A new chalcone methyl ether, named sappanchalcone (I), C16H14O5, mp 199.5-200.5°C was isolated from the heartwood of Caesalpima sappan L. (Sappan Lignum). On the basis of the spectrometric data and the synthesis from 2-O-methylresacetophenone (=isopaeonol) and protochatechualdehyde, the chemical structure of I was established as 2'-methoxy-3, 4, 4'-trihydroxychalcone (=2'-O-methylbutein). It has been proposed that brazilin, a distinguished constituent of this heartwood, is biosynthesized via a homoisoflavone intermediate from a hypothetic chalcone methyl ether, to which sappanchalcone (I) just corresponds.
