Methyl cyclopentenolone occurs in beechwood tar
and has a caramel-like (burnt sugar) odor. It has been identified as a flavor
component in food. Crystals of the compound usually contain 1 mol
of water. Synthetic routes of production are of limited importance in comparison
with isolation from beechwood tar. Homologs of cyclotene such as
3-ethyl-2-hydroxy-2-cyclopenten-1-one, C7H10O2, Mr 126.16,
2-hydroxy-3,4-dimethyl-2-cyclopenten-1-one, C7H10O2, Mr 126.16, and 2-hydroxy-3,5-dimethyl-2-cyclopenten-1-one, C7H10O2, Mr 126.16,
are also used as flavor ingredients and have similar caramel-like
properties.
Cyclotene and its homologs are frequently used in flavor compositions for its
caramel note, for example, in beverages and in confectionery.
Reported to be found during the dry distillation of wood and in the corresponding tar oil. It has also been identified in fenugreek (FenaroWs Handbook of Flavor Ingredients, 1975).
Methyl Cyclopentenolone is a flavoring agent that is a white crys-
talline powder. it has a nutty odor suggesting a maple-licorice aroma
when diluted. it is soluble in alcohol and propylene glycol, slightly
soluble in most fixed oils, and sparingly soluble in water. it is obtained
by synthesis. it is also termed 3-methyl-cyclopentane-1,2-dione.
Methyl cyclopentenolone may be used as an analytical reference standard for the quantification of the analyte in commercial products using different chromatography techniques.
By ketonic hydrolysis of the corresponding dicarboxylic ester (Arctander, 1969)
Methyl cyclopentenolone is
used sparingly in perfume compositions often
in combination with Coumarin or Coumarin
derivatives. It is an excellent fortifier for such
materials in Lavender fragrances, New Mown
Hay, "tabac" type fragrances, spicy bases,
etc. It falls naturally into Celery seed oil,
Lovage, Fenugreek, Tonka, Liatris, Flouve,
etc.
It is, however, in flavor compositions that
Methyl cyclopentenolone has found its truly extensive
application.
The acute oral LD50 value in guinea-pigs was reported as 1.4 g/kg (Dow Chemical Company, 1953) and that in rats as > 1.85 g/kg, while the acute dermal LD50 value in guinea-pigs exceeded 2 g/kg (Moreno, 1976). Methylcyclopentenolone was lethal to mice and rats at ip doses of 0.5-1 g/kg (Shugaev, 1959), and at a concentration of 7 χ 10-4 m was toxic to cultured human leucocytes (Withers, 1966).
Methyl cyclopentenolone is one of the flavor compounds of maple syrup, coffee oil and wood smoke. It is reported to be one the key aroma compounds in Wasanbon sugar, contributing to the maple-like flavor. Methyl cyclopentenolone is also one of the major volatile compound formed during the thermal degradation of glucose.
