Clifford C. Leznoff

Publications (19)0 Total impact

• Source

  Available from: nrcresearchpress.com

  Article: Asymmetric Syntheses Towards (3Z,6R)-3-Methyl-6-isopropenyl-3,9-decadien-1-yl Acetate, a Component of the California Red Scale Pheromone

  Clifford C. Leznoff, Colin R. McArthur, Mark Whittaker
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  ABSTRACT: The key chiral synthons, (R)-3-isopropenyl-6-heptenoic acid and (R)-3-isopropenyl-6-heptenal, needed for the synthesis of (3Z,6R)-3-methyl-6-isopropenyl-3,9-decadien-1-yl acetate, a component of the sex pheromone of the California red scale, Aonidiellaaurantii, have been prepared by asymmetric synthesis. The chiral acid was synthesized in 86% ee by an asymmetric 1,4-addition of isopropenylmagnesium bromide to the l-ephedrine amide derived from (E)-2,6-heptadienoic acid, followed by base hydrolysis. Acid hydrolysis gave the chiral 3-(3-buten-1-yl)-4,4-dimethylbutyrolactone. The chiral aldehyde was prepared in greater than 99% ee by an asymmetric 1,4-addition of isopropenylmagnesium bromide to the imine derived from (S)-(+)-tert-butyl 2-amino-3,3-dimethylbutyrate and (E)-2,6-heptadienal. The 1,4-addition reactions of n-butyllithium or isopropenyllithium to (4S,5S)-(+)-2-[1-(E-1,5-hexadienyl)]-4-methoxymethyl-5-phenyl-2-oxazoline gave the addition products, and sequential mild hydrolysis and reduction of these adducts yielded chiral 3-n-butyl-6-hepten-1-ol for the former adduct but a mixture of products was obtained from the latter adduct.
  02/2011;
• Source

  Available from: nrcresearchpress.com

  Article: Multisubstituted phthalonitriles, naphthalenedicarbonitriles, and phenanthrenetetracarbonitriles as precursors for phthalocyanine syntheses

  Jing Li, Steven Vigh, Colin R. McArthur, Dmitri S. Terekhov, Clifford C. Leznoff
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  ABSTRACT: Electrophilic aromatic nitration under mild conditions of 4-hydroxyphthalonitrile gave 4-hydroxy-3-nitrophthalonitrile and 4-hydroxy-5-nitrophthalonitrile, while bromination yielded 3-bromo-4-hydroxyphthalonitrile, 4-bromo-5-hydroxyphthalonitrile, and 3,5-dibromo-4-hydroxyphthalonitrile. Iodination gave 4-hydroxy-5-iodophthalonitrile and 4-hydroxy-3,5-diidophthalonitrile. Coupling of 4-iodophthalonitrile, 3-iodophthalonitrile, and 5-iodo-2,3-dicyanonaphthalene with trans-1,2-bis(tri-n-butylstannyl)ethene gave trans-1,2-bis(3,4-dicyanophenyl)ethene, trans-1,2-bis(2,3-dicyanophenyl)ethene, and trans-1,2-bis(6,7-dicyanonaphthyl)ethene. Photocyclization of a dilute solution of cis- or trans-1,2-bis(3,4-dicyanophenyl)ethene in dioxane gave a 1:1 mixture of 2,3,6,7- and 2,3,5,6-tetracyanophenanthrenes separable by chromatography. Keywords: phthalonitriles, naphthalenedicarbonitriles, phenanthrenetetracarbonitriles, electrophilic substitution.
  02/2011;
• Article: Asymmetrische Synthese von 2‐Alkylcyclohexanonen an festen Trägern

  Paul M. Worster, Colin R. McArthur, Clifford C. Leznoff
  Angewandte Chemie 01/2006; 91(3):255 - 255.
• Article: Synthesis, Structure, and Properties of New Phthalocyanines

  Nagao Kobayashi, Clifford C. Leznoff
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  ABSTRACT: For Abstract see ChemInform Abstract in Full Text.
  ChemInform 07/2005; 36(33).
• Source

  Available from: A.B.P. Lever

  Article: Electrochemistry and spectroelectrochemistry of 1,8-naphthalene- and 1,8-anthracene-linked cofacial binuclear metallophthalocyanines. New mixed-valence metallophthalocyanines

  Nagao Kobayashi, Herman Lam, W. Andrew Nevin, Pavel Janda, Clifford C. Leznoff, A. B. P. Lever
  04/2002;
• Article: Synthesis, spectroscopy, electrochemistry, spectroelectrochemistry, Langmuir-Blodgett film formation, and molecular orbital calculations of planar binuclear phthalocyanines

  Nagao Kobayashi, Herman Lam, W. Andrew Nevin, Pavel Janda, Clifford C. Leznoff, Toshiki Koyama, Atsushi Monden, Hirofusa Shirai
  04/2002;
• Source

  Available from: A.B.P. Lever

  Article: Syntheses of monometalated and unsymmetrically substituted binuclear phthalocyanines and a pentanuclear phthalocyanine by solution and polymer support methods

  Clifford C. Leznoff, Polina I. Svirskaya, Ben Khouw, Ronald L. Cerny, Penny Seymour, A. B. P. Lever
  04/2002;
• Source

  Available from: A.B.P. Lever

  Article: Surface electrochemistry of chloro(phthalocyaninato)rhodium(III) species and oxygen reduction electrocatalysis. Formation of a dimeric species

  Yu Hong. Tse, Penny. Seymour, Nagao. Kobayashi, Herman. Lam, Clifford C. Leznoff, A. B. P. Lever
  04/2002;
• Article: N-(Ethoxycarbonyl)phthalimide. An improved procedure

  Paul M. Worster, Clifford C. Leznoff, Colin R. McArthur
  04/2002;
• Article: Absorption, Fluorescence, and Magnetic Circular Dichroism Spectra of and Molecular Orbital Calculations on Tetrabenzotriazaporphyrins and Tetranaphthotriazaporphyrins

  John Mack, Nagao Kobayashi, Clifford C. Leznoff, Martin J. Stillman
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  ABSTRACT: Extensive analyses of the electronic absorption, magnetic circular dichroism (MCD), and fluorescence emission and excitation spectra of peripherally-substituted tetrabenzotriazaporphyrin (TBTrAP) and tetranaphthotriazaporphyrin (TNTrAP) complexes are reported. ZINDO calculations of the UV−visible absorption spectra of free base and dianionic (deprotonated) TBTrAP and TNTrAP complexes are described. The optical spectra of TBTrAP and TNTrAP are assigned on the basis of molecular orbital (MO) calculations using the ZINDO program and the theory that has been developed previously to account for the spectral properties of porphyrin and phthalocyanine complexes. Analysis of the absorption and MCD spectra of the ring-reduced anion radical species of Pc and TBTrAP complexes shows that the optical spectra of [TBTrAP(−3)]- are markedly different from those of analogous Pc species. EPR signals observed at 77 K for Pc(−3) radical species provide evidence for a doublet ground state, while the absence of an EPR signal for [TBTrAP(−3)]- indicates that the species dimerizes upon reduction. The absorption and MCD spectra of the dimeric [TBTrAP(−3)]- species are found to be consistent with the band assignment developed previously to account for the spectral properties of main group Pc anion radicals.
  11/1997;
• Article: Asymmetric induction in the cycloaddition of 1,3-butadiene to a polymer-bound chiral acrylate

  Michael D. Corbridge, Colin R. McArthur, Clifford C. Leznoff
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  ABSTRACT: Crosslinked polystyrene resins containing pendant benzyl acrylate or chiral acrylates derived from R-(−)-1,3-butanedoil reacted with 1,3-butadiene or 2,3-dimethyl-1,3-butadiene in the presence of the Lewis acid catalysts TiCl4, TiCl3(OiPr), or TiCl2(OiPr)2 to yield Diels-Alder adducts. Cleavage of the adducts gave racemic or optically active 3-cyclohexen-1-ylmethanol and 3,4-dimethyl-3-cyclohexen-1-ylmethanol. The polymerbound Diels-Alder reactions were compared with their analogous reactions in solution. In reactions leading to optically active products the enantiomeric excesses on the polymer were at least as high as those performed in solution.
  Reactive Polymers Ion Exchangers Sorbents 8(2):173-188.
• Article: Vibrational spectra of halophthalonitriles

  Mathew D Halls, Ricardo Aroca, Dmitri S Terekhov, Anna D'Ascanio, Clifford C Leznoff
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  ABSTRACT: The fundamental vibrational modes of a series of six halophthalonitriles have been studied using Raman and infrared spectroscopy. The vibrational assignment of experimental wave numbers obtained from solid samples was aided using quantum chemical computations. Semi-empirical methods and the local SVWN functional were used to obtain vibrational wave numbers and atomic displacement representations of the fundamental molecular vibrations. The study of a series of molecules with similar structure permits the identification of characteristic wave numbers and the effect of the halosubstitution in the molecular structure.
  Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy.
• Article: A Planar Binuclear Phthalocyanine and its Dicobalt Derivative

  A.B.P. Lever, Nagao Kobayashi, Pavel Janda, Andrew W. Nevin, Sebastian M. Marcuccio, Herman Lam, Clifford C. Leznoff
• Article: 1,8-Naphthalene Linked Cofacial Binuclear Phthalocyanines

  A.B.P. Lever, Pavel Janda, Nagao Kobayashi, Andrew W. Nevin, Herman Lam, Clifford C. Leznoff
• Article: Dioxgen Reduction at a Graphite Electrode Modified by Mononuclear Tetraneopentoxyphthalocyaninatocobalt (II) and Related Polynuclear Species

  A.B.P. Lever, Clifford C. Leznoff, Herman Lam, Pamela R. Auburn, Nagao Kobayashi, Pavel Janda
• Article: The Synthesis of Phthalocyanines at Room Temperature

  Kieran J. M. Nolan, Mougang Hu, Clifford C. Leznoff
• Article: The Asymmetric Synthesis of 4,4-Dimethyl-3-substitutedbutyrolactones

  Mark Whittaker, Colin R. McArthur, Clifford C. Leznoff
• Source

  Available from: Dmitri S Terekhov

  Article: Synthesis and NMR Studies of a Single Isomer of an Alkynyl Substituted Binuclear Phthalocyanine

  Hiroaki Isago, Dmitri S. Terekhov, Clifford C. Leznoff
• Article: The Syntheses of Octaalkynylphthalocyanines From Halophthalonitriles

  Dmitri S. Terekhov, Anna M. D'Ascanio, Hiroaki Isago, Zhaopeng Li, Clifford C. Leznoff