A isomerization

Figure A3.12.1. Schematic potential energy profiles for tluee types of iinimolecular reactions, (a) Isomerization, (b) Dissociation where there is an energy barrier for reaction in both the forward and reverse directions, (c) Dissociation where the potential energy rises monotonically as for rotational gronnd-state species, so that there is no barrier to the reverse association reaction. (Adapted from [5].)...

A -Reduction and —A -Isomerization Inhibitors. Only one group of compounds that act as inhibitors for both the A -reduction... 

A. Isomerization of Isoxazoles Bearing Electron-Donating Groups. 60... 

Substituted perhydropyrido[l,2-n]pyrazines were reacted with 2-fluorobenzohydroximinoyl chlorides in the presence of DBU in CHCI3 to yield a isomeric mixture of 7-substituted 2-[(hydroxyimino)phenylmethyl]-perhydropyrido[l, 2-u]pyrazines (99MIP9). 

Isolieruug,/. isolation insulation. Isolier-vermSgen, n. insulating power, -werk-stoff, m. insulating niaterial. -zustand, m. state of insulation or isolation, isolog, a. isologous, isomer, a. isomeric. 

Benjamin, I. Pohorille, A., Isomerization reaction dynamics and equilibrium at the liquid-vapor interface of water. A molecular dynamics study, J. Chem. Phys. 1993, 98, 236-242... 

Pohorille, A. Wilson, M.A. Isomerization reactions at aqueous interfaces, in Reaction Dynamics in Clusters and Condensed Phases — The Jerusalem Symposia on Quantum Chemistry and Biochemistry, lortner, J. Levine, R. Pullman, B., Eds., vol. 26. Kluwer Dordrecht, 1993, p. 207... 

Scheme 6 a Isomerization of 3-agostic propyl complexes 1.19 and 1.20. b Isomerization and trapping by ethylene of tert-butyl complex 1.22, showing unfavorability of ethylene complexation to 3° agostic complexes... 

A. Isomerization and Formation of HH and HT Pt(II) Dimer Complexes Studied by NMR Spectroscopy... 

As shown for 65 and 66 in Scheme 16, compounds of this particular formula type can also undergo an intermolecular ligand exchange in solution ([D6]DMSO, room temperature detection of the thermodynamic equilibrium 65 + 66 2 76).47 However, this ligand exchange is significantly slower than the intramolecular (A)/(A)-isomerization mentioned earlier. 

Levsen, K. Heimbach, H. Shaw, G.J. MUne, G.W.A. Isomerization of Hydrocarbon Ions. VIII. The Electron Impact Induced Decomposition of n-Dodecane. Org. Mass Spectrom. 1977, 72, 663-670. 

Rate parameters for these classes a isomerizations are extremely scarce. Our computational studies, however, suggest that for 1,2 hydrogen shift in alkanes, barrier heights should be about 25-40 kcal/mol, the same order of magnitude as the strain energy associated with the formation of three-centered rings. In Table XI some values reported in the literature are also presented (Dente and Ranzi, 1983). 

Although termed "SI" or "EBI" compounds, the latter referring to ergosterol biosythesis inhibitors, these compounds do not all inhibit ergosterol biosynthesis at the same metabolic site (Fig. 2). For instance, the fungicide tridemorph, unlike most EBI compounds, does not inhibit demethylation at C-14 but rather it apparently prevents the A A isomerization resulting in the accumulation of A containing sterols in treated cells (3). 

From the base-catalyzed degradation of D-fructose (pH 8.0), Shaw and coworkers147 identified 18 compounds, none of which was (a) isomeric with the starting material, or (b) a simple dehydration product. Among the products, the hydroxy-2-butanones and 1-hydroxy-2-propanone (acetol) were shown to participate in forming the carbo-cyclic products identified, but the mechanism of their formation was not elucidated. Several furan derivatives were isolated, but no lactic acid was isolated. In a similar study but with weak acid,41 most of the products were formed by a combination of enolization and dehydration steps, with little fragmentation. 

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