M. Suarez et al., A joint experimental and theoretical structural study of novel substituted2,5-dioxo-1,2,3,4,5,6,7,8-octahydroquinolines, TETRAHEDRON, 55(3), 1999, pp. 875-884
A series of substituted 2,5-dioxo-1,2,3,4,5,5,7,8-octahydroquinolines have
been synthesised from Meldrum's acid and dimedone in the presence of differ
ent aldehydes by following an approach similar to the one developed by Hant
zch. The structure of these compounds has been thoroughly studied by X-ray
crystallographic analysis and semiempirical (AM1) and ab initio (HF/3-21G)
methods, and two favoured conformations are possible. A good agreement is f
ound between the theoretical and experimental values. The most stable confo
rmation (A) in the solid state is also that favoured in solution, according
to the proton coupling constant determined from Karplus' and Altona's equa
tions and H-1 NMR spectroscopic experiments. (C) 1998 Elsevier Science Ltd.
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