Six novel marine natural products, dysidamides B [3] and C [5], three highly oxygenated sterols 9, 11, and 13, and a 1,4-dideoxyhexose 15 were isolated from the Red Sea sponge Dysidea herbácea, along with the previously known 24-methylene-5ot-cholest-7--3ß,5,6ß-« 1 [7], furodysinin lactone, and -D-xy lopy ranose. Structures of all new compounds were determined from spectroscopic data, especially extensive ID and 2D nmr experiments.Many interesting metabolites have been isolated from Dysidea species (1-7). Recently we have reported the isolation of a chlorinated nitrogenous metabolite, dysidamide [1], from a Dysidea sp. collected near Massawa, Ethiopia (8), a sponge which has now been fully identified as Dysidea herbácea Keller (family Dysideidae, order Dictyoceratida). An unusually diverse array of metabolites has been isolated from various specimens of D. herbácea (1,4). Herewith we wish to report several minor metabolites from the same sponge: two new dysidamides, B [31 and C {5}, four polyoxygenated sterols 7, 9, 11, and 13, and a dideoxyhexose 15, which were isolated with Dxylose and furodysinin lactone (7).The EtOH extract of the sponge was separated into four fractions by chromotography on a Sephadex LH-20 column prepared and eluted with petroleum ether-CH2Cl2-MeOH (2:1:1); the fractions contained (a) glycerides and non-polar sterols, (b) dysidamides, (c) polar sterols, and (d) monosaccharides. The three latter fractions were further purified by repeated chromatography on Sephadex LH-20 and RP-18 columns and also, in some cases, on Si gel after acetylation with Ac2OZpyridine (it was verified that there are no natural acetates of the new compounds). Together with compound 1, which was the major metabolite (2% dry wt of the sponge), we have now isolated small
