as ingredients or components, leading to the formation of low molecular weight species with diverse functional groups that impart off-odors and off-flavors. Aiming to control this process, antioxidants are commonly added to these products, often deployed as combinations of two or more compounds, a strategy that allows for lowering the amount used while boosting the total antioxidant capacity of the formulation. While this approach allows for minimizing the potential organoleptic and toxic effects of these compounds, predicting how these mixtures of antioxidants will behave has traditionally been one of the most challenging tasks, often leading to simple additive, antagonistic, or synergistic effects. Approaches to understanding these interactions have been predominantly empirically driven but thus far, inefficient and unable to account for the complexity and multifaceted nature of antioxidant responses. To address this current gap in knowledge, we describe the use of an artificial intelligence model based on deep learning architecture to predict the type of interaction (synergistic, additive, and antagonistic) of antioxidant combinations. Here, each mixture was associated with a combination index value (CI) and used as input for our model, which was challenged against a test (n = 140) data set. Despite the encouraging preliminary results, this algorithm failed to provide accurate predictions of oxidation experiments performed in-house using binary mixtures of phenolic antioxidants and a lard sample. To overcome this problem, the AI algorithm was then enhanced with various amounts of experimental data (antioxidant power data assessed by the TBARS assay), demonstrating the importance of having chemically relevant experimental data to enhance the model's performance and provide suitable predictions with statistical relevance. We believe the proposed method could be used as an auxiliary tool in benchmark analysis routines, offering a novel strategy to enable broader and more rational predictions related to the behavior of antioxidant mixtures.

Correction: Removal of metals and inorganics from rendered fat using polyamine-modified cellulose nanocrystals

[This corrects the article DOI: 10.1039/D3SU00116D.].

Exploring the interactive mechanism of acarbose with the amylase SusG in the starch utilization system of the human gut symbiont Bacteroides thetaiotaomicron through molecular modeling

The α-amylase, SusG, is a principal component of the Bacteroides thetaiotaomicron (Bt) starch utilization system (Sus) used to metabolize complex starch molecules in the human gastrointestinal (GI) tract. We previously reported the non-microbicidal growth inhibition of Bt by the acarbose-mediated arrest of the Sus as a potential therapeutic strategy. Herein, we report a computational approach using density functional theory (DFT), molecular docking, and molecular dynamics (MD) simulation to explore the interactive mechanism between acarbose and SusG at the atomic level in an effort to understand how acarbose shuts down the Bt Sus. The docking analysis reveals that acarbose binds orthosterically to SusG with a binding affinity of -8.3 kcal/mol. The MD simulation provides evidence of conformational variability of acarbose at the active site of SusG and also suggests that acarbose interacts with the main catalytic residues via a general acid-base double-displacement catalytic mechanism. These results suggest that small molecule competitive inhibition against the SusG protein could impact the entire Bt Sus and eliminate or reduce the system's ability to metabolize starch. This computational strategy could serve as a potential avenue for structure-based drug design to discover other small molecules capable of inhibiting the Sus of Bt with high potency, thus providing a holistic approach for selective modulation of the GI microbiota.

A cathepsin C-like protease mediates the post-translation modification of Toxoplasma gondii secretory proteins for optimal invasion and egress

Microbial pathogens use proteases for their infections, such as digestion of proteins for nutrients and activation of their virulence factors. As an obligate intracellular parasite, Toxoplasma gondii must invade host cells to establish its intracellular propagation. To facilitate invasion, the parasites secrete invasion effectors from microneme and rhoptry, two unique organelles in apicomplexans. Previous work has shown that some micronemal invasion effectors experience a series of proteolytic cleavages within the parasite's secretion pathway for maturation, such as the aspartyl protease (TgASP3) and the cathepsin L-like protease (TgCPL), localized within the post-Golgi compartment and the endolysosomal system, respectively. Furthermore, it has been shown that the precise maturation of micronemal effectors is critical for Toxoplasma invasion and egress. Here, we show that an endosome-like compartment (ELC)-residing cathepsin C-like protease (TgCPC1) mediates the final trimming of some micronemal effectors, and its loss further results in defects in the steps of invasion, egress, and migration throughout the parasite's lytic cycle. Notably, the deletion of TgCPC1 completely blocks the activation of subtilisin-like protease 1 (TgSUB1) in the parasites, which globally impairs the surface-trimming of many key micronemal invasion and egress effectors. Additionally, we found that Toxoplasma is not efficiently inhibited by the chemical inhibitor targeting the malarial CPC ortholog, suggesting that these cathepsin C-like orthologs are structurally different within the apicomplexan phylum. Collectively, our findings identify a novel function of TgCPC1 in processing micronemal proteins within the Toxoplasma parasite's secretory pathway and expand the understanding of the roles of cathepsin C protease. IMPORTANCE Toxoplasma gondii is a microbial pathogen that is well adapted for disseminating infections. It can infect virtually all warm-blooded animals. Approximately one-third of the human population carries toxoplasmosis. During infection, the parasites sequentially secrete protein effectors from the microneme, rhoptry, and dense granule, three organelles exclusively found in apicomplexan parasites, to help establish their lytic cycle. Proteolytic cleavage of these secretory proteins is required for the parasite's optimal function. Previous work has revealed that two proteases residing within the parasite's secretory pathway cleave micronemal and rhoptry proteins, which mediate parasite invasion and egress. Here, we demonstrate that a cathepsin C-like protease (TgCPC1) is involved in processing several invasion and egress effectors. The genetic deletion of TgCPC1 prevented the complete maturation of some effectors in the parasites. Strikingly, the deletion led to a full inactivation of one surface-anchored protease, which globally impaired the trimming of some key micronemal proteins before secretion. Therefore, this finding represents a novel post-translational mechanism for the processing of virulence factors within microbial pathogens.

Removal of metals and inorganics from rendered fat using polyamine-modified cellulose nanocrystals

Meatpacking and poultry operations produce an enormous amount of co-products including offal, fat, blood, feathers etc. that are collected and processed by the rendering industry into value-added materials such as various protein meals and rendered fat products. Rendered fats (mainly composed of triglycerides from the adipose tissue of animals or used cooking oil from the restaurant industry) are sold for a variety of applications including animal feed formulations. Nonetheless, in the current context of energy scarcity, their use as feedstocks for the generation of renewable fuels including biodiesel and renewable diesel represents a growing market. The diverse composition of the source material can impose significant challenges in terms of compliance, requiring the control (and reduction) of the concentration of elements such as phosphorus, sulfur, calcium, magnesium, sodium, potassium, and other undesirable metals that can otherwise interfere with critical aspects of the refining process or contaminate the renewable fuel products. To address this critical need, we describe the application of poly(ethylenimine)-modified cellulose nanocrystals as a low-cost material for the removal of unwanted metal/inorganic cations from rendered fat. A total of 28 real samples including poultry, white pork grease, and beef tallow were analyzed. Test results showed that the approach can effectively decrease the concentration of the target elements by 95 ± 2%, suggesting that this treatment protocol could dramatically improve the application of rendered fat products for renewable fuel refining.

Lignocellulosic-Based Nanoparticles with Photoluminescent Properties for Bioimaging

Natural and renewable resources from plants or animals are an important source of biomaterials due to their biocompatibility and high availability. Lignin is a biopolymer present in the biomass of plants, where it is intertwined and cross-linked with other polymers and macromolecules in the cell walls, generating a lignocellulosic material with potential applications. We have prepared lignocellulosic-based nanoparticles with an average size of 156 nm that exhibit a high photoluminescence signal when excited at 500 nm with emission in the near-infrared (NIR) region at 800 nm. The advantage of these lignocellulosic-based nanoparticles is their natural luminescent properties and their origin from rose biomass waste, which eliminates the need for encapsulation or functionalization of imaging agents. Moreover, the in vitro cell growth inhibition (IC50) of lignocellulosic-based nanoparticles is about 3 mg/mL, and no in vivo toxicity was registered up to 57 mg/kg, which suggests that they are suitable for bioimaging applications. In addition, these nanoparticles can circulate in the blood and are excreted in urine. The combined high luminescence signal in NIR, small size, low in vitro toxicity, low in vivo toxicity, and blood circulation support the potential of lignin-based nanoparticles as a novel bioimaging agent.

Comparison between nanocellulose-polyethylenimine composites synthesis methods towards multiple water pollutants removal: A review

Nanocellulose/polyethylenimine composites have attracted growing attention due to their versatility as new materials for application in different fields. Water remediation is one of the traditional applications of these composites and their investigation as adsorbents for single water pollutants is well established. However, most water resources such as rivers, lakes, and even oceans contain complex mixtures of pollutants. Despite several recently published reviews on water purification technology, they only focused on these material as single pollutant removers and hardly mentioned their capacity to simultaneously recover multiple pollutants. Therefore, there is still a gap in the archived literature considering nanocellulose/polyethylenimine composites targeting water remediation with multiple water pollutants. In this review, methods for synthesizing such composites are classified and compared according to the mechanism of reactions, such as chemical crosslinking and physical adsorption, while outlining advantages and limitations. Then, the water pollutants mainly targeted by those composites are discussed in detail to expound the relationship between the synthesis method and the type and adsorption capacity. Finally, the last section presents challenges and opportunities of these nanocellulose/polyethylenimine composites as emerging sorbents for sustainable multiple water pollutants purification technologies. This review aims to lay out the basis for future developments of these composites for multiple water pollutants.

A cathepsin C-like protease post-translationally modifies Toxoplasma gondii secretory proteins for optimal invasion and egress

Microbial pathogens use proteases for their infections, such as digestion of proteins for nutrients and activation of their virulence factors. As an obligate intracellular parasite, Toxoplasma gondii must invade host cells to establish its intracellular propagation. To facilitate invasion, the parasites secrete invasion effectors from microneme and rhoptry, two unique organelles in apicomplexans. Previous work has shown that some micronemal invasion effectors experience a series of proteolytic cleavages within the parasite's secretion pathway for maturation, such as the aspartyl protease (TgASP3) and the cathepsin L-like protease (TgCPL), localized within the post-Golgi compartment (1) and the endolysosomal system (2), respectively. Furthermore, it has been shown that the precise maturation of micronemal effectors is critical for Toxoplasma invasion and egress (1). Here, we show that an endosome-like compartment (ELC)-residing cathepsin C-like protease (TgCPC1) mediates the final trimming of some micronemal effectors, and its loss further results in defects in the steps of invasion, egress, and migration throughout the parasite's lytic cycle. Notably, the deletion of TgCPC1 completely blocks the activation of subtilisin-like protease 1 (TgSUB1) in the parasites, which globally impairs the surface-trimming of many key micronemal invasion and egress effectors. Additionally, we found that TgCPC1 was not efficiently inhibited by the chemical inhibitor targeting its malarial ortholog, suggesting that these cathepsin C-like orthologs are structurally different within the apicomplexan phylum. Taken together, our findings identify a novel function of TgCPC1 in the processing of micronemal proteins within the secretory pathway of Toxoplasma parasites and expand the understanding of the roles of cathepsin C protease.

IMPORTANCE

Toxoplasma gondii is a microbial pathogen that is well adapted for disseminating infections. It can infect virtually all warm-blooded animals. Approximately one-third of the human population carries toxoplasmosis. During infection, the parasites sequentially secrete protein effectors from the microneme, rhoptry, and dense granule, three organelles exclusively found in apicomplexan parasites, to help establish their lytic cycle. Proteolytic cleavage of these secretory proteins is required for the parasite's optimal function. Previous work has revealed that two proteases residing within the parasite's secretory pathway cleave micronemal and rhoptry proteins, which mediate parasite invasion and egress. Here, we demonstrate that a cathepsin C-like protease (TgCPC1) is involved in processing several invasion and egress effectors. The genetic deletion of TgCPC1 prevented the complete maturation of some effectors in the parasites. Strikingly, the deletion led to a full inactivation of one surface-anchored protease, which globally impaired the trimming of some key micronemal proteins before secretion. Therefore, this finding represents a novel post-translational mechanism for the processing of virulence factors within microbial pathogens.

Radiopaque Iodosilane-Coated Lipid Hybrid Nanoparticle Contrast Agent for Dual-Modality Ultrasound and X-ray Bioimaging

Here, we report the synthesis of robust hybrid iodinated silica-lipid nanoemulsions (HSLNEs) for use as a contrast agent for ultrasound and X-ray applications. We engineered iodinated silica nanoparticles (SNPs), lipid nanoemulsions, and a series of HSLNEs by a low-energy spontaneous nanoemulsification process. The formation of a silica shell requires sonication to hydrolyze and polymerize/condensate the iodomethyltrimethoxysilane at the oil/water interface of the nanoemulsion droplets. The resulting nanoemulsions (NEs) exhibited a homogeneous spherical morphology under transmission electron microscopy. The particles had diameters ranging from 20 to 120 nm with both negative and positive surface charges in the absence and presence of cetyltrimethylammonium bromide (CTAB), respectively. Unlike CTAB-coated nanoformulations, the CTAB-free NEs showed excellent biocompatibility in murine RAW macrophages and human U87-MG cell lines in vitro. The maximum tolerated dose assessment was evaluated to verify their safety profiles in vivo. In vitro X-ray and ultrasound imaging and in vivo computed tomography were used to monitor both iodinated SNPs and HSLNEs, validating their significant contrast-enhancing properties and suggesting their potential as dual-modality clinical agents in the future.

Cellulose-based hydrogels towards an antibacterial wound dressing

Hydrogels are promising candidates for wound healing bandages because they can mimic the native skin microenvironment. Additionally, there is increasing growth in the use of naturally derived materials and plant-based biomaterials to produce healthcare products with healing purposes because of their biocompatibility and biodegradation properties. In this study, cellulose extracted from biodiverse sources in Ecuador was used as the raw material for the fabrication of hydrogels with enhanced antifouling properties. Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to characterize the cellulose and hydrogels. In vitro and ex vivo tests were performed to evaluate the antimicrobial activity of hydrogels against Gram-negative bacteria as a model. Finally, the hydrogel synthesized with cellulose extracted from pitahaya showed improved antibacterial activity when applied over pigskin as a proof of concept for wound dressing. Therefore, the present results suggest that cellulose-based hydrogels are good candidates for application as wound dressings.

Oxadiazon Derivatives Elicit Potent Intracellular Growth Inhibition against Toxoplasma gondii by Disrupting Heme Biosynthesis

Infections of Toxoplasma gondii can cause severe and sometimes fatal diseases in immunocompromised individuals. The de novo heme biosynthesis pathway is required for intracellular growth and pathogenesis, making it an appealing therapeutic target. We synthesized a small library of derivatives of the herbicide oxadiazon, a known inhibitor of the penultimate reaction within the heme biosynthesis pathway in plants, catalyzed by protoporphyrinogen oxidase (PPO). Seven of the 18 analogs exhibit potent intracellular growth inhibition of wild-type T. gondii (IC₅₀ = 1 to 2.4 μM). An assay of the compounds against Toxoplasma PPO knockout and complementation strains confirmed the mode of action to be due to the potent inhibition of PPO. The most potent compounds have no detectable cytotoxicity against human foreskin fibroblast cells up to 100 μM. This study suggests that oxadiazon derivatives may represent a new molecular scaffold for the effective treatment of T. gondii infections.

Telescoped Oxidation and Cycloaddition of Urazoles to Access Diazacyclobutenes

Our previous method to access the diazacyclobutene scaffold did not allow for modification of the substituent originating from the 1,2,4-triazoline-3,5-dione component. We have circumvented this challenge and expanded access to additional structural diversity of the scaffold. A telescoped urazole oxidation and Lewis acid-catalyzed cyclization provided R³-substituted diazacyclobutenes. Calcium hypochlorite-mediated oxidation of urazoles followed by MgCl₂-catalyzed cyclization of the resulting triazolinediones with thioalkynes promoted the formation of diazacyclobutenes bearing substitution at the R³ position originating from the triazolinedione component.

Scaled Synthesis of Polyamine-Modified Cellulose Nanocrystals from Bulk Cotton and Their Use for Capturing Volatile Organic Compounds

We have previously demonstrated that cellulose nanocrystals modified with poly(ethylenimine) (PEI-f-CNC) are capable of capturing volatile organic compounds (VOCs) associated with malodors. In this manuscript, we describe our efforts to develop a scalable synthesis of these materials from bulk cotton. This work culminated in a reliable protocol for the synthesis of unmodified cellulose nanocrystals (CNCs) from bulk cotton on a 0.5 kg scale. Additionally, we developed a protocol for the modification of the CNCs by means of sequential 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidation and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) coupling to modify their surface with poly(ethylenimine) on a 100 g scale. Subsequently, we evaluated the performance of the PEI-f-CNC materials that were prepared in a series of VOC capture experiments. First, we demonstrated their efficacy in capturing volatile fatty acids emitted at a rendering plant when formulated as packed-bed filter cartridges. Secondly, we evaluated the potential to use aqueous PEI-f-CNC suspensions as a spray-based delivery method for VOC remediation. In both cases, the PEI-f-CNC formulations reduced detectable malodor VOCs by greater than 90%. The facile scaled synthesis of these materials and their excellent performance at VOC remediation suggest that they may emerge as a useful strategy for the remediation of VOCs associated with odor.

Bimodal Ultrasound and X-ray Bioimaging Properties of Particulate Calcium Fluoride Biomaterial

Ultrasound (US) and X-ray imaging are diagnostic methods that are commonly used to image internal body structures. Several organic and inorganic imaging contrast agents are commercially available. However, their synthesis and purification remain challenging, in addition to posing safety issues. Here, we report on the promise of widespread, safe, and easy-to-produce particulate calcium fluoride (part-CaF₂) as a bimodal US and X-ray contrast agent. Pure and highly crystalline part-CaF₂ is obtained using a cheap commercial product. Scanning electron microscopy (SEM) depicts the morphology of these particles, while energy-dispersive X-ray spectroscopy (EDS) confirms their chemical composition. Diffuse reflectance ultraviolet-visible spectroscopy highlights their insulating behavior. The X-ray diffraction (XRD) pattern reveals that part-CaF₂ crystallizes in the face-centered cubic cell lattice. Further analyses regarding peak broadening are performed using the Scherrer and Williamson–Hall (W-H) methods, which pinpoint the small crystallite size and the presence of lattice strain. X-ray photoelectron spectroscopy (XPS) solely exhibits specific peaks related to CaF₂, confirming the absence of any contamination. Additionally, in vitro cytotoxicity and in vivo maximum tolerated dose (MTD) tests prove the biocompatibility of part-CaF₂. Finally, the results of the US and X-ray imaging tests strongly signal that part-CaF₂ could be exploited in bimodal bioimaging applications. These findings may shed a new light on calcium fluoride and the opportunities it offers in biomedical engineering.

In Situ Photopolymerization of Acrylamide Hydrogel to Coat Cellulose Acetate Nanofibers for Drug Delivery System

In this study we developed electrospun cellulose acetate nanofibers (CANFs) that were loaded with a model non-steroidal anti-inflammatory drug (NSAID) (ibuprofen, Ib) and coated with poly(acrylamide) (poly-AAm) hydrogel polymer using two consecutive steps: an electrospinning process followed by photopolymerization of AAm. Coated and non-coated CANF formulations were characterized by several microscopic and spectroscopic techniques to evaluate their physicochemical properties. An analysis of the kinetic release profile of Ib showed noticeable differences due to the presence or absence of the poly-AAm hydrogel polymer. Poly-AAm coating facilitated a constant release rate of drug as opposed to a more conventional burst release. The non-coated CANFs showed low cumulative drug release concentrations (ca. 35 and 83% at 5 and 10% loading, respectively). Conversely, poly-AAm coated CANFs were found to promote the release of drug (ca. 84 and 99.8% at 5 and 10% loading, respectively). Finally, the CANFs were found to be superbly cytocompatible.

Polytetrafluoroethylene-like Nanoparticles as a Promising Contrast Agent for Dual Modal Ultrasound and X-ray Bioimaging

Various noninvasive imaging techniques are used to produce deep-tissue and high-resolution images for biomedical research and clinical purposes. Organic and inorganic bioimaging agents have been developed to enhance the resolution and contrast intensity. This paper describes the synthesis of polytetrafluoroethylene-like nanoparticles (PTFE≈ NPs), their characterization, biological activity, and bioimaging properties. Transmission electron microscopy (TEM) images showed the shape and the size of the as-obtained small and ultrasmall PTFE≈ NPs. Fourier transform infrared spectroscopy (FTIR) confirmed the PTFE-like character of the samples. X-ray diffraction (XRD) enabled the determination of the crystallization system, cell lattice, and index of crystallinity of the material in addition to the presence of titania (TiO₂) as the contamination. These findings were corroborated by X-ray photoelectron spectroscopy (XPS) that identifies the chemical states of the elements present in the samples along with their atomic percentages allowing the determination of both the purity index of the sample and the nature of the impurities. Additionally, diffuse reflectance ultraviolet-visible spectroscopy (UV-vis) was used to further assess the optical properties of the materials. Importantly, PTFE≈ NPs showed significant in vitro and in vivo biocompatibility. Lastly, PTFE≈ NPs were tested for their ultrasound and X-ray contrast properties. Our encouraging preliminary results open new avenues for PTFE-like nanomaterials as a suitable multifunctional contrast agent for biomedical imaging applications. Combined with suitable surface chemistry and morphology design, these findings shed light to new opportunities offered by PTFE nanoparticles in the ever-booming biomedical field.

Guanidinium sulfates as directors of noncentrosymmetric structures

Guanidinium sulfate hydrogen bonding networks are found to have a remarkable tendency to crystallize in noncentrosymmetric, chiral, and polar frameworks.

Natural Cellulose Fibers for Surgical Suture Applications

Suture biomaterials are critical in wound repair by providing support to the healing of different tissues including vascular surgery, hemostasis, and plastic surgery. Important properties of a suture material include physical properties, handling characteristics, and biological response for successful performance. However, bacteria can bind to sutures and become a source of infection. For this reason, there is a need for new biomaterials for suture with antifouling properties. Here we report two types of cellulose fibers from coconut (Cocos nucifera) and sisal (Agave sisalana), which were purified with a chemical method, characterized, and tested in vitro and in vivo. According to SEM images, the cellulose fiber from coconut has a porous surface, and sisal has a uniform structure without internal spaces. It was found that the cellulose fiber from sisal has mechanical properties closer to silk fiber biomaterial using Ultimate Tensile Strength. When evaluating the cellulose fibers biodegradability, the cellulose from coconut showed a rapid weight loss compared to sisal. The antifouling test was negative, which demonstrated that neither possesses intrinsic microbicidal activity. Yet, a weak biofilm was formed on sisal cellulose fibers suggesting it possesses antifouling properties compared to cellulose from coconut. In vivo experiments using healthy mice demonstrated that the scarring and mechanical connection was like silk for both cellulose fibers. Overall, our results showed the potential use of cellulose fibers from vegetal for surgical sutures due to excellent mechanical properties, rapid degradation, and no bacterial adhesion.

Polymer-Scaffolded Synthesis of Periodic Mesoporous Organosilica Nanomaterials for Delivery Systems in Cancer Cells

We developed four types of para-phenylene-bridged periodic mesoporous organosilica NPs (p-P PMO NPs) with tailored physical parameters including size, morphology, porosity, and surface area using a new polymer-scaffolding approach. The particles have been formulated to facilitate the codelivery of small-molecule hydrophobic/hydrophilic cargos such as model anticancer drugs (i.e., doxorubicin hydrochloride (DOX) and O⁶-benzylguanine) and model fluorescent dyes (i.e., rhodamine 6G and Nile red). p-P PMO NPs were synthesized via a cetyltrimethylammonium bromide (CTAB)-directed sol-gel process using two different organic solvents and in the presence of polymeric scaffolding constituents that led to morphologically distinct PMO NPs despite using the same organosilane precursors. After the formulation process, the polymeric scaffolding agent was conveniently washed away from the PMO NPs. Extensive analyses were used to characterize the physicochemical attributes of the PMO NPs such as their chemical composition, morphologies, etc. Spherical and rod-shaped PMOs of diameters ranging between 79 and 342 nm, surface areas between 770 and 1060 m²/g, and pore volumes between 0.79 and 1.37 cm³/g were prepared using the polymer-scaffolding approach. The performance of these materials toward drug-loading capacity, cytotoxicity, and cancer cell internalization was evaluated. Interestingly, the designed particles exhibited significantly high payloads of drugs and dyes (up to 78 and 94%, respectively). Cellular studies also demonstrated exceptional biocompatibility and marked internalization into both human breast cancer MCF-7 and glioblastoma U-87 MG cells. Further, DOX also possessed a noticeable release from particles and accumulation in cell nuclei with increased incubation time in vitro. Ultimately, this work validates the controlled design and synthesis of PMO NPs using a polymer-scaffolding approach and highlights the potential of these materials as excellent delivery systems for combination therapy with high loading capability to improve the therapeutic index for cancers.

Microcrystalline Cellulose Extracted from Native Plants as an Excipient for Solid Dosage Formulations in Drug Delivery

Excipients represent the complement of the active principle in any pharmaceutical form. Their function is to provide stability, protection, and to ensure absorption of the drug and acceptability in patients. Cellulose is a conventional excipient in many pharmaceutical solid dosage products. Most of the sources used to extract microcrystalline cellulose come from cotton or wood, which are expensive and in high demand from other industries. As plants are considered the main source of excipient production, we have taken advantage of the biodiversity of Ecuador to evaluate microcrystalline cellulose extracted from borojó (Alibertia patinoi), a native plant, as an excipient for solid dosage formulations. The method of choice for tablet manufacturing was direct compression since it is a conventional fabrication method in the pharmaceutical industry. First, we performed scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) in order to compare the structure and characteristics of the extracted cellulose with two reference commercial cellulose materials. Second, we performed quality tests to evaluate the use of the isolate as an excipient including fluidity, hardness, friability, and disintegration. Compared with commercial and microcrystalline cellulose, the extracted cellulose from the native plant showed comparable characteristics and is consequently a potential excipient that could be used in the pharmaceutical industry. Last, we performed a dissolution test in which we concluded that all tablets have a short release time of active principle.

Toxoplasma gondii requires its plant-like heme biosynthesis pathway for infection

Heme, an iron-containing organic ring, is essential for virtually all living organisms by serving as a prosthetic group in proteins that function in diverse cellular activities ranging from diatomic gas transport and sensing, to mitochondrial respiration, to detoxification. Cellular heme levels in microbial pathogens can be a composite of endogenous de novo synthesis or exogenous uptake of heme or heme synthesis intermediates. Intracellular pathogenic microbes switch routes for heme supply when heme availability fluctuates in their replicative environment throughout infection. Here, we show that Toxoplasma gondii, an obligate intracellular human pathogen, encodes a functional heme biosynthesis pathway. A chloroplast-derived organelle, termed apicoplast, is involved in heme production. Genetic and chemical manipulation revealed that de novo heme production is essential for T. gondii intracellular growth and pathogenesis. Surprisingly, the herbicide oxadiazon significantly impaired Toxoplasma growth, consistent with phylogenetic analyses that show T. gondii protoporphyrinogen oxidase is more closely related to plants than mammals. This inhibition can be enhanced by 15- to 25-fold with two oxadiazon derivatives, lending therapeutic proof that Toxoplasma heme biosynthesis is a druggable target. As T. gondii has been used to model other apicomplexan parasites, our study underscores the utility of targeting heme biosynthesis in other pathogenic apicomplexans, such as Plasmodium spp., Cystoisospora, Eimeria, Neospora, and Sarcocystis.

Mechanistic Insights into the Origin of Stereoselectivity in an Asymmetric Chlorolactonization Catalyzed by (DHQD)2PHAL

Electrophilic halofunctionalization reactions have undergone a resurgence sparked by recent discoveries in the field of catalytic asymmetric halocyclizations. To build mechanistic understanding of these asymmetric transformations, a toolbox of analytical methods has been deployed, addressing the roles of catalyst, electrophile (halenium donor), and nucleophile in determining rates and stereopreferences. The test reaction, (DHQD)₂PHAL-catalyzed chlorocyclization of 4-arylpent-4-enoic acid with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH), is revealed to be first order in catalyst and chlorenium ion donor and zero order in alkenoic acid substrate under synthetically relevant conditions. The simplest interpretation is that rapid substrate-catalyst binding precedes rate-limiting chlorenium attack, controlling the face selectivity of both chlorine attack and lactone closure. ROESY and DFT studies, aided by crystal structures of carboxylic acids bound by the catalyst, point to a plausible resting state of the catalyst-substrate complex predisposed for asymmetric chlorolactonization. As revealed by our earlier labeling studies, these findings suggest modes of binding in the (DHQD)₂PHAL chiral pocket that explain the system's remarkable control over rate- and enantioselection-determining events. Though a comprehensive modeling analysis is beyond the scope of the present work, quantum chemical analysis of the fragments' interactions and candidate reaction paths point to a one-step concerted process, with the nucleophile playing a critical role in activating the olefin for concomitant electrophilic attack.

Iodinated Polyesters with Enhanced X-ray Contrast Properties for Biomedical Imaging

Synthetic materials exhibiting contrast imaging properties have become vital to the field of biomedical imaging. However, polymeric biomaterials are lacking imaging contrast properties for deep tissue imaging. This report details the synthesis and characterization of a suite of aryl-iodo monomers, which were used to prepare iodinated polyesters using a pre-functionalization approach. Commercially available 4-iodo-phenylalanine or 4-iodobenzyl bromide served as the starting materials for the synthesis of three iodinated monomeric moieties (a modified lactide, morpholine-2,5-dione, and caprolactone), which under a tin-mediated ring-opening polymerization (ROP), generated their respective polyesters (PE) or poly(ester amides) (PEA). An increase in X-ray intensity of all synthesized iodine-containing polymers, in comparison to non-iodinated poly(lactic acid) (PLA), validated their functionality as radio-opaque materials. The iodinated-poly(lactic acid) (iPLA) material was visualized through varying thicknesses of chicken tissue, thus demonstrating its potenial as a radio-opaque biomaterial.

Periodic mesoporous organosilica nanomaterials for rapid capture of VOCs

Periodic mesoporous organosilica nanoparticles (PMO SiNPs) were developed for the targeted capture of specific volatile organic compounds (VOCs). The removal kinetics for adsorbing VOCs were fast and the maximum removal could be achieved within less than 30 min. PMO SiNPs removed >99% of VOCs at a low sorbent dose (i.e. >0.5 mL analyte per g PMO SiNPs). They also showed good recyclability and maintained reasonable removal efficiencies after five cycles (i.e. 77% and 65% for hexanal and butyric acid vapors, respectively).

Cellulose particles capture aldehyde VOC pollutants

Aldehydes are commonly encountered Volatile Organic Compounds (VOCs) released to the atmosphere from a variety of anthropogenic sources. Based on the increasing interest in developing sustainable and environmentally friendly materials for the decontamination of VOCs, cellulose particles have emerged as one possible candidate, but there is a lack of understanding of the physicochemical properties affecting the adsorption of VOCs, and the effect of the extraction source on these intrinsic features. The present study was focused on the evaluation of unmodified cellulose particles extracted from biodiverse sources in Ecuador as potential VOC decontaminants. Modifications of the natural fibers with polyethylenimine (PEI) coating were performed to enhance the adsorption effectiveness. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) measurements, and scanning electron microscopy (SEM) methods were used to characterize the physicochemical properties of the isolates. Gas chromatography assays demonstrated that unmodified cellulose can adsorb an aldehyde VOC, hexanal, reaching up to a 56.42 ± 7.30% reduction. Electrostatic coating of the cellulose particles with small quantities of PEI enhanced the VOC remediation capacities (i.e. 98.12 ± 1.18%). Results demonstrated that the biodiverse plant source of the cellulose isolate can affect the gas capturing properties, and that these particles can be an environmentally friendly solution for effective adsorption of VOC pollutants.

Cellulose particles isolated from biodiverse sources are capable of capturing aldehyde VOCs.

Degradation of pesticides using amine-functionalized cellulose nanocrystals

A series of amine-functionalized cellulose nanocrystal materials were successfully synthesized, characterized, and evaluated for the remediation of pesticide contaminants from organic and aqueous media. Their ability to degrade malathion in organic systems has been examined, resulting in up to 100% degradation of the compound into detectable lower molecular weight by-products. A poly(ethylenimine) cellulose nanocrystal (CNC-PEI) material was also capable of degrading aqueous solutions of malathion, deltamethrin, and permethrin with 100%, 95%, and 78% degradation, respectively. Thus, these materials can potentially serve as a new and viable remediation technique based on their ability to effectively degrade various pesticides. The reusability of the CNC-PEI was also explored. The CNC-PEI material maintained its ability to degrade malathion throughout two wash and re-use cycles.

A series of amine-functionalized cellulose nanocrystal materials were successfully synthesized, characterized, and evaluated for the remediation of pesticide contaminants from organic and aqueous media.

In situ preparation of gold–polyester nanoparticles for biomedical imaging

Hybrid gold-polyester nanoparticles were synthesized by UV irradiation of a gold salt and photoinitiator encapsulated in a polyester nanoparticle. The resulting materials exhibit excellent cellular imaging and surface plasmon resonance properties.

Cycloaddition/Electrocyclic Ring Opening Sequence between Alkynyl Sulfides and Azodicarboxylates To Provide N,N-Dicarbamoyl 2-Iminothioimidates

The α-oxidized thioimidates are useful bidentate ligands and are important motifs in pharmaceuticals, pesticides, and fungicides. Despite their broad utility, a direct route for their synthesis has been elusive. Herein, we describe a one-step synthesis of N,N-dicarbamoyl 2-iminothioimidates from easily accessible thioacetylenes and commercially available azodicarboxylates (20 examples, ≤99% yield). Additionally, the mechanism of the transformation was extensively explored by variable-temperature NMR, in situ IR, and quantum mechanical simulations. These experiments suggest that the reaction commences with a highly asynchronous [2 + 2] cycloaddition, which leads to a four-membered diazacyclobutene intermediate with a barrier consistent with the observed reaction rate. This intermediate was then isolated for subsequent kinetic measurements, which yielded an experimental barrier within 1 kcal/mol of the calculated barrier for a subsequent 4π electrocyclic ring opening leading to the observed iminothioimidate products. This method represents the first direct route to α-oxidized thioimidates from readily accessible starting materials.

Non-lethal growth inhibition by arresting the starch utilization system of clinically relevant human isolates of Bacteroides dorei

We describe the inhibition of the starch utilization system (Sus) belonging to various strains of Bacteroides dorei in a non-lethal manner using the small molecule probe, acarbose. Concentrations of acarbose as low as 5 μM significantly impede the growth of B. dorei and increase the doubling time of cultures. The successful inhibition of this species of Bacteroides is relevant to several disease states including type I diabetes mellitus. This method continues to explore a new, potential route to intervene in illnesses associated with aberrant changes in the composition of the human gut microbiota through the strategic manipulation of its constituents.

Accessing the Rare Diazacyclobutene Motif

A formal [2 + 2] cycloaddition of 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) with electron-rich alkynyl sulfides and selenides is described. These investigations provide a convenient method to access diazacyclobutenes in good yield while tolerating a relatively broad substrate scope of thio-acetylenes. This method provides ready access to a unique and hitherto rarely accessible class of heterocycles. A combination of dynamic NMR, X-ray crystallography, and computation sheds light on the potential aromaticity of the scaffold.

Poly(amine) modified kaolinite clay for VOC capture

Polyethylenimine (PEI) functionalized kaolinite clay was successfully prepared, characterized, and assessed for the remediation of volatile organic compounds (VOCs) comprising the aldehyde, carboxylic acid, and disulfide functional group classes. A gas chromatographic vapor capture assay evaluated the capability of unmodified and modified clay material to capture representative aldehyde, carboxylic acid, and disulfide VOCs in a laboratory setting. Unmodified kaolinite (Kao) clay was moderately or poorly effective at remediating these VOCs, while the poly(amine) functionalized Kao was capable of capturing VOCs in the vapor phase with reductions up to 100%. Sample cartridge tubes were packed with PEI-functionalized clay in order to assess their ability to reduce the detectable volatile fatty acid load at an open-air rendering plant in a relevant field test for applying these materials in a packed-bed scrubber application. The PEI-Kao packed cartridges were capable of significantly reducing the detectable concentration of volatile fatty acid effluent from the rendering operation. These volatile fatty acids are major contributors to nuisance odors associated with rendering.

Recent Advances in Polyesters for Biomedical Imaging

Several synthetic materials exhibiting contrast imaging properties have become vital to the field of biomedical imaging. Polymeric biomaterials and metals are commonly used imaging agents and can assist in the monitoring of therapy response, migration, degradation, changes in morphology, defects, and image-guided surgery. In comparison to metals, most bio and synthetic polymers lack inherent imaging properties. Polymeric biomaterials, specifically polyesters, have gained a considerable amount of attention due to their unique properties including biocompatibility, biodegradation, facile synthesis, and modification capability. Polyester implants and nanomaterials are available on the market or are in clinical trials for many applications including: dental implants, cranio-maxilofacial implants, soft tissue sutures and staples, abdominal wall repair, tendon and ligament reconstruction, fracture fixation devices, and coronary drug eluting stents. This review aims to provide a summary of the recent developments of polyesters with bioimaging contrast properties. The three main approaches to prepare bioimaging polyesters (coating, encapsulation, and functionalization) are discussed in depth. Furthermore, commonly used imaging modalities including X-ray computed tomography, magnetic resonance imaging, ultrasound, fluorescence, and radionucleotide polyester contrast agents are highlighted. In each section, examples of impactful bioimaging polyesters in the five major imaging modalities are evaluated.

Nanotechnology for Environmental Remediation: Materials and Applications

Environmental remediation relies mainly on using various technologies (e.g., adsorption, absorption, chemical reactions, photocatalysis, and filtration) for the removal of contaminants from different environmental media (e.g., soil, water, and air). The enhanced properties and effectiveness of nanotechnology-based materials makes them particularly suitable for such processes given that they have a high surface area-to-volume ratio, which often results in higher reactivity. This review provides an overview of three main categories of nanomaterials (inorganic, carbon-based, and polymeric-based materials) used for environmental remediation. The use of these nanomaterials for the remediation of different environmental contaminants-such as heavy metals, dyes, chlorinated organic compounds, organophosphorus compounds, volatile organic compounds, and halogenated herbicides-is reviewed. Various recent examples are extensively highlighted focusing on the materials and their applications.

Nonmicrobicidal Small Molecule Inhibition of Polysaccharide Metabolism in Human Gut Microbes: A Potential Therapeutic Avenue

A new approach for the nonmicrobicidal phenotypic manipulation of prominent gastrointestinal microbes is presented. Low micromolar concentrations of a chemical probe, acarbose, can selectively inhibit the Starch Utilization System and ablate the ability of Bacteroides thetaiotaomicron and B. fragilis strains to metabolize potato starch and pullulan. This strategy has potential therapeutic relevance for the selective modulation of the GI microbiota in a nonmicrobicidal manner.

A targeted delivery strategy for the development of potent trypanocides

A new drug delivery strategy was investigated for the development of potent anti-parasitic compounds against Trypanosoma brucei, the causative agent of African sleeping sickness. Thus, potent in vitro hexokinase inhibitors were rendered cytotoxic by appending a tripeptide peroxosomal targeting sequence that facilitated delivery of the molecular cargo to the appropriate organelle in the parasite.

Evaluation of substituted ebselen derivatives as potential trypanocidal agents

Human African trypanosomiasis is a disease of sub-Saharan Africa, where millions are at risk for the illness. The disease, commonly referred to as African sleeping sickness, is caused by an infection by the eukaryotic pathogen, Trypanosoma brucei. Previously, a target-based high throughput screen revealed ebselen (EbSe), and its sulfur analog, EbS, to be potent in vitro inhibitors of the T. brucei hexokinase 1 (TbHK1). These molecules also exhibited potent trypanocidal activity in vivo. In this manuscript, we synthesized a series of sixteen EbSe and EbS derivatives bearing electron-withdrawing carboxylic acid and methyl ester functional groups, and evaluated the influence of these substituents on the biological efficacy of the parent scaffold. With the exception of one methyl ester derivative, these modifications ablated or blunted the potent TbHK1 inhibition of the parent scaffold. Nonetheless, a few of the methyl ester derivatives still exhibited trypanocidal effects with single-digit micromolar or high nanomolar EC₅₀ values.

Room-temperature catalytic oxidation of alcohols with the polyoxovanadate salt Cs5(V14As8O42Cl)

Herein we present some initial results demonstrating the room temperature oxidation of secondary alcohols catalyzed by the reduced salt-inclusion polyoxometalate, Cs₅(V₁₄As₈O₄₂Cl).