Abstract
The 13C NMR spectra of the pyridones 7a-d recorded in DMSO-d6 show three groups of signals which correspond to the two diastereomers of the 7-exo tautomer and the 7-endo tautomer. The X-ray powder analysis and the molecular structures of 7a-c clearly prove that these compounds, and probably 7d, are present in the solid state as a single diastereomer of the 7-exo tautomer which, on being dissolved, establishes an equilibrium with the other diastereomer through the 7-endo tautomer. This later had been proposed as a hey intermediate in the cyclization of the 1,5-dinitrile system present in 7a-d but was not previously detected.
Original language | English |
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Pages (from-to) | 4487-4496 |
Journal | Tetrahedron |
Volume | 53 |
DOIs | |
Publication status | Published - 24 Mar 1997 |