1
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Kang H, Torruellas C, Kozlowski MC. Asymmetric Total Synthesis of Chaetoglobin A. J Org Chem 2023; 88:6691-6703. [PMID: 37195069 PMCID: PMC10411588 DOI: 10.1021/acs.joc.3c00002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
An asymmetric total synthesis of chaetoglobin A was achieved. Atroposelective oxidative coupling of a phenol incorporating all but one carbon of the final product was used as a key step to generate axial chirality. The stereochemical outcome of the catalytic oxidative phenolic with the highly substituted phenol used herein was found to be opposite that of the simpler congeners reported previously, providing a cautionary tale about extrapolating asymmetric processes from simple to more complex substrates. Optimization of the postphenolic coupling steps including formylation, oxidative dearomatization, and selective deprotection steps are outlined. The tertiary acetates of chaetoglobin A were exceptionally labile due to activation by the adjacent keto groups, which complicated each of these steps. In contrast, the final oxygen to nitrogen exchange proceeded readily and the spectroscopic data from the synthetic material matches that of the isolated natural product in all respects.
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Affiliation(s)
- Houng Kang
- Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Chemistry Education, Chungbuk National University, Cheongju, Chungbuk 28644, South Korea
| | - Carilyn Torruellas
- Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Marisa C. Kozlowski
- Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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2
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Sánchez‐Muñoz GK, Ortega‐Rojas MA, Chavelas‐Hernández L, Razo‐Hernández RS, Valdéz‐Camacho JR, Escalante J. Solvent‐Free Lipase‐Catalyzed Transesterification of Alcohols with Methyl Esters Under Vacuum‐Assisted Conditions. ChemistrySelect 2022. [DOI: 10.1002/slct.202202643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Grecia K. Sánchez‐Muñoz
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigaciones Químicas Universidad Autónoma del Estado de Morelos Av. Universidad No. 1001, Col. Chamilpa C.P. 62210 Cuernavaca Morelos México
| | - Marina A. Ortega‐Rojas
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigaciones Químicas Universidad Autónoma del Estado de Morelos Av. Universidad No. 1001, Col. Chamilpa C.P. 62210 Cuernavaca Morelos México
| | - Leticia Chavelas‐Hernández
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigaciones Químicas Universidad Autónoma del Estado de Morelos Av. Universidad No. 1001, Col. Chamilpa C.P. 62210 Cuernavaca Morelos México
| | - Rodrigo S. Razo‐Hernández
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigación en Dinámica Celular Universidad Autónoma del Estado de Morelos Av. Universidad No. 1001, Col. Chamilpa C.P. 62210 Cuernavaca Morelos México
| | - Jonathan R. Valdéz‐Camacho
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigaciones Químicas Universidad Autónoma del Estado de Morelos Av. Universidad No. 1001, Col. Chamilpa C.P. 62210 Cuernavaca Morelos México
| | - Jaime Escalante
- Instituto de Investigación en Ciencias Básicas y Aplicadas, Centro de Investigaciones Químicas Universidad Autónoma del Estado de Morelos Av. Universidad No. 1001, Col. Chamilpa C.P. 62210 Cuernavaca Morelos México
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3
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Gurawa A, Kumar M, Kashyap S. Me 3SI-promoted chemoselective deacetylation: a general and mild protocol. RSC Adv 2021; 11:19310-19315. [PMID: 35478635 PMCID: PMC9033574 DOI: 10.1039/d1ra03209g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 05/16/2021] [Indexed: 11/21/2022] Open
Abstract
A catalytic and practical approach for the selective removal of acetyl groups using various substrates bearing orthogonal moieties has been demonstrated under ambient conditions.
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Affiliation(s)
- Aakanksha Gurawa
- Carbohydrate Chemistry Research Laboratory (CCRL)
- Department of Chemistry
- Malaviya National Institute of Technology Jaipur, (MNIT)
- Jaipur-302017
- India
| | - Manoj Kumar
- Carbohydrate Chemistry Research Laboratory (CCRL)
- Department of Chemistry
- Malaviya National Institute of Technology Jaipur, (MNIT)
- Jaipur-302017
- India
| | - Sudhir Kashyap
- Carbohydrate Chemistry Research Laboratory (CCRL)
- Department of Chemistry
- Malaviya National Institute of Technology Jaipur, (MNIT)
- Jaipur-302017
- India
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4
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Wosniok PR, Knopf C, Dreisigacker S, Orozco‐Rodriguez JM, Hinkelmann B, Mueller PP, Brönstrup M, Menche D. SAR Studies of the Leupyrrins: Design and Total Synthesis of Highly Potent Simplified Leupylogs. Chemistry 2020; 26:15074-15078. [PMID: 32608026 PMCID: PMC7756798 DOI: 10.1002/chem.202002622] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Indexed: 02/01/2023]
Abstract
Leupyrrins are highly potent antifungal agents. A structure-activity-relationship study of natural and synthetic derivatives is reported which reveals important insights into the biological relevance of several structural subunits leading to the discovery of highly potent but drastically simplified leupylogs that incorporate a stable and readily available aromatic side chain. For their synthesis a concise strategy is described that enables a short and versatile access.
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Affiliation(s)
- Paul R. Wosniok
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Str. 153121BonnGermany
- Current address: Eurofins Umwelt West GmbH Wesseling, Vorgebirgsstrasse 20, 50389 Wesseling, Germany
| | - Christopher Knopf
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Str. 153121BonnGermany
- Current address: Eurofins Umwelt West GmbH Wesseling, Eurofins Genomics Europe Synthesis GmbH, Anzinger Str. 7a, 85560 Ebersberg, Germany
| | - Sandra Dreisigacker
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Str. 153121BonnGermany
- Current address: HWI pharma services GmbHRheinzaberner Straße 876761RuelzheimGermany
| | | | - Bettina Hinkelmann
- Helmholtz Centre for Infection ResearchInhoffenstraße 738124BraunschweigGermany
| | - Peter P. Mueller
- Helmholtz Centre for Infection ResearchInhoffenstraße 738124BraunschweigGermany
| | - Mark Brönstrup
- Helmholtz Centre for Infection ResearchInhoffenstraße 738124BraunschweigGermany
| | - Dirk Menche
- Kekulé-Institut für Organische Chemie und BiochemieUniversität BonnGerhard-Domagk-Str. 153121BonnGermany
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5
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Ni M, Guerrini M, Naggi A, Petitou M. Efficient selective deacetylation of complex oligosaccharides using the neutral organotin catalyst [tBu 2SnOH(Cl)] 2. Carbohydr Res 2020; 498:108172. [PMID: 33099244 DOI: 10.1016/j.carres.2020.108172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/29/2020] [Accepted: 10/05/2020] [Indexed: 11/20/2022]
Abstract
Tetra-tert-butyl-3-chloro-1-hydroxydistannoxane has been found to selectively cleave with high efficiency primary acetates on complex oligosaccharides containing esterified l-iduronic acid and bearing an anomeric acetate. This tin based catalyst was found much more effective than magnesium methoxide to carry out selective deacetylation.
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Affiliation(s)
- Minghong Ni
- Istituto di Ricerche Chimiche e Biochimiche G. Ronzoni, Via G. Colombo, 81, 20133, Milan, Italy.
| | - Marco Guerrini
- Istituto di Ricerche Chimiche e Biochimiche G. Ronzoni, Via G. Colombo, 81, 20133, Milan, Italy.
| | - Annamaria Naggi
- Istituto di Ricerche Chimiche e Biochimiche G. Ronzoni, Via G. Colombo, 81, 20133, Milan, Italy.
| | - Maurice Petitou
- Istituto di Ricerche Chimiche e Biochimiche G. Ronzoni, Via G. Colombo, 81, 20133, Milan, Italy.
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6
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Abstract
The synthesis of strophasterols C, E, and F has been accomplished from a 14,15-secoergostane derivative via a 1,3-dipolar cycloaddition of a nitrile oxide intermediate to simultaneously install an isolated cyclopentane ring and a C23 oxygen functionality in a diastereoselective manner and a regio- and diastereoselective selenohydroxylation of an olefinic intermediate under thermodynamic conditions. This synthesis also enabled the stereochemical confirmation of strophasterol C.
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Affiliation(s)
- Shuntaro Sato
- Laboratory of Applied Bioorganic Chemistry, Graduate School of Agricultural Science , Tohoku University , 468-1 Aramaki Aza-Aoba , Aoba-ku, Sendai 980-8572 , Japan
| | - Shigefumi Kuwahara
- Laboratory of Applied Bioorganic Chemistry, Graduate School of Agricultural Science , Tohoku University , 468-1 Aramaki Aza-Aoba , Aoba-ku, Sendai 980-8572 , Japan
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7
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Yan Z, Zhao C, Gong J, Yang Z. Asymmetric Total Synthesis of (−)-Guignardones A and B. Org Lett 2020; 22:1644-1647. [DOI: 10.1021/acs.orglett.0c00241] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Zhiming Yan
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Chunbo Zhao
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Jianxian Gong
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Zhen Yang
- State Key Laboratory of Chemical Oncogenomics, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
- Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education and Beijing National Laboratory for Molecular Science (BNLMS), and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
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8
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Gurawa A, Kumar M, Rao DS, Kashyap S. KMnO 4-catalyzed chemoselective deprotection of acetate and controllable deacetylation–oxidation in one pot. NEW J CHEM 2020. [DOI: 10.1039/d0nj04321d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A highly chemoselective and facile protocol for deacetylation of a diverse range of substrates tolerating several sensitive functionalities was accomplished under environmentally friendly conditions.
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Affiliation(s)
- Aakanksha Gurawa
- Carbohydrate Chemistry Research Laboratory (CCRL)
- Department of Chemistry
- Malaviya National Institute of Technology
- Jaipur-302017
- India
| | - Manoj Kumar
- Carbohydrate Chemistry Research Laboratory (CCRL)
- Department of Chemistry
- Malaviya National Institute of Technology
- Jaipur-302017
- India
| | - Dodla S. Rao
- Carbohydrate Chemistry Research Laboratory (CCRL)
- Department of Chemistry
- Malaviya National Institute of Technology
- Jaipur-302017
- India
| | - Sudhir Kashyap
- Carbohydrate Chemistry Research Laboratory (CCRL)
- Department of Chemistry
- Malaviya National Institute of Technology
- Jaipur-302017
- India
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9
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Komissarova NG, Dubovitskii SN, Orlov AV, Shitikova OV. New Conjugates of Betulin with 2-Aminoethanesulfonic Acid. Chem Nat Compd 2019. [DOI: 10.1007/s10600-019-02672-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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10
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Tanaka N, Kurita M, Murakami Y, Usuki T. Chichibabin and IsoChichibabin Pyridinium Syntheses of Isodesmosine, Desmosine, and their Derivatives. European J Org Chem 2018. [DOI: 10.1002/ejoc.201801156] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Nao Tanaka
- Department of Materials and Life Sciences; Faculty of Science and Technology; Sophia University; 7-1 Kioicho 102-8554 Chiyoda-ku Tokyo Japan
| | - Manami Kurita
- Department of Materials and Life Sciences; Faculty of Science and Technology; Sophia University; 7-1 Kioicho 102-8554 Chiyoda-ku Tokyo Japan
| | - Yuko Murakami
- Department of Materials and Life Sciences; Faculty of Science and Technology; Sophia University; 7-1 Kioicho 102-8554 Chiyoda-ku Tokyo Japan
| | - Toyonobu Usuki
- Department of Materials and Life Sciences; Faculty of Science and Technology; Sophia University; 7-1 Kioicho 102-8554 Chiyoda-ku Tokyo Japan
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11
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Kang H, Torruellas C, Liu J, Kozlowski MC. Total Synthesis of Chaetoglobin A via Catalytic, Atroposelective Oxidative Phenol Coupling. Org Lett 2018; 20:5554-5558. [PMID: 30207731 DOI: 10.1021/acs.orglett.8b02183] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The first total synthesis of chaetoglobin A (1), which features a chiral axis between two identical highly oxygenated bicyclic cores, was successfully completed in 12 steps from 2,6-dimethoxytoluene. Vanadium-catalyzed oxidative phenol coupling, as a key step, enabled generation of the axial chirality.
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Affiliation(s)
- Houng Kang
- Department of Chemistry, Roy and Diana Vagelos Laboratories , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Carilyn Torruellas
- U.S. Army Edgewood Chemical Biological Center , RDCB-DRC-P/Building E3400 , Aberdeen Proving Ground , Maryland 21010-5424 , United States
| | - Jinchu Liu
- Department of Process Research and Development , Merck Research Laboratories , Rahway , New Jersey 07065 , United States
| | - Marisa C Kozlowski
- Department of Chemistry, Roy and Diana Vagelos Laboratories , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
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12
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Shen GH, Hong JH. Recent advances in the synthesis of cyclic 5′-nornucleoside phosphonate analogues. Carbohydr Res 2018; 463:47-106. [DOI: 10.1016/j.carres.2018.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 03/22/2018] [Accepted: 04/17/2018] [Indexed: 10/17/2022]
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13
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Pettit GR, Melody N, Chapuis JC. Antineoplastic Agents. 606. The Betulastatins. JOURNAL OF NATURAL PRODUCTS 2018; 81:458-464. [PMID: 29303263 DOI: 10.1021/acs.jnatprod.7b00536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The medicinal potential of the plant pentacyclic triterpene betulin has generated long-term interest focused on various SAR research avenues. The present approach was based on producing further analogues (chimeras) arising from a studied modification of betulin bonded to the Dov-Val-Dil-Dap unit of the powerful anticancer drug dolastatin 10, which provided betulastatins 1 (7b), 2 (11b), 3 (16b), and 4 (18b). Betulastatin 1, 2, and 4 exhibited modest levels of cancer cell growth inhibition against six cancer cell lines. Betulastatin 3 proved to be the most potent cancer cell growth inhibitor (GI50 0.01 μg/mL) and seems worthy of further development, as the presumed mixture of anticancer mechanisms of action may prove to be useful.
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Affiliation(s)
- George R Pettit
- Department of Chemistry and Biochemistry , Arizona State University , P.O. Box 871604, Tempe , Arizona 85287-1604 , United States
| | - Noeleen Melody
- Department of Chemistry and Biochemistry , Arizona State University , P.O. Box 871604, Tempe , Arizona 85287-1604 , United States
| | - Jean-Charles Chapuis
- Department of Chemistry and Biochemistry , Arizona State University , P.O. Box 871604, Tempe , Arizona 85287-1604 , United States
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14
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De S, De Jonghe S, Herdewijn P. Synthesis of a 3′-Fluoro-3′-deoxytetrose Adenine Phosphonate. J Org Chem 2017; 82:9464-9478. [DOI: 10.1021/acs.joc.7b01482] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Swarup De
- Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
| | - Steven De Jonghe
- Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
| | - Piet Herdewijn
- Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Herestraat 49, 3000 Leuven, Belgium
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15
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Khong DT, Judeh ZMA. Total synthesis of phenylpropanoid glycoside osmanthuside-B6 facilitated by double isomerisation of glucose–rhamnose orthoesters. Org Biomol Chem 2017; 15:2638-2646. [DOI: 10.1039/c7ob00198c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Osmanthuside-B6 was synthesized in 22% overall yield. The synthesis involved a newly discovered glucose–rhamnose orthoester double isomerization process.
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Affiliation(s)
- Duc Thinh Khong
- School of Chemical and Biomedical Engineering
- Nanyang Technological University
- Singapore 637459
- Singapore
| | - Zaher M. A. Judeh
- School of Chemical and Biomedical Engineering
- Nanyang Technological University
- Singapore 637459
- Singapore
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16
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Scott AE, Christ WJ, George AJ, Stokes MGM, Lohman GJS, Guo Y, Jones M, Titball RW, Atkins TP, Campbell AS, Prior JL. Protection against Experimental Melioidosis with a Synthetic manno-Heptopyranose Hexasaccharide Glycoconjugate. Bioconjug Chem 2016; 27:1435-46. [PMID: 27124182 PMCID: PMC4911622 DOI: 10.1021/acs.bioconjchem.5b00525] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
Melioidosis is an emerging infectious
disease caused by Burkholderia pseudomallei and is associated with
high morbidity and mortality rates in endemic areas. Antibiotic treatment
is protracted and not always successful; even with appropriate therapy,
up to 40% of individuals presenting with melioidosis in Thailand succumb
to infection. In these circumstances, an effective vaccine has the
potential to have a dramatic impact on both the scale and the severity
of disease. Currently, no vaccines are licensed for human use. A leading
vaccine candidate is the capsular polysaccharide consisting of a homopolymer
of unbranched 1→3 linked 2-O-acetyl-6-deoxy-β-d-manno-heptopyranose. Here, we present the
chemical synthesis of this challenging antigen using a novel modular
disaccharide assembly approach. The resulting hexasaccharide was coupled
to the nontoxic Hc domain of tetanus toxin as a carrier
protein to promote recruitment of T-cell help and provide a scaffold
for antigen display. Mice immunized with the glycoconjugate developed
IgM and IgG responses capable of recognizing native capsule, and were
protected against infection with over 120 × LD50 of B. pseudomallei strain K96243. This is the first
report of the chemical synthesis of an immunologically relevant and
protective hexasaccharide fragment of the capsular polysaccharide
of B. pseudomallei and serves as the
rational starting point for the development of an effective licensed
vaccine for this emerging infectious disease.
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Affiliation(s)
- Andrew E Scott
- Defence Science and Technology Laboratory , Porton Down, Salisbury, Wiltshire SP4 0JQ, United Kingdom
| | - William J Christ
- Corden Pharma International Inc. (formerly Ancora Pharmaceuticals Inc.) , Woburn, Massachusetts 01801 United States
| | - Alison J George
- Defence Science and Technology Laboratory , Porton Down, Salisbury, Wiltshire SP4 0JQ, United Kingdom
| | - Margaret G M Stokes
- Defence Science and Technology Laboratory , Porton Down, Salisbury, Wiltshire SP4 0JQ, United Kingdom
| | - Gregory J S Lohman
- Corden Pharma International Inc. (formerly Ancora Pharmaceuticals Inc.) , Woburn, Massachusetts 01801 United States
| | - Yuhong Guo
- Corden Pharma International Inc. (formerly Ancora Pharmaceuticals Inc.) , Woburn, Massachusetts 01801 United States
| | - Matthew Jones
- Corden Pharma International Inc. (formerly Ancora Pharmaceuticals Inc.) , Woburn, Massachusetts 01801 United States
| | - Richard W Titball
- College of Life and Environmental Sciences, University of Exeter , Exeter, Devon EX4 4QD, United Kingdom
| | - Timothy P Atkins
- Defence Science and Technology Laboratory , Porton Down, Salisbury, Wiltshire SP4 0JQ, United Kingdom
| | - A Stewart Campbell
- Corden Pharma International Inc. (formerly Ancora Pharmaceuticals Inc.) , Woburn, Massachusetts 01801 United States
| | - Joann L Prior
- Defence Science and Technology Laboratory , Porton Down, Salisbury, Wiltshire SP4 0JQ, United Kingdom
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17
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Liu CY, Chen HL, Ko CM, Chen CT. Chemoselective deacylation of functionalized esters catalyzed by dioxomolybdenum dichloride. Tetrahedron 2011. [DOI: 10.1016/j.tet.2010.12.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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18
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19
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Morley TJ, Withers SG. Chemoenzymatic synthesis and enzymatic analysis of 8-modified cytidine monophosphate-sialic acid and sialyl lactose derivatives. J Am Chem Soc 2010; 132:9430-7. [PMID: 20557044 DOI: 10.1021/ja102644a] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The sialic acids found on eukaryotic glycans have remarkably diverse core structures, with a range of modifications at C5, C7, C8 and C9. These carbohydrates have been found to play key roles in cell-cell interactions within eukaryotes and often serve as the initial site of attachment for viruses and bacteria. Consequently simple changes to the structures of the sialic acids can result in profoundly different and often opposing biological effects. Of particular importance are modifications at the 8-position. These include O-acetylation, carried out by an acetyl transferase, and particularly polysialylation, catalyzed by a polysialyltransferase. As part of a structural and mechanistic study of sialyltransferases and polysialyltransferases, access was needed to sialic acid-containing oligosaccharides that are modified at the 8-position of the sialic acid to render this center non-nucleophilic. The free 8-modified sialic acid analogues were synthesized using a concise, divergent chemical synthetic approach, and each was converted to its cytidine monophosphate (CMP) sugar donor form using a bacterial CMP-sialic acid synthetase. The transfer of each of the modified donors to lactose by each of two sialyltransferases was investigated, and kinetic parameters were determined. These yielded insights into the roles of interactions occurring at that position during enzymatic sialyl transfer. A transferase from Campylobacter jejuni was identified as the most suitable for the enzymatic coupling and utilized to synthesize the 8''-modified sialyl lactose trisaccharides in multimilligram amounts.
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Affiliation(s)
- Thomas J Morley
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver V6T 1Z1, Canada
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20
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Singh S, Duffy CD, Shah STA, Guiry PJ. ZrCl4 as an efficient catalyst for a novel one-pot protection/deprotection synthetic methodology. J Org Chem 2008; 73:6429-32. [PMID: 18642872 DOI: 10.1021/jo800932t] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A catalytic quantity of ZrCl 4 (20 mol %) was found to be an efficient catalyst for the one-pot esterification and deprotection of (5 S,6 R)-5,6-diacetoxyoct-7-enoic acid in good yields (44-62%) with a lactone formed as a minor byproduct. ZrCl 4 (10-20 mol %) was also sufficient to deprotect 1,3-dioxalane, bis-TBDMS ethers, and diacetate functional groups in excellent yields of up to 93%. ZrCl 4 (1-10 mol %) also promoted diol protection as the acetonide in 90% yield and acted as a trans-esterification catalyst for a range of esters.
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Affiliation(s)
- Surendra Singh
- Centre for Synthesis and Chemical Biology, School of Chemistry and Chemical Biology, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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21
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Thibeault D, Gauthier C, Legault J, Bouchard J, Dufour P, Pichette A. Synthesis and structure–activity relationship study of cytotoxic germanicane- and lupane-type 3β-O-monodesmosidic saponins starting from betulin. Bioorg Med Chem 2007; 15:6144-57. [PMID: 17614290 DOI: 10.1016/j.bmc.2007.06.033] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 06/11/2007] [Accepted: 06/13/2007] [Indexed: 10/23/2022]
Abstract
Germanicane-type triterpenes allobetulin (3) and 28-oxoallobetulin (4) can be obtained by the Wagner-Meerwein rearrangement of the more available lupane-type triterpenes betulin (1) and betulinic acid (2), respectively. The medical uses of betulinic acid (2) and its derivatives are limited because of their poor hydrosolubility and pharmacokinetics properties. In order to overcome this major problem, we synthesized and studied the in vitro anticancer activity of a series of 3beta-O-monodesmosidic saponins derived from betulin (14-16), betulinic acid (20-22), allobetulin (23-28) and 28-oxoallobetulin (29-34) based on six different natural sugar residues (d-glucose, l-rhamnose, d-arabinose, d-galactose, d-mannose and d-xylose). This structure-activity relationship study confirmed that betulinic acid saponins are generally better in vitro anticancer agents than those derived from betulin with the exception of betulin 3beta-O-alpha-d-mannopyranoside (15) which exerted a potent cytotoxic activity against lung carcinoma (A-549) and colorectal adenocarcinoma (DLD-1) human cell lines with IC(50) ranging from 7.3 to 10.1mumol/L. Furthermore, although the synthesis of novel germanicane-type saponins was carried out with success, the bioactivity measured for these glycosides was not as high as we anticipated since only the 3beta-O-beta-d-glucopyranoside and 3beta-O-beta-d-galactopyranoside of allobetulin (23,24) showed moderate anticancer activity (IC(50) 30-40 micromol/L).
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Affiliation(s)
- Dominic Thibeault
- Laboratoire d'Analyse et de Séparation des Essences Végétales, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, 555 boul. de l'Université, Chicoutimi, Québec, Canada
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22
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23
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Gauthier C, Legault J, Lebrun M, Dufour P, Pichette A. Glycosidation of lupane-type triterpenoids as potent in vitro cytotoxic agents. Bioorg Med Chem 2006; 14:6713-25. [PMID: 16787747 DOI: 10.1016/j.bmc.2006.05.075] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Revised: 05/26/2006] [Accepted: 05/30/2006] [Indexed: 11/20/2022]
Abstract
The weak hydrosolubility of betulinic acid (3) hampers the clinical development of this natural anticancer agent. In order to circumvent this problem and to enhance the pharmacological properties of betulinic acid (3) and the lupane-type triterpenes lupeol (1), betulin (2), and methyl betulinate (7), glycosides (beta-D-glucosides, alpha-L-rhamnosides, and alpha-D-arabinosides) were synthesized and in vitro tested for cytotoxicity against three cancerous (A-549, DLD-1, and B16-F1) and one healthy (WS1) cell lines. The addition of a sugar moiety at the C-3 or C-28 position of betulin (2) resulted in a loss of cytotoxicity. In contrast, the 3-O-beta-D-glucosidation of lupeol (1) improved the activity by 7- to 12-fold (IC50 14-15.0 microM). Moreover, the results showed that cancer cell lines are 8- to 12-fold more sensitive to the 3-O-alpha-L-rhamnopyranoside derivative of betulinic acid (IC50 2.6-3.9 microM, 22) than the healthy cells (IC50 31 microM). Thus, this study indicates that 3-O-glycosides of lupane-type triterpenoids represent an interesting class of potent in vitro cytotoxic agents.
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Affiliation(s)
- Charles Gauthier
- Laboratoire LASEVE, Département des Sciences Fondamentales, UQAC, Chicoutimi, Québec, Canada G7H 2B1
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24
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Krauser JA, Guengerich FP. Cytochrome P450 3A4-catalyzed Testosterone 6β-Hydroxylation Stereochemistry, Kinetic Deuterium Isotope Effects, and Rate-limiting Steps. J Biol Chem 2005; 280:19496-506. [PMID: 15772082 DOI: 10.1074/jbc.m501854200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Testosterone 6beta-hydroxylation is a prototypic reaction of cytochrome P450 (P450) 3A4, the major human P450. Biomimetic reactions produced a variety of testosterone oxidation products with 6beta-hydroxylation being only a minor reaction, indicating that P450 3A4 has considerable control over the course of steroid hydroxylation because 6beta-hydroxylation is not dominant in a thermodynamically controlled oxidation of the substrate. Several isotopically labeled testosterone substrates were prepared and used to probe the catalytic mechanism of P450 3A4: (i) 2,2,4,6,6-(2)H(5); (ii) 6,6-(2)H(2); (iii) 6alpha-(2)H; (iv) 6beta-(2)H; and (v) 6beta-(3)H testosterone. Only the 6beta-hydrogen was removed by P450 3A4 and not the 6alpha, indicating that P450 3A4 abstracts hydrogen and rebounds oxygen only at the beta face. Analysis of the rates of hydroxylation of 6beta-(1)H-, 6beta-(2)H-, and 6beta-(3)H-labeled testosterone and application of the Northrop method yielded an apparent intrinsic kinetic deuterium isotope effect ((D)k) of 15. The deuterium isotope effects on k(cat) and k(cat)/K(m) in non-competitive reactions were only 2-3. Some "switching" to other hydroxylations occurred because of 6beta-(2)H substitution. The high (D)k value is consistent with an initial hydrogen atom abstraction reaction. Attenuation of the high (D)k in the non-competitive experiments implies that C-H bond breaking is not a dominant rate-limiting step. Considerable attenuation of a high (D)k value was also seen with a slower P450 3A4 reaction, the O-dealkylation of 7-benzyloxyquinoline. Thus P450 3A4 is an enzyme with regioselective flexibility but also considerable regioselectivity and stereoselectivity in product formation, not necessarily dominated by the ease of C-H bond breaking.
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Affiliation(s)
- Joel A Krauser
- Department of Biochemistry and Center in Molecular Toxicology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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25
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Madhusudan SK, Agnihotri G, Negi DS, Misra AK. Direct one-pot conversion of acylated carbohydrates into their alkylated derivatives under heterogeneous reaction conditions using solid NaOH and a phase transfer catalyst. Carbohydr Res 2005; 340:1373-7. [PMID: 15854608 DOI: 10.1016/j.carres.2005.03.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2005] [Revised: 03/17/2005] [Accepted: 03/28/2005] [Indexed: 11/17/2022]
Abstract
A convenient one-pot protocol for the direct conversion of acyl-protected carbohydrates into their alkylated counterparts has been developed by using alkyl halides in the presence of solid sodium hydroxide and a phase transfer catalyst. These economically convenient, mild, two-phase reaction conditions allow the preparation of a variety of monosaccharide intermediates for use in the synthesis of complex oligosaccharides.
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Affiliation(s)
- Soni Kamlesh Madhusudan
- Medicinal and Process Chemistry Division, Central Drug Research Institute (CDRI), Chattar Manzil Palace, Lucknow 226 001, UP, India
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Nicholas GM, Eckman LL, Kovác P, Otero-Quintero S, Bewley CA. Synthesis of 1-D- and 1-L-myo-inosityl 2-N-acetamido-2-deoxy-alpha-D-glucopyranoside establishes substrate specificity of the Mycobacterium tuberculosis enzyme AcGI deacetylase. Bioorg Med Chem 2003; 11:2641-7. [PMID: 12757730 DOI: 10.1016/s0968-0896(03)00154-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mycothiol (MSH, 1-D-myo-inosityl 2-(N-acetyl-L-cysteinyl)amido-2-deoxy-alpha-D-glucopyranoside) is the principal low molecular weight thiol in actinomycetes. The enzyme 1-D-myo-inosityl 2-N-acetamido-2-deoxy-alpha-D-glucopyranoside deacetylase (AcGI deacetylase) is involved in the biosynthesis of MSH and forms the free amine 1-D-myo-inosityl 2-amino-2-deoxy-alpha-D-glucopyranoside, which is used in the third of four steps of MSH biosynthesis. Here, we report the synthesis of two isomers of AcGI, which contain either 1-L-myo-inositol or 1-D-myo-inositol. These synthetic products were used to investigate substrate specificity of the Mycobacterium tuberculosis enzyme AcGI deacetylase.
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Affiliation(s)
- Gillian M Nicholas
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, USA
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Ma D, Yang J. Total synthesis of kaitocephalin, the first naturally occurring AMPA/KA receptor antagonist. J Am Chem Soc 2001; 123:9706-7. [PMID: 11572705 DOI: 10.1021/ja016403w] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- D Ma
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
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Orita A, Hamada Y, Nakano T, Toyoshima S, Otera J. Highly efficient deacetylation by use of the neutral organotin catalyst [tBu2SnOH(Cl)]2. Chemistry 2001; 7:3321-7. [PMID: 11531118 DOI: 10.1002/1521-3765(20010803)7:15<3321::aid-chem3321>3.0.co;2-h] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Deprotection of acetyl esters is effected cleanly by the neutral organotin catalyst, [tBu2SnOH(Cl)]2. The mildness of the reaction gives rise to great synthetic versatility and in the process a variety of functional groups are tolerated. Differentiations between primary, secondary, and tertiary alcohols and between acetyl ester and other esters are feasible. No racemization occurs with chiral acetyl esters. Exclusive deprotection of primary acetyl esters in carbohydrates and nucleosides is observed. The crude product thus obtained can be used for further reactions without purification.
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Affiliation(s)
- A Orita
- Department of Applied Chemistry, Okayama University of Science, Japan
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Abstract
A new approach to the asymmetric synthesis of pentadeca-1,3,5,7,9,11,13,15-octols and their derivatives is presented. It is based on the Sharpless asymmetric dihydroxylation (AD) of 4,4'-methylene[(1R,1'S,6R,6'S)-6-acetoxycyclohept-3-en-1-yl]bis(4-methoxybenzoate) (9), derived from a double [3+4] cycloaddition of the 1,1,3-trichloro-2-oxyallyl cation with 2,2'-methylenedifuran (1). The diol (-)-10, obtained in 98.4% ee from 9 with "AD-mix-beta(5x), was oxidised into (2R and 2S,4S,6R)-tetrahydro-2-hydroxy-6-((4S,6S)-(6-hydroxy-4-[(4-methoxybenzoyl)oxy]cyclohept-1-en-1-yl)-2-oxopropyl)-2H-pyran-4-yl 4-methoxybenzoates ((-)-18). By the combinations of Evans' anti and Nasaraka's syn reductions of aldol (-)-18 with the double Mitsunobu reaction, 16 diastereomeric pentadeca-1,3,5,7,9,11,13,15-octols and analogues can be obtained, in principle, with high enantio- and diastereoselectivities.
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Affiliation(s)
- M E Schwenter
- Section de chimie de l'Université, Lausanne-Dorigny, Switzerland
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Harris PW, Woodgate PD. Functionalisation of Alkylalkoxysilanes. Studies Towards Annulations of Diterpenoids. Tetrahedron 2000. [DOI: 10.1016/s0040-4020(00)00302-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Sammakia T, Jacobs JS. Picolinic acid as a partner in the Mitsunobu reaction: Subsequent hydrolysis of picolinate esters under essentially neutral conditions with copper acetate in methanol. Tetrahedron Lett 1999. [DOI: 10.1016/s0040-4039(99)00332-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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