2758-18-1

May be prepared by dehydrohalogenation of 2-chloro-l-methylcyclopentan-3-one.

1-Methyl-1-cyclopenten-3-one has a sweet-floral, warm-spicy and diffusive yet quite tenacious odor.

clear light yellow to yellow-brownish liquid

Reported found in roasted onion, cooked pork, black tea, soybean and dried bonito

It is an important raw material and intermediate used in Organic Synthesis, Pharmaceuticals, Agrochemicals.

3-Methyl-2-cyclopentenone is used as an important intermediate in the production of various natural products and petrol additives^[1].

ChEBI: 3-Methyl-2-cyclopenten-1-one is a cyclic ketone.

By dehydrohalogenation of 2-chloro-1-methyl-cyclopentan-3-one.

Journal of the American Chemical Society, 101, p. 494, 1979 DOI: 10.1021/ja00496a044
The Journal of Organic Chemistry, 55, p. 371, 1990

3-Methyl-2-cyclopentenone (MCP) can be selectively synthesised via 2,5-hexanedione (HD) using a heterogeneous catalyst as a support. In a heterogeneous catalytic system, Bell et al. found that a Mg-Al-Ox catalyst, prepared by calcining MgAl hydrotalcite at 700 °C, achieved both a yield and selectivity of 98% when converting HD to MCP in a formaldehyde/water two-phase medium. In addition, the use of simple alumina-based solid acid catalysts, such as γ-Al₂O₃ and AlOOH, can achieve a selectivity of over 71% in the conversion of HD to MCP^[1].

[1] Shun Nishimura, Kohki E., Shintaro Ohmatsu. (2019). Selective synthesis of 3-methyl-2-cyclopentenone via intramolecular aldol condensation of 2,5-hexanedione with γ-Al2O3/AlOOH nanocomposite catalyst. Fuel Processing Technology, 196, Article 106185. https://doi.org/10.1016/j.fuproc.2019.106185