Low-temperature 1H and 13C NMR spectra of N-substituted 1,2,3,4-tetrahydropyrazino[1,2-a]indoles
Copyright (c) 2005 John Wiley & Sons, Ltd.
| Publié dans: | Magnetic resonance in chemistry : MRC. - 1985. - 43(2005), 5 vom: 30. Mai, Seite 351-8 |
|---|---|
| Auteur principal: | |
| Autres auteurs: | , , , |
| Format: | Article |
| Langue: | English |
| Publié: |
2005
|
| Accès à la collection: | Magnetic resonance in chemistry : MRC |
| Sujets: | Journal Article 1,2,3,4-Tetrahydropyrazino(1,2-a)indole Carbon Isotopes Indoles Protons Pyrazines Nitrogen N762921K75 |
| Résumé: | Copyright (c) 2005 John Wiley & Sons, Ltd. The temperature-dependent (1)H and (13)C NMR spectra of 2-(2-butynyl)-10-methyl-1,2,3,4-tetrahydropyrazino[1,2-a]indole (4) (as a representative example of 1-9) in CFCl(3) + CD(2)Cl(2) solution are described and discussed. Below 183 K, the hexahydropyrazine ring inversions become slow on the NMR time-scale and 4 exists in principle as two conformational diastereomers. In fact, only one was observed with the N-2 substituent in an equatorial position as shown by a low-temperature NOESY experiment. The energy barrier for conformational interchange was calculated from NMR data to be 8.3 kcal mol(-1) (1 kcal = 4.184 kJ), in agreement with quantum chemical calculations. Unambiguous assignments for all proton and carbon resonances of 1-9 were made using 1D (APT, DEPT, NOE difference) and 2D (COSY, NOESY, gHMQC, gHMBC) NMR techniques |
|---|---|
| Description: | Date Completed 29.08.2005 Date Revised 21.11.2013 published: Print Citation Status MEDLINE |
| ISSN: | 1097-458X |