Rhodocomatulin-Type Anthraquinones from the Australian Marine Invertebrates Clathria hirsuta and Comatula rotalaria

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• 作者：Shahan Khokhar ; Gregory K. Pierens ; John N. A. Hooper ; Merrick G. Ekins ; Yunjiang Feng ; Rohan A. Davis
• 刊名：Journal of Natural Products
• 出版年：2016
• 出版时间：April 22, 2016
• 年：2016
• 卷：79
• 期：4
• 页码：946-953
• 全文大小：359K
• 年卷期：0
• ISSN：1520-6025

文摘

Chemical investigations of an Australian sponge, Clathria hirsuta, from the Great Barrier Reef, have resulted in the isolation of two known anthraquinones, rhodocomatulin 5,7-dimethyl ether (1) and rhodocomatulin 7-methyl ether (2). Additionally, four new anthraquinone metabolites, 6-methoxyrhodocomatulin 7-methyl ether, 3-bromo-6-methoxy-12-desethylrhodocomatulin 7-methyl ether, 3-bromo-6-methoxyrhodocomatulin 7-methyl ether, and 3-bromorhodocomatulin 7-methyl ether (3–6), were also isolated and characterized. This is the first report of the rhodocomatulin-type anthraquinones from a marine sponge, as 1 and 2 were previously isolated from the marine crinoid genus Comatula. An additional chemical investigation of the marine crinoid Comatula rotalaria enabled the isolation of further quantities of 1 and 2, as well as two additional new crinoid metabolites, 12-desethylrhodocomatulin 5,7-dimethyl ether and 12-desethylrhodocomatulin 7-methyl ether (7 and 8). An NMR spectroscopic analysis of compounds 7 and 8 provided further insight into the rhodocomatulin planar structure and, together with the successful implementation of DFT-NMR calculations, confirmed that the rhodocomatulin metabolites existed as para rather than ortho quinones.