Approaches to the preparation of echinodithianic acid (5) from 2, 5-dicarbomethoxy-1, 4-dithiane (1) were not successful, due to the inability to carboxylate or carboalkoxylate 1 at carbons 2 and 5. Studies toward the synthesis of 5 utilizing methyl 2-acetamidoacrylate (8) have been investigated. The electrophilic addition of sulfur dichloride to 8 yielded bis-( 2-acetamido-2-carbo-methoxyvin- 1-yl) sulfide, while the addition of thiocyanogen chloride to 8 produced methyl 2-acetamido-J-thiocyanato-acrylate.
As electrophilic additions of unsymmetrical dipolar reagents to methyl 2-acetamidoacrylate (8) are not reported in the literature, the addition of hydrogen bromide to 8 was studied to determine the orientation effect of the acetamido group.
Methyl 2-acetamido-2-bromopropionate (69) was found to be the kinetically favored adduct, while under equilibrium conditions the Michael addition product, methyl 2-acetamido-3- bromopropionate (68), was favored.
The rates of exchange of the acetyl (a) and the N-methyl (b) protons from the cis to the trans form of methyl N-acetylsarcosinate (72) were measured by a total NMR lineshape method and found to be the same within the limits of the experimental method. Thermodynamic activation parameters are reported,
From these data it was concluded that the exchanges of each of the four types of protons (a, b, c, d) in 72 depend solely on hindered rotation about the amide C-N bond.
| Identifer | oai:union.ndltd.org:UTAHS/oai:digitalcommons.usu.edu:etd-8308 |
| Date | 01 May 1971 |
| Creators | Love, Alan LeRoy |
| 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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