1
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Abstract
Transformations catalyzed by germanium are scarce, with examples mainly limited to widely catalyzed processes such as polymerisation of lactide and hydroboration of carbonyls. Reported is the first example of hydrophosphination using a germanium pre-catalyst, yielding anti-Markovnikov products when diphenylphosphine is reacted with styrenes or internal alkynes at room temperature.
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Affiliation(s)
- A N Barrett
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - H J Sanderson
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - M F Mahon
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - R L Webster
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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2
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Abstract
A catalytic hydrophosphination route to 1,1-diphosphines is yet to be reported: these narrow bite angle pro-ligands have been used to great effect as ligands in homogeneous catalysis. We herein demonstrate that terminal alkynes readily undergo double hydrophosphination with HPPh2 and catalytic potassium hexamethyldisilazane (KHMDS) to generate 1,1-diphosphines. A change to H2PPh leads to the formation of P,P-divinyl phosphines.
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Affiliation(s)
- N T Coles
- Department of Chemistry, University of Bath, Bath, BA2 7AY, UK.
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3
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McKeown P, Davidson MG, Lowe JP, Mahon MF, Thomas LH, Woodman TJ, Jones MD. Aminopiperidine based complexes for lactide polymerisation. Dalton Trans 2016; 45:5374-87. [DOI: 10.1039/c5dt04695e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A series of new ligands based on a 2-(aminomethyl)piperidine motif have been prepared. An interesting diversity in structure is observed, all complexes have been trialled for the polymerisation of rac-lactide.
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Affiliation(s)
- P. McKeown
- Doctoral Training Centre in Sustainable Chemical Technologies
- University of Bath
- Bath BA2 7AY
- UK
- Department of Chemistry
| | - M. G. Davidson
- Doctoral Training Centre in Sustainable Chemical Technologies
- University of Bath
- Bath BA2 7AY
- UK
- Department of Chemistry
| | - J. P. Lowe
- Department of Chemistry
- University of Bath
- Bath BA2 7AY
- UK
| | - M. F. Mahon
- Crystallography Centre
- Department of Chemistry
- University of Bath
- Bath BA2 7AY
- UK
| | - L. H. Thomas
- Department of Chemistry
- University of Bath
- Bath BA2 7AY
- UK
| | - T. J. Woodman
- Doctoral Training Centre in Sustainable Chemical Technologies
- University of Bath
- Bath BA2 7AY
- UK
| | - M. D. Jones
- Department of Chemistry
- University of Bath
- Bath BA2 7AY
- UK
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4
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Abstract
A series of copper(i) malonamide complexes have been synthesised and their catalytic activity explored in 1,3-dipolar cycloaddition reactions: the first time this ligand motif has been reported in a catalytic transformation.
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Affiliation(s)
- S. J. Bent
- Department of Chemistry
- University of Bath
- Bath
- UK
| | - M. F. Mahon
- Department of Chemistry
- University of Bath
- Bath
- UK
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5
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Sparkes HA, Mahon MF, Raithby PR, Allen FH, Shields GP. Carbonyl-carbonyl interactions in first-row transition metal complexes. Acta Crystallogr A 2005. [DOI: 10.1107/s010876730507995x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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6
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Burrows AD, Burke NJ, Harrington RW, Mahon MF, Teat SJ. Structural manipulation of hydrogen-bonded networks – inclusion of metal centres and chromophores and response to loss of symmetry. Acta Crystallogr A 2004. [DOI: 10.1107/s0108767304097879] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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7
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Hague C, Patmore NJ, Frost CG, Mahon MF, Weller AS. [(PPh3)Ag(CB11H6Y6)] (Y = H, Br): highly active, selective and recyclable Lewis acids for a hetero-Diels-Alder reaction. Chem Commun (Camb) 2001:2286-7. [PMID: 12240153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
The complex [(PPh3)Ag(CB11H6Br6)] 1 is an effective and selective catalyst (0.1 mol% loading) for a hetero-Diels-Alder reaction, which shows a marked dependence on the presence of trace amounts of water, while addition of Ag[Y] [Y = CB11H12, CB11H6Br6, O3SCF3] to a phosphine functionalized support gives an efficient and recyclable Lewis acid catalyst for this transformation.
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Affiliation(s)
- C Hague
- Department of Chemistry, University of Bath, Bath, UK BA2 7AY
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8
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Ahrens B, Davidson MG, Forsyth VT, Mahon MF, Johnson AL, Mason SA, Price RD, Raithby PR. Neutron diffraction study of a phenol.nitroxide radical adduct: a structural model for hydrogen atom abstraction by peroxyl radicals from vitamin E and related phenolic antioxidants. J Am Chem Soc 2001; 123:9164-5. [PMID: 11552826 DOI: 10.1021/ja015849+] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- B Ahrens
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
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9
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Barret MC, Mahon MF, Molloy KC, Steed JW, Wright P. Synthesis and structural characterization of tin(II) and zinc(II) derivatives of cyclic alpha-hydroxyketones, including the structures of Sn(maltol)(2), Sn(tropolone)(2), Zn(tropolone)(2), and Zn(hinokitiol)(2). Inorg Chem 2001; 40:4384-8. [PMID: 11487346 DOI: 10.1021/ic0100368] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Zinc(II) and tin(II) derivatives of maltol (Hmalt), ethylmaltol (HEtmalt), tropolone (Htrop), hinokitiol (Hhino), and kojic acid (Hkoj) have been prepared and characterized, and the crystal structures of M(trop)(2) (M = Zn, Sn), Zn(hino)(2).EtOH, and Sn(malt)(2) have been determined. The Zn(trop)(2) is a polymeric structure in which tropolone has both a bridging and chelating role; zinc(hino)(2) crystallizes as an ethanol adduct of which the structure is a dimeric fragment of the Zn(trop)(2) polymer and in which each metal is "capped" by a molecule of alcohol. The tin complexes are notably air-stable despite adopting monomeric pseudo-trigonal-bipyramidal structures (SnO(4)E; E is a stereochemically active lone electron pair) in which the ligands only chelate a single metal center.
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Affiliation(s)
- M C Barret
- Department of Chemistry, University of Bath, Bath BA2 7AY, UK
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10
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Riley AM, Correa V, Mahon MF, Taylor CW, Potter BV. Bicyclic analogues of D-myo-inositol 1,4,5-trisphosphate related to adenophostin A: synthesis and biological activity. J Med Chem 2001; 44:2108-17. [PMID: 11405648 DOI: 10.1021/jm0005499] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The high affinity of adenophostin A for 1D-myo-inositol 1,4,5-trisphosphate [Ins(1,4,5)P(3)] receptors may be related to an alteration in the position of its 2'-phosphate group relative to the corresponding 1-phosphate group in Ins(1,4,5)P(3). To investigate this possibility, two bicyclic trisphosphates 9 and 10, designed to explore the effect of relocating the 1-phosphate group of Ins(1,4,5)P(3) using a novel fused-ring system, were synthesized from myo-inositol. Biological evaluation of 9 and 10 at the Ins(1,4,5)P(3) receptors of hepatocytes showed that both were recognized by hepatic Ins(1,4,5)P(3) receptors and both stimulated release of Ca(2+) from intracellular stores, but they had lower affinity than Ins(1,4,5)P(3). This finding may be explained by considering the three-dimensional structures of 9 and 10 in light of recent studies on the conformation of adenophostin A.
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MESH Headings
- Adenosine/analogs & derivatives
- Adenosine/chemistry
- Adenosine/pharmacology
- Animals
- Calcium/metabolism
- Calcium Channel Agonists/chemistry
- Calcium Channel Agonists/pharmacology
- Chromatography, Thin Layer
- Crystallography, X-Ray
- Hepatocytes/drug effects
- Hepatocytes/metabolism
- In Vitro Techniques
- Indicators and Reagents
- Inositol 1,4,5-Trisphosphate/analogs & derivatives
- Inositol 1,4,5-Trisphosphate/chemical synthesis
- Inositol 1,4,5-Trisphosphate/pharmacology
- Kinetics
- Liver/drug effects
- Liver/metabolism
- Membranes/drug effects
- Membranes/metabolism
- Models, Molecular
- Molecular Conformation
- Rats
- Spectrophotometry, Ultraviolet
- Stereoisomerism
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Affiliation(s)
- A M Riley
- Wolfson Laboratory of Medicinal Chemistry, Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, U.K
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11
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Ataie M, Buchanan JG, Edgar AR, Kinsman RG, Lyssikatou M, Mahon MF, Welsh PM. 3,4-anhydro-1,2-O-isopropylidene-beta-D-tagatopyranose and 4,5-Anhydro-1,2-O-isopropylidene-beta-D-fructopyranose. Carbohydr Res 2000; 323:36-43. [PMID: 10782283 DOI: 10.1016/s0008-6215(99)00272-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
3,4-Anhydro-1,2-O-isopropylidene-beta-D-tagatopyranose (8) and 4,5-anhydro-1,2-O-isopropylidene-beta-D-fructopyranose (10) have been prepared by treatment of 3,5-di-O-acetyl-1,2-O- isopropylidene-4-O-toluene-p-sulfonyl-beta-D-fructopyranose with methanolic sodium methoxide. The structures of 8 and 10 were assigned by 1H and 13C NMR spectroscopy and that of 10 by X-ray crystallography; both exist in half-chair conformations. Compounds 8 and 10 interconvert in aqueous sodium hydroxide, giving a ratio of 1:2 at equilibrium. The monoacetates of 8 and 10 (5-O-acetyl-3,4-anhydro-1,2-O-isopropylidene-beta-D-tagatopyranose and 3-O-acetyl-4,5-anhydro-1,2-O-isopropylidene-beta-D-fructopyranose) undergo stereospecific epoxide ring opening in 80% acetic acid to give mainly the axial monoacetates 5-O-acetyl-1,2-O-isopropylidene-beta-D-fructopyranose and 4-O-acetyl-1,2-O-isopropylidene-beta-D-tagatopyranose, respectively.
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Affiliation(s)
- M Ataie
- Department of Chemistry, Heriot-Watt University, Riccarton, Edinburgh, UK
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12
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Abstract
The use of platinum complexes as catalysts for allylic substitution has been studied. A variety of different complexes catalyse the reaction, and several substrates have been tested. In the alkylation of mono(alkyl)-substituted allylic acetates, regioselectivity is highly dependent on ligand choice. By using tricyclohexylphosphine as the ligand, almost complete formation of branched products is observed. The development of a highly enantioselective (ca. 80-90% ee) reaction that makes use of chiral diphenylphosphinooxazoline ligands (abbreviated as (S)-PN) is also described. The enantioselectivity is highly dependent on the ratio of ligand to platinum (when the ratio ligand/Pt is greater than 1:1, the ee drops off dramatically). This is in contrast to palladium and is interpreted in terms of differing coordination chemistry for the two metals ((S)-PN is hemilabile when complexed to platinum) and should be of significance to future systems that utilise heterobidentate ligands. The crystal structures of two isoelectronic platinum and palladium complexes [[(S)-PN]MCl2] are also described.
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13
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14
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Abstract
With tetrahydrofuran as the solvent [Rh(thf)(2)(cod)](+) promotes the selective coupling of tBuC(2)H to form triene-yne 1; at high alkyne concentrations, however, an unusual C-H activation process intervenes, leading to the formation of complex 2, which contains two linked five-membered rings. cod=1,5-cyclooctadiene.
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Affiliation(s)
- AD Burrows
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (UK)
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15
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Hejaz HA, Purohit A, Mahon MF, Reed MJ, Potter BV. Synthesis and biological activity of the superestrogen (E)-17-oximino-3-O-sulfamoyl-1,3,5(10)-estratriene: x-ray crystal structure of (E)-17-oximino-3-hydroxy-1,3,5(10)-estratriene. J Med Chem 1999; 42:3188-92. [PMID: 10447965 DOI: 10.1021/jm980717l] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Steroid sulfatases regulate the formation of estrogenic steroids which can support the growth of endocrine-dependent breast tumors. Therefore, the development of potent steroid sulfatase inhibitors could have considerable therapeutic potential. Several such inhibitors have now been developed including estrone 3-O-sulfamate (EMATE, 1), which shows potent active site-directed inhibition. However, EMATE was subsequently shown to be also a potent estrogen. In an attempt to reduce the estrogenicity while retaining the potent sulfatase inhibitory properties associated with this type of molecule, (E)-17-oximino-3-O-sulfamoyl-1,3,5(10)-estratriene (5) (estrone oxime 3-O-sulfamate, OMATE) was synthesized. The X-ray crystal structure of (E)-17-oximino-3-hydroxy-1,3,5(10)-estratriene (4) (estrone oxime) demonstrated the presence of only one geometrical isomer [anti-isomer, (E)]. OMATE potently inhibited estrone sulfatase (E1-STS) activity and was similar to EMATE (>99% inhibition at 0.1 microM in MCF-7 breast cancer cells). It was also evaluated in vivo for its estrogenicity and ability to inhibit sulfatase activity. While it was equipotent with EMATE in vivo as a sulfatase inhibitor, it surprisingly had a stimulatory effect on uterine growth in ovariectomized rats about 1.5-fold greater than that of EMATE. Thus, OMATE possesses potential as a superestrogen and modification at C-17 is identified as a useful route for enhancement of estrogenicity in sulfamate-based estrogens.
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Affiliation(s)
- H A Hejaz
- Wolfson Laboratory of Medicinal Chemistry & Sterix Limited, Department of Pharmacy & Pharmacology, and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K
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16
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Molloy KC, Mahon MF, Barret MC. (1-Phenyl-1H-1,2,3,4-tetrazole-5-thiolato-S)bis(triphenylphosphine)silver(I) methanol solvate. Acta Crystallogr C 1999. [DOI: 10.1107/s0108270199000311] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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17
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Kalsoom A, Mazhar M, Ali S, Mahon MF, Molloy KC, Chaudry MI. Synthesis, Characterization and Biological Activity of Organotin Derivatives of 2-Thionaphthalene, Including the Crystal Structures of (Naphthalenethiolato-S)triphenyltin(IV) and Bis(naphthalenethiolato-S)dimethyltin(IV). Appl Organomet Chem 1997. [DOI: 10.1002/(sici)1099-0739(199701)11:1<47::aid-aoc538>3.0.co;2-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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19
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Gallagher T, Giles ME, Mahon MF, Molloy KC, Hadley MS. Structure of 1,2,4-trideoxy-1,4-imino-3,5;6,7-di-O-isopropylidene-L-glycero-D-gluco-octitol: a key intermediate in the enantioselective synthesis of 8-epicastanospermine. Acta Crystallogr C 1993. [DOI: 10.1107/s0108270192004517] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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20
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Anderson M, Gallagher T, Mahon MF, Molloy KC, Shaw R. Structure of (Z,Z)-3,11-diiodo-N,N-ditosyl-1,9-diazacyclohexadeca-3,11-diene. Acta Crystallogr C 1992. [DOI: 10.1107/s0108270191011782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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21
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Molloy KC, Purcell TG, Mahon MF, Minshall E. Organotin biocides. XII. Synthesis and structural characterization of organotin derivatives of 3-indolylacetic acid, including the crystal structures of tributylstannyl 3-indolylacetate and tricyclohexylstannylN-methyl-3-indolylacetate. Appl Organomet Chem 1987. [DOI: 10.1002/aoc.590010604] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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