According to this invention, there is provided a novel 4,8 dimethylbicyclononane derivative represented by the formula : ##STR2{HEAD ~ ##} wherein one of {TAIL ~ X} and Y represents a hydroxyl group, a straight or branched alkoxy group having 1 to 5 carbon atoms or an acyloxy group having 2 or 3 carbon atoms and the other represents a hydrogen atom, or 57 jointly represent an oxo group ; and a dotted line represents optional presence of a double bond 