Abstract: 2,3-Dihydro-3-[(S)-1-phenethyl]quinazolinone and some new 2-substitutedderivatives bearing isopropyl, o-nitrophenyl and p-nitrophenyl groups were prepared in40-90% yield by amidation of isatoic anhydride with (S)-phenylethylamine, followed bycondensation with triethyl orthoformate, isopropylaldehyde, o-nitro- and p-nitro-benzaldehyde, respectively. The two 2-subtituted dihydroquinazolinones obtained eitherby using isopropylaldehyde, o-nitro- or p-nitrobenzaldehyde, were separated and purifiedbefore their NMR spectra in CDCl3 solutions were recorded. The detection of the lowenergy conformation of O=C-N-phenethyl segment in solution allowed the correlation ofthe NMR data with the configuration of newly stereogenic carbon C-2; thus, onediastereomer was labeled SS while the other was RS. Configurations determined by theNMR method were corroborated by X-ray diffraction analysis. X-ray structures of eachdiastereomeric series showed characteristic conformational types: a propeller-like for theSS and a hairpin for the RS series. Interatomic distances of the hairpin conformationsuggest the existence of intramolecular face-to-face interactions between two aromaticrings.
This is an open access article distributed under the
Creative Commons Attribution License which permits unrestricted use, distribution,
and reproduction in any medium, provided the original work is properly cited.
Export to BibTeX
MDPI and ACS Style
Escalante, J.; Ortíz-Nava, C.; Flores, P.; Priego, J.M.; García-Martínez, C. Synthesis, NMR and Crystallographic Studies of 2-Substituted Dihydroquinazolinones Derived from (S)-Phenylethylamine. Molecules 2007, 12, 173-182.
Escalante J, Ortíz-Nava C, Flores P, Priego JM, García-Martínez C. Synthesis, NMR and Crystallographic Studies of 2-Substituted Dihydroquinazolinones Derived from (S)-Phenylethylamine. Molecules. 2007; 12(2):173-182.
Escalante, Jaime; Ortíz-Nava, Claudia; Flores, Patricia; Priego, Jaime M.; García-Martínez, Cirilo. 2007. "Synthesis, NMR and Crystallographic Studies of 2-Substituted Dihydroquinazolinones Derived from (S)-Phenylethylamine." Molecules 12, no. 2: 173-182.