Conformationally locked heterocycles. Structure of a doubly bridged pyrimido[1,2-a]pyrimidine from the Hantzsch synthesis with 4-(2-hydroxyphenyl)but-3-en-2-one

Authors
Svetlik, J Liptaj, T Turecek, F
Citation
J. Svetlik et al., Conformationally locked heterocycles. Structure of a doubly bridged pyrimido[1,2-a]pyrimidine from the Hantzsch synthesis with 4-(2-hydroxyphenyl)but-3-en-2-one, J HETERO CH, 36(1), 1999, pp. 209-215
Citations number
11
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
JOURNAL OF HETEROCYCLIC CHEMISTRY
ISSN journal
0022152X → ACNP
Volume
36
Issue
1
Year of publication
1999
Pages
209 - 215
Database
ISI
SICI code
0022-152X(199901/02)36:1<209:CLHSOA>2.0.ZU;2-1
Abstract
1D and 2D nmr spectroscopy was used to assign the structure to the minor pr oduct from cyclocondensation of 4-(2-hydroxyphenyl)but-3-en-2-one with cyan amide, which was identified as (6R*, 9R*, 15R*, 17R*)-6,9-dimethyl-6, 9-dim ethly-6,17:9,15-dimethano-6H,15H,17H-[1,3,5]benzoxadiazocino[4,5-d][1,3,5]b enzoxadiazocine-7(9H)-carbonitrile, a doubly oxygen-bridged pyrimido[1,2-a] pyrimidine derivative. The observed stereoselectivity and reaction mechanis ms are discussed with the help of molecular mechanics and semi-empirical PM 3 calculations.