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Synthesis, autoxidation and photooxidation of hindered pyrrole derivatives. Hindered pyrrolic nitroxide radicals; Synthese, autoxydation et photoxidation de pyrroles encombres radicaux nitroxydes pyrroliques encombres

Abstract

2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole are prepared from pinacoline and their structure is confirmed by comparison with 2,5-di-t-butyl furan and thiophene (I.R., U.V. and N.M.R. {sup 13}C satellites observation giving J{sub 13{sub C-H}} and J{sub H{sub 3}-H{sub 4}}). The sensitized photooxidation of these hindered pyrroles gives corresponding hydroperoxides which most likely structure is determined using physical and chemical methods. Oxidation of 2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole by hydrogen peroxide in presence of inorganic per-acid of by p-nitro-perbenzoic acid does not give the pyrrolic nitroxides in contrast with secondary amines. Some N-hydroxypyrroles are then prepared from pinacoline and ethyl pivaloyl-acetate. Their oxidation by lead dioxide gives the corresponding pyrrolic nitroxides. 2,5-di-t-butyl 3,4-di-ethoxycarbonyl pyrryl 1-oxy is isolated and studied spectroscopically (visible and U.V., E.P.R.). In marked contrast with ordinary nitroxides it does not show solvent effect. It can be compared with 2,4-di-t-butyl cyclopentadienone, a carbon analog. For both, the long wave length transition does not show the usual n - {pi}* behaviour; that is confirmed by E.P.R. Using Huckel method for pyrrolic nitroxide skeleton, it is possible to have a good interpretation of experimental data. (author) [French] Les di-t-butyl 2,5 et tri-t-butyl-2,3,5 pyrrole sont synthetises a partir de la pinacoline et leur structure confirmee  More>>
Authors:
Ramasseul, R [1] 
  1. Commissariat a l'Energie Atomique, Grenoble (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1969
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-3737
Resource Relation:
Other Information: TH: These docteur es sciences physiques; 134 refs; PBD: 1969
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ALKYLATION; BENZOIC ACID; BUTYL RADICALS; CARBONYL RADICALS; COUPLING CONSTANTS; ETHOXY RADICALS; ETHYL RADICALS; FURANS; HYDROGEN PEROXIDE; HYDROXY COMPOUNDS; HYPERFINE STRUCTURE; INFRARED SPECTRA; ISOMERS; LANDE FACTOR; LEAD OXIDES; NMR SPECTRA; OXIDATION; PHOTOCHEMICAL REACTIONS; POLYCYCLIC SULFUR HETEROCYCLES; PYRROLES; SYNTHESIS; ULTRAVIOLET SPECTRA
OSTI ID:
20528735
Research Organizations:
CEA Grenoble, 38 (France); Grenoble-Univ., Faculte des Sciences, 38 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR04R3737095001
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
[117] pages
Announcement Date:

Citation Formats

Ramasseul, R. Synthesis, autoxidation and photooxidation of hindered pyrrole derivatives. Hindered pyrrolic nitroxide radicals; Synthese, autoxydation et photoxidation de pyrroles encombres radicaux nitroxydes pyrroliques encombres. France: N. p., 1969. Web.
Ramasseul, R. Synthesis, autoxidation and photooxidation of hindered pyrrole derivatives. Hindered pyrrolic nitroxide radicals; Synthese, autoxydation et photoxidation de pyrroles encombres radicaux nitroxydes pyrroliques encombres. France.
Ramasseul, R. 1969. "Synthesis, autoxidation and photooxidation of hindered pyrrole derivatives. Hindered pyrrolic nitroxide radicals; Synthese, autoxydation et photoxidation de pyrroles encombres radicaux nitroxydes pyrroliques encombres." France.
@misc{etde_20528735,
title = {Synthesis, autoxidation and photooxidation of hindered pyrrole derivatives. Hindered pyrrolic nitroxide radicals; Synthese, autoxydation et photoxidation de pyrroles encombres radicaux nitroxydes pyrroliques encombres}
author = {Ramasseul, R}
abstractNote = {2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole are prepared from pinacoline and their structure is confirmed by comparison with 2,5-di-t-butyl furan and thiophene (I.R., U.V. and N.M.R. {sup 13}C satellites observation giving J{sub 13{sub C-H}} and J{sub H{sub 3}-H{sub 4}}). The sensitized photooxidation of these hindered pyrroles gives corresponding hydroperoxides which most likely structure is determined using physical and chemical methods. Oxidation of 2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole by hydrogen peroxide in presence of inorganic per-acid of by p-nitro-perbenzoic acid does not give the pyrrolic nitroxides in contrast with secondary amines. Some N-hydroxypyrroles are then prepared from pinacoline and ethyl pivaloyl-acetate. Their oxidation by lead dioxide gives the corresponding pyrrolic nitroxides. 2,5-di-t-butyl 3,4-di-ethoxycarbonyl pyrryl 1-oxy is isolated and studied spectroscopically (visible and U.V., E.P.R.). In marked contrast with ordinary nitroxides it does not show solvent effect. It can be compared with 2,4-di-t-butyl cyclopentadienone, a carbon analog. For both, the long wave length transition does not show the usual n - {pi}* behaviour; that is confirmed by E.P.R. Using Huckel method for pyrrolic nitroxide skeleton, it is possible to have a good interpretation of experimental data. (author) [French] Les di-t-butyl 2,5 et tri-t-butyl-2,3,5 pyrrole sont synthetises a partir de la pinacoline et leur structure confirmee par comparaison avec les di-t-butyl-2,5 furanne et thiophene (I.R., U.V. et R.M.N.: observation des satellites {sup 13}C conduisant a la mesure des J{sub 13{sub C-H}} et J{sub H{sub 3}{sub -H{sub 4}}). La photoxydation sensibilisee de ces pyrroles encombres conduit aux hydroperoxydes correspondants dont la structure la plus probable est determinee par les methodes physicochimiques. L'oxydation des di-t-butyl-2,5 et tri-t-butyl-2,3,5 pyrrole par l'eau oxygenee en presence de peracide mineral ou par l'acide p-nitroperbenzoique ne conduit pas comme dans le cas des amines secondaires aux nitroxydes correspondants. Divers N-hydroxy-pyrroles ont alors ete synthetises en partant de la pinacoline et du pivaloylacetate d'ethyle. L'oxydation de ceux-ci par le bioxyde de plomb conduit aux nitroxydes pyrroliques correspondants. L'oxyl-1 di-t-butyl-2,5 diethoxycarbonyl-3,4 pyrrole a pu etre isole et etudie spectroscopiquement (U.V. et visible, R.P.E. ). Par opposition aux nitroxydes habituellement etudies, celui-ci ne presente pas d'effet de solvant ce qui est a rapprocher d'un de ses homologues carbones, la di-t-butyl-2,4 cyclopentadienone. Dans les deux cas, la transition de plus grande longueur d'onde ne se comporte pas comme une transition n - {pi}{sup *} et la R.P.E. confirme ce comportement anormal. L'application de la methode de Hueckel au squelette des nitroxydes pyrroliques donne une bonne interpretation des resultats experimentaux. (auteur)}
place = {France}
year = {1969}
month = {Jul}
}