title: Diastereoselective reactions in glycine templates containing an ent-ardeemin fragment.
abstract: Self-consistent reaction field solvation models derived from SCF-MO calculations are shown to be reliable in modeling the diastereoselectivity of the reactions of the anion and cation derived from (4S)-2,4-dimethyl-2,4-dihydro-1H-pyrazino[2,1-b]quinazoline-3,6-dione (1) at C(1) with electrophiles and nucleophiles, respectively. The found anti/syn ratio of compound 8, which is a seco-ent-ardeemin analogue obtained by alkylation of 1 with gramine methiodide, confirms this computational model. A close similarity between the calculated geometry of the piperazine ring in the anti isomers of 1,2,4-trialkyl derivatives and that deduced from their (1)H NMR (solution) and X-ray data has been also established.
authors.affiliation: Department of Chemistry, Imperial College of Science, Technology and Medicine, London SW7 2AY, United Kingdom.
authors.forename: Sonsoles
authors.initials: S
authors.lastname: Martín-Santamaría
authors.forename: Raúl
authors.initials: R
authors.lastname: Corzo-Suárez
authors.forename: Carmen
authors.initials: C
authors.lastname: Avendaño
authors.forename: Modesta
authors.initials: M
authors.lastname: Espada
authors.forename: Federico
authors.initials: F
authors.lastname: Gago
authors.forename: Santiago
authors.initials: S
authors.lastname: García-Granda
authors.forename: Henry S
authors.initials: HS
authors.lastname: Rzepa
mesh_terms: D000478:Alkylation; D002625:Chemistry, Organic / Q000379:methods; D018360:Crystallography, X-Ray; D005998:Glycine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D010879:Piperazines / Q000737:chemistry; D011719:Pyrazines / Q000737:chemistry; D011744:Pyrimidinones / Q000737:chemistry*; D011799:Quinazolines / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: C459259:2,4-dimethyl-2,4-dihydro-1H-pyrazino(2,1-b)quinazoline-3,6-dione; D010879:Piperazines; D011719:Pyrazines; D011744:Pyrimidinones; D011799:Quinazolines; C080891:5-N-acetylardeemin; D005998:Glycine