Studies on the constituents of marine opisthobranchia, III. Isolation and structure of two 5,8α‐epidioxysterols and a cholesteryl ester mixture from the albumen gland of <i>Aplysia juliana</i>

Abstract

Abstract From the albumen glands of the sea hare Aplysia juliana , collected in Kumamoto Prefecture, a mixture of cholesteryl esters ( 1 ) and two 5,8α‐epidioxysterols 5 and 8 have been isolated. Acid‐catalyzed methanolysis of 1 afforded four methyl esters of fatty acids [palmitate (major component), stearate, margarate, and an isomer of margarate] and cholesterol. 5 and 8 were identified by spectroscopic and synthetical evidence to be 5,8α‐epidioxy‐5α‐cholest‐6‐en‐3β‐ol and 5,8α‐epidioxy‐5α‐cholesta‐6,9(11)‐dien‐3β‐ol, respectively.