these compounds ( citral , pseudo-ionon . beta-ionon aldehyde c14 , ketone c18 and its derivatives -- 4,18-diketone , alcohol c18 , semicarbazide ketone c18 ) , as well as vitamin a and its derivatives -- retinal , acetate , retinoic acid -- differ in composition , structure and substituents of c-atoms in beta-ionon ring and in polyenoic chain .
C0042839
vitamin a
C0040845
retinoic acid