1
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Foubelo F, Nájera C, Retamosa MG, Sansano JM, Yus M. Catalytic asymmetric synthesis of 1,2-diamines. Chem Soc Rev 2024. [PMID: 38990173 DOI: 10.1039/d3cs00379e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
The asymmetric catalytic synthesis of 1,2-diamines has received considerable interest, especially in the last ten years, due to their presence in biologically active compounds and their applications for the development of synthetic building blocks, chiral ligands and organocatalysts. Synthetic strategies based on C-N bond-forming reactions involve mainly (a) ring opening of aziridines and azabenzonorbornadienes, (b) hydroamination of allylic amines, (c) hydroamination of enamines and (d) diamination of olefins. In the case of C-C bond-forming reactions are included (a) the aza-Mannich reaction of imino esters, imino nitriles, azlactones, isocyano acetates, and isothiocyanates with imines, (b) the aza-Henry reaction of nitroalkanes with imines, (c) imine-imine coupling reactions, and (d) reductive coupling of enamines with imines, and (e) [3+2] cycloaddition with imines. C-H bond forming reactions include hydrogenation of CN bonds and C-H amination reactions. Other catalytic methods include desymmetrization reactions of meso-diamines.
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Affiliation(s)
- Francisco Foubelo
- Departamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
| | - Carmen Nájera
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
| | - Ma Gracia Retamosa
- Departamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
| | - José M Sansano
- Departamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
| | - Miguel Yus
- Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Alicante, Apdo. 99, E-03080 Alicante, Spain.
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2
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Thorpe MP, Blackwell DJ, Knollmann BC, Johnston JN. Backbone-Determined Antiarrhythmic Structure-Activity Relationships for a Mirror Image, Oligomeric Depsipeptide Natural Product. J Med Chem 2024. [PMID: 38958200 DOI: 10.1021/acs.jmedchem.4c00923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Cyclic oligomeric depsipeptides (COD) are a structural class within naturally occurring compounds with a wide range of biological activity. Verticilide is a COD (24-membered ring) that was identified by its inhibition of insect ryanodine receptor (RyR). We have since found that the enantiomer of verticilide (ent-verticilide, 1) is a potent inhibitor of mammalian RyR2, a cardiac calcium channel, and therefore a potential antiarrhythmic agent. Oddly, nat-verticilide does not inhibit RyR2. To further develop ent-verticilide as an antiarrhythmic, we explored potential SAR through systematic modification of the ester's functionality to both N-H and N-Me amides. The syntheses of these ent-verticilide-inspired analogs are detailed using a monomer-based platform enabled by enantioselective catalysis. Two analogs among 23 exhibited measurable reduction of calcium sparks in a functional assay of RyR2 activity. These findings illustrate the value of natural product-inspired therapeutic development, but the less-studied approach where the non-natural enantiomeric series harbors important SAR.
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Affiliation(s)
- Madelaine P Thorpe
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Daniel J Blackwell
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37235, United States
| | - Bjorn C Knollmann
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37235, United States
| | - Jeffrey N Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
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3
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Guerrero-Corella A, Fraile A, Alemán J. Intramolecular Hydrogen-Bond Activation: Strategies, Benefits, and Influence in Catalysis. ACS ORGANIC & INORGANIC AU 2022; 2:197-204. [PMID: 35673681 PMCID: PMC9164241 DOI: 10.1021/acsorginorgau.1c00053] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/21/2022] [Accepted: 01/21/2022] [Indexed: 12/12/2022]
Abstract
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The activation of
molecules through intramolecular hydrogen-bond
formation to promote chemical reactions appears as a suitable strategy
in organic synthesis, especially for the preparation of chiral compounds
under metal and organocatalytic conditions. The use of this interaction
has enabled reactivity enhancement of reagents, as well as stabilization
of the chemical species and enantiocontrol of the processes.
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Affiliation(s)
| | - Alberto Fraile
- Organic Chemistry Department, Módulo 1, Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - José Alemán
- Organic Chemistry Department, Módulo 1, Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
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4
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Struble TJ, Smajlagic I, Foy H, Dudding T, Johnston JN. DFT-Based Stereochemical Rationales for the Bifunctional Brønsted Acid/Base-Catalyzed Diastereodivergent and Enantioselective aza-Henry Reactions of α-Nitro Esters. J Org Chem 2021; 86:15606-15617. [PMID: 34669416 DOI: 10.1021/acs.joc.1c02112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A pair of chiral bis(amidine) [BAM] proton complexes provide reagent (catalyst)-controlled, highly diastereo- and enantioselective direct aza-Henry reactions leading to α-alkyl-substituted α,β-diamino esters. A C2-symmetric ligand provides high anti-selectivity, while a nonsymmetric congener exhibits syn-selectivity in this example of diastereodivergent, enantioselective catalysis. A detailed computational analysis is reported for the first time, one that supports distinct models for selectivity resulting from the more hindered binding cavity of the C1-symmetric ligand. Binding in this congested pocket accommodates four hydrogen bond contacts among ligands and substrates, ultimately favoring a pre-syn arrangement highlighted by pyridinium-azomethine activation and quinolinium-nitronate activation. The complementary transition states reveal a wide range of alternatives. Comparing the C1- and C2-symmetric catalysts highlights distinct electrophile binding orientations despite their common hydrogen bond donor-acceptor features. Among the factors driving unusual high syn-diastereoselection are favorable dispersion forces that leverage the anthracenyl substituent of the C1-symmetric ligand.
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Affiliation(s)
- Thomas J Struble
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Ivor Smajlagic
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Hayden Foy
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Travis Dudding
- Department of Chemistry, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada
| | - Jeffrey N Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
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5
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Guerrero‐Corella A, Valle‐Amores MA, Fraile A, Alemán J. Enantioselective Organocatalyzed
aza
‐Michael Addition Reaction of 2‐Hydroxybenzophenone Imines to Nitroolefins under Batch and Flow Conditions. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100635] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
| | - Miguel A. Valle‐Amores
- Organic Chemistry Department, Módulo 1 Universidad Autónoma de Madrid 28049 Madrid Spain
| | - Alberto Fraile
- Organic Chemistry Department, Módulo 1 Universidad Autónoma de Madrid 28049 Madrid Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem) Universidad Autónoma de Madrid 28049 Madrid Spain
| | - José Alemán
- Organic Chemistry Department, Módulo 1 Universidad Autónoma de Madrid 28049 Madrid Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem) Universidad Autónoma de Madrid 28049 Madrid Spain
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6
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Han B, He XH, Liu YQ, He G, Peng C, Li JL. Asymmetric organocatalysis: an enabling technology for medicinal chemistry. Chem Soc Rev 2021; 50:1522-1586. [PMID: 33496291 DOI: 10.1039/d0cs00196a] [Citation(s) in RCA: 162] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The efficacy and synthetic versatility of asymmetric organocatalysis have contributed enormously to the field of organic synthesis since the early 2000s. As asymmetric organocatalytic methods mature, they have extended beyond the academia and undergone scale-up for the production of chiral drugs, natural products, and enantiomerically enriched bioactive molecules. This review provides a comprehensive overview of the applications of asymmetric organocatalysis in medicinal chemistry. A general picture of asymmetric organocatalytic strategies in medicinal chemistry is firstly presented, and the specific applications of these strategies in pharmaceutical synthesis are systematically described, with a focus on the preparation of antiviral, anticancer, neuroprotective, cardiovascular, antibacterial, and antiparasitic agents, as well as several miscellaneous bioactive agents. The review concludes with a discussion of the challenges, limitations and future prospects for organocatalytic asymmetric synthesis of medicinally valuable compounds.
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Affiliation(s)
- Bo Han
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Xiang-Hong He
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Yan-Qing Liu
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Gu He
- State Key Laboratory of Biotherapy and Cancer Centre, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Cheng Peng
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Jun-Long Li
- State Key Laboratory of Southwestern Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China. and Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy, Chengdu University, Chengdu 610106, China.
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7
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Faisca Phillips AM, Guedes da Silva MFC, Pombeiro AJL. The Stereoselective Nitro-Mannich Reaction in the Synthesis of Active Pharmaceutical Ingredients and Other Biologically Active Compounds. Front Chem 2020; 8:30. [PMID: 32047742 PMCID: PMC6997535 DOI: 10.3389/fchem.2020.00030] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/09/2020] [Indexed: 11/13/2022] Open
Abstract
The nitro-Mannich (aza-Henry) reaction, in which a nitroalkane and an imine react to form a β-nitroamine, is a versatile tool for target-oriented synthesis. Although the first stereoselective reaction was developed only 20 years ago, and enantioselective and diastereoselective versions for the synthesis of non-racemic compounds soon after, there are nowadays a variety of reliable methods which can be used for the synthesis of APIs and other biologically active substances. Hence many anticancer drugs, antivirals, antimicrobials, enzyme inhibitors and many more substances, containing C-N bonds, have been synthesized using this reaction. Several transition metal complexes and organocatalysts were shown to be compatible with the presence of a wide range of functional groups in these molecules, and very high levels of asymmetric induction have been achieved in some cases. The reaction has also been applied in cascade processes. The structural diversity of the products, ranging from simple heterocycles or azabicycles to complex alkaloids, iminosugars, amino acids or diamino acids and phosphonates, shows the versatility of the nitro-Mannich reaction and its potential for future developments.
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Affiliation(s)
| | | | - Armando J L Pombeiro
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisbon, Portugal
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8
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Villalta F, Rachakonda G. Advances in preclinical approaches to Chagas disease drug discovery. Expert Opin Drug Discov 2019; 14:1161-1174. [PMID: 31411084 PMCID: PMC6779130 DOI: 10.1080/17460441.2019.1652593] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 08/02/2019] [Indexed: 12/21/2022]
Abstract
Introduction: Chagas disease affects 8-10 million people worldwide, mainly in Latin America. The current therapy for Chagas disease is limited to nifurtimox and benznidazole, which are effective in treating only the acute phase of the disease but with severe side effects. Therefore, there is an unmet need for new drugs and for the exploration of innovative approaches which may lead to the discovery of new effective and safe drugs for its treatment. Areas covered: The authors report and discuss recent approaches including structure-based design that have led to the discovery of new promising small molecule candidates for Chagas disease which affect prime targets that intervene in the sterol pathway of T. cruzi. Other trypanosome targets, phenotypic screening, the use of artificial intelligence and the challenges with Chagas disease drug discovery are also discussed. Expert opinion: The application of recent scientific innovations to the field of Chagas disease have led to the discovery of new promising drug candidates for Chagas disease. Phenotypic screening brought new hits and opportunities for drug discovery. Artificial intelligence also has the potential to accelerate drug discovery in Chagas disease and further research into this is warranted.
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Affiliation(s)
- Fernando Villalta
- Department of Microbiology, Immunology and Physiology, School of Medicine, Meharry Medical College , Nashville , TN , USA
| | - Girish Rachakonda
- Department of Microbiology, Immunology and Physiology, School of Medicine, Meharry Medical College , Nashville , TN , USA
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9
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Vishe M, Johnston JN. The inverted ketene synthon: a double umpolung approach to enantioselective β 2,3-amino amide synthesis. Chem Sci 2019; 10:1138-1143. [PMID: 30774911 PMCID: PMC6349014 DOI: 10.1039/c8sc04330b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 11/11/2018] [Indexed: 12/29/2022] Open
Abstract
A stereocontrolled synthesis of β2,3-amino amides is reported. Innovation is encapsulated by the first use of nitroalkenes to achieve double umpolung in enantioselective β-amino amide synthesis. Step economy is also fulfilled by the use of Umpolung Amide Synthesis (UmAS) in the second step, delivering the amide product without intermediacy of a carboxylic acid or activated derivative. Molybdenum oxide-mediated hydride reduction provides the anti-β2,3-amino amide with high selectivity.
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Affiliation(s)
- Mahesh Vishe
- Department of Chemistry , Vanderbilt Institute of Chemical Biology Vanderbilt University , Nashville , Tennessee 37235 , USA .
| | - Jeffrey N Johnston
- Department of Chemistry , Vanderbilt Institute of Chemical Biology Vanderbilt University , Nashville , Tennessee 37235 , USA .
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10
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Friggeri L, Hargrove TY, Rachakonda G, Blobaum AL, Fisher P, de Oliveira GM, da Silva CF, Soeiro MDNC, Nes WD, Lindsley CW, Villalta F, Guengerich FP, Lepesheva GI. Sterol 14α-Demethylase Structure-Based Optimization of Drug Candidates for Human Infections with the Protozoan Trypanosomatidae. J Med Chem 2018; 61:10910-10921. [PMID: 30451500 DOI: 10.1021/acs.jmedchem.8b01671] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Sterol 14α-demethylases (CYP51) are cytochrome P450 enzymes essential for sterol biosynthesis in eukaryotes and therapeutic targets for antifungal azoles. Multiple attempts to repurpose antifungals for treatment of human infections with protozoa (Trypanosomatidae) have been undertaken, yet so far none of them have revealed sufficient efficacy. VNI and its derivative VFV are two potent experimental inhibitors of Trypanosomatidae CYP51, effective in vivo against Chagas disease, visceral leishmaniasis, and sleeping sickness and currently under consideration as antiprotozoal drug candidates. However, VNI is less potent against Leishmania and drug-resistant strains of Trypanosoma cruzi and VFV, while displaying a broader spectrum of antiprotozoal activity, and is metabolically less stable. In this work we have designed, synthesized, and characterized a set of close analogues and identified two new compounds (7 and 9) that exceed VNI/VFV in their spectra of antiprotozoal activity, microsomal stability, and pharmacokinetics (tissue distribution in particular) and, like VNI/VFV, reveal no acute toxicity.
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Affiliation(s)
- Laura Friggeri
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232 , United States
| | - Tatiana Y Hargrove
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232 , United States
| | - Girish Rachakonda
- Department of Microbiology, Immunology and Physiology , Meharry Medical College , Nashville , Tennessee 37208 , United States
| | - Anna L Blobaum
- Vanderbilt Center for Neuroscience Drug Discovery , Franklin , Tennessee 37067 , United States
| | - Paxtyn Fisher
- Department of Chemistry and Biochemistry , Texas Tech University , Lubbock , Texas 79409 , United States
| | - Gabriel Melo de Oliveira
- Laboratório de Biologia Celular , Instituto Oswaldo Cruz , Fundação Oswaldo Cruz , Rio de Janeiro , RJ 21040-360 , Brazil
| | - Cristiane França da Silva
- Laboratório de Biologia Celular , Instituto Oswaldo Cruz , Fundação Oswaldo Cruz , Rio de Janeiro , RJ 21040-360 , Brazil
| | - Maria de Nazaré C Soeiro
- Laboratório de Biologia Celular , Instituto Oswaldo Cruz , Fundação Oswaldo Cruz , Rio de Janeiro , RJ 21040-360 , Brazil
| | - W David Nes
- Department of Chemistry and Biochemistry , Texas Tech University , Lubbock , Texas 79409 , United States
| | - Craig W Lindsley
- Vanderbilt Center for Neuroscience Drug Discovery , Franklin , Tennessee 37067 , United States
| | - Fernando Villalta
- Department of Microbiology, Immunology and Physiology , Meharry Medical College , Nashville , Tennessee 37208 , United States
| | - F Peter Guengerich
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232 , United States
| | - Galina I Lepesheva
- Department of Biochemistry , Vanderbilt University School of Medicine , Nashville , Tennessee 37232 , United States.,Center for Structural Biology , Vanderbilt University , Nashville , Tennessee 37232 , United States
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11
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Tsukanov SV, Johnson MD, May SA, Kolis SP, Yates MH, Johnston JN. Continuous Platform to Generate Nitroalkanes On-Demand (in situ) using Peracetic Acid-Mediated Oxidation in a PFA Pipes-in-Series Reactor. Org Process Res Dev 2018; 22:971-977. [PMID: 30906182 DOI: 10.1021/acs.oprd.8b00113] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthetic utility of the aza-Henry reaction can be diminished on scale by potential hazards associated with the use of peracid to prepare nitroalkane substrates, and the nitroalkanes themselves. In response, a continuous and scalable chemistry platform to prepare aliphatic nitroalkanes on-demand is reported, using the oxidation of oximes with peracetic acid and direct reaction of the nitroalkane intermediate in an aza-Henry reaction. A uniquely designed pipes-in-series plug flow tube reactor addresses a range of process challenges including stability and safe handling of peroxides and nitroalkanes. The subsequent continuous extraction generates a solution of purified nitroalkane which can be directly used in the following enantioselective aza-Henry chemistry to furnish valuable chiral diamine precursors in high selectivity, thus, completely avoiding isolation of potentially unsafe low molecular weight nitroalkane intermediate. A continuous campaign (16 h) established that these conditions were effective in processing 100 g of the oxime and furnishing 1.4 L of nitroalkane solution.
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Affiliation(s)
- Sergey V Tsukanov
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States.,Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Martin D Johnson
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Scott A May
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Stanley P Kolis
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Matthew H Yates
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Jeffrey N Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
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12
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Tokumaru K, Bera K, Johnston JN. 1,3,4-Oxadiazole and Heteroaromatic-Fused 1,2,4-Triazole Synthesis using Diverted Umpolung Amide Synthesis. SYNTHESIS-STUTTGART 2018; 49:4670-4675. [PMID: 29507449 DOI: 10.1055/s-0036-1590802] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Umpolung Amide Synthesis (UmAS) has emerged as a superior alternative to conventional amide synthesis methods based on carbonyl electrophiles in a range of situations, particularly when epimerization-prone couplings are prescribed. In an unanticipated development during our most recent studies, it was discovered that diacyl hydrazide products from UmAS were not formed as intermediates when using an acyl hydrazide as the amine acceptor. This resulted in a new preparation of 1,3,4-oxadiazoles from α-bromonitroalkane donors. We hypothesized that a key tetrahedral intermediate in UmAS was diverted toward a more direct pathway to the heterocycle product rather than through formation of the diacyl hydrazide, a typical oxadiazole progenitor. In studies reported here, diversion to 1,2,4-triazole products is described, a behavior hypothesized to also result from an analogous tetrahedral intermediate, but one formed from heteroaromatic hydrazine acceptors.
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Affiliation(s)
- Kazuyuki Tokumaru
- Department of Chemistry, and Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235
| | - Kalisankar Bera
- Department of Chemistry, and Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235
| | - Jeffrey N Johnston
- Department of Chemistry, and Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235
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13
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Lepesheva G, Christov P, Sulikowski GA, Kim K. A convergent, scalable and stereoselective synthesis of azole CYP51 inhibitors. Tetrahedron Lett 2017; 58:4248-4250. [PMID: 29371747 DOI: 10.1016/j.tetlet.2017.09.070] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The study and development of azole-based CYP51 inhibitors is an active area of research across disciplines of biochemistry, pharmacology and infectious disease. Support of in vitro and in vivo studies require the development of robust asymmetric routes to single enantiomer products of this class of compounds. Herein, we describe a scalable and enantioselective synthesis to VNI and VFV, the two potent inhibitors of protozoan sterol 14α-demethylase (CYP51) that are currently under consideration for clinical trials for Chagas disease. A key transformation is the Jacobsen Hydrolytic Kinetic Resolution (HKR) reaction. The utility of the synthetic route is illustrated by the preparation of >25 g quantities of single enantiomers of VNI and VFV.
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Affiliation(s)
- Galina Lepesheva
- Departments of Chemistry and Biochemistry, Institute of Chemical Biology, Vanderbilt University, Nashville, TN 77842-3012, USA
| | - Plamen Christov
- Departments of Chemistry and Biochemistry, Institute of Chemical Biology, Vanderbilt University, Nashville, TN 77842-3012, USA
| | - Gary A Sulikowski
- Departments of Chemistry and Biochemistry, Institute of Chemical Biology, Vanderbilt University, Nashville, TN 77842-3012, USA
| | - Kwangho Kim
- Departments of Chemistry and Biochemistry, Institute of Chemical Biology, Vanderbilt University, Nashville, TN 77842-3012, USA
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14
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Tokumaru K, Johnston JN. A convergent synthesis of 1,3,4-oxadiazoles from acyl hydrazides under semiaqueous conditions. Chem Sci 2017; 8:3187-3191. [PMID: 28507694 PMCID: PMC5414388 DOI: 10.1039/c7sc00195a] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 02/16/2017] [Indexed: 12/22/2022] Open
Abstract
The 1,3,4-oxadiazole is an aromatic heterocycle valued for its low-lipophilicity in drug development. Substituents at the 2- and/or 5-positions can modulate the heterocycle's electronic and hydrogen bond-accepting capability, while exploiting its use as a carbonyl bioisostere. A new approach to 1,3,4-oxadiazoles is described wherein α-bromo nitroalkanes are coupled to acyl hydrazides to deliver the 2,5-disubstituted oxadiazole directly, avoiding a 1,2-diacyl hydrazide intermediate. Access to new building blocks of oxadiazole-substituted secondary amines is improved by leveraging chiral α-bromo nitroalkane or amino acid hydrazide substrates. The non-dehydrative conditions for oxadiazole synthesis are particularly notable, in contrast to alternatives reliant on highly oxophilic reagents to effect cyclization of unsymmetrical 1,2-diacyl hydrazides. The mild conditions are punctuated by the straightforward removal of co-products by a standard aqueous wash.
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Affiliation(s)
- Kazuyuki Tokumaru
- Department of Chemistry , Vanderbilt Institute of Chemical Biology , Vanderbilt University , Nashville , Tennessee 37235 , USA .
| | - Jeffrey N Johnston
- Department of Chemistry , Vanderbilt Institute of Chemical Biology , Vanderbilt University , Nashville , Tennessee 37235 , USA .
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15
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Antitrypanosomal Activity of Sterol 14α-Demethylase (CYP51) Inhibitors VNI and VFV in the Swiss Mouse Models of Chagas Disease Induced by the Trypanosoma cruzi Y Strain. Antimicrob Agents Chemother 2017; 61:AAC.02098-16. [PMID: 28167559 DOI: 10.1128/aac.02098-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/22/2017] [Indexed: 11/20/2022] Open
Abstract
Chagas disease is a life-threatening infection caused by a variety of genetically diverse strains of the protozoan parasite Trypanosoma cruzi The current treatment (benznidazole and nifurtimox) is unsatisfactory, and potential alternatives include inhibitors of sterol 14α-demethylase (CYP51), the cytochrome P450 enzyme essential for the biosynthesis of sterols in eukaryotes and the major target of clinical and agricultural antifungals. Here we performed a comparative investigation of two protozoon-specific CYP51 inhibitors, VNI and its CYP51 structure-based derivative VFV, in the murine models of infection caused by the Y strain of T. cruzi The effects of different treatment regimens and drug delivery vehicles were evaluated in animals of both genders, with benznidazole serving as the reference drug. Regardless of the treatment scheme or delivery vehicle, VFV was more potent in both genders, causing a >99.7% peak parasitemia reduction, while the VNI values varied from 91 to 100%. Treatments with VNI and VFV resulted in 100% animal survival and 0% natural relapse after the end of therapy, though, except for the 120-day treatment schemes with VFV, relapses after three cycles of immunosuppression were observed in each animal group, and quantitative PCR analysis revealed a very light parasite load in the blood samples (sometimes below or near the detection limit, which was 1.5 parasite equivalents/ml). Our studies support further investigations of this class of compounds, including their testing against other T. cruzi strains and in combination with other drugs.
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Vara BA, Johnston JN. Enantioselective Synthesis of β-Fluoro Amines via β-Amino α-Fluoro Nitroalkanes and a Traceless Activating Group Strategy. J Am Chem Soc 2016; 138:13794-13797. [PMID: 27749040 PMCID: PMC5453840 DOI: 10.1021/jacs.6b07731] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Preparation of a range of enantioenriched β-fluoro amines (α,β-disubstituted) is described in which the nitrogen and fluorine atoms are attached to sp3-hybridized carbons. The key finding is a chiral bifunctional Brønsted acid/base catalyst that can deliver β-amino-α-fluoro nitroalkanes with high enantio- and diastereoselection. A denitration step renders the nitro group "traceless" and delivers secondary, tertiary, or vinyl alkyl fluorides embedded within a vicinal fluoro amine functional group. A synthesis of each possible stereoisomer of a β-fluoro lanicemine illustrates the potential ease with which fluorinated small molecules relevant to neuroscience drug development can be prepared in a stereochemically comprehensive manner.
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Affiliation(s)
- Brandon A. Vara
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235-1822
| | - Jeffrey N. Johnston
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235-1822
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Stereoselective reactions of nitro compounds in the synthesis of natural compound analogs and active pharmaceutical ingredients. Tetrahedron 2016. [DOI: 10.1016/j.tet.2016.07.067] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Tsukanov SV, Johnson MD, May SA, Rosemeyer M, Watkins MA, Kolis SP, Yates MH, Johnston JN. Development of an Intermittent-Flow Enantioselective Aza-Henry Reaction Using an Arylnitromethane and Homogeneous Brønsted Acid-Base Catalyst with Recycle. Org Process Res Dev 2016; 20:215-226. [PMID: 27065720 PMCID: PMC4821467 DOI: 10.1021/acs.oprd.5b00245] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A stereoselective aza-Henry reaction between an arylnitromethane and Boc-protected aryl aldimine using a homogeneous Brønsted acid-base catalyst was translated from batch format to an automated intermittent-flow process. This work demonstrates the advantages of a novel intermittent-flow setup with product crystallization and slow reagent addition which is not amenable to the standard continuous equipment: plug flow tube reactor (PFR) or continuous stirred tank reactor (CSTR). A significant benefit of this strategy was the integration of an organocatalytic enantioselective reaction with straightforward product separation, including recycle of the catalyst, resulting in increased intensity of the process by maintaining high catalyst concentration in the reactor. A continuous campaign confirmed that these conditions could effectively provide high throughput of material using an automated system while maintaining high selectivity, thereby addressing nitroalkane safety and minimizing catalyst usage.
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Affiliation(s)
- Sergey V. Tsukanov
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Martin D. Johnson
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Scott A. May
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Morgan Rosemeyer
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Michael A. Watkins
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Stanley P. Kolis
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Matthew H. Yates
- Small Molecule Design and Development, Eli Lilly and Company, Indianapolis, Indiana 46285, Unites States
| | - Jeffrey N. Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
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Abstract
A two-step, one-pot oxidative amidation of primary nitroalkanes involving tandem halogenation/umpolung amide synthesis (UmAS) is described.
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Affiliation(s)
- Kenneth E. Schwieter
- Department of Chemistry and Vanderbilt Institute of Chemical Biology
- Vanderbilt University
- Nashville
- USA
| | - Jeffrey N. Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology
- Vanderbilt University
- Nashville
- USA
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Zlotin SG, Kochetkov SV. C2-Symmetric diamines and their derivatives as promising organocatalysts for asymmetric synthesis. RUSSIAN CHEMICAL REVIEWS 2015. [DOI: 10.1070/rcr4562] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Novel approaches to pharmacology-oriented and energy rich organic nitrogen–oxygen systems. MENDELEEV COMMUNICATIONS 2015. [DOI: 10.1016/j.mencom.2015.11.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Lepesheva GI, Hargrove TY, Rachakonda G, Wawrzak Z, Pomel S, Cojean S, Nde PN, Nes WD, Locuson CW, Calcutt MW, Waterman MR, Daniels JS, Loiseau PM, Villalta F. VFV as a New Effective CYP51 Structure-Derived Drug Candidate for Chagas Disease and Visceral Leishmaniasis. J Infect Dis 2015; 212:1439-48. [DOI: 10.1093/infdis/jiv228] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 04/08/2015] [Indexed: 11/14/2022] Open
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Eloy JO, Saraiva J, Albuquerque SD, Marchetti JM. Preparation, characterization and evaluation of the in vivo trypanocidal activity of ursolic acid-loaded solid dispersion with poloxamer 407 and sodium caprate. BRAZ J PHARM SCI 2015. [DOI: 10.1590/s1984-82502015000100011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Ursolic acid is a promising candidate for treatment of Chagas disease; however it has low aqueous solubility and intestinal absorption, which are both limiting factors for bioavailability. Among the strategies to enhance the solubility and dissolution of lipophilic drugs, solid dispersions are growing in popularity. In this study, we employed a mixture of the surfactants poloxamer 407 with sodium caprate to produce a solid dispersion containing ursolic acid aimed at enhancing both drug dissolution and in vivo trypanocidal activity. Compared to the physical mixture, the solid dispersion presented higher bulk density and smaller particle size. Fourier Transform Infrared Spectroscopy results showed hydrogen bonding intermolecular interactions between drug and poloxamer 407. X-ray diffractometry experiments revealed the conversion of the drug from its crystalline form to a more soluble amorphous structure. Consequently, the solubility of ursolic acid in the solid dispersion was increased and the drug dissolved in a fast and complete manner. Taken together with the oral absorption-enhancing property of sodium caprate, these results explained the increase of the in vivo trypanocidal activity of ursolic acid in solid dispersion, which also proved to be safe by cytotoxicity evaluation using the LLC-MK2 cell line.
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Schwieter KE, Johnston JN. Enantioselective Synthesis of D-α-Amino Amides from Aliphatic Aldehydes. Chem Sci 2015; 6:2590-2595. [PMID: 25838883 PMCID: PMC4378585 DOI: 10.1039/c5sc00064e] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Bromonitromethane is used in a phase transfer-catalysed enantioselective aza-Henry reaction, leading to d-amino amide bearing an alkyl chain.
Peptides consisting of d-amino amides are highly represented among both biologically active natural products and non-natural small molecules used in therapeutic development. Chemical synthesis of d-amino amides most often involves approaches based on enzymatic resolution or fractional recrystallization of their diastereomeric amino acid salt precursors, techniques that produce an equal amount of the l-amino acid. Enantioselective synthesis, however, promises selective and general access to a specific α-amino amide, and may enable efficient peptide synthesis regardless of the availability of the corresponding α-amino acid. This report describes the use of a cinchona alkaloid-catalyzed aza-Henry reaction using bromonitromethane, and the integration of its product with umpolung amide synthesis. The result is a straightforward 3-step protocol beginning from aliphatic aldehydes that provides homologated peptides bearing an aliphatic side chain at the resulting d-α-amino amide.
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Affiliation(s)
- Kenneth E Schwieter
- Department of Chemistry and Vanderbilt Institute of Chemical Biology Vanderbilt University, Nashville, Tennessee 37235
| | - Jeffrey N Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology Vanderbilt University, Nashville, Tennessee 37235
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Schwieter KE, Johnston JN. Enantioselective Addition of Bromonitromethane to Aliphatic N-Boc Aldimines Using a Homogeneous Bifunctional Chiral Organocatalyst. ACS Catal 2015; 5:6559-6562. [PMID: 27019764 DOI: 10.1021/acscatal.5b01901] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This report details the enantioselective synthesis of β-amino-α-bromo nitroalkanes with β-alkyl substituents, using homogeneous catalysis to prepare either antipode. Use of a bifunctional Brønsted base/acid catalyst allows equal access to either enantiomer of the products, enabling the use of Umpolung Amide Synthesis (UmAS) to prepare the corresponding L- or D-α-amino amide bearing alkyl side chains - overall, in only 4 steps from aldehyde. The approach also addresses an underlying incompatibility between bromonitromethane and solid hydroxide bases.
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Affiliation(s)
- Kenneth E. Schwieter
- Department of Chemistry and
Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jeffrey N. Johnston
- Department of Chemistry and
Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
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Soengas RG, Acúrcio RC, Silva AMS. Recent Developments in the Chemistry ofgem-Halonitro Compounds. European J Org Chem 2014. [DOI: 10.1002/ejoc.201402043] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Hong KB, Johnston JN. Alkene Diamination Using Electron-Rich Amines: Hypervalent Iodine-Promoted Inter-/Intramolecular C–N Bond Formation. Org Lett 2014; 16:3804-7. [DOI: 10.1021/ol501693j] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Ki Bum Hong
- Department of Chemistry and
Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Jeffrey N. Johnston
- Department of Chemistry and
Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
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Lepesheva GI. Design or screening of drugs for the treatment of Chagas disease: what shows the most promise? Expert Opin Drug Discov 2013; 8:1479-89. [PMID: 24079515 PMCID: PMC3867292 DOI: 10.1517/17460441.2013.845554] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Endemic in Latin America, Chagas disease is now becoming a serious global health problem, and yet has no financial viability for the pharmaceutical industry and remains incurable. In 2012, two antimycotic drugs inhibitors of fungal sterol 14α-demethylase (CYP51) - posaconazole and ravuconazole - entered clinical trials. Availability of the X-ray structure of the orthologous enzyme from the causative agent of the disease, protozoan parasite Trypanosoma cruzi, determined in complexes with posaconazole as well as with several experimental protozoa-specific CYP51 inhibitors opens an excellent opportunity to improve the situation. AREAS COVERED This article summarizes the information available in PubMed and Google on the outcomes of treatment of the chronic Chagas disease. It also outlines the major features of the T. cruzi CYP51 structure and the possible structure-based strategies for rational design of novel T. cruzi specific drugs. EXPERT OPINION There is no doubt that screenings for alternative drug-like molecules as well as mining the T. cruzi genome for novel drug targets are of great value and might eventually lead to groundbreaking discoveries. However, all newly identified molecules must proceed through the long, expensive and low-yielding drug optimization process, and all novel potential drug targets must be validated in terms of their essentiality and druggability. CYP51 is already a well-validated and highly successful target for clinical and agricultural antifungals. With minimal investments into the final stages of their development/trials, T. cruzi-specific CYP51 inhibitors can provide an immediate treatment for Chagas disease, either on their own or in combination with the currently available drugs.
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Affiliation(s)
- Galina I Lepesheva
- Vanderbilt University, Institute for Global Health, School of Medicine, Center for Structural Biology, Department of Biochemistry , 622 RRB, 23rd at Pierce, Nashville, TN 37232 , USA +1 615 343 1373 ; +1 615 322 4349 ;
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Davis TA, Vilgelm AE, Richmond A, Johnston JN. Preparation of (-)-Nutlin-3 using enantioselective organocatalysis at decagram scale. J Org Chem 2013; 78:10605-16. [PMID: 24127627 DOI: 10.1021/jo401321a] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Chiral nonracemic cis-4,5-bis(aryl)imidazolines have emerged as a powerful platform for the development of cancer chemotherapeutics, stimulated by the Hoffmann-La Roche discovery that Nutlin-3 can restore apoptosis in cells with wild-type p53. The lack of efficient methods for the enantioselective synthesis of cis-imidazolines, however, has limited their more general use. Our disclosure of the first enantioselective synthesis of (-)-Nutlin-3 provided a basis to prepare larger amounts of this tool used widely in cancer biology. Key to the decagram-scale synthesis described here was the discovery of a novel bis(amidine) organocatalyst that provides high enantioselectivity at warmer reaction temperature (-20 °C) and low catalyst loadings. Further refinements to the procedure led to the synthesis of (-)-Nutlin-3 in a 17 g batch and elimination of all but three chromatographic purifications.
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Affiliation(s)
- Tyler A Davis
- Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University , Nashville, Tennessee 37235-1822, United States
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Hargrove TY, Wawrzak Z, Alexander PW, Chaplin JH, Keenan M, Charman SA, Perez CJ, Waterman MR, Chatelain E, Lepesheva GI. Complexes of Trypanosoma cruzi sterol 14α-demethylase (CYP51) with two pyridine-based drug candidates for Chagas disease: structural basis for pathogen selectivity. J Biol Chem 2013; 288:31602-15. [PMID: 24047900 DOI: 10.1074/jbc.m113.497990] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Chagas disease, caused by the eukaryotic (protozoan) parasite Trypanosoma cruzi, is an alarming emerging global health problem with no clinical drugs available to treat the chronic stage. Azole inhibitors of sterol 14α-demethylase (CYP51) were proven effective against Chagas, and antifungal drugs posaconazole and ravuconazole have entered clinical trials in Spain, Bolivia, and Argentina. Here we present the x-ray structures of T. cruzi CYP51 in complexes with two alternative drug candidates, pyridine derivatives (S)-(4-chlorophenyl)-1-(4-(4-(trifluoromethyl)phenyl)-piperazin-1-yl)-2-(pyridin-3-yl)ethanone (UDO; Protein Data Bank code 3ZG2) and N-[4-(trifluoromethyl)phenyl]-N-[1-[5-(trifluoromethyl)-2-pyridyl]-4-piperi-dyl]pyridin-3-amine (UDD; Protein Data Bank code 3ZG3). These compounds have been developed by the Drugs for Neglected Diseases initiative (DNDi) and are highly promising antichagasic agents in both cellular and in vivo experiments. The binding parameters and inhibitory effects on sterol 14α-demethylase activity in reconstituted enzyme reactions confirmed UDO and UDD as potent and selective T. cruzi CYP51 inhibitors. Comparative analysis of the pyridine- and azole-bound CYP51 structures uncovered the features that make UDO and UDD T. cruzi CYP51-specific. The structures suggest that although a precise fit between the shape of the inhibitor molecules and T. cruzi CYP51 active site topology underlies their high inhibitory potency, a longer coordination bond between the catalytic heme iron and the pyridine nitrogen implies a weaker influence of pyridines on the iron reduction potential, which may be the basis for the observed selectivity of these compounds toward the target enzyme versus other cytochrome P450s, including human drug-metabolizing P450s. These findings may pave the way for the development of novel CYP51-targeted drugs with optimized metabolic properties that are very much needed for the treatment of human infections caused by eukaryotic microbial pathogens.
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Affiliation(s)
- Tatiana Y Hargrove
- From the Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232
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Cellular response to Trypanosoma cruzi infection induces secretion of defensin α-1, which damages the flagellum, neutralizes trypanosome motility, and inhibits infection. Infect Immun 2013; 81:4139-48. [PMID: 23980110 DOI: 10.1128/iai.01459-12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human defensins play a fundamental role in the initiation of innate immune responses to some microbial pathogens. Here we show that colonic epithelial model HCT116 cells respond to Trypanosoma cruzi infection by secreting defensin α-1, which reduces infection. We also report the early effects of defensin α-1 on invasive trypomastigotes that involve damage of the flagellar structure to inhibit parasite motility and reduce cellular infection. Short exposure of defensin α-1 to trypomastigotes shows that defensin α-1 binds to the flagellum, resulting in flagellar membrane and axoneme alterations, followed by breaking of the flagellar membrane connected to the trypanosome body, leading to detachment and release of the parasite flagellum. In addition, defensin α-1 induces a significant reduction in parasite motility in a peptide concentration-dependent manner, which is abrogated by anti-defensin α-1 IgG. Preincubation of trypomastigotes with a concentration of defensin α-1 that inhibits 50% trypanosome motility significantly reduced cellular infection by 80%. Thus, human defensin α-1 is an innate immune molecule that is secreted by HCT116 cells in response to T. cruzi infection, inhibits T. cruzi motility, and plays an important role in reducing cellular infection. This is the first report showing a novel cellular innate immune response to a human parasite by secretion of defensin α-1, which neutralizes the motility of a human parasite to reduce cellular infection. The mode of activity of human defensin α-1 against T. cruzi and its function may provide insights for the development of new antiparasitic strategies.
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Villalta F, Dobish MC, Nde PN, Kleshchenko YY, Hargrove TY, Johnson CA, Waterman MR, Johnston JN, Lepesheva GI. VNI cures acute and chronic experimental Chagas disease. J Infect Dis 2013; 208:504-11. [PMID: 23372180 DOI: 10.1093/infdis/jit042] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Chagas disease is a deadly infection caused by the protozoan parasite Trypanosoma cruzi. Afflicting approximately 8 million people in Latin America, Chagas disease is now becoming a serious global health problem proliferating beyond the traditional geographical borders, mainly because of human and vector migration. Because the disease is endemic in low-resource areas, industrial drug development has been lethargic. The chronic form remains incurable, there are no vaccines, and 2 existing drugs for the acute form are toxic and have low efficacy. Here we report the efficacy of a small molecule, VNI, including evidence of its effectiveness against chronic Chagas disease. VNI is a potent experimental inhibitor of T. cruzi sterol 14α-demethylase. Nontoxic and highly selective, VNI displays promising pharmacokinetics and administered orally to mice at 25 mg/kg for 30 days cures, with 100% cure rate and 100% survival, the acute and chronic T. cruzi infection.
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Affiliation(s)
- Fernando Villalta
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, TN, USA
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