The structures of three new meliacins isolated from Khaya anthotheca heartwood

Further examination of the light petroleum extract of the heartwood of Khaya anthotheca has led to the isolation of 24-methylenecycloartanol, a new compound C30H52O, azadirone (9), and three new meliacins in addition to the already reported anthothecol (1). The new meliacins have been shown to be 11β-acetoxyazadirone (10), 11α-acetoxyazadirone (11), and 1α,11:14β,15β-diepoxy-6-hydroxymeliaca-5,9,20,22-tetraene-3,7-dione (20) with a novel dihydrofuran ring. The 13C n.m.r. spectra of compound (20) and of related meliacins have been analysed.