1
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Zhou X, Zhang H, Zhou Y, Yi Y, Yuan R, Pu W, Wang S, Shang R. Antimicrobial activity, safety and pharmacokinetics evaluation of PMTM: A novel pleuromutilin candidate. Biomed Pharmacother 2024; 179:117378. [PMID: 39241564 DOI: 10.1016/j.biopha.2024.117378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Revised: 08/26/2024] [Accepted: 08/27/2024] [Indexed: 09/09/2024] Open
Abstract
The prevalence of infections by methicillin-resistant Staphylococcus aureus (MRSA) has led to dramatically increased mortality and threated the public health worldwide. Pleuromutilin compound 14-O-[(4-(pyrrolidine-1-yl)-6-methylpyrimidine-2-yl) thioacetyl] mutilin (PMTM) is a new antibacterial agent with excellent antibacterial efficacy against Gram positive bacteria. For further developing PMTM as a potential drug against MRSA infections, the in vitro antibacterial efficacy and preclinical safety were explored in this study. The results revealed that PMTM presented the higher anti-MRSA activity, increasing post-antibiotic effect (PAE) and limited potential to develop resistance. In safety evaluation, PMTM demonstrated low cytotoxicity, poor hemolytic activity, tolerable oral acute toxic effects in rats, devoid of mutagenic response and weak inhibitory potential on CYP3A4, but displayed moderate potential hERG K+ channel inhibition. Furthermore, two salts of PMTM with sulfuric acid and hydrochloric acid were prepared and confirmed. The sulfate salt of PMTM exhibited the highest solubility based on powder dissolution experiments and was chosen to evaluate pharmacokinetics properties, in which it displayed improved mouse pharmacokinetics parameters and oral bioavailability. The present study successfully provides a good foundation of PMTM for new antibacterial drug development.
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Affiliation(s)
- Xingqian Zhou
- Key Laboratory of New Animal Drug Project, Gansu Province/Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs/Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, China.
| | - Hongjuan Zhang
- Key Laboratory of New Animal Drug Project, Gansu Province/Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs/Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, China.
| | - Yuhang Zhou
- Key Laboratory of New Animal Drug Project, Gansu Province/Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs/Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, China
| | - Yunpeng Yi
- Shandong Provincial Animal and Poultry Green Health Products Creation Engineering Laboratory, Institute of Poultry Science, Shandong Academy of Agricultural Science, Jinan, Shandong 250023, China
| | - Ruili Yuan
- Key Laboratory of New Animal Drug Project, Gansu Province/Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs/Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, China
| | - Wanxia Pu
- Key Laboratory of New Animal Drug Project, Gansu Province/Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs/Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, China
| | - Shengyi Wang
- Key Laboratory of New Animal Drug Project, Gansu Province/Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs/Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, China.
| | - Ruofeng Shang
- Key Laboratory of New Animal Drug Project, Gansu Province/Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs/Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Lanzhou 730050, China.
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2
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Bakanas I, Lusi RF, Wiesler S, Hayward Cooke J, Sarpong R. Strategic application of C-H oxidation in natural product total synthesis. Nat Rev Chem 2023; 7:783-799. [PMID: 37730908 DOI: 10.1038/s41570-023-00534-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2023] [Indexed: 09/22/2023]
Abstract
The oxidation of unactivated C-H bonds has emerged as an effective tactic in natural product synthesis and has altered how chemists approach the synthesis of complex molecules. The use of C-H oxidation methods has simplified the process of synthesis planning by expanding the choice of starting materials, limiting functional group interconversion and protecting group manipulations, and enabling late-stage diversification. In this Review, we propose classifications for C-H oxidations on the basis of their strategic purpose: type 1, which installs functionality that is used to establish the carbon skeleton of the target; type 2, which is used to construct a heterocyclic ring; and type 3, which installs peripheral functional groups. The reactions are further divided based on whether they are directed or undirected. For each classification, examples from recent literature are analysed. Finally, we provide two case studies of syntheses from our laboratory that were streamlined by the judicious use of C-H oxidation reactions.
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Affiliation(s)
- Ian Bakanas
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Robert F Lusi
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Stefan Wiesler
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Jack Hayward Cooke
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Richmond Sarpong
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
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3
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Yu IF, Wilson JW, Hartwig JF. Transition-Metal-Catalyzed Silylation and Borylation of C-H Bonds for the Synthesis and Functionalization of Complex Molecules. Chem Rev 2023; 123:11619-11663. [PMID: 37751601 DOI: 10.1021/acs.chemrev.3c00207] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/28/2023]
Abstract
The functionalization of C-H bonds in organic molecules containing functional groups has been one of the holy grails of catalysis. One synthetically important approach to the diverse functionalization of C-H bonds is the catalytic silylation or borylation of C-H bonds, which enables a broad array of downstream transformations to afford diverse structures. Advances in both undirected and directed methods for the transition-metal-catalyzed silylation and borylation of C-H bonds have led to their rapid adoption in early-, mid-, and late-stage of the synthesis of complex molecules. In this Review, we review the application of the transition-metal-catalyzed silylation and borylation of C-H bonds to the synthesis of bioactive molecules, organic materials, and ligands. Overall, we aim to provide a picture of the state of art of the silylation and borylation of C-H bonds as applied to the synthesis and modification of diverse architectures that will spur further application and development of these reactions.
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Affiliation(s)
- Isaac F Yu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jake W Wilson
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John F Hartwig
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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4
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Wilson JW, Su B, Yoritate M, Shi JX, Hartwig JF. Iridium-Catalyzed, Site-Selective Silylation of Secondary C(sp 3)-H Bonds in Secondary Alcohols and Ketones. J Am Chem Soc 2023; 145:19490-19495. [PMID: 37638874 DOI: 10.1021/jacs.3c03127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2023]
Abstract
We report the iridium-catalyzed, stereoselective conversion of secondary alcohols or ketones to anti-1,3-diols by the silylation of secondary C-H bonds γ to oxygen and oxidation of the resulting oxasilolane. The silylation of secondary C-H bonds in secondary silyl ethers derived from alcohols or ketones is enabled by a catalyst formed from a simple bisamidine ligand. The silylation occurs with high selectivity at a secondary C-H bond γ to oxygen over distal primary or proximal secondary C-H bonds. Initial mechanistic investigations suggest that the source of the newly achieved reactivity is a long catalyst lifetime resulting from the high binding constant of the strongly electron-donating bisamidine ligand.
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Affiliation(s)
- Jake W Wilson
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Bo Su
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Makoto Yoritate
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Jake X Shi
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John F Hartwig
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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5
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Lusi RF, Sennari G, Sarpong R. Strategy Evolution in a Skeletal Remodeling and C-H Functionalization-Based Synthesis of the Longiborneol Sesquiterpenoids. J Am Chem Soc 2022; 144:17277-17294. [PMID: 36098550 DOI: 10.1021/jacs.2c08136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Detailed herein are our synthesis studies of longiborneol and related natural products. Our overarching goals of utilizing a "camphor first" strategy enabled by skeletal remodeling of carvone, and late-stage diversification using C-H functionalizations, led to divergent syntheses of the target natural products. Our initial approach proposed a lithiate addition to unite two fragments followed by a Conia-ene or Pd-mediated cycloalkylation reaction sequence to install the seven-membered ring emblematic of the longibornane core. This approach was unsuccessful and evolved into a revised plan that employed a Wittig coupling and a radical cyclization to establish the core. A reductive radical cyclization, which was explored first, led to a synthesis of copaborneol, a structural isomer of longiborneol. Alternatively, a metal-hydride hydrogen atom transfer-initiated cyclization was effective for a synthesis of longiborneol. Late-stage C-H functionalization of the longibornane core led to a number of hydroxylated longiborneol congeners. The need for significant optimization of the strategies that were employed as well as the methods for C-H functionalization to implement these strategies highlights the ongoing challenges in applying these powerful reactions. Nevertheless, the reported approach enables functionalization of every natural product-relevant C-H bond in the longibornane skeleton.
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Affiliation(s)
- Robert F Lusi
- Department of Chemistry, University of California─Berkeley, Berkeley, California 94720, United States
| | - Goh Sennari
- Department of Chemistry, University of California─Berkeley, Berkeley, California 94720, United States.,O̅mura Satoshi Memorial Institute, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Richmond Sarpong
- Department of Chemistry, University of California─Berkeley, Berkeley, California 94720, United States
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6
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Total synthesis of nine longiborneol sesquiterpenoids using a functionalized camphor strategy. Nat Chem 2022; 14:450-456. [DOI: 10.1038/s41557-021-00870-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 11/24/2021] [Indexed: 01/01/2023]
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7
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Bols M, Frihed TG, Pedersen MJ, Pedersen CM. Silylated Sugars – Synthesis and Properties. Synlett 2021. [DOI: 10.1055/s-0040-1719854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractSilicon has been used in carbohydrate chemistry for half a century, but mostly as a protective group for sugar alcohols. Recently, the use of silicon has expanded to functionalization via C–H activation, conformational arming of glycosyl donors, and conformational alteration of carbohydrates. Silicon has proven useful as more than a protective group and during the last one and a half decades we have demonstrated how it influences both the reactivity of glycosyl donors and stereochemical outcome of glycosylations. Silicon can also be attached directly to the sugar C-backbone, which has even more pronounced effects on the chemistry and properties of the molecules. In this Account, we will give a tour through our work involving silicon and carbohydrates.1 Introduction2 Conformational Arming of Glycosyl Donors with Silyl Groups3 Silyl Protective Groups for Tethering Glycosyl Donors4. Si–C Glycosides via C–H Activation4.1 C–H Activation and Oxidation of Methyl 6-Deoxy-l-glycosides4.2 Synthesis of All Eight 6-Deoxy-l-sugars4.3 Synthesis of All Eight l-Sugars by C–H Activation4.4 Modification of the Oxasilolane Ring5 C–Si in Glycosyl Donors – Activating or Not?6 Si–C-Substituted Pyranosides7 Perspective
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Affiliation(s)
- Mikael Bols
- University of Copenhagen, Department of Chemistry
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8
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Hong B, Luo T, Lei X. Late-Stage Diversification of Natural Products. ACS CENTRAL SCIENCE 2020; 6:622-635. [PMID: 32490181 PMCID: PMC7256965 DOI: 10.1021/acscentsci.9b00916] [Citation(s) in RCA: 158] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Indexed: 05/18/2023]
Abstract
Late-stage diversification of natural products is an efficient way to generate natural product derivatives for drug discovery and chemical biology. Benefiting from the development of site-selective synthetic methodologies, late-stage diversification of natural products has achieved notable success. This outlook will outline selected examples of novel methodologies for site-selective transformations of reactive functional groups and inert C-H bonds that enable late-stage diversification of complex natural products. Accordingly, late-stage diversification provides an opportunity to rapidly access various derivatives for modifying lead compounds, identifying cellular targets, probing protein-protein interactions, and elucidating natural product biosynthetic relationships.
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Affiliation(s)
- Benke Hong
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic
Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing 100871, China
- Department
of Chemical Biology, Peking University, Beijing 100871, China
- College
of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- Synthetic
and Functional Biomolecules Center, Peking
University, Beijing 100871, China
- Peking-Tsinghua
Center for Life Sciences, Peking University, Beijing 100871, China
| | - Tuoping Luo
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic
Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing 100871, China
- College
of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- Peking-Tsinghua
Center for Life Sciences, Peking University, Beijing 100871, China
- Academy
for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Xiaoguang Lei
- Beijing
National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic
Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing 100871, China
- Department
of Chemical Biology, Peking University, Beijing 100871, China
- College
of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- Synthetic
and Functional Biomolecules Center, Peking
University, Beijing 100871, China
- Peking-Tsinghua
Center for Life Sciences, Peking University, Beijing 100871, China
- E-mail:
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9
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Karmel C, Hartwig JF. Mechanism of the Iridium-Catalyzed Silylation of Aromatic C-H Bonds. J Am Chem Soc 2020; 142:10494-10505. [PMID: 32375477 DOI: 10.1021/jacs.0c03301] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Phenanthroline ligands and [Ir(cod)(OMe)]2 form complexes that catalyze the silylation of aromatic and aliphatic C-H bonds. However, no experimental data on the identity of complexes related to the mechanism of this process or the mechanisms by which they react to functionalize C-H bonds have been reported. Herein, we describe our studies on the mechanism of the iridium-catalyzed silylation of aryl C-H bonds. The resting state of the catalyst is an iridium disilyl hydride complex (phenanthroline)Ir(SiMe(OTMS)2)2(H)(L), in which L varies with the arene and additives. An iridium disilyl hydride complex was isolated, characterized, and allowed to react with arenes to form aryl silanes. The kinetics of the reactions of electron-rich and electron-poor arenes showed that the rate-limiting step varies with the electronic properties of the arene. Computational studies on related iridium silyl complexes revealed that the high activity of iridium complexes containing sterically encumbered phenanthroline ligands is due to a change in the number of silyl groups bound to iridium between the resting state of the catalyst containing the hindered phenanthroline and that containing less-hindered phenanthroline.
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Affiliation(s)
- Caleb Karmel
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - John F Hartwig
- Department of Chemistry, University of California, Berkeley, California 94720, United States
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10
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Gasperini D, King AK, Coles NT, Mahon MF, Webster RL. Seeking Heteroatom-Rich Compounds: Synthetic and Mechanistic Studies into Iron Catalyzed Dehydrocoupling of Silanes. ACS Catal 2020. [DOI: 10.1021/acscatal.0c01440] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Danila Gasperini
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Andrew K. King
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Nathan T. Coles
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Mary F. Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Ruth L. Webster
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
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11
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Affiliation(s)
| | - Wilfred A van der Donk
- Department of Chemistry , University of Illinois at Urbana-Champaign and Howard Hughes Medical Institute
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12
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Abstract
The functionalization of primary C-H bonds has been a longstanding challenge in catalysis. Our group has developed a series of silylations of primary C-H bonds that occur with site selectivity and diastereoselectivity resulting from an approach to run the reactions as intramolecular processes. These reactions have become practical by using an alcohol or amine as a docking site for a hydrosilyl group, thereby leading to intramolecular silylations of C-H bonds at positions dictated by the presence common functional groups in the reactants. Oxidation of the C-Si bond leads to the introduction of alcohol functionality at the position of the primary C-H bond of the reactant. The development, scope, and applications of these functionalization reactions is described in this minireview.
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Affiliation(s)
- John F Hartwig
- Department of Chemistry, University of California, Berkeley CA 94720
| | - Erik A Romero
- Department of Chemistry, University of California, Berkeley CA 94720
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13
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Llabani E, Hicklin RW, Lee HY, Motika SE, Crawford LA, Weerapana E, Hergenrother PJ. Diverse compounds from pleuromutilin lead to a thioredoxin inhibitor and inducer of ferroptosis. Nat Chem 2019; 11:521-532. [PMID: 31086302 PMCID: PMC6639018 DOI: 10.1038/s41557-019-0261-6] [Citation(s) in RCA: 158] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 03/25/2019] [Indexed: 02/08/2023]
Abstract
The chemical diversification of natural products provides a robust and general method for the creation of stereochemically rich and structurally diverse small molecules. The resulting compounds have physicochemical traits different from those in most screening collections, and as such are an excellent source for biological discovery. Herein, we subject the diterpene natural product pleuromutilin to reaction sequences focused on creating ring system diversity in few synthetic steps. This effort resulted in a collection of compounds with previously unreported ring systems, providing a novel set of structurally diverse and highly complex compounds suitable for screening in a variety of different settings. Biological evaluation identified the novel compound ferroptocide, a small molecule that rapidly and robustly induces ferroptotic death of cancer cells. Target identification efforts and CRISPR knockout studies reveal that ferroptocide is an inhibitor of thioredoxin, a key component of the antioxidant system in the cell. Ferroptocide positively modulates the immune system in a murine model of breast cancer and will be a useful tool to study the utility of pro-ferroptotic agents for treatment of cancer.
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Affiliation(s)
- Evijola Llabani
- Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL, USA
| | - Robert W Hicklin
- Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL, USA
| | - Hyang Yeon Lee
- Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL, USA
| | - Stephen E Motika
- Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL, USA
| | - Lisa A Crawford
- Department of Chemistry, Boston College, Chestnut Hill, MA, USA
| | | | - Paul J Hergenrother
- Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL, USA.
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14
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Yñigez-Gutierrez AE, Bachmann BO. Fixing the Unfixable: The Art of Optimizing Natural Products for Human Medicine. J Med Chem 2019; 62:8412-8428. [PMID: 31026161 DOI: 10.1021/acs.jmedchem.9b00246] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Molecules isolated from natural sources including bacteria, fungi, and plants are a long-standing source of therapeutics that continue to add to our medicinal arsenal today. Despite their potency and prominence in the clinic, complex natural products often exhibit a number of liabilities that hinder their development as therapeutics, which may be partially responsible for the current trend away from natural product discovery, research, and development. However, advances in synthetic biology and organic synthesis have inspired a new generation of natural product chemists to tackle powerful undeveloped scaffolds. In this Perspective, we will present case studies demonstrating the historical and current focus on making targeted, but significant, changes to natural product scaffolds via biosynthetic gene cluster manipulation, total synthesis, semisynthesis, or a combination of these methods, with a focus on increasing activity, decreasing toxicity, or improving chemical and pharmacological properties.
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Affiliation(s)
| | - Brian O Bachmann
- Department of Chemistry , Vanderbilt University , Nashville , Tennessee 37235 , United States
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15
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Hung K, Condakes ML, Novaes LFT, Harwood SJ, Morikawa T, Yang Z, Maimone TJ. Development of a Terpene Feedstock-Based Oxidative Synthetic Approach to the Illicium Sesquiterpenes. J Am Chem Soc 2019; 141:3083-3099. [PMID: 30698435 DOI: 10.1021/jacs.8b12247] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The Illicium sesquiterpenes are a family of natural products containing over 100 highly oxidized and structurally complex members, many of which display interesting biological activities. This comprehensive account chronicles the evolution of a semisynthetic strategy toward these molecules from (+)-cedrol, seeking to emulate key aspects of their presumed biosynthesis. An initial route generated lower oxidation state analogs but failed in delivering a crucial hydroxy group in the final step. Insight gathered during these studies, however, ultimately led to a synthesis of the pseudoanisatinoids along with the allo-cedrane natural product 11- O-debenzoyltashironin. A second-generation strategy was then developed to access the more highly oxidized majucinoid compounds including jiadifenolide and majucin itself. Overall, one dozen natural products can be accessed from an abundant and inexpensive terpene feedstock. A multitude of general observations regarding site-selective C(sp3)-H bond functionalization reactions in complex polycyclic architectures are reported.
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Affiliation(s)
- Kevin Hung
- Department of Chemistry , University of California, Berkeley , 826 Latimer Hall , Berkeley , California 94720 , United States
| | - Matthew L Condakes
- Department of Chemistry , University of California, Berkeley , 826 Latimer Hall , Berkeley , California 94720 , United States
| | - Luiz F T Novaes
- Department of Chemistry , University of California, Berkeley , 826 Latimer Hall , Berkeley , California 94720 , United States
| | - Stephen J Harwood
- Department of Chemistry , University of California, Berkeley , 826 Latimer Hall , Berkeley , California 94720 , United States
| | - Takahiro Morikawa
- Department of Chemistry , University of California, Berkeley , 826 Latimer Hall , Berkeley , California 94720 , United States
| | - Zhi Yang
- Department of Chemistry , University of California, Berkeley , 826 Latimer Hall , Berkeley , California 94720 , United States
| | - Thomas J Maimone
- Department of Chemistry , University of California, Berkeley , 826 Latimer Hall , Berkeley , California 94720 , United States
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16
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Goethe O, Heuer A, Ma X, Wang Z, Herzon SB. Antibacterial properties and clinical potential of pleuromutilins. Nat Prod Rep 2019; 36:220-247. [PMID: 29979463 DOI: 10.1039/c8np00042e] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Covering: up to 2018Pleuromutilins are a clinically validated class of antibiotics derived from the fungal diterpene (+)-pleuromutilin (1). Pleuromutilins inhibit bacterial protein synthesis by binding to the peptidyl transferase center (PTC) of the ribosome. In this review we summarize the biosynthesis and recent total syntheses of (+)-pleuromutilin (1). We review the mode of interaction of pleuromutilins with the bacterial ribosome, which involves binding of the C14 extension and the tricyclic core to the P and A sites of the PTC, respectively. We provide an overview of existing clinical agents, and discuss the three primary modes of bacterial resistance (mutations in ribosomal protein L3, Cfr methylation, and efflux). Finally we collect structure-activity relationships from publicly available reports, and close with some forward looking statements regarding future development.
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Affiliation(s)
- Olivia Goethe
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Abigail Heuer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Xiaoshen Ma
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Zhixun Wang
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
| | - Seth B Herzon
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA. and Department of Pharmacology, Yale School of Medicine, New Haven, Connecticut 06520, USA
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17
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Su B, Lee T, Hartwig JF. Iridium-Catalyzed, β-Selective C(sp 3)-H Silylation of Aliphatic Amines To Form Silapyrrolidines and 1,2-Amino Alcohols. J Am Chem Soc 2018; 140:18032-18038. [PMID: 30354144 DOI: 10.1021/jacs.8b10428] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The functionalization of unactivated C(sp3)-H bonds of aliphatic amines catalyzed by transition-metal complexes is important because amine-based functionality is present in a majority of biologically active molecules and commercial pharmaceuticals. However, such reactions are underdeveloped and challenging to achieve in general because the basicity and reducing properties of alkylamines tends to interfere with potential reagents and catalysts. The functionalization of C-H bonds β to the nitrogen of aliphatic amines to form prevalent 1,2-amino functionalized structures is particularly challenging because the C-H bond β to nitrogen is stronger than the C-H bond α to nitrogen, and the nitrogen in the amine or its derivatives usually directs a catalyst to react at more distal γ- and δ-C-H bonds to form 5- or 6-membered metallacyclic intermediate. The enantioselective functionalization of a C-H bond at any position in amines also has been vexing and is currently limited to reactions of specific, sterically hindered, cyclic structures. We report iridium-catalyzed, β-selective silylations of unactivated C(sp3)-H bonds of aliphatic amines to form silapyrrolidines that are both silicon-containing analogs of common saturated nitrogen heterocycles and precursors to 1,2-amino alcohols by Tamao-Fleming oxidation. These silylations of amines are accomplished by introducing a simple methylene linker between the heteroatom and silicon that has not been used previously for the silylation of C-H bonds. The reactions occur with high enantioselectivity when catalyzed by complexes of new chiral, pyridyl imidazoline ligands, and the rates of reactions with catalysts of these highly basic ligands are particularly fast, occuring in some cases at or even below room temperature.
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Affiliation(s)
- Bo Su
- Department of Chemistry , University of California, Berkeley , Berkeley , California 94720 , United States
| | - Taegyo Lee
- Department of Chemistry , University of California, Berkeley , Berkeley , California 94720 , United States
| | - John F Hartwig
- Department of Chemistry , University of California, Berkeley , Berkeley , California 94720 , United States
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Green SA, Crossley SWM, Matos JLM, Vásquez-Céspedes S, Shevick SL, Shenvi RA. The High Chemofidelity of Metal-Catalyzed Hydrogen Atom Transfer. Acc Chem Res 2018; 51:2628-2640. [PMID: 30406655 DOI: 10.1021/acs.accounts.8b00337] [Citation(s) in RCA: 194] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The implementation of any chemical reaction in a structurally complex setting ( King , S. M. J. Org. Chem. 2014 , 79 , 8937 ) confronts structurally defined barriers: steric environment, functional group reactivity, product instability, and through-bond electronics. However, there are also practical barriers. Late-stage reactions conducted on small quantities of material are run inevitably at lower than optimal concentrations. Access to late-stage material limits extensive optimization. Impurities from past reactions can interfere, especially with catalytic reactions. Therefore, chemical reactions on which one can rely at the front lines of a complex synthesis campaign emerge from the crucible of total synthesis as robust, dependable, and widely applied. Trost conceptualized "chemoselectivity" as a reagent's selective reaction of one functional group or reactive site in preference to others ( Trost , B. M. Science 1983 , 219 , 245 ). Chemoselectivity and functional group tolerance can be evaluated quickly using robustness screens ( Collins , K. D. Nat. Chem. 2013 , 5 , 597 ). A reaction may also be characterized by its "chemofidelity", that is, its reliable reaction with a functional group in any molecular context. For example, ketone reduction by an electride (dissolving metal conditions) exhibits high chemofidelity but low chemoselectivity: it usually works, but many other functional groups are reduced at similar rates. Conversely, alkene coordination chemistry effected by π Lewis acids can exhibit high chemoselectivity ( Trost , B. M. Science 1983 , 219 , 245 ) but low chemofidelity: it can be highly selective for alkenes but sensitive to the substitution pattern ( Larionov , E. Chem. Commun. 2014 , 50 , 9816 ). In contrast, alkenes undergo reliable, robust, and diverse hydrogen atom transfer reactions from metal hydrides to generate carbon-centered radicals. Although there are many potential applications of this chemistry, its functional group tolerance, high rates, and ease of execution have led to its rapid deployment in complex synthesis campaigns. Its success derives from high chemofidelity, that is, its dependable reactivity in many molecular environments and with many alkene substitution patterns. Metal hydride H atom transfer (MHAT) reactions convert diverse, simple building blocks to more stereochemically and functionally dense products ( Crossley , S. W. M. Chem. Rev. 2016 , 116 , 8912 ). When hydrogen is returned to the metal, MHAT can be considered the radical equivalent of Brønsted acid catalysis-itself a broad reactivity paradigm. This Account summarizes our group's contributions to method development, reagent discovery, and mechanistic interrogation. Our earliest contribution to this area-a stepwise hydrogenation with high chemoselectivity and high chemofidelity-has found application to many problems. More recently, we reported the first examples of dual-catalytic cross-couplings that rely on the merger of MHAT cycles and nickel catalysis. With time, we anticipate that MHAT will become a staple of chemical synthesis.
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Affiliation(s)
- Samantha A. Green
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Steven W. M. Crossley
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Jeishla L. M. Matos
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Suhelen Vásquez-Céspedes
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Sophia L. Shevick
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Ryan A. Shenvi
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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