Novel Trinor‐eremophilanes (Dendryphiellin B, C, and D), Eremophilanes (Dendryphiellin E, F, and G), and Branched C9‐Carboxylic Acids (Dendryphiellic Acid A and B) from the Marine Deuteromycete Dendryphiella salina (SUTHERLAND) PUGHet NICOT

Abstract

AbstractFurther investigation of global extracts from cultures of the marine deuteromycete Dendryphiella salina leads to the isolation of three novel trinor‐eremophilanes esterified by branched C9‐carboxylic acids, dendryphiellin B(= (+)‐(1R*,2S*,7R*,8aR*)‐1,2,6,7,8,8a‐hexahydro‐7‐hydroxy‐1,8a‐dimethyl‐6‐oxonaphthalen‐2‐yl (6R*, 2E, 4E)‐6‐hydroxy‐6‐methylocta‐2,4‐dienoate; (+)‐2), dendryphiellin C (=(+)‐(1R*, 2S*, 7R*, 8aR*)‐1,2,6,7,8,8a‐hexa‐hydro‐7‐hydroxy‐1,8a‐dimethyl‐6‐oxonaphthalen‐2‐yl (6S, 2E, 4E)‐6‐methylocta‐2,4‐dienoate; (+)‐3)), and dendryphiellin D (=(+)‐(1R*, 2S*, 7R*, 8aR*)‐1,2,6,7(8,8a‐hexahydro‐7‐hydroxy‐1,8a‐dimethyl‐6‐oxonaphthalen‐2‐yl (6R*,2E,4E)‐6‐(hydroxymethyl)octa‐2,4‐dienoate; (+)‐4). An intact eremophilane, dendryphiellin E (5), and its ethanolysis product dendryphiellin F whose absolute configuration is represented by structural formula (+)‐6 are also isolated from the above extracts. Dendryphiellin E exists as an open form 5a in equilibrium with a closed form 5b. A similar equilibrium exists between the open form 8a and the closed form 8b of a non‐esterified eremophilane, dendryphiellin G (8), which is isolated too from the above extracts and proves structurally related to the cyclic portion of 5. Finally, the free, branched C9‐carboxylic acids dendryphiellic acid A ((+)‐9) and B ((+)‐10) which correspond to side chains of the above esterified terpenes are also isolated from the above extracts.