The opisthobranch Aplysia depilans contains in its dorsum five unprecedented C-16 and C-18 fatty acid lactones (2-6). Their structures were assigned on the bases of chemical and spectral methods. Lactone 2 is derived by cyclization of 15(S)-hydroxyhexadeca-4(2),7(2),10(2),13(Z)-tetraenoic acid. The absolute stereochemistry at C-15 was determined by Mosher's method after opening of the lactone ring. Two other lactones (3 and 5) result from the cyclization either at C-15 or C-16 of 15,16-dihydroxyoctadeca-9(Z),12(Z)-dienoic acid. They differ from the remaining pair (4 and 6) by the absence of an additional double bond at C-6. S absolute stereochemistry of the free carbinols in 3-6 was suggested by applying Mosher's method. The same absolute stereochemistry was assigned at all lactonized carbinol centers by isomerization of the lactones by ring opening and subsequent enzymatic cyclization.

Structure and stereochemistry of aplyolides A-E, lactonized dihydroxy fatty acids from the skin of the marine mollusk Aplysia depilans

SPINELLA, Aldo;
1997

Abstract

The opisthobranch Aplysia depilans contains in its dorsum five unprecedented C-16 and C-18 fatty acid lactones (2-6). Their structures were assigned on the bases of chemical and spectral methods. Lactone 2 is derived by cyclization of 15(S)-hydroxyhexadeca-4(2),7(2),10(2),13(Z)-tetraenoic acid. The absolute stereochemistry at C-15 was determined by Mosher's method after opening of the lactone ring. Two other lactones (3 and 5) result from the cyclization either at C-15 or C-16 of 15,16-dihydroxyoctadeca-9(Z),12(Z)-dienoic acid. They differ from the remaining pair (4 and 6) by the absence of an additional double bond at C-6. S absolute stereochemistry of the free carbinols in 3-6 was suggested by applying Mosher's method. The same absolute stereochemistry was assigned at all lactonized carbinol centers by isomerization of the lactones by ring opening and subsequent enzymatic cyclization.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11386/3250908
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