1128-08-1

Basic information

• Product Name: 2-Pentyl-3-methyl-2-cyclopenten-1-one
• Synonyms: 3-methyl-2-pentylcyclopent-2-enone;3-Methyl-2-(2-penten-1-yl)-2-cyclopentene;DIHYDROJASMONE 98+%;DIHYDROJASMONE, TERPENE STANDARD;3-methyl-2-n-pentylcyclopent-2-en-1-one;DIHYDROJASMONE(RG);3-METHYL-2-(N-PENTANYL)-2-CYCLOPENTENE-1-ONE;3-Methyl-2-pentylcyclopent-2-enon
• CAS NO: 1128-08-1
• Molecular Formula: C₁₁H₁₈O
• Molecular Weight: 166.26
• EINECS: 214-434-5
• Mol File: 1128-08-1.mol

Chemical Properties

• Boiling Point: 120-121 °C12 mm Hg(lit.)
• Flash Point: 230 °F
• Appearance: /
• Density: 0.916 g/mL at 25 °C(lit.)
• Refractive Index: n20/D 1.479(lit.)
• BRN: 1906471
• CAS DataBase Reference: 2-Pentyl-3-methyl-2-cyclopenten-1-one(CAS DataBase Reference)
• NIST Chemistry Reference: 2-Pentyl-3-methyl-2-cyclopenten-1-one(1128-08-1)
• EPA Substance Registry System: 2-Pentyl-3-methyl-2-cyclopenten-1-one(1128-08-1)

Safety Data

• WGK Germany: 2
• RTECS: GY7302000
• TSCA: Yes
• Hazardous Substances Data: 1128-08-1(Hazardous Substances Data)

Usage

Uses

Used in Perfumery:
2-Pentyl-3-methyl-2-cyclopenten-1-one is used as a fragrance ingredient in jasmine bases and, more generally, in floral and fruity fragrances. Its fresh, fruity, jasmine odor with woody and herbal nuances makes it a valuable addition to perfume compositions.
Used in Flavor Industry:
2-Pentyl-3-methyl-2-cyclopenten-1-one can be used as a flavoring agent in the food and beverage industry, due to its sweet, floral, green, and herbal taste characteristics with a citrus nuance. This makes it suitable for enhancing the flavor profiles of various products, particularly those with fruity or floral notes.

Preparation

Hexyl bromide plus levulinic ester yields a lactone, which is reacted with polyphosphoric acid or phosphorus pentoxide to produce hydrojasmone.

Synthesis Reference(s)

Canadian Journal of Chemistry, 56, p. 2301, 1978 DOI: 10.1139/v78-379Journal of the American Chemical Society, 92, p. 7428, 1970 DOI: 10.1021/ja00728a029

Upstream product

• 111-13-7 hexyl-methyl-ketone 
• 123-25-1 succinic acid diethyl ester 
• 92984-80-0 4-methyl-dec-4-enoic acid 
• 101099-32-5 2-acetonyl-3-oxo-nonanoic acid ethyl ester 
• 62055-70-3 methyl-4 pentyl-3 pentatriene-1,2,4 
• 69818-14-0 4-methyl-3-pentyl-pent-4-en-2-one 
• 13074-63-0 2-pentyl-3-methyl-cyclopentan-1-one 
• 128893-59-4 4-Methyl-5-oxo-decanenitrile 
• 128192-00-7 2-pentyl-3-methyl-5-(phenylthio)-2-cyclopenten-1-one 
• 78763-73-2 3-Methyl-2-(1-pentylidene)cyclopentanone 
• 59078-91-0 1-Diazo-3-isopropenyl-octan-2-one 
• 87349-05-1 2-pentyl-3-methyl-1-trimethylsiloxycyclopentene 
• 693-39-0 1-nitroheptane 
• 78-94-4 methyl vinyl ketone 

Downstream Products

• 92984-83-3 3-Methyl-2-pentyl-cyclopent-2-enol 
• 123-76-2 levulinic acid 
• 97635-25-1 3,4-dihydro-5-methyl-6-pentyl-2H-pyran-2-one 
• 192058-81-4 4-Nitro-benzoic acid (1R,2R,5S)-5-methyl-1-pentyl-6-oxa-bicyclo[3.1.0]hex-2-yl ester 
• 4933-45-3 3-methyl-2-pentyl-cyclopent-2-enone-(2,4-dinitro-phenylhydrazone) 
• 13074-63-0 2-pentyl-3-methyl-cyclopentan-1-one 

Relevant articles and documents

2-METHYLENE-3-ALKOXYCYCLOPENTANONES AS REACTIVE INTERMEDIATES AND THEIR APPLICATION TO THE SYNTHESES OF DIHYDROJASMONE, CIS-JASMONE AND (+/-)-JASMOLONE

Dihydrojasmone and cis-jasmone were synthesized in high yields by the Michael addition of lithium di-n-butylcuprate and bromomagnesium di-1-butenylcuprate, respectively, to 2-methylene-3-methyl-3-methoxy-methyloxycyclopentanone. (+/-)-Jasmolone was also synthesized by the Michael addition of dialkenylcuprate to 2-methylene-3-methyl-3-methoxymethyloxy-4-ethoxyethyloxycyclopentanone.

Coupling Reactions of 1-Tributylstannyl-1-octen-3-ol Catalyzed by Palladium: The Synthesis of PGB1 and Coriolic Acid

The palladium catalyzed coupling of (S)-E-1-tributylstannyl-1-octen-3-ol (3) with 2-(6-carbethoxyhexyl)-3-iodo-2-cyclopenten-1-one gave a 70percent yield of the (S)-ethyl ester of PGB1.Coriolic acid was synthesized in 75percent yield by coupling 3 with Z-10-iododecenoic acid, demonstrating the tolerance of this coupling reaction to the carboxylic acid function.

Utilization of Basic Alumina in a One-Pot Synthesis of 1,4-Diketones, 1,4,7-Triketones, and Dihydrojasmone by Conjugate Addition of Nitroalkanes to Enones

The one-pot synthesis of functionalized 1,4-diketones was achieved in good yields by conjugate addition of primary nitroalkanes to α,β-unsaturated carbonyl compounds on basic alumina without solvent, followed by in situ oxidation with 30percent aqueous hydrogen peroxide in methanol.The one-pot syntheses of 1,4,7-triketones and dihydrojasmone are also reported.

Unusual endoperoxide isomerizations: a convenient entry into 2-vinyl-2-cyclopentenones from saturated fulvene endoperoxides

An unusual peroxide base-promoted isomerization is uncovered. Saturated endoperoxides derived from fulvenes give rise to 2-vinyl-2-cyclopentenones upon treatment with DBU in CH2Cl2 in a one-pot reaction. This methodology is applied to a convenient synthesis of dihydrojasmone. Moreover, functional groups placed on the side chain at C-6 participate in the base-catalyzed isomerizations via conjugate attack at the enone moiety to give 2-cyclopentenones carrying oxygen heterocycles at C-2.

A new synthesis of methyl 3-oxo-2-pentyl-1-cyclopentene-1-acetate

The 92:8 equilibrium mixture of (±)-trans-methyl dihydrojasmonate (1) and its cis-isomer is transformed in 63% overall yield into the title compound 4 by epoxidation of the derived enol acetate 2 with peracetic acid/Na2CO3 in toluene and heating the resulting α-acetoxy epoxide 3 in MeOH in the presence of catalytic amounts of methanesulfonic acid.

A SIMPLE SYNTHESIS OF DIHYDROJASMONE

Acetalization of a γ-substituted α,β-unsaturated ketone, followed by acid hydrolysis gave a cyclopentenone.

Development of modified Pauson-Khand reactions with ethylene and utilisation in the total synthesis of (+)-taylorione

Two complementary Pauson-Khanol annulation protocols for use with the gaseous alkene, ethylene, are described. These N-oxide promoted reactions (10 examples) are shown to proceed under both mild autoclave condition or, more conveniently, at atmospheric pressure. The developed methodology has been utilised as the key transformation in the total synthesis of the sesquiterpene (+)-taylorione which has been realised in a good overall yield from readily available (+)-2-carene.

α,β-Unsaturated ketones via copper(II) bromide mediated oxidation

A protocol for effecting a rapid Saegusa-type oxidation of enol acetates is reported. This new method relies on the in situ elimination of an α-bromo intermediate to generate α,β-unsaturated ketones using copper(II) bromide. The methodology developed was applied to a range of substrates including a cyclohexanone, which could be directly converted to the corresponding phenol derivative. A catalytic system in which a non-masked ketone was successfully oxidised using substoichiometric CuBr2 was also developed as a proof of principle.

Cyclopentenones from γ-Nitroalkanoic Acids. Dihydrojasmone Synthesis

Treatment of γ-nitroalkanoic acids with polyphosphoric acid or P2O5-MeSO3H led to cyclopentenones.

A Novel Acetonylation of Carbonucleophiles via Palladium-Catalyzed Allylation with Isopropyl 2-Methylene-3,5-dioxahexyl Carbonate

Carbonucleophiles such as malonate esters, β-keto esters, phenylacetate ester, and phenylacetonitrile were acetonylated in high yields by allylation with isopropyl (or methyl) 2-methylene-3,5-dioxahexyl carbonate (4b or 4a) in the presence of palladium-phosphine catalyst under neutral conditions, followed by acidic hydrolysis.Adopting this procedure dihydrojasmone (7) was prepared from ethyl 3-oxononanoate (6) in an overall yield of 72percent.