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1.
Chem Soc Rev ; 50(16): 9121-9151, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34212944

RESUMO

COVID-19 has resulted in huge numbers of infections and deaths worldwide and brought the most severe disruptions to societies and economies since the Great Depression. Massive experimental and computational research effort to understand and characterize the disease and rapidly develop diagnostics, vaccines, and drugs has emerged in response to this devastating pandemic and more than 130 000 COVID-19-related research papers have been published in peer-reviewed journals or deposited in preprint servers. Much of the research effort has focused on the discovery of novel drug candidates or repurposing of existing drugs against COVID-19, and many such projects have been either exclusively computational or computer-aided experimental studies. Herein, we provide an expert overview of the key computational methods and their applications for the discovery of COVID-19 small-molecule therapeutics that have been reported in the research literature. We further outline that, after the first year the COVID-19 pandemic, it appears that drug repurposing has not produced rapid and global solutions. However, several known drugs have been used in the clinic to cure COVID-19 patients, and a few repurposed drugs continue to be considered in clinical trials, along with several novel clinical candidates. We posit that truly impactful computational tools must deliver actionable, experimentally testable hypotheses enabling the discovery of novel drugs and drug combinations, and that open science and rapid sharing of research results are critical to accelerate the development of novel, much needed therapeutics for COVID-19.


Assuntos
Tratamento Farmacológico da COVID-19 , Simulação por Computador , Desenho de Fármacos , Descoberta de Drogas/métodos , Reposicionamento de Medicamentos , Antivirais/uso terapêutico , COVID-19/virologia , Ensaios Clínicos como Assunto , Humanos , Pandemias , SARS-CoV-2/efeitos dos fármacos
2.
J Org Chem ; 85(21): 13438-13452, 2020 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-32786609

RESUMO

We have discovered and studied a tele-substitution reaction in a biologically important heterocyclic ring system. Conditions that favor the tele-substitution pathway were identified: the use of increased equivalents of the nucleophile or decreased equivalents of base or the use of softer nucleophiles, less polar solvents, and larger halogens on the electrophile. Using results from X-ray crystallographic and isotope labeling experiments, a mechanism for this unusual transformation is proposed. We focused on this triazolopyrazine as it is the core structure of the in vivo active antiplasmodium compounds of Series 4 of the Open Source Malaria consortium.


Assuntos
Antimaláricos , Antimaláricos/farmacologia , Halogênios , Pirazinas , Solventes
3.
Malar J ; 18(1): 93, 2019 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-30902052

RESUMO

Great progress has been made in recent years to reduce the high level of suffering caused by malaria worldwide. Notably, the use of insecticide-treated mosquito nets for malaria prevention and the use of artemisinin-based combination therapy (ACT) for malaria treatment have made a significant impact. Nevertheless, the development of resistance to the past and present anti-malarial drugs highlights the need for continued research to stay one step ahead. New drugs are needed, particularly those with new mechanisms of action. Here the range of anti-malarial medicines developed over the years are reviewed, beginning with the discovery of quinine in the early 1800s, through to modern day ACT and the recently-approved tafenoquine. A number of new potential anti-malarial drugs currently in development are outlined, along with a description of the hit to lead campaign from which it originated. Finally, promising novel mechanisms of action for these and future anti-malarial medicines are outlined.


Assuntos
Antimaláricos/farmacologia , Malária/tratamento farmacológico , Humanos
4.
Chemistry ; 24(7): 1573-1585, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29052259

RESUMO

Molecular switches have many potential applications in nanoscience and biomedicine. Transition metal complexes that can be switched from an inert, unreactive state to a catalytically active one by a simple change in conditions (e.g. pH shift) or by binding to a specific biomolecular target-so-called target-activated metal complexes (TAMCs)-hold particular allure as a means of harnessing the potent but at times indiscriminate reactivity of metal-based drugs. Towards this goal, we have prepared a series of ten structurally related ligands, each of which bears a different pendant side-arm functional group appended to a common macrocyclic core, along with copper(II) and nickel(II) complexes of these cyclam-based "molecular scorpionands". X-ray crystal structures reveal a variety of binding modes between pendant side-arm and metal centre that depend on the constituent donor atoms. To investigate the switchability of side-arm coordination in solution, spectrophotometric pH titrations were carried out for all 20 metal complexes. The majority of the complexes undergo spectroscopic changes that are consistent with a switch in pendant coordination state at a specific pH. This ligand series represents a comprehensive model platform from which to build pH-switchable metal complexes for applications in nanoscience and biomedicine.

6.
Chemistry ; 23(39): 9313-9318, 2017 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-28523850

RESUMO

The mechanism of cross-dehydrogenative coupling (CDC) reactions has been examined by experimental and computational methods. We provide a rationale for the ubiquity of the N-aryl group in these reactions. The aryl substituent stabilizes two intermediates and the high-energy transition state that connects them, which together represent the rate-determining step. This knowledge has enabled us to predict whether new CDC substrates will react either well or poorly.

7.
Molecules ; 22(2)2017 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-28125069

RESUMO

Small-molecule fluorescent probes play a myriad of important roles in chemical sensing. Many such systems incorporating a receptor component designed to recognise and bind a specific analyte, and a reporter or transducer component which signals the binding event with a change in fluorescence output have been developed. Fluorescent probes use a variety of mechanisms to transmit the binding event to the reporter unit, including photoinduced electron transfer (PET), charge transfer (CT), Förster resonance energy transfer (FRET), excimer formation, and aggregation induced emission (AIE) or aggregation caused quenching (ACQ). These systems respond to a wide array of potential analytes including protons, metal cations, anions, carbohydrates, and other biomolecules. This review surveys important new fluorescence-based probes for these and other analytes that have been reported over the past five years, focusing on the most widely exploited macrocyclic recognition components, those based on cyclam, calixarenes, cyclodextrins and crown ethers; other macrocyclic and non-macrocyclic receptors are also discussed.


Assuntos
Técnicas Biossensoriais , Corantes Fluorescentes/química , Íons/química , Compostos Macrocíclicos/química , Éteres de Coroa/química , Ciclodextrinas/química , Compostos Heterocíclicos/química , Pontos Quânticos
8.
Beilstein J Org Chem ; 12: 2457-2461, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28144313

RESUMO

An efficient protocol for the direct synthesis of N-tetraalkylated derivatives of the azamacrocycles cyclam and cyclen has been developed, using a partially miscible aqueous-organic solvent system with propargyl bromide, benzyl bromide, and related halides. The method works most effectively when the reaction mixture is shaken, not stirred. A crystal structure of the N-tetrapropargyl cyclam derivative 1,4,8,11-tetra(prop-2-yn-1-yl)-1,4,8,11-tetraazacyclotetradecane diperchlorate is reported.

9.
Beilstein J Org Chem ; 11: 37-41, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25670990

RESUMO

The effective and efficient removal of the BF2 moiety from F-BODIPY derivatives has been achieved using two common Brønsted acids; treatment with trifluoroacetic acid (TFA) or methanolic hydrogen chloride (HCl) followed by work-up with Ambersep(®) 900 resin (hydroxide form) effects this conversion in near-quantitative yields. Compared to existing methods, these conditions are relatively mild and operationally simple, requiring only reaction at room temperature for six hours (TFA) or overnight (HCl).

10.
Parasitology ; 141(1): 148-57, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23985301

RESUMO

Open science is a new concept for the practice of experimental laboratory-based research, such as drug discovery. The authors have recently gained experience in how to run such projects and here describe some straightforward steps others may wish to take towards more openness in their own research programmes. Existing and inexpensive online tools can solve many challenges, while some psychological barriers to the free sharing of all data and ideas are more substantial.


Assuntos
Revelação/ética , Descoberta de Drogas , Disseminação de Informação/métodos , Software , Anti-Helmínticos/síntese química , Anti-Helmínticos/farmacologia , Antimaláricos/síntese química , Antimaláricos/farmacologia , Humanos , Disseminação de Informação/ética , Internet , Malária/tratamento farmacológico , Malária/parasitologia , Esquistossomose/tratamento farmacológico , Esquistossomose/parasitologia
11.
Pharmaceuticals (Basel) ; 17(7)2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-39065687

RESUMO

Optimized syntheses of (E)-5-(2-ethoxyphenyl)-N-(3-(methylsulfonyl)allyl)-1H-pyrazole-3-carboxamide (RA-0002034, 1), a promising antiviral covalent cysteine protease inhibitor lead, were developed. The syntheses avoid the contamination of 1 with the inactive cyclic dihydropyrazolo[1,5-a]pyrazin-4(5H)-one 2, which is formed by the intramolecular aza-Michael reaction of the vinyl sulfone warhead under basic conditions and slowly at pH 7.4 in phosphate buffer. The pure cysteine protease inhibitor 1 could be synthesized using either modified amide coupling conditions or through the introduction of a MOM-protecting group and was stable as a TFA or HCl salt. Although acyclic 1 demonstrated poor pharmacokinetics with high in vivo clearance in mice, inactive cyclic 2 showed improved plasma exposure. The potential use of cyclic dihydropyrazolo[1,5-a]pyrazin-4(5H)-ones as prodrugs for the acyclic ß-amidomethyl vinyl sulfone warhead was demonstrated by GSH capture experiments with an analog of 2.

12.
Nat Commun ; 15(1): 937, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38297033

RESUMO

Malaria poses an enormous threat to human health. With ever increasing resistance to currently deployed drugs, breakthrough compounds with novel mechanisms of action are urgently needed. Here, we explore pyrimidine-based sulfonamides as a new low molecular weight inhibitor class with drug-like physical parameters and a synthetically accessible scaffold. We show that the exemplar, OSM-S-106, has potent activity against parasite cultures, low mammalian cell toxicity and low propensity for resistance development. In vitro evolution of resistance using a slow ramp-up approach pointed to the Plasmodium falciparum cytoplasmic asparaginyl-tRNA synthetase (PfAsnRS) as the target, consistent with our finding that OSM-S-106 inhibits protein translation and activates the amino acid starvation response. Targeted mass spectrometry confirms that OSM-S-106 is a pro-inhibitor and that inhibition of PfAsnRS occurs via enzyme-mediated production of an Asn-OSM-S-106 adduct. Human AsnRS is much less susceptible to this reaction hijacking mechanism. X-ray crystallographic studies of human AsnRS in complex with inhibitor adducts and docking of pro-inhibitors into a model of Asn-tRNA-bound PfAsnRS provide insights into the structure-activity relationship and the selectivity mechanism.


Assuntos
Antimaláricos , Aspartato-tRNA Ligase , Animais , Humanos , Plasmodium falciparum/genética , Asparagina/metabolismo , Aspartato-tRNA Ligase/genética , Aminoacil-RNA de Transferência/metabolismo , Antimaláricos/farmacologia , Mamíferos/genética
13.
Chembiochem ; 14(2): 224-9, 2013 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-23303717

RESUMO

We describe a new class of fluorescent reporter and its employment to visualize the biotin/avidin binding interaction. Derivatives of the azamacrocycle cyclam that contain a pendant naphthalimide dye are inherently fluorescent when zinc(II) is coordinated. Introducing a second pendant group--biotin--affords an unsymmetrical bis-triazole-scorpionand ligand that interacts specifically with avidin. This ligand has been assembled by using a one-pot "double-click" strategy and complexed with copper(II) and zinc(II). The zinc(II) complex is fluorescent, and its fluorescence output changes in the presence of avidin. Upon avidin binding, the fluorescence output is diminished by interaction with the protein, at [complex]/[avidin] ratios of up to 4:1. The observed change might arise from a specific quenching effect in the biotin binding pocket or from a binding-induced change in the coordination geometry of the complex.


Assuntos
Avidina/metabolismo , Biotina/análogos & derivados , Biotina/metabolismo , Complexos de Coordenação/química , Corantes Fluorescentes/química , Zinco/química , Complexos de Coordenação/metabolismo , Corantes Fluorescentes/metabolismo , Compostos Heterocíclicos/química , Compostos Heterocíclicos/metabolismo , Naftalimidas/química , Naftalimidas/metabolismo , Ligação Proteica , Espectrometria de Fluorescência , Zinco/metabolismo
14.
Org Biomol Chem ; 11(30): 4921-4, 2013 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-23820826

RESUMO

A removable protecting group has been identified that allows the products of widely-used cross dehydrogenative couplings to be synthetically elaborated. The method can be used with enantiopure amines with no loss of enantiomeric excess. The methodology is exemplified by a new synthesis of enantiopure praziquantel, the drug used in the treatment of millions of people suffering from the neglected tropical disease, schistosomiasis.


Assuntos
Aminas/química , Anti-Helmínticos/síntese química , Praziquantel/síntese química , Anti-Helmínticos/química , Hidrogenação , Estrutura Molecular , Praziquantel/química , Estereoisomerismo
15.
ACS Chem Neurosci ; 14(1): 87-98, 2023 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-36542544

RESUMO

Alzheimer's disease is imposing a growing social and economic burden worldwide, and effective therapies are urgently required. One possible approach to modulation of the disease outcome is to use small molecules to limit the conversion of monomeric amyloid (Aß42) to cytotoxic amyloid oligomers and fibrils. We have synthesized modulators of amyloid assembly that are unlike others studied to date: these compounds act primarily by sequestering the Aß42 monomer. We provide kinetic and nuclear magnetic resonance data showing that these perphenazine conjugates divert the Aß42 monomer into amorphous aggregates that are not cytotoxic. Rapid monomer sequestration by the compounds reduces fibril assembly, even in the presence of pre-formed fibrillar seeds. The compounds are therefore also able to disrupt monomer-dependent secondary nucleation, the autocatalytic process that generates the majority of toxic oligomers. The inhibitors have a modular design that is easily varied, aiding future exploration and use of these tools to probe the impact of distinct Aß42 species populated during amyloid assembly.


Assuntos
Doença de Alzheimer , Perfenazina , Humanos , Peptídeos beta-Amiloides , Amiloide , Proteínas Amiloidogênicas , Fragmentos de Peptídeos
16.
ACS Infect Dis ; 9(8): 1470-1487, 2023 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-37417544

RESUMO

Leishmaniasis is a collection of diseases caused by more than 20 Leishmania parasite species that manifest as either visceral, cutaneous, or mucocutaneous leishmaniasis. Despite the significant mortality and morbidity associated with leishmaniasis, it remains a neglected tropical disease. Existing treatments have variable efficacy, significant toxicity, rising resistance, and limited oral bioavailability, which necessitates the development of novel and affordable therapeutics. Here, we report on the continued optimization of a series of imidazopyridines for visceral leishmaniasis and a scaffold hop to a series of substituted 2-(pyridin-2-yl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazoles with improved absorption, distribution, metabolism, and elimination properties.


Assuntos
Leishmania , Leishmaniose Visceral , Leishmaniose , Humanos , Leishmaniose Visceral/tratamento farmacológico , Doenças Negligenciadas , Imidazóis/farmacologia
17.
ACS Infect Dis ; 9(12): 2423-2435, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-37991879

RESUMO

Antimicrobial resistance (AMR) is widely acknowledged as one of the most serious public health threats facing the world, yet the private sector finds it challenging to generate much-needed medicines. As an alternative discovery approach, a small array of diarylimidazoles was screened against the ESKAPE pathogens, and the results were made publicly available through the Open Source Antibiotics (OSA) consortium (https://github.com/opensourceantibiotics). Of the 18 compounds tested (at 32 µg/mL), 15 showed >90% growth inhibition activity against methicillin-resistant Staphylococcus aureus (MRSA) alone. In the subsequent hit-to-lead optimization of this chemotype, 147 new heterocyclic compounds containing the diarylimidazole and other core motifs were synthesized and tested against MRSA, and their structure-activity relationships were identified. While potent, these compounds have moderate to high intrinsic clearance and some associated toxicity. The best overall balance of parameters was found with OSA_975, a compound with good potency, good solubility, and reduced intrinsic clearance in rat hepatocytes. We have progressed toward the knowledge of the molecular target of these phenotypically active compounds, with proteomic techniques suggesting TGFBR1 is potentially involved in the mechanism of action. Further development of these compounds toward antimicrobial medicines is available to anyone under the licensing terms of the project.


Assuntos
Antibacterianos , Staphylococcus aureus Resistente à Meticilina , Ratos , Animais , Antibacterianos/farmacologia , Proteômica , Testes de Sensibilidade Microbiana , Relação Estrutura-Atividade
18.
RSC Med Chem ; 14(6): 1002-1011, 2023 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-37360399

RESUMO

Target 2035, an international federation of biomedical scientists from the public and private sectors, is leveraging 'open' principles to develop a pharmacological tool for every human protein. These tools are important reagents for scientists studying human health and disease and will facilitate the development of new medicines. It is therefore not surprising that pharmaceutical companies are joining Target 2035, contributing both knowledge and reagents to study novel proteins. Here, we present a brief progress update on Target 2035 and highlight some of industry's contributions.

19.
Res Sq ; 2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37546892

RESUMO

Malaria poses an enormous threat to human health. With ever increasing resistance to currently deployed drugs, breakthrough compounds with novel mechanisms of action are urgently needed. Here, we explore pyrimidine-based sulfonamides as a new low molecular weight inhibitor class with drug-like physical parameters and a synthetically accessible scaffold. We show that the exemplar, OSM-S-106, has potent activity against parasite cultures, low mammalian cell toxicity and low propensity for resistance development. In vitro evolution of resistance using a slow ramp-up approach pointed to the Plasmodium falciparum cytoplasmic asparaginyl tRNA synthetase (PfAsnRS) as the target, consistent with our finding that OSM-S-106 inhibits protein translation and activates the amino acid starvation response. Targeted mass spectrometry confirms that OSM-S-106 is a pro-inhibitor and that inhibition of PfAsnRS occurs via enzyme-mediated production of an Asn-OSM-S-106 adduct. Human AsnRS is much less susceptible to this reaction hijacking mechanism. X-ray crystallographic studies of human AsnRS in complex with inhibitor adducts and docking of pro-inhibitors into a model of Asn-tRNA-bound PfAsnRS provide insights into the structure activity relationship and the selectivity mechanism.

20.
J Org Chem ; 77(2): 949-55, 2012 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-22142205

RESUMO

We report the use of a previously intractable nucleophile, anisole, in an oxidative "cross-dehydrogenative coupling" (CDC) reaction with the cyclic ether isochroman, as well as derivatives of both components. Metal catalysis was required for the reaction to proceed efficiently, and the reaction is highly sensitive to modification of either coupling partner but is able to produce a range of novel compounds via what is a synthetic alternative to the traditional oxa-Pictet-Spengler reaction.

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