1
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Carlson E, Tam W. Type 1 Ring-Opening Reactions of Cyclopropanated 7-Azabenzonorbornadienes with Organocuprates. Org Lett 2016; 18:2134-7. [PMID: 27055059 DOI: 10.1021/acs.orglett.6b00757] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The first nucleophilic ring-opening reactions of cyclopropanated 7-azabenzonorbornadienes have been achieved using organocuprates. Tricyclic or tetracyclic γ-lactams were obtained as the sole product in good yields of up to 98% when alkoxycarbonyl groups occupied the N-substituent position. Successful conversions to lactams were observed for primary, secondary, tertiary, and aromatic nucleophiles, as well as for a variety of substrates functionalized on the benzene ring. A possible mechanism for these transformations is discussed.
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Affiliation(s)
- Emily Carlson
- Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
| | - William Tam
- Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry, University of Guelph , Guelph, Ontario N1G 2W1, Canada
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2
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Gibson S, Fernando R, Jacobs HK, Gopalan AS. Preparation of 3-benzyloxy-2-pyridinone functional linkers: Tools for the synthesis of 3,2-hydroxypyridinone (HOPO) and HOPO/hydroxamic acid chelators. Tetrahedron 2015; 71:9271-9281. [PMID: 26640304 PMCID: PMC4665106 DOI: 10.1016/j.tet.2015.10.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
In contrast to 2,3-dihydroxypyridine, the 3-benzyloxy protected derivative, 2, undergoes facile alkylation at ambient temperatures with a variety of functionalized alkyl halides in good yields. This alkylation has been used to prepare a number of linkers that permit the attachment of 3,2-HOPO moieties onto various scaffolds using a wide range of coupling methods. The Mitsunobu reaction of 2 with representative alcohols was found to be of limited value due to competing O-alkylation that led to product mixtures. The phthalimide 3j can be converted in two steps to HOPO isocyanate 6 in excellent yields. Isocyanate 6 can be coupled to amines at room temperature or to alcohols in refluxing dichloroethane to obtain the corresponding urea or carbamate linked ligand systems. The coupling of isocyanate 6 with TREN followed by deprotection gave the tris-HOPO 10, an interesting target as it has both cationic and anionic binding sites. The HOPO hydroxylamine linker 11 was shown to be especially valuable as its coupling with carboxylic acids proceeds with the concomitant generation of an additional hydroxamate ligand moiety in the framework. The utility of this linker was shown by the preparation of two mixed HOPO-hydroxamate chelators, 16 and 19, based on the structure of desferrioxamine, a well-known trihydroxamate siderophore.
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Affiliation(s)
- Sarah Gibson
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
| | - Rasika Fernando
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
| | - Hollie K. Jacobs
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
| | - Aravamudan S. Gopalan
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
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3
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Lim DSW, Lew TTS, Zhang Y. Direct Amidation of N-Boc- and N-Cbz-Protected Amines via Rhodium-Catalyzed Coupling of Arylboroxines and Carbamates. Org Lett 2015; 17:6054-7. [DOI: 10.1021/acs.orglett.5b03061] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Diane S. W. Lim
- Institute of Bioengineering and Nanotechnology, 31
Biopolis Way, The Nanos, Singapore 138669, Singapore
| | - Tedrick T. S. Lew
- Institute of Bioengineering and Nanotechnology, 31
Biopolis Way, The Nanos, Singapore 138669, Singapore
| | - Yugen Zhang
- Institute of Bioengineering and Nanotechnology, 31
Biopolis Way, The Nanos, Singapore 138669, Singapore
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4
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Pailloux SL, Nguyen S, Zhou S, Hom ME, Keyser MN, Smiles D, Raymond KN. Synthesis and chemical reactivity of a 6-Me-3,2-hydroxypyridinone dithiazolide with primary amines: a route to new hexadentate chelators for hard metal(III) ions. J Heterocycl Chem 2015; 53:1065-1073. [PMID: 27667855 DOI: 10.1002/jhet.2372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A hydroxypyridinone building block, bifunctionalized with thiazoline, has been prepared from orthogonally protected 2-(3-(benzyloxy)-4-(ethoxycarbonyl)-6-methyl-2-oxopyridin-1(2H)-yl) acetic acid. The reactivity of the dithiazolide has been explored with two primary amines, leading to the synthesis and characterization of four new hexadentate ligands. Their complexes with selected hard trivalent ions pertinent to potential molecular imaging applications have been surveyed.
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Affiliation(s)
- Sylvie L Pailloux
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Sean Nguyen
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Stephanie Zhou
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Marisa E Hom
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Michelle N Keyser
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Danil Smiles
- Department of Chemistry, University of California, Berkeley, California 94720-1460
| | - Kenneth N Raymond
- Department of Chemistry, University of California, Berkeley, California 94720-1460
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5
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Synthesis and antimalarial evaluation of prodrugs of novel fosmidomycin analogues. Bioorg Med Chem Lett 2015; 25:2112-6. [PMID: 25881827 DOI: 10.1016/j.bmcl.2015.03.077] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 03/24/2015] [Accepted: 03/25/2015] [Indexed: 01/30/2023]
Abstract
The continuous development of drug resistance by Plasmodium falciparum, the agent responsible for the most severe forms of malaria, creates the need for the development of novel drugs to fight this disease. Fosmidomycin is an effective antimalarial and potent antibiotic, known to act by inhibiting the enzyme 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR), essential for the synthesis of isoprenoids in eubacteria and plasmodia, but not in humans. In this study, novel constrained cyclic prodrug analogues of fosmidomycin were synthesized. One, in which the hydroxamate function is incorporated into a six-membered ring, was found have higher antimalarial activity than fosmidomycin against the chloroquine and mefloquine resistant P. falciparum Dd2 strain. In addition, it showed very low cytotoxicity against cultured human cells.
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6
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7
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Martinez G, Arumugam J, Jacobs HK, Gopalan AS. 3,2-Hydroxypyridinone (3,2-HOPO) vinyl sulfonamide and acrylamide linkers: Aza-Michael addition reactions and the preparation of poly-HOPO chelators. Tetrahedron Lett 2013; 54:630-634. [PMID: 23355751 PMCID: PMC3551596 DOI: 10.1016/j.tetlet.2012.11.136] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The HOPO vinyl sulfonamide 3 and the corresponding HOPO acrylamide 10, were easily prepared by short synthetic sequences. Investigation of the aza-Michael reactions of these linkers showed that they proceed at a higher rate in solvent systems containing water. The scope and limits of the aza-Michael reactions of 3 and 10 were examined. Reagents 3 and 10 reacted cleanly with piperazine to give the corresponding adducts which were deprotected to give the di-HOPO ligands 7 and 16. Reaction of HOPO acrylamide 10 with 1,4,7-triazacyclononane gave the tris-adduct 17 which was deprotected to give the desired tris-HOPO ligand 18. Overall, the aza-Michael reactions of 3 and 10 appear to be governed not only by the solvent but also by the nature of the amine and the solubility of the reaction intermediates.
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Affiliation(s)
- Gloria Martinez
- Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University, Las Cruces, NM 88003-8001 USA
| | - Jayanthi Arumugam
- Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University, Las Cruces, NM 88003-8001 USA
| | - Hollie K. Jacobs
- Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University, Las Cruces, NM 88003-8001 USA
| | - Aravamudan S. Gopalan
- Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University, Las Cruces, NM 88003-8001 USA
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8
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Young JA, Karmakar S, Jacobs HK, Gopalan AS. Synthetic approaches to mixed ligand chelators on t-butylphenol-formaldehyde oligomer (PFO) platforms. Tetrahedron 2012; 68:10030-10039. [PMID: 23226883 PMCID: PMC3513921 DOI: 10.1016/j.tet.2012.09.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Synthetic approaches to mixed ligand chelators on readily available t-butylphenol-formaldehyde oligomer, PFO, scaffolds were examined. In a promising approach, tris and tetraphenol oligomers were selectively mono or di protected using t-butyldiphenyl silyl chloride. The utility of these protected intermediates to prepare representative mixed PFO chelators, carrying ligands such as hydroxamic acid, 3,2-hydroxypyridinones and others was then demonstrated. The introduction of the ligand tethers onto the phenolic scaffold can be done sequentially under relatively mild conditions that tolerate the presence of other sensitive ligand groups. The differential reactivity of the disilyl derivative 20b, allowed stepwise introduction of two different ligands on the internal phenolic positions. This enabled the introduction of three different ligand groups of choice onto the tetra phenol platform.
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Affiliation(s)
- Jennifer A. Young
- Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University Tel: 575 646 2589; Fax: 575 646 2649
| | - Sukhen Karmakar
- Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University Tel: 575 646 2589; Fax: 575 646 2649
| | - Hollie K. Jacobs
- Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University Tel: 575 646 2589; Fax: 575 646 2649
| | - Aravamudan S. Gopalan
- Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University Tel: 575 646 2589; Fax: 575 646 2649
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9
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Fernando R, Shirley JM, Torres E, Jacobs HK, Gopalan AS. Preparation of bifunctional isocyanate hydroxamate linkers: Synthesis of carbamate and urea tethered polyhydroxamic acid chelators. Tetrahedron Lett 2012; 53:6367-6371. [PMID: 23162172 PMCID: PMC3498463 DOI: 10.1016/j.tetlet.2012.09.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Two novel bifunctional N-methylhydroxamate-isocyanate linkers 20 and 21 were prepared in good yield and high purity from the corresponding amine salts using a biphasic reaction with phosgene. The facile ring opening reaction of N-Boc lactams using the anion of O-benzylhydroxylamine gave the protected amino hydroxamates 6a and 6c in good yields. The selective methylation of the hydroxamate nitrogen in the presence of the N-Boc group in these intermediates could be readily accomplished. The utility of the linkers was clearly demonstrated by the synthesis of the carbamate-tethered trishydroxamic acid 27 and the urea-tethered 29.
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Affiliation(s)
- Rasika Fernando
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
| | - Jonathan M. Shirley
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
| | - Emilio Torres
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
| | - Hollie K. Jacobs
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
| | - Aravamudan S. Gopalan
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
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10
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Liu Y, Jacobs HK, Gopalan AS. A new approach to cyclic hydroxamic acids: Intramolecular cyclization of N-benzyloxy carbamates with carbon nucleophiles. Tetrahedron 2011; 67:2206-2214. [PMID: 21499514 DOI: 10.1016/j.tet.2011.01.073] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
N-Alkyl-N-benzyloxy carbamates, 2, undergo facile intramolecular cyclization with a variety of carbon nucleophiles to give functionalized 5- and 6-membered protected cyclic hydroxamic acids, 3, in good to excellent yields. This method can be extended to prepare seven-membered cyclic hydroxamic acids in moderate yields. The sulfone intermediates 3 from this study can be alkylated while the corresponding phosphonates have been shown to undergo HWE reaction. The α,β-unsaturated synthon, 8, prepared by thermal elimination of sulfoxide 3m, undergoes Michael addition with secondary amines. The usefulness of this approach to prepare polydentate chelators has been demonstrated by the synthesis of bis cyclic hydroxamic acids 12, 14, and 15.
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Affiliation(s)
- Yuan Liu
- Department of Chemistry and Biochemistry, MSC 3C, New Mexico State University, Las Cruces, NM 88003-8001
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11
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Arumugam J, Brown HA, Jacobs HK, Gopalan AS. New Synthetic Approach for the Incorporation of 3,2-Hydroxypyridinone (HOPO) Ligands: Synthesis of Structurally Diverse Poly HOPO Chelators. SYNTHESIS-STUTTGART 2011; 2011:57-64. [PMID: 21709749 DOI: 10.1055/s-0030-1258337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The HOPO sulfonamide reagent, 3, was prepared from commercial 2,3-dihydroxypyridine in four steps in good yields. Sulfonamide 3 readily underwent selective alkylation with dibromides in the presence of base or could be coupled to alcohols using Mitsunobu conditions. The utility of this nucleophilic HOPO reagent was demonstrated by the synthesis some tris and tetraHOPO chelators. This approach for tethering HOPO ligands is unique and flexible as shown by the preparation of HOPO/iminocarboxylic acid chelator 17.
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Affiliation(s)
- Jayanthi Arumugam
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8001
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12
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Herndon JW. The chemistry of the carbon–transition metal double and triple bond: Annual survey covering the year 2009. Coord Chem Rev 2011. [DOI: 10.1016/j.ccr.2010.07.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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