The conformational preferences of beta-sulfonamidopeptides in chloroform solution were investigated by variable-temperature H-1 NMR spectroscopy and FT-IR spectroscopy. The following hydrogen-bonding acceptor scale was derived from the experiments: RCON approximate to tBuOCON > COOMe greater than or equal to RSO2N. An intermolecular study gave results complementary to those described above: the N-H stretch bands of N-methylacetamide and N-methyl methanesulfonamide in chloroform were followed during titration with excess methanesulfonylpyrrolidine and N,N-dimethylacetamide. Shifts to lower frequencies were observed which are correlated with the hydrogen-bond strengths and show that the amide is a stronger hydrogen-bond acceptor than the sulfonamide.
Hydrogen-bonding donor/acceptor scales in beta-sulfonamidopeptides / C.M.A. Gennari, M. Gude, D. Potenza, U. Piarulli. - In: CHEMISTRY-A EUROPEAN JOURNAL. - ISSN 0947-6539. - 4:10(1998), pp. 1924-1931. [10.1002/(SICI)1521-3765(19981002)4:10<1924::AID-CHEM1924>3.0.CO;2-P]
Hydrogen-bonding donor/acceptor scales in beta-sulfonamidopeptides
C.M.A. GennariPrimo
;D. PotenzaPenultimo
;
1998
Abstract
The conformational preferences of beta-sulfonamidopeptides in chloroform solution were investigated by variable-temperature H-1 NMR spectroscopy and FT-IR spectroscopy. The following hydrogen-bonding acceptor scale was derived from the experiments: RCON approximate to tBuOCON > COOMe greater than or equal to RSO2N. An intermolecular study gave results complementary to those described above: the N-H stretch bands of N-methylacetamide and N-methyl methanesulfonamide in chloroform were followed during titration with excess methanesulfonylpyrrolidine and N,N-dimethylacetamide. Shifts to lower frequencies were observed which are correlated with the hydrogen-bond strengths and show that the amide is a stronger hydrogen-bond acceptor than the sulfonamide.
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