What is the Structure of Peptide Antibiotic Tü 1718 B? Previously Proposed Structure Disproved by Synthesis
✍ Scribed by Postels, Hans-Thomas ;König, Wilfried A.
- Book ID
- 102903212
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 819 KB
- Volume
- 1992
- Category
- Article
- ISSN
- 0947-3440
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Two stereoisomers (1a and 1b) of N‐(L‐valyl)‐2′,5‐dihydroxyhomoproline, the proposed structure of the dipeptide antibiotic Tü 1718 B, were synthesized by starting from natural (2__S__,4__R__)‐hydroxyproline. The ^1^H‐ and ^13^C‐NMR spectra of 1a and 1b clearly differ from the corresponding spectra of the natural product. From both synthetic stereoisomers characteristic mass spectra were obtained after esterification and trifluoroacetylation. Isomer 1a is present as a mixture of two stable conformers, as indicated by peak splitting in the^1^H‐NMR spectra, which disappears at higher temperature, while 1b exits as a single conformer. Both synthetic stereoisomers are antibiotically inactive.