The conformational preferences of chiral vinylogous aminosulfonic acids (vs-amino acids) and of the corresponding oligomers (vs-peptide) were investigated by a combination of X-ray crystallography, variable-temperature (VT) H-1 NMR spectroscopy, FT-IR spectroscopy, and NOE experiments. The major source of conformational freedom in the monomers is the rotation around the C-C bond connecting the double bond with the allylic stereocenter (N-C*-C=C). The allylic conformational preferences can be altered in the oligomers by the formation of secondary structures enforced by hydrogen bonding, Twelve-membered-ring hydrogen bonding is detected in the crystal structure of vs-dipeptide 9, while fourteen-membered-ring hydrogen bonding is the most common folding pattern for the oligomers in chloroform solution. The experimental results are complemented by computer modeling: suitable force-field (FF) parameters for the unsaturated sulfonamide group were developed from ab initio calculations. A Goodman-Still systematic pseudo-Monte-Carlo search was used for the conformational search. The conformers were minimized ill chloroform with the GB/SA model. The calculations correctly predicted both the size of the hydrogen-bonded ring and its relative importance, in agreement with the experimental data in solution.

Conformational studies of chiral vinylogous sulfonamidopeptides / C.M.A. Gennari, B. Salom, D. Potenza, C. Longari, E. Fioravanzo, O. Carugo, N. Sardone. - In: CHEMISTRY-A EUROPEAN JOURNAL. - ISSN 0947-6539. - 2:6(1996), pp. 644-655.

Conformational studies of chiral vinylogous sulfonamidopeptides

C.M.A. Gennari
Primo
;
D. Potenza;
1996

Abstract

The conformational preferences of chiral vinylogous aminosulfonic acids (vs-amino acids) and of the corresponding oligomers (vs-peptide) were investigated by a combination of X-ray crystallography, variable-temperature (VT) H-1 NMR spectroscopy, FT-IR spectroscopy, and NOE experiments. The major source of conformational freedom in the monomers is the rotation around the C-C bond connecting the double bond with the allylic stereocenter (N-C*-C=C). The allylic conformational preferences can be altered in the oligomers by the formation of secondary structures enforced by hydrogen bonding, Twelve-membered-ring hydrogen bonding is detected in the crystal structure of vs-dipeptide 9, while fourteen-membered-ring hydrogen bonding is the most common folding pattern for the oligomers in chloroform solution. The experimental results are complemented by computer modeling: suitable force-field (FF) parameters for the unsaturated sulfonamide group were developed from ab initio calculations. A Goodman-Still systematic pseudo-Monte-Carlo search was used for the conformational search. The conformers were minimized ill chloroform with the GB/SA model. The calculations correctly predicted both the size of the hydrogen-bonded ring and its relative importance, in agreement with the experimental data in solution.
Settore CHIM/06 - Chimica Organica
Article (author)
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/177120
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 60
  • ???jsp.display-item.citation.isi??? 57
social impact