Synthesis, NMR and crystallographic studies of 2-substituted dihydroquinazolinones derived from (S)-phenylethylamine.
Molecules
; 12(2): 173-82, 2007 Feb 12.
Article
em En
| MEDLINE
| ID: mdl-17846567
ABSTRACT
2,3-Dihydro-3-[(S)-1-phenethyl]quinazolinone and some new 2-substituted derivatives bearing isopropyl, o-nitrophenyl and p-nitrophenyl groups were prepared in 40-90% yield by amidation of isatoic anhydride with (S)-phenylethylamine, followed by condensation with triethyl orthoformate, isopropylaldehyde, o-nitro- and p-nitro-benzaldehyde, respectively. The two 2-subtituted dihydroquinazolinones obtained either by using isopropylaldehyde, o-nitro- or p-nitrobenzaldehyde, were separated and purified before their NMR spectra in CDCl3 solutions were recorded. The detection of the low energy conformation of O=C-N-phenethyl segment in solution allowed the correlation of the NMR data with the configuration of newly stereogenic carbon C-2; thus, one diastereomer was labeled SS while the other was RS. Configurations determined by the NMR method were corroborated by X-ray diffraction analysis. X-ray structures of each diastereomeric series showed characteristic conformational types a propeller-like for the SS and a hairpin for the RS series. Interatomic distances of the hairpin conformation suggest the existence of intramolecular face-to-face interactions between two aromatic rings.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fenetilaminas
/
Quinazolinonas
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article