24156-95-4

Basic information

• Product Name: 3,5,5-Trimethyl-2-cyclopenten-1-one
• Synonyms: 3,5,5-Trimethyl-2-cyclopenten-1-one
• CAS NO: 24156-95-4
• Molecular Formula: C₈H₁₂O
• Molecular Weight: 124.1803
• Mol File: 24156-95-4.mol
• Article Data: 9

Chemical Properties

• Boiling Point: 173°Cat760mmHg
• Flash Point: 62.1°C
• Appearance: /
• Density: 0.92g/cm³
• Vapor Pressure: 1.29mmHg at 25°C
• Refractive Index: 1.458
• CAS DataBase Reference: 3,5,5-Trimethyl-2-cyclopenten-1-one(CAS DataBase Reference)
• NIST Chemistry Reference: 3,5,5-Trimethyl-2-cyclopenten-1-one(24156-95-4)
• EPA Substance Registry System: 3,5,5-Trimethyl-2-cyclopenten-1-one(24156-95-4)

Safety Data

• Hazardous Substances Data: 24156-95-4(Hazardous Substances Data)

Usage

InChI:InChI=1/C8H12O/c1-6-4-7(9)8(2,3)5-6/h4H,5H2,1-3H3

Upstream product

• 74-99-7 prop-1-yne 
• 5455-94-7 2,2,5,5-tetramethyltetrahydro-3-oxofuran 
• 866-71-7 3,3-dimethyl-hexane-2,5-dione 
• 142-30-3 2,5-dihydroxy-2,5-dimethyl-3-hexyne 
• 111258-54-9 tetrahydro-2,3,5,5-tetramethyl-2,3-furandiol 
• 931-22-6 3,5-dimethyl-2-cyclopenten-1-one 
• 74-88-4 methyl iodide 
• 2758-18-1 3-Methyl-2-cyclopenten-1-one 
• 513-35-9 2-methyl-but-2-ene 
• 39482-50-3 2,2,4-trimethylpent-4-enal 
• 112841-81-3 methyl 5-hydroxy-2,4,4,5-tetramethyl-4,5-dihydro-3-furoate 
• 113895-25-3 methyl 2,4,4-trimethyl-5-methylene-4,5-dihydro-3-furoate 
• 118768-39-1 2,4,4-trimethyl-5-methylene-4,5-dihydro-3-furoic acid 
• 1111-97-3 3-chloro-3-methylbut-1-yne 

Downstream Products

• 101088-54-4 2-benzyl-3,5,5-trimethyl-cyclopent-2-enone 
• 28056-54-4 2,2,4-trimethylcyclopentan-1-one 
• 1215117-75-1 4,4,6-trimethyl-3,7-dioxabicyclo[4.1.0]heptan-2-one 

Relevant articles and documents

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Total synthesis of (+/-)-cameroonan-7alpha-ol and biomimetic rearrangements to related nopsane sesquiterpenes.

A total synthesis of the novel silphinane sesquiterpene alcohol (+/-)-cameroonanol (6-OH) from bicyclic enone 10 was accomplished by conjugate addition of crotylsilane, photochemical hydrobromination, intramolecular alkylation, and hydride reduction. The stereoisomers cameroonan-7beta-ol (18-OH) and 9-epicamerooonanols (19 and 20) were separated from isomer mixtures and the 9-desmethylcameroonanols (21-OH and 22-OH) were obtained by similar means. Solvolysis of 6-OMs and 18-OMs effected skeletal rearrangements to (+/-)-silphiperfol-6-ene (5), (+/-)-prenopsanol (7) and (+/-)-nopsanol (8), and (+/-)-silphiperfolan-7beta-ol (9) in parallel with biogenetic schemes proposed for these naturally occurring sesquiterpenes. The nor analogues 21-OMs and 22-OMs underwent solvolytic rearrangments to a similar set of nor products. The increase in solvolytic rates for the 7beta-mesylates 18-OMs and 22-OMs in comparison to the 7alpha epimers is attributed to concerted antiperiplanar Wagner-Meerwein rearrangements to the prenopsyl and norprenopsyl carbocations. Further analysis of the kinetic data and comparisons with solvolysis rates for the structurally related silphin-1beta-yl and silphin-1alpha-yl mesylates (28 and 29) are presented. The rearrangements observed afford chemical precedent for the biogenetic pathways in the literature for these silphinane sesquiterpenes.

The chemoselective cyclisation of unsymmetrical γ-diketones to cyclopentenones by ditected aldol reaction using a magnesium chelate

The feasibility of synthesising disubstituted cyclopent-2-enones chemoselectively from unsymmetrical γ-diketones, using an aldol reaction directed by magnesium chelation, has been studied.Treatment of 3,3-dimethylhexane-2,5-dione 15 with aqueous sodium hydroxide (0.5 mol dm-3) gives a mixture of 3,5,5-trimethyl- 12 and 3,4,4-trimethylcyclopent-2-enone 14 in an isomer ratio 2.2:1.Insertion of an α-methoxycarbonyl grouping as a control element allows formation of a magnesium chelate 17 when treated with magnesium methoxide, and the major product is then mainly the undehydrated aldol 21.This, when treated with aqueous sodium hydroxide (0.5 mol dm-3) to dehydrate, hydrolyse and decarboxylate, gives the 3,5,5-trimethyl- and 3,4,4-trimethylcyclopent-2-enones in a nearly chemospecific ratio of 1:49.When 3-methoxycarbonyl-4,4-dimethylhexane-2,5-dione 16 is treated with aqueous sodium hydroxide (0.5 mol dm-3), omitting the magnesium methoxide treatment, the corresponding ratio of cyclopentenones was still an interesting 1:7.3.Treatment with sodium methoxide in methanol gives, by contrast γ-lactone 27.Treatment of undecane-4,7-dione 34 with aqueous sodium hydroxide (0.5 mol dm-3) at reflux gives 2,3-dipropylcyclopent-2-enone 36 and 3-butyl-2-ethylcyclopent-2-enones 35 in a ratio of almost 1:1.Treatment of 6-methoxycarbonylundecane-4,7-dione 33 with magnesium methoxide in methanol gives undehydrated aldol which when treated with aqueous sodium hydroxide gives the dipropylcyclopent-2-enone 36 and 3-butyl-2-ethylcyclopent-2-enones 35 in 9:1 ratio.Conversely, the 5-methoxycarbonyldione 32 gives a corresponding ratio of 36 to 35 of 1:9.The best ratios attained, 1:15 for 36 and 35 from 32 and 20:1 for 36 and 35 from 33, were when magnesium methoxide in refluxing benzene or toluene were employed.There is still a strong chemoselective effect when the magnesium treatment is omitted.Preliminary examination of the corresponding cyclohex-2-enone systems gave poorer chemoselectivities when either procedure was employed. 6-Methoxycarbonyldodecane-5,9-dione 52 gave 2,3-dipropyl-54 and 3-butyl-2-ethyl-cyclohex-2-enone 55 in a ratio of ca. 4:1 whilst the 5-methoxycarbonyldodecane-4,8-dione 53 gave a 1: ca. 4 ratio.