Zobrazeno 1 - 10 of 475 pro vyhledávání: '"D. M. Brouwer"'
1
Alkyltetrahydrofuryl and -pyryl cations: Formation by cyclization of protonated alkenones and transformations in different acids
Autor: D. M. Brouwer
Publikováno v: Recueil des Travaux Chimiques des Pays-Bas. 88:530-544
A PMR spectroscopic study has been made of the protonation of 1-hexen-5-one (I), 2-methyl-l-hexen-5-one (II), 2-hepten-6-one (III) and 2-methyl-2-hepten-6-one (IV) in different acids (HF, HF-SbF5, H2SO4, FSO3H, FSO3H-SbF5). With two exceptions, the f
Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::0721d8a6cc88e0ce3f578c2660f968a6
https://doi.org/10.1002/recl.19690880504
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2
Kinetics of rearrangements of methylbenzenium ions in HF
Autor: D. M. Brouwer
Publikováno v: Recueil des Travaux Chimiques des Pays-Bas. 87:611-622
Rate constants and activation parameters of the following methylbenzenium ion rearrangements have been determined by direct measurement in HF containing SbF5: o-xylenium and p-xylenium to m-xylenium, 1,2,3,4- to 1,2,3,5-tetramethylbenzenium, 1,2,3- t
Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::b8a5ebe8767a2aa6f7b5abb9e95e5c2f
https://doi.org/10.1002/recl.19680870603
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3
Reactions of hydroxycarbonium ions in strong acids. VII: Rearrangement of the 2,5,5-trimethyldihydrofuryl ion, a heteroaromatic carbonium-ion rearrangement
Autor: J. A. Van Doorn, A. A. Kiffen, D. M. Brouwer
Publikováno v: Recueil des Travaux Chimiques des Pays-Bas. 91:1359-1363
The rearrangement of 2,5,5- to 2,4,5-trimethyldihydrofuryl ion, a heteroaromatic rearrangement via 1,2-methyl and hydride shifts, is reported. The half-life of the reaction is about 25 minutes at 100°.
Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::b20a94a0848ab004c72101688ad3799b
https://doi.org/10.1002/recl.19720911111
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4
Alkenesulfonic acids: PMR spectra and rates of base- and acid-catalysed double-bond isomerization and hydrogen-deuterium exchange reactions
Autor: J. A. Van Doorn, D. M. Brouwer
Publikováno v: Recueil des Travaux Chimiques des Pays-Bas. 88:1041-1057
Proton magnetic resonance spectra of a number of simple alkenesulfonic acids and related hydroxyalkanesulfonic acids have been measured. The compound described in the literature as 2-methylpropene-1,3-disulfonic acid (I) has been found to be 2-methyl
Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::442cc981428eed4b0001ea3fe6ea8a62
https://doi.org/10.1002/recl.19690880904
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5
Protonation of 9-ethyl-10-methylanthracene: Absence of a large Baker-Nathan effect in alkylarenium-ion formation
Autor: D. M. Brouwer, J. A. Van Doorn
Publikováno v: Recueil des Travaux Chimiques des Pays-Bas. 89:88-96
Protonation of 9-ethyl-10-methylanthracene in HF or CF3COOH/H2O · BF3 affords a mixture of the 9H+- and 10H+-9-ethyl-10-methylanthracenium ions. These ions differ in free energy by only 0.9-1.0 kcal · mole−1. This small difference in stability, w
Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::5d42d532c3c44e3b71a5167284673c00
https://doi.org/10.1002/recl.19700890113
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7
Rearrangements of 1,2,3,4,5-, 1,2,4,4,5-, 1,3,4,4,5- and 1,2,3,4,4-pentamethylcyclopentenyl ions and of 1,3,4,4,5,5- and 1,2,3,4,4,5-hexamethylcyclopentenyl ions. stability of pentamethylcyclopentenyl ions
Autor: J. A. Van Doorn, D. M. Brouwer
Publikováno v: Recueil des Travaux Chimiques des Pays-Bas. 89:333-352
A detailed investigation has been made of the reversible rearrangement of the 1,2,3,4,5-pentamethylcyclopentenyl ion (1) to the 1,2,3,4,4-pentamethylcyclopentenyl ion (3). In 5: 1 FSO3H-SbF5 this reaction proceeds entirely intramolecularly by 1,2-hyd
Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::a197ae2c4d298548b29f7c770d540a12
https://doi.org/10.1002/recl.19700890402
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8
Protonation of halogen-containing benzenes in HF-SbF5. Part I.: PMR spectra of fluoro-, chloro- and bromomesitylenium and xylenium ions
Autor: D. M. Brouwer
Publikováno v: Recueil des Travaux Chimiques des Pays-Bas. 87:335-341
2-Fluoro-, chloro- and bromomesitylenes, and 5-fluoro-, chloro- and bromo-m-xylenes have been found to form stable benzenium ions in HF-SbF5. The cations give well-resolved PMR spectra, from which their structures have been derived. The 2-halomesityl
Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::cee596c882cdd17515154f8f7daac015
https://doi.org/10.1002/recl.19680870313
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10
Reactions of hydroxycarbonium ions in strong acids VIII. Cyclization of hydroxyallyl to tetrahydrofuryl ions and related reactions
Autor: D. M. Brouwer, J. A. van Doom, A. A. Kiffen
Publikováno v: Recueil des Travaux Chimiques des Pays-Bas. 94:198-203
The cyclization of hydroxyallyl ions (protonated 3-alken-2-ones) to tetrahydrofuryl ions in a series of strong acids (HF, H2SO4, FSO3H) and superacids (FSO3HSbF5, HFSbF5) has been studied, together with some related reactions. The rates of cyclizatio
Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::03cf9a1b458009f2299278fee067a34e
https://doi.org/10.1002/recl.19750940808
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