The equilibrium structures of the 11 possible oxo-derivatives of sparteine were investigated by DFT, using the B3LYP functional. The conformational preferences of the seven amino-ketonic sparteines are consonant with those of the parent free base, whose lowest energy conformer consists of a chair–chair quinolizidine A/B-trans system and a boat–chair quinolizidine C/D-trans system. A similar situation occurs for lactams 2-oxo- (lupanine), 15-oxo-, and 17-oxo-sparteine, whose ketonized ring has a half-chair/sofa, half-chair, and sofa shape, respectively. Unlike the other isomers, the most stable conformer of lactam aphylline (10-oxo-sparteine) adopts the chair–sofa A/B-transoid, chair–chair C/D-cisoid disposition of the two quinolizidine moieties. These theoretical predictions are consistent with the available X-ray experimental results. The electronic structure of the oxo-sparteines was examined by measuring and calculating relevant parameters of their NMR and photoelectron spectra.

Structural and spectroscopic characterization of oxo-sparteines

GALASSO, VINICIO;ASARO, FIORETTA;BERTI, FEDERICO;
2004-01-01

Abstract

The equilibrium structures of the 11 possible oxo-derivatives of sparteine were investigated by DFT, using the B3LYP functional. The conformational preferences of the seven amino-ketonic sparteines are consonant with those of the parent free base, whose lowest energy conformer consists of a chair–chair quinolizidine A/B-trans system and a boat–chair quinolizidine C/D-trans system. A similar situation occurs for lactams 2-oxo- (lupanine), 15-oxo-, and 17-oxo-sparteine, whose ketonized ring has a half-chair/sofa, half-chair, and sofa shape, respectively. Unlike the other isomers, the most stable conformer of lactam aphylline (10-oxo-sparteine) adopts the chair–sofa A/B-transoid, chair–chair C/D-cisoid disposition of the two quinolizidine moieties. These theoretical predictions are consistent with the available X-ray experimental results. The electronic structure of the oxo-sparteines was examined by measuring and calculating relevant parameters of their NMR and photoelectron spectra.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
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/11368/1894724
 Avviso

Registrazione in corso di verifica.
La registrazione di questo prodotto non è ancora stata validata in ArTS.

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 23
  • ???jsp.display-item.citation.isi??? 25
social impact