University of the Pacific
Diastereoselective acylation of trans-2-substituted-cyclohexanols and glycosidase inhibition studies
Abstract
dc:description.abstract<p>Part I. The reaction between chiral acyl chlorides and trans -2-substituted-cyclohexanols proceeds diastereoselectively, i.e. produces mixtures of unequal amounts of diastereomers. We found for the first time that addition of pyridine or diisopropylethylamine accelerates the acylation, and unexpectedly for some substituents (RX) may completely invert its diastereoselectivity. These observations have been rationalized in terms of a stereoselective intramolecular assistance by the RX group to the acylation of the neighboring hydroxyl ("bait-and-hook" mechanism). A series of trans -2-substituted-cyclohexanols were synthesized and acylated with a racemic reagent in presence and absence of pyridine. The results showed that the presence of a nucleophilic group on the second carbon allowed for the preferred formation of one of the diastereomers in the absence of pyridine. However, in the presence of pyridine, the diastereoselectivity would inverse, and the reaction would favor the formation of the other diastereomer. To test the intramolecular acyl transfer hypothesis in detail a series of thioglucosides has been synthesized. Part II. The synthesized thioglucosides were tested as inhibitors of fungal glycosidases. Two compounds showed greater than 80% inhibition values in excess of the activity of β-D-glucosidases. More interestingly, the same compounds showed a marked enhancement of α-D-galactosidase activity by as much as 35%.</p>
Degree
thesis:*- Name thesis:degree_name
- Master of Science (M.S.)
- Level thesis:degree_level
- Thesis - Pacific Access Restricted
- Discipline thesis:degree_discipline
- Chemistry
- Year dc:date.available
- 2011
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Samoshin, Andrey V.
- Contributors dc:contributor
-
- Andreas Franz
Subjects
dc:subject × 10Rights
dc:rightsIdentifiers
dc:identifier.*- Identifier
- 9781124933740
- OAI identifier oai:identifier
- oai:scholarlycommons.pacific.edu:uop_etds-1274