Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Epoxidation versus hydroxylation

Figure 16.1-17. Hydroxylation versus epoxidation of two spiro-bicyclic amides. Figure 16.1-17. Hydroxylation versus epoxidation of two spiro-bicyclic amides.
The structure-activity study of the ryanoids showed that both C-l and C-14 substituents play an important role in their antifeedant and toxic activity against S. littoralis, as previously shown for their antifeedant effects on S. litura [10]. The p-stereochemistry at C-l (5 versus 3) and its O- acetylation (4), increased the toxic and/or antifeedant activity of these compounds. Hydroxylation (1), 0- acetylation (2) and pyrrolcarboxylate-esterification (10) at C-l 4 along with the hydrophobicity of the cyclohexane ring (6) resulted in intermediate activities. Additionally, the presence of a C-2/C-3 epoxide (15,16) increased the toxicity against this lepidopteran (table 2, Figure (1)) [17]. [Pg.853]

The polarity of the pocket and hydrogenbonding machinery were found to increase the dominance of the LS reactivity in arene hydroxylation and the HS reactivity in sulfoxidation. Similarly, these factors will have a strong impact on the appearance of cationic intermediates during hydroxylation and epoxidation. More intriguing is the result that these properties of the protein pocket have a major impact on the regioselectivity of C-H hydroxylation versus C=C epoxidation as well as on the stereospecificity of both processes. Time will show whether these are generalities or isolated findings. [Pg.79]

Oxidation to phenols, dihydrodiols, catechols, quinones, and acids are the principal reactions of most hydrocarbons. Catechols probably develop by hydrolysis of an epoxide to a dihydrodiol followed by dehydrogenation (see Fig. 4). The hydroxylases operate independently of the glutathione S-transferaaes. Evidently the relative amount of hydroxylation versus conjugation with glutathione for a particular hydrocarbon depends on the relative rates of competing reactions. [Pg.285]


See other pages where Epoxidation versus hydroxylation is mentioned: [Pg.1086]    [Pg.1086]    [Pg.229]    [Pg.55]    [Pg.1708]    [Pg.82]    [Pg.527]    [Pg.608]    [Pg.8519]    [Pg.78]   
See also in sourсe #XX -- [ Pg.79 ]




SEARCH



Epoxides hydroxyls

© 2024 chempedia.info