synthesis, nmr and crystallographic studies of 2-substituted dihydroquinazolinones derived from (s)-phenylethylamine合成、核磁共振以及晶体的研究2-substituted dihydroquinazolinones来自(s)苯乙胺.pdf

Molecules 2007, 12, 173-182 molecules ISSN 1420-3049 Full Paper Synthesis, NMR and Crystallographic Studies of 2-Substituted Dihydroquinazolinones Derived from (S)-Phenylethylamine Jaime Escalante 1,*, Claudia Ortíz-Nava 1, Patricia Flores 1, Jaime M. Priego 1 and Cirilo García-Martínez 2,* 1 Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos. Av. Universidad No. 1001, Col. Chamilpa, C.P. 62210 Cuernavaca-Mor. México. 2 Universidad Autónoma Metropolitana, Area de Química. San Pablo No. 180, Col. Reynosa Tamaulipas, México 02200, D.F. * Authors to whom correspondence should be addressed; E-mails: jaime@ciq.uaem.mx or gmc@correo.azc.uam.mx Received: 5 December 2006; in revised form: 2 February 2007 / Accepted: 5 February 2007 / Published: 12 February 2007 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