4-Hydroxy-3-(2′-pyridyl)coumarins (4) (R = 6-Cl, H, 6-NO2, 8-NO2) were prepared in moderate to good yields by the intramolecular nucleophilic aromatic substitution reaction of β-ketoesters (I) in refluxing xylenes; evidence for the reversible formation of benzo[c]quinolizinium III from I (X = 4-Cl), with eventual formation of 4 (R = 6-Cl), is also presented.
|Original language||English (US)|
|Number of pages||2|
|State||Published - Apr 7 2001|
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