. . . . "Maple lactone, Methylcyclopentenolone, Corylon" . . . . . "3-Methylcyclopentane-1,2-dione" . . . "2-Hydroxy-3-methyl-2-cyclopenten-1-one" . . "2-Hydroxy-3-methyl-2-cyclopenten-1-one" . "2-hydroxy-3-methyl-2-cyclopenten-1-one" . . . . .