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Kaushik V, Cook N, Liang AY, Desai UR, Sidorov V. Chemoselective precipitation of lactose from a lactose/sucrose mixture: proof of concept for a new separation methodology. Supramol Chem 2010. [DOI: 10.1080/10610278.2010.500732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Vivek Kaushik
- a Department of Chemistry , Virginia Commonwealth University , Richmond , VA , 23284 , USA
| | - Nicole Cook
- a Department of Chemistry , Virginia Commonwealth University , Richmond , VA , 23284 , USA
| | - Ayie Y. Liang
- b Institute of Structural Biology and Drug Discovery, Virginia Commonwealth University , Richmond , VA , 23298 , USA
| | - Umesh R. Desai
- b Institute of Structural Biology and Drug Discovery, Virginia Commonwealth University , Richmond , VA , 23298 , USA
| | - Vladimir Sidorov
- a Department of Chemistry , Virginia Commonwealth University , Richmond , VA , 23284 , USA
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Kabir MS, Monte A, Cook JM. An efficient palladium-catalyzed Negishi cross-coupling reaction with arylvinyl iodides: facile regioselective synthesis of E-stilbenes and their analogues. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.08.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Tsarevsky NV, Matyjaszewski K. “Green” Atom Transfer Radical Polymerization: From Process Design to Preparation of Well-Defined Environmentally Friendly Polymeric Materials. Chem Rev 2007; 107:2270-99. [PMID: 17530906 DOI: 10.1021/cr050947p] [Citation(s) in RCA: 1017] [Impact Index Per Article: 59.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nicolay V Tsarevsky
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, USA
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Ams MR, Wilcox CS. Benzil-tethered precipitons for controlling solubility: a round-trip energy-transfer mechanism in the isomerization of extended stilbene analogues. J Am Chem Soc 2007; 129:3966-72. [PMID: 17348650 DOI: 10.1021/ja068211c] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We are investigating photoresponsive molecules called "precipitons" that undergo a solubility change co-incident with isomerization. Isomerization can be induced by light or by catalytic reagents. Previous work demonstrated that covalent attachment of a metal complex, Ru(II)(bpy)3, greatly accelerates photoisomerization and influences the photostationary state. In this paper, we describe precipitons (1,2-biphenylethenes; analogous to stilbenes) that are activated by a covalently attached organic sensitizer (benzil). We find that isomerization of these stilbene analogues is little effected by the presence of benzil in solution but that the intramolecular benzil effect is to increase the rate of isomerization and to significantly change the photostationary state. What is most interesting about these observations is that the precipiton is the primary chromophore in this bichromophoric system (precipiton absorbance is many times greater than benzil absorbance in the 300-400 nm range), yet the neighboring benzil has a significant effect on the rate and the photostationary state. The effect of unattached benzil on the rate was small, about a 24% increase in rate as compared with 4-6-fold changes for an attached benzil. We speculate that the isomerization process occurs by a "round-trip" energy-transfer mechanism. Initial excitation of the precipiton chromophore initiates a sequence that includes (1) formation of the precipiton singlet state, (2) singlet excitation transfer from the precipiton unit to the benzil, (3) benzil-centered intersystem crossing to the localized benzil triplet state, (4) triplet energy transfer from the benzil moiety back to the precipiton, and (5) isomerization.
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Affiliation(s)
- Mark R Ams
- Department of Chemistry and The Combinatorial Chemistry Center, University of Pittsburgh, Pittsburgh, PA 15260, USA
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Temperature-Controlled Catalyst Recycling: New Protocols Based upon Temperature-Dependent Solubilities of Fluorous Compounds and Solid/Liquid Phase Separations. TOP ORGANOMETAL CHEM 2006. [DOI: 10.1007/3418_043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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Ams MR, Wilcox CS. Intramolecularly Sensitized Precipitons: A Model System for Application to Metal Sequestration. J Am Chem Soc 2005; 128:250-6. [PMID: 16390154 DOI: 10.1021/ja0561340] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated light-triggered or catalytically activated precipitation agents and have proposed the name "precipiton" for such molecules or molecular fragments. A phase separation is induced when the precipiton isomerizes to a low-solubility form. In this paper we describe the first intramolecularly activated precipitons. The isomerization process is induced by intramolecular triplet energy transfer from a covalently attached metal complex. As expected, intramolecular sensitization leads to a more rapid isomerization than can be achieved by intermolecular sensitization at accessible concentrations. Two isomeric bichromophoric precipiton species, each containing [Ru(bpy)(3)](2+) and 1,2-bis(biphenyl)ethene units covalently linked together by an ether tether, have been synthesized and characterized, and their photochemical properties have been investigated. The rates of photoisomerization of these complexes, [((Z)-1,2-bis(biphenyl)ethene-bpy)Ru(bpy)(2)](PF(6))(2) (2Z) and [((E)-1,2-bis(biphenyl)ethene-bpy)Ru(bpy)(2)](PF(6))(2) (2E), were compared to those of their untethered analogues, (Z)-1,2-bis(biphenyl)ethene-OTBS (1Z) and (E)-1,2-bis(biphenyl)ethene-OTBS (1E), where ruthenium sensitization occurred through an intermolecular pathway. Upon irradiation with visible light (lambda > or = 400 nm) in degassed solution, 2Z/E and 1Z/E obeyed reversible first-order rate kinetics. The intramolecularly sensitized precipiton 2Z isomerized 250 times faster (k(2Z-->2E) = 1.0 x 10(-3) s(-1) with a 51% neutral density filter) than the intermolecular case 1Z (k(1Z-->1E) = 0.80 x 10(-5) s(-1)). For 1E and 2E, the isomerization rates were k(1E-->1Z) = 11.0 x 10(-5) s(-1) and k(2E-->2Z) = 1.6 x 10(-3) s(-1), respectively. The average Z/E mole ratio at the photostationary state was 62/38 for 2Z/E and 93/7 for 1Z/E. The impetus for this study was our desire to evaluate the possibility of using metal-binding precipitons that would precipitate only upon metal-to-precipiton binding and would be inert to visible light in the absence of metals.
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Affiliation(s)
- Mark R Ams
- Department of Chemistry and The Combinatorial Chemistry Center, University of Pittsburgh, Pittsburgh, PA 15260, USA
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Kuang C, Yang Q, Senboku H, Tokuda M. Synthesis of (Z)-1-bromo-1-alkenes and terminal alkynes from anti-2,3-dibromoalkanoic acids by microwave-induced reaction. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.02.043] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Bosanac T, Wilcox CS. Precipiton reagents: precipiton phosphines for solution-phase reductions. Org Lett 2005; 6:2321-4. [PMID: 15228269 DOI: 10.1021/ol049369+] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[structure: see text] [structure: see text] [structure: see text] Several Precipiton phosphines were prepared and employed in the Staudinger reaction and in the reduction of secondary ozonides. Both amines and aldehdyes were obtained in good to excellent yields and purities. After use of the phosphine, isomerization and precipitation of the spent phosphorus reagent were induced by exposure to visible light in the presence of erythrosin B, a triplet sensitizer. Products were isolated by simple filtration. The use of the triplet sensitizer has the added advantage of eliminating [2 + 2] cycloaddition reactions between trans-Precipitons.
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Affiliation(s)
- Todd Bosanac
- Department of Chemistry and The Combinatorial Chemistry Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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Ferré-Filmon K, Delaude L, Demonceau A, Noels AF. Catalytic methods for the synthesis of stilbenes with an emphasis on their phytoalexins. Coord Chem Rev 2004. [DOI: 10.1016/j.ccr.2004.02.011] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Kamenjicki M, Asher SA. Photochemically Controlled Cross-Linking in Polymerized Crystalline Colloidal Array Photonic Crystals. Macromolecules 2004. [DOI: 10.1021/ma049678f] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marta Kamenjicki
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Sanford A. Asher
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
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Affiliation(s)
- Jun-Ichi Yoshida
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Yoshida, Kyoto 606-8501, Japan.
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Chang S, Na Y, Shin HJ, Choi E, Jeong LS. A short and efficient synthetic approach to hydroxy (E)-stilbenoids via solid-phase cross metathesis. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)01528-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Moore JD, Harned AM, Henle J, Flynn DL, Hanson PR. Scavenge-ROMP-filter: a facile strategy for soluble scavenging via norbornenyl tagging of electrophilic Reagents. Org Lett 2002; 4:1847-9. [PMID: 12027629 DOI: 10.1021/ol0257880] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] A new "chemical tagging" method for homogeneous electrophilic scavenging is described. The method utilizes 5-norbornene-2-methanol to scavenge/tag a variety of electrophiles that are present in excess. Once tagging is complete, the crude reaction mixture is subjected to a rapid ROM polymerization event utilizing the second generation Grubbs catalyst. This process yields a polymer that can be precipitated with methanol or ether/hexane, leaving products in excellent yield and purity.
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Affiliation(s)
- Joel D Moore
- Department of Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, Kansas 66045-7582, USA
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Honigfort ME, Brittain WJ, Bosanac T, Wilcox CS. Use of Precipitons for Copper Removal in Atom Transfer Radical Polymerization. Macromolecules 2002. [DOI: 10.1021/ma020155m] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Bosanac T, Wilcox CS. A photoactivated precipiton for reagent sequestration in solution-phase synthesis. J Am Chem Soc 2002; 124:4194-5. [PMID: 11960432 DOI: 10.1021/ja017577g] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Precipitons are molecular phase tags for chemical separations. They can be switched from a high-solubility to a low-solubility state to facilitate product, reagent, or catalyst isolation. This paper presents the first photoactivated precipiton and demonstrates that this precipiton is an efficient amine scavenging agent in solution-phase syntheses of amides, ureas, and imines. This approach to amine scavenging offers advantages over solid-phase scavenging methods. The amine is captured in a homogeneous medium, so the capture is much faster than seen with isocyanate resins, and only a small excess of the scavenger is required.
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Affiliation(s)
- Todd Bosanac
- Department of Chemistry and The Combinatorial Chemistry Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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