Preparation of amides from acids and resin bound azides: Suppression of intramolecular lactam formation
โ Scribed by Zhilian Tang; Jeffrey C. Pelletier
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- French
- Weight
- 210 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0040-4039
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โฆ Synopsis
A new method for the formation of amides on solid phase has been developed. The procedure involves the reaction between activated acids in solution and resin bound iminophosphoranes generated from the corresponding azides and tributylphosphine. The method is particularly attractive when starting from 8 azido acids since amides can form without internal cyclization to the lactam.
๐ SIMILAR VOLUMES
We studied the coupling of thiocarboxylic acid and alkyl azide using various triaryl phosphines. Amide formation greater than 95% was achieved when the free-formation of Staudinger intermediate with electron deficient triaryl phosphines was employed.
Resin-bound N-acylated amino acid aldehydes iv were converted in a single step to a-hydroxy phosphonates vii (Pudovik reaction) and in six-steps to hydroxystatine amides viii, demonstrating the utility of intermediates iv for constructing multiple aspartic acid transition-state isosteres.