Three different synthetic approaches toward N-[(2SR, 4S)-4-hydroxy-2,5-dimethyl-3-oxohexanoyl]-Lleucine methyl esters were carried out by use of i) aldol condensation and amination ii) Claisen condensation and soft acid coupling reaction iii) methylation of Hia-Leu derivative in relatively high yields. (4S)-3-[(2SR,4S)-2,5-Dimethyl-1,3-dioxo-4-(methoxyethoxymethyloxy) hexyl]-4-(1-methylethyl)-2-oxazolidinone was prepared by the reaction of aldol condensation of lithium enolate of Evans' chiral auxilary in 80 : 20 diastereomeric ratio. A new method for the synthesis of (4S)-4-(t-butoxycarbonyl)amino-5-methyl-3- oxoheptanoic acid ethyl ester (Statone) was developed by the reaction of Boc-leucine with Meldrum's acid, followed by transesterification and decarboxylation in modest yield. Other a-amino acids also were applied to this methodology in successful yields. Attempts to prepare the linear molecule, containing Statone-(4S)-5-methyl- 3-oxohexanoyl- Leu-OCpa, an analogue of Epista-Hip-Leu, was not successful.
| Identifer | oai:union.ndltd.org:UTAHS/oai:digitalcommons.usu.edu:etd-8315 |
| Date | 01 May 1988 |
| Creators | Kim, Ok-Soon |
| Publisher | DigitalCommons@USU |
| Source Sets | Utah State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | All Graduate Theses and Dissertations |
| Rights | Copyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact digitalcommons@usu.edu. |
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