Paul Kropp - Academia.edu (original) (raw)
Papers by Paul Kropp
J Am Chem Soc, 1981
nitrile-tert-butyl alcohol was irradiated at 254 nm for various periods of time. Results of the G... more nitrile-tert-butyl alcohol was irradiated at 254 nm for various periods of time. Results of the GC analysis of the samples before and after irradiation are given in Stern-Volmer Quenching Studies. A range of concentrations of cis-1,3-pentadiene for a given benzyl chloride was made with use of the benzyl chloride and 20% acetonitrile-tert-butyl alcohol. The concentration of the benzyl chloride was such that at least 99% of the incident light during the irradiations would be absorbed by the chloride. Samples, one of each concentration, were irradiated and analyzed for aryl tertbutyl ether, using column A. Data and results are given in .
Encyclopedia of Reagents for Organic Synthesis, 2001
ABSTRACT
Journal of the American Chemical Society, 1974
a) Since only 0.24 M docosane is-produced. and since kd/k, for primary radicals is 0.15.22 only 0... more a) Since only 0.24 M docosane is-produced. and since kd/k, for primary radicals is 0.15.22 only 0.036 M, or 20%. of the undecane is prcduced in disproportionation reactions. Thi s undecane does not interfere because we follow substrate disappearance, not product appearance. (b) The average decrease in the concentration of the substituted toluenes, 12% (0.1 M), is less than the amount of undecane formed (0.18 M). We cannot'account for all of the excess undecane. but ca. 0.03 M of it arises from disproportionation. (c) In a solution of 0.8 M toluene in benzene, the amount of undecyibenzene formed (0.024 M ) is less than half that formed by thermolysis of 0.6 M LPO in neat benzene (0.053 M). Shelton, in his study of homolytic aromatic cyclohexybtion, reports a similar change in addition product (arylcyclohexane) yield when the solvent was changed from toluene to benzene. J. R. Shelton and C. W. Uzelmeier, J. Amer. Chsm. Soc., 88, 5222 (1966). especially p 5223. (d) Important termination reactions are U-combinations to give docosane and benzyl radical combination to form bibenzyls. (22) M. J. Gibian and R. C. Corky, Chem. Rev., 73, 441 (1973). (23) Preliminary studies of methyl radical addition to substituted benzenes indicate a p = 0 and an abstraction to addition ratio for toluene greater than ten.24a Other studies of addhion/abstraction ratios have been reported: (1) Piyor's compilation of his and that of Szwarc2" for methyl radicals predicts a relative reactivity of toluene to benzene of 2: 1. Since these workers obtained data at different temperatures, this ratio may not be very accurate.
Journal of the American Chemical Society, 1968
Journal of the American Chemical Society, 1976
Journal of the American Chemical Society, 1983
Journal of the American Chemical Society, 1974
Journal of the American Chemical Society, 1973
The Journal of Organic Chemistry, 1975
The Journal of Organic Chemistry, 1982
Page 1. 1904 J. Org. Chem. 1982,47, 1904-1909 80963-52-6; triphenyl(3-butenyl) stannane, 29972-16... more Page 1. 1904 J. Org. Chem. 1982,47, 1904-1909 80963-52-6; triphenyl(3-butenyl) stannane, 29972-16-5; trimethyl(5-hexenyl)stannane, 73017-74-0; trimethyl( cyclopenty1methyl)stan-nane, 73017-75-1; triphenyl(cyclopentylmethyl ...
The Journal of Organic Chemistry, 1994
Page 1. 3102 J. Org. Chem. 1994,59, 3102-3112 Surface-Mediated Reactions. 4. Hydrohalogenation of... more Page 1. 3102 J. Org. Chem. 1994,59, 3102-3112 Surface-Mediated Reactions. 4. Hydrohalogenation of Alkynes' Paul J. Kropp' and Scott D. Crawford Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290 Received October 5, 19938 ...
The Journal of Organic Chemistry, 1967
The Journal of Organic Chemistry, 1967
Canadian Journal of Chemistry, 1985
Chemischer Informationsdienst, 1973
The Journal of Organic Chemistry, Sep 1, 2000
OXONE over silica gel or, in some cases, alumina has been found to oxidize the primary and second... more OXONE over silica gel or, in some cases, alumina has been found to oxidize the primary and secondary amines 3 selectively to the corresponding hydroxylamines 4, in either the presence or absence of a solvent. Treatment of Boc-protected L-lysine (6) under the latter conditions afforded hydroxylamine 7 in excellent yield. The trialkylamine 1a and pyridine (1b), in which selectivity is not an issue, were readily oxidized to the corresponding oxides 2 by OXONE over silica gel or alumina, as well as by (CH(3))(3)COOH over silica gel. Solvent-free oxidation assisted by microwave irradiation was more forcing, while still affording the hydroxylamines 4 selectively, and is the synthetic method of choice. The mechanistic aspects of these reactions are discussed.
J Am Chem Soc, 1981
nitrile-tert-butyl alcohol was irradiated at 254 nm for various periods of time. Results of the G... more nitrile-tert-butyl alcohol was irradiated at 254 nm for various periods of time. Results of the GC analysis of the samples before and after irradiation are given in Stern-Volmer Quenching Studies. A range of concentrations of cis-1,3-pentadiene for a given benzyl chloride was made with use of the benzyl chloride and 20% acetonitrile-tert-butyl alcohol. The concentration of the benzyl chloride was such that at least 99% of the incident light during the irradiations would be absorbed by the chloride. Samples, one of each concentration, were irradiated and analyzed for aryl tertbutyl ether, using column A. Data and results are given in .
Encyclopedia of Reagents for Organic Synthesis, 2001
ABSTRACT
Journal of the American Chemical Society, 1974
a) Since only 0.24 M docosane is-produced. and since kd/k, for primary radicals is 0.15.22 only 0... more a) Since only 0.24 M docosane is-produced. and since kd/k, for primary radicals is 0.15.22 only 0.036 M, or 20%. of the undecane is prcduced in disproportionation reactions. Thi s undecane does not interfere because we follow substrate disappearance, not product appearance. (b) The average decrease in the concentration of the substituted toluenes, 12% (0.1 M), is less than the amount of undecane formed (0.18 M). We cannot'account for all of the excess undecane. but ca. 0.03 M of it arises from disproportionation. (c) In a solution of 0.8 M toluene in benzene, the amount of undecyibenzene formed (0.024 M ) is less than half that formed by thermolysis of 0.6 M LPO in neat benzene (0.053 M). Shelton, in his study of homolytic aromatic cyclohexybtion, reports a similar change in addition product (arylcyclohexane) yield when the solvent was changed from toluene to benzene. J. R. Shelton and C. W. Uzelmeier, J. Amer. Chsm. Soc., 88, 5222 (1966). especially p 5223. (d) Important termination reactions are U-combinations to give docosane and benzyl radical combination to form bibenzyls. (22) M. J. Gibian and R. C. Corky, Chem. Rev., 73, 441 (1973). (23) Preliminary studies of methyl radical addition to substituted benzenes indicate a p = 0 and an abstraction to addition ratio for toluene greater than ten.24a Other studies of addhion/abstraction ratios have been reported: (1) Piyor's compilation of his and that of Szwarc2" for methyl radicals predicts a relative reactivity of toluene to benzene of 2: 1. Since these workers obtained data at different temperatures, this ratio may not be very accurate.
Journal of the American Chemical Society, 1968
Journal of the American Chemical Society, 1976
Journal of the American Chemical Society, 1983
Journal of the American Chemical Society, 1974
Journal of the American Chemical Society, 1973
The Journal of Organic Chemistry, 1975
The Journal of Organic Chemistry, 1982
Page 1. 1904 J. Org. Chem. 1982,47, 1904-1909 80963-52-6; triphenyl(3-butenyl) stannane, 29972-16... more Page 1. 1904 J. Org. Chem. 1982,47, 1904-1909 80963-52-6; triphenyl(3-butenyl) stannane, 29972-16-5; trimethyl(5-hexenyl)stannane, 73017-74-0; trimethyl( cyclopenty1methyl)stan-nane, 73017-75-1; triphenyl(cyclopentylmethyl ...
The Journal of Organic Chemistry, 1994
Page 1. 3102 J. Org. Chem. 1994,59, 3102-3112 Surface-Mediated Reactions. 4. Hydrohalogenation of... more Page 1. 3102 J. Org. Chem. 1994,59, 3102-3112 Surface-Mediated Reactions. 4. Hydrohalogenation of Alkynes' Paul J. Kropp' and Scott D. Crawford Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290 Received October 5, 19938 ...
The Journal of Organic Chemistry, 1967
The Journal of Organic Chemistry, 1967
Canadian Journal of Chemistry, 1985
Chemischer Informationsdienst, 1973
The Journal of Organic Chemistry, Sep 1, 2000
OXONE over silica gel or, in some cases, alumina has been found to oxidize the primary and second... more OXONE over silica gel or, in some cases, alumina has been found to oxidize the primary and secondary amines 3 selectively to the corresponding hydroxylamines 4, in either the presence or absence of a solvent. Treatment of Boc-protected L-lysine (6) under the latter conditions afforded hydroxylamine 7 in excellent yield. The trialkylamine 1a and pyridine (1b), in which selectivity is not an issue, were readily oxidized to the corresponding oxides 2 by OXONE over silica gel or alumina, as well as by (CH(3))(3)COOH over silica gel. Solvent-free oxidation assisted by microwave irradiation was more forcing, while still affording the hydroxylamines 4 selectively, and is the synthetic method of choice. The mechanistic aspects of these reactions are discussed.