486439-56-9Relevant academic research and scientific papers
A general approach to dehydro-Freidinger lactams: Ex-chiral pool synthesis and spectroscopic evaluation as potential reverse turn inducers
Hoffmann, Tobias,Waibel, Reiner,Gmeiner, Peter
, p. 62 - 69 (2007/10/03)
Starting from natural α-amino acids, a practical synthesis of the dehydro-Freidinger lactams 9a-h based on the ring-closing olefin metathesis reaction was investigated. The presented examples comprise 6-, 7-, 8-, 9-, and 10-membered cyclic dipeptide mimics. Structural variations were demonstrated. We approached the metathesis precursors 8a-h employing an N-alkylation/peptide-coupling strategy. Subsequent ring closure was promoted by the ruthenium-based catalyst 10a or 10b. The resulting tetraresidue 11d was shown to undergo intramolecular hydrogen bonding based on NMR and FT-IR studies. Thus, the development of dehydro-Freidinger lactams as potential reverse turn inducers stabilizing an intramolecular NHi+3...COi hydrogen-bond was demonstrated.
