V. Lynch - Academia.edu (original) (raw)
Papers by V. Lynch
![Research paper thumbnail of ChemInform Abstract: Calix[4]pyridine: A New Arrival in the Heterocalixarene Family](https://attachments.academia-assets.com/46276560/thumbnails/1.jpg)
](ChemInform, 1998
Calix[4]pyridine: A New Arrival in the Heterocalixarene Family. -A universal and easy method for ... more Calix[4]pyridine: A New Arrival in the Heterocalixarene Family. -A universal and easy method for the preparation of calixpyridinopyrroles, e.g. (I), and calixpyridines such as (II) proceeds by reaction of meso-octamethylcalix[4]pyrrole with dichlorocarbene via ring expansion of pyrrole. Isomers are present in the reaction mixture, since the intermediate dichlorocarbene formed can insert into either of the two double bonds present in each of the various pyrrole rings under attack. -(KRAL, V.; GALE, P. A.; ANZENBACHER, P. JUN.; JURSIKOVA, K.; LYNCH, V.; SESSLER, J. L.; Chem. Commun. (Cambridge) (1998) 1, 9-10; Dep. Chem. Biochem., Univ. Tex., Austin, TX 78712, USA; EN)
The European respiratory journal, 1999
Tetrahedron Letters, 2005
The benzofuranone dimers 9 and 10/11 readily (ca. 75°C) dissociate to the persistent radicals 16 ... more The benzofuranone dimers 9 and 10/11 readily (ca. 75°C) dissociate to the persistent radicals 16 and 17 respectively, which are stable to, dioxygen. The OMe analog 25 dissociates to form the radical 24, which reacts with dioxygen of TEMPO to give 26.
Organic Letters, 2001
[reaction: see text] The first examples of copper-catalyzed intramolecular cyclopropanations of g... more [reaction: see text] The first examples of copper-catalyzed intramolecular cyclopropanations of glycal-derived diazoacetates are reported. The new cyclopropanes are converted into advanced intermediates for the synthesis of bislactone natural products. Synthetic highlights include the selective monodeprotection of a di-tert-butylsilylene ether and a zinc-mediated ring opening cascade reaction.
Journal of the American Chemical Society, 2001
Manganese and iron porphyrins, 1-3 as well as other macrocyclic metal complexes, 4 have recently ... more Manganese and iron porphyrins, 1-3 as well as other macrocyclic metal complexes, 4 have recently been reported to be highly active catalysts for peroxynitrite decomposition. Peroxynitrite anion, ONOO -, formed in vivo by combination of nitric oxide and superoxide anion, 5 has been implicated as a cytotoxic agent in connection with numerous conditions and diseases including atherosclerosis, 6 ALS, 7 cancer, 8 and ischemia-reperfusion injury. 9 It is believed that peroxynitrite forms RNSs (reactive nitrogen species) during its decay into less reactive nitrate and nitrite anions, and it is these RNSs that react with biological targets. 10 The resulting damage includes oxidation of lipids and nitration of tyrosine residues and DNA. 11 Metalloproteins are particularly sensitive to peroxynitrite anion due to rapid oxidation of iron and manganese centers. 12 Therefore, finding synthetic metal complexes that can act catalytically and safely to decompose peroxynitrite without forming RNSs would constitute an important pharmacological advance. In this communication, we report the synthesis of the first structurally characterized Mn(II)-texaphyrin complex 13 (Mn-Tex) and its ability to catalyze the decomposition of peroxynitrite without causing concomitant phenol nitration in aqueous solution at pH 7.4.
Journal of the American Chemical Society, 2002
The preparation of first-row transition-metal complexes of texaphyrin, a porphyrin-like, monoanio... more The preparation of first-row transition-metal complexes of texaphyrin, a porphyrin-like, monoanionic penta-aza macrocyclic ligand, is reported. Specifically, the synthesis of organic-soluble Mn(II) (1), Co(II) (2), Ni(II) (3), Zn(II) (4), and Fe(III) (5) texaphyrin derivatives and their water-soluble counterparts (6-10) from appropriate metal-free, nonaromatic macrocyclic precursors is described. It was found that metal cations of sufficient reduction potential could act to oxidize the nonaromatic macrocyclic precursor in the course of metal insertion. Complexes were characterized by X-ray diffraction analysis, electrochemistry, flash photolysis, and EPR spectroscopy. The structural and electronic properties of these "expanded porphyrin" complexes are compared with those of analogous porphyrins. Notably, the texaphyrin ligand is found to support the complexation of cations in a lower valence and a higher spin state than do porphyrins. Interactions between the coordinated cation and the ligand π system appear to contribute to the overall bonding. Texaphyrin complexes of Mn(II), Co(II), and Fe(III) in particular may possess sufficient aqueous stability to permit their use in pharmaceutical applications. Tvermoes, N. A.; Guldi, D. M.; Mody, T. D.; Allen, W. E. J. Phys. Chem. A 1999, 103, 787-794. (3) (a) Rosenthal, D. I.; Nurenberg, P.; Becerra, C. R.; Frenkel, E. P.; Carbone, D. P.; Lum, B. L.; Miller, R.; Engel, J.; Young, S.; Miles, D.; Renschler, M. F. Clin. Cancer Res. 1945, 5, 739-745. (b) Viala, J.; Vanel, D.; Meingan, P.; Lartigau, E.; Carde, P.; Renschler, M. Radiology 1999, 212, 755-759. (c) Carde, P.; Timmerman, R.; Mehta, M. P.; Koprowski, C. D.; Ford, J.; Tishler, R. B.; Miles, D.; Miller, R. A.; Renschler, M. F.
Journal of the American Chemical Society, 1993
Structure and Selectivity in Catalytic Metal-Carbene ... Michael P. Doyle,'J William R. ... more Structure and Selectivity in Catalytic Metal-Carbene ... Michael P. Doyle,'J William R. Winchester,t Johannes A. A. Hoorn,t Vincent Lynch,'v# Stanley H. Simonsen,'v* and Ratna Ghosht ... Contribution from the Department of Chemistry, Trinity University, San Antonio, Texas ...
![Research paper thumbnail of Formation and Properties of Cyclo[6]pyrrole and Cyclo[7]pyrrole](https://attachments.academia-assets.com/46276546/thumbnails/1.jpg)
](Journal of the American Chemical Society, 2003
In recent years, expanded porphyrins have been attracting increasing attention. 1-3 While sharing... more In recent years, expanded porphyrins have been attracting increasing attention. 1-3 While sharing a number of attributes with porphyrins, the expanded porphyrins show unique features, such as the ability to bind anions 4 or coordinate large cations in a 1:1 in-plane fashion, 5 that have made them particularly attractive for study. This, in turn, has focused interest on new preparative methodologies, including oxidative couplings, 5a-7 that might serve to extend the synthetic scope of more traditional cyclization strategies, such as those embodied in classic or MacDonald-type 2,9 condensations, as well as newer In the context of such efforts, we recently reported that 3,3′,4,4′-tetraalkylbipyrroles (e.g., 2) may be coupled under biphasic oxidative conditions (FeCl 3 ; dichloromethane-1 M aqueous sulfuric acid) to produce cyclo[8]pyrroles [30]octaphyrins(0.0.0.0.0.0.0.0) such as 1. As inferred from simple molecular modeling studies, such macrocycles, which contain no meso bridges, were thought to represent the smallest possible "contracted" expanded porphyrins. However, much to our surprise, we have now succeeded in producing the smaller cyclo[6]-and cyclo[7]pyrrole analogues, title compounds 3 and 4.
Journal of Solid State Chemistry, 2007
The crystal structures of compounds with nominal compositions Bi6FeP2O15+x (I), Bi6NiP2O15+x (II)... more The crystal structures of compounds with nominal compositions Bi6FeP2O15+x (I), Bi6NiP2O15+x (II) and Bi6ZnP2O15+x (III) were determined from single-crystal X-ray diffraction data. They are monoclinic, space group I2, Z=2. The lattice parameters for (I) are a=11.2644(7), b=5.4380(3), c=11.1440(5)Å, β=96.154(4)°; for (II) a=11.259(7), b=5.461(4), c=11.109(7)Å, β=96.65(1)°; for (III) a=19.7271(5), b=5.4376(2), c=16.9730(6)Å, β=131.932(1)°. Least squares refinements on F2 converged for (I) to
Journal of Solid State Chemistry, 2007
Bi6.4Pb0.6P2O15.2 is a polymorph of structures with the general stoichiometry Bi6+xM1-xP2O15+y. H... more Bi6.4Pb0.6P2O15.2 is a polymorph of structures with the general stoichiometry Bi6+xM1-xP2O15+y. However, unlike previously published structures that consist of layers formed by edge sharing OBi4 tetrahedra bridged by PO4 and TO6 (T=transition metal) tetrahedra and octahedra the title compound's structure is more complex. It is monoclinic, C2, a=19.4698(4) Å, b=11.3692(3) Å, c=16.3809(5) Å, beta=101.167(1)°, Z=10. Single-crystal X-ray diffraction data were
ChemInform, 1998
Calix[4]pyridine: A New Arrival in the Heterocalixarene Family. -A universal and easy method for ... more Calix[4]pyridine: A New Arrival in the Heterocalixarene Family. -A universal and easy method for the preparation of calixpyridinopyrroles, e.g. (I), and calixpyridines such as (II) proceeds by reaction of meso-octamethylcalix[4]pyrrole with dichlorocarbene via ring expansion of pyrrole. Isomers are present in the reaction mixture, since the intermediate dichlorocarbene formed can insert into either of the two double bonds present in each of the various pyrrole rings under attack. -(KRAL, V.; GALE, P. A.; ANZENBACHER, P. JUN.; JURSIKOVA, K.; LYNCH, V.; SESSLER, J. L.; Chem. Commun. (Cambridge) (1998) 1, 9-10; Dep. Chem. Biochem., Univ. Tex., Austin, TX 78712, USA; EN)
The European respiratory journal, 1999
Tetrahedron Letters, 2005
The benzofuranone dimers 9 and 10/11 readily (ca. 75°C) dissociate to the persistent radicals 16 ... more The benzofuranone dimers 9 and 10/11 readily (ca. 75°C) dissociate to the persistent radicals 16 and 17 respectively, which are stable to, dioxygen. The OMe analog 25 dissociates to form the radical 24, which reacts with dioxygen of TEMPO to give 26.
Organic Letters, 2001
[reaction: see text] The first examples of copper-catalyzed intramolecular cyclopropanations of g... more [reaction: see text] The first examples of copper-catalyzed intramolecular cyclopropanations of glycal-derived diazoacetates are reported. The new cyclopropanes are converted into advanced intermediates for the synthesis of bislactone natural products. Synthetic highlights include the selective monodeprotection of a di-tert-butylsilylene ether and a zinc-mediated ring opening cascade reaction.
Journal of the American Chemical Society, 2001
Manganese and iron porphyrins, 1-3 as well as other macrocyclic metal complexes, 4 have recently ... more Manganese and iron porphyrins, 1-3 as well as other macrocyclic metal complexes, 4 have recently been reported to be highly active catalysts for peroxynitrite decomposition. Peroxynitrite anion, ONOO -, formed in vivo by combination of nitric oxide and superoxide anion, 5 has been implicated as a cytotoxic agent in connection with numerous conditions and diseases including atherosclerosis, 6 ALS, 7 cancer, 8 and ischemia-reperfusion injury. 9 It is believed that peroxynitrite forms RNSs (reactive nitrogen species) during its decay into less reactive nitrate and nitrite anions, and it is these RNSs that react with biological targets. 10 The resulting damage includes oxidation of lipids and nitration of tyrosine residues and DNA. 11 Metalloproteins are particularly sensitive to peroxynitrite anion due to rapid oxidation of iron and manganese centers. 12 Therefore, finding synthetic metal complexes that can act catalytically and safely to decompose peroxynitrite without forming RNSs would constitute an important pharmacological advance. In this communication, we report the synthesis of the first structurally characterized Mn(II)-texaphyrin complex 13 (Mn-Tex) and its ability to catalyze the decomposition of peroxynitrite without causing concomitant phenol nitration in aqueous solution at pH 7.4.
Journal of the American Chemical Society, 2002
The preparation of first-row transition-metal complexes of texaphyrin, a porphyrin-like, monoanio... more The preparation of first-row transition-metal complexes of texaphyrin, a porphyrin-like, monoanionic penta-aza macrocyclic ligand, is reported. Specifically, the synthesis of organic-soluble Mn(II) (1), Co(II) (2), Ni(II) (3), Zn(II) (4), and Fe(III) (5) texaphyrin derivatives and their water-soluble counterparts (6-10) from appropriate metal-free, nonaromatic macrocyclic precursors is described. It was found that metal cations of sufficient reduction potential could act to oxidize the nonaromatic macrocyclic precursor in the course of metal insertion. Complexes were characterized by X-ray diffraction analysis, electrochemistry, flash photolysis, and EPR spectroscopy. The structural and electronic properties of these "expanded porphyrin" complexes are compared with those of analogous porphyrins. Notably, the texaphyrin ligand is found to support the complexation of cations in a lower valence and a higher spin state than do porphyrins. Interactions between the coordinated cation and the ligand π system appear to contribute to the overall bonding. Texaphyrin complexes of Mn(II), Co(II), and Fe(III) in particular may possess sufficient aqueous stability to permit their use in pharmaceutical applications. Tvermoes, N. A.; Guldi, D. M.; Mody, T. D.; Allen, W. E. J. Phys. Chem. A 1999, 103, 787-794. (3) (a) Rosenthal, D. I.; Nurenberg, P.; Becerra, C. R.; Frenkel, E. P.; Carbone, D. P.; Lum, B. L.; Miller, R.; Engel, J.; Young, S.; Miles, D.; Renschler, M. F. Clin. Cancer Res. 1945, 5, 739-745. (b) Viala, J.; Vanel, D.; Meingan, P.; Lartigau, E.; Carde, P.; Renschler, M. Radiology 1999, 212, 755-759. (c) Carde, P.; Timmerman, R.; Mehta, M. P.; Koprowski, C. D.; Ford, J.; Tishler, R. B.; Miles, D.; Miller, R. A.; Renschler, M. F.
Journal of the American Chemical Society, 1993
Structure and Selectivity in Catalytic Metal-Carbene ... Michael P. Doyle,'J William R. ... more Structure and Selectivity in Catalytic Metal-Carbene ... Michael P. Doyle,'J William R. Winchester,t Johannes A. A. Hoorn,t Vincent Lynch,'v# Stanley H. Simonsen,'v* and Ratna Ghosht ... Contribution from the Department of Chemistry, Trinity University, San Antonio, Texas ...
Journal of the American Chemical Society, 2003
In recent years, expanded porphyrins have been attracting increasing attention. 1-3 While sharing... more In recent years, expanded porphyrins have been attracting increasing attention. 1-3 While sharing a number of attributes with porphyrins, the expanded porphyrins show unique features, such as the ability to bind anions 4 or coordinate large cations in a 1:1 in-plane fashion, 5 that have made them particularly attractive for study. This, in turn, has focused interest on new preparative methodologies, including oxidative couplings, 5a-7 that might serve to extend the synthetic scope of more traditional cyclization strategies, such as those embodied in classic or MacDonald-type 2,9 condensations, as well as newer In the context of such efforts, we recently reported that 3,3′,4,4′-tetraalkylbipyrroles (e.g., 2) may be coupled under biphasic oxidative conditions (FeCl 3 ; dichloromethane-1 M aqueous sulfuric acid) to produce cyclo[8]pyrroles [30]octaphyrins(0.0.0.0.0.0.0.0) such as 1. As inferred from simple molecular modeling studies, such macrocycles, which contain no meso bridges, were thought to represent the smallest possible "contracted" expanded porphyrins. However, much to our surprise, we have now succeeded in producing the smaller cyclo[6]-and cyclo[7]pyrrole analogues, title compounds 3 and 4.
Journal of Solid State Chemistry, 2007
The crystal structures of compounds with nominal compositions Bi6FeP2O15+x (I), Bi6NiP2O15+x (II)... more The crystal structures of compounds with nominal compositions Bi6FeP2O15+x (I), Bi6NiP2O15+x (II) and Bi6ZnP2O15+x (III) were determined from single-crystal X-ray diffraction data. They are monoclinic, space group I2, Z=2. The lattice parameters for (I) are a=11.2644(7), b=5.4380(3), c=11.1440(5)Å, β=96.154(4)°; for (II) a=11.259(7), b=5.461(4), c=11.109(7)Å, β=96.65(1)°; for (III) a=19.7271(5), b=5.4376(2), c=16.9730(6)Å, β=131.932(1)°. Least squares refinements on F2 converged for (I) to
Journal of Solid State Chemistry, 2007
Bi6.4Pb0.6P2O15.2 is a polymorph of structures with the general stoichiometry Bi6+xM1-xP2O15+y. H... more Bi6.4Pb0.6P2O15.2 is a polymorph of structures with the general stoichiometry Bi6+xM1-xP2O15+y. However, unlike previously published structures that consist of layers formed by edge sharing OBi4 tetrahedra bridged by PO4 and TO6 (T=transition metal) tetrahedra and octahedra the title compound's structure is more complex. It is monoclinic, C2, a=19.4698(4) Å, b=11.3692(3) Å, c=16.3809(5) Å, beta=101.167(1)°, Z=10. Single-crystal X-ray diffraction data were