The known alkaloids, evoxanthine, melicopidine, 1, 2, 3-trimethoxy-10- methylacridan-9-one, its 1-demethyl derivative, and kokusaginine have been isolated from the bark of Evodia data collected in New Guinea, together with a new alkaloid, evoprenine. By synthesis from evoxanthine, evoprenine was shown to be 1-hydroxy-2-methoxy-3-[(3-methylbut-2-enyl)oxy]-10-methylacridan-9-one. Some aspects of the N.M.R. and mass spectrometry of acridone derivatives are discussed. © 1967 CSIRO. All rights reserved.