Mononuclear rearrangement of heterocycles in zwitterionic micelles of amine oxide surfactants.
Rate constants for the mononuclear rearrangement (MRH) of Z-phenylhydrazones of some 5-substituted-3-benzoyl-1,2,4-oxadiazoles in water have been measured in the presence of zwitterionic micelles. The use of micellized N-tetradecyl-N,N-dimethylamineoxide (C(14)DMAO) as the reaction medium allowed to solubilize the otherwise water-insoluble oxadiazoles. Micellar rate effects were analyzed by using a simple pseudo-phase model and compared with those obtained in non-ionic micelles (Triton X-100). Evidence that both the rate of the rearrangement reaction and the binding of the substrates to the micelles are mainly governed by substrate hydrophobicity is obtained. The disagreement with the primarily sterically controlled MRH in Triton X-100 micelles highlights large and intriguing differences between the two micellar environments.
Dipartimento di Chimica Organica A. Mangini, Università degli Studi di Bologna, Via S. Giacomo 11, 40126 Bologna, Italy.
Susanna
S
Guernelli
Antonella
A
Fontana
Renato
R
Noto
Domenico
D
Spinelli
Maria Liria
ML
Turco Liveri
D004123:Dimethylamines / Q000737:chemistry*; D006835:Hydrazones / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008823:Micelles; D009227:Myristic Acids / Q000737:chemistry*; D017830:Octoxynol / Q000737:chemistry*; D010069:Oxadiazoles / Q000737:chemistry*; D012995:Solubility; D021241:Spectrometry, Mass, Electrospray Ionization; D013501:Surface-Active Agents / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D004123:Dimethylamines; D006835:Hydrazones; D008823:Micelles; D009227:Myristic Acids; D010069:Oxadiazoles; D013501:Surface-Active Agents; D014867:Water; D017830:Octoxynol; C518255:myristyldimethylamine oxide