• Citer

Mise En Evidence Par Rmn‐1H Et ‐13C D'Isomerisme Z/E Et D'Equilibre Conformationnel Sur Une Serie De Derives Mono‐ Et Diacetyles De 2‐Alkylamino‐1‐Phenylpropan‐1‐Ols

par Tytgat, D.;Gelbcke, Michel
Référence Bulletin des Sociétés chimiques belges, 101, 6, page (479-489)
Publication Publié, 1992

Article révisé par les pairs

• Détails
• Contenu

Résumé :

1H‐ and 13C‐NMR studies of mono‐ and diacetylated‐erythro‐ and threo‐2‐alkylamino‐1‐phenylpropan‐1‐ols, C6H5CHOHCHNHRCH3 (R = H, CH3, C2H5 and i‐C3H7) show that the series exhibit Z/E isomerism about the C‐N amide bond. The Z/E ratio increases in the monoacetylated series CH3 < C2H5 < i‐C3H7 indicating that the hydrogen bond between the hydroxylic proton and the carbonyl function of the amide is in the case of the isopropyl substituent favoured. In the diacetylated series, where an hydrogen bond is not possible, the Z/E ratio is respectively in the erythro and threo series about 3 and 1. The progressive increase of the volume of the substituent N‐alkyl modifies the conformational equilibrium about the C1‐C2 and N‐C2 bonds. In the Z configuration, the conformer Z‐s‐syn where the proton H‐2 is syn with the N‐alkyl substituent predominates. Copyright © 1992 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim