The structures of five cyclic diketones isolated from coffee

Gianturco, Maurizio; Giammarino, A.S.; Pitcher, Ross G.

doi:10.1016/0040-4020(63)85020-6

Cited by 57 publications

(25 citation statements)

References 6 publications

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“…[17] Scheme 8. Rearrangement of 2,3-epoxy-3-methylcyclohexan-1-one (11) to 3-methyl-1,2-cyclohexanedione (12) and 1-methyl-2-oxocyclopentane-1-carbaldehyde (13) 3-Methyl-1,2-cyclopentanedione (15) is a flavour ingredient of maple syrup and roasted coffee, [18] and has found widespread use as a food flavour. [9] It should be noted that 1,2-dione 15 largely exists as its enolic tautomer; this propensity is often observed for 1,2-diones because, in this way, a higher degree of conjugation is obtained and dipole repulsions between the carbonyl oxygens are relieved.…”

Section: Rearrangement Of Other αβ-Epoxy Ketonesmentioning

confidence: 99%

Solid-Acid Catalysed Rearrangement of Cyclic α,β-Epoxy Ketones

2000

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Various cyclic α,β‐epoxy ketones rearranged to α‐formyl ketones and/or vic‐diones in the presence of catalytic amounts of zeolites and montmorillonite K10. This provides an excellent alternative to conventional homogeneous systems with respect to yields and workup. Differences in product distribution and type of products in the rearrangement of pulegone oxide could be reasonably explained by invoking different pathways for homogeneous and heterogeneous catalysts.

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Section: Rearrangement Of Other αβ-Epoxy Ketonesmentioning

confidence: 99%

Solid-Acid Catalysed Rearrangement of Cyclic α,β-Epoxy Ketones

2000

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“…-The title compound 1 was first isolated from the essential oil of Backhousia angustifolia in 1931 [1] and later identified in roasted coffee [2], as well as in the Maillard reaction of casein pancreatic hydrolyzate derived peptides with glucose [3]. Three syntheses have been published which are summarized in Scheme 1 1 ).…”

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confidence: 99%

“…The efficiency of this process could be improved by using Swern conditions (oxalyl chloride, CH 2 Cl 2 , DMSO, Et 3 N, 25% yield) during the last step 7 ). This nonindustrial approach at least allowed us to obtain a sample of 1, thus facilitating the 2 ], 62% yield, [24]) to the cis-epoxy alcohol 15 8 ). This compound is also very sensitive and was readily transformed into triol 16 by a simple washing with 15% aqueous HCl solution during an extraction.…”

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confidence: 99%

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Alternative Synthesis of 2‐Hydroxy‐3,5,5‐trimethylcyclopent‐2‐en‐1‐one

Chapuis

Saint-Léger

2010

Helvetica Chimica Acta

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The 2-hydroxy-3,5,5-trimethylcyclopent-2-en-1-one (1) was synthesized in 42% yield by rearrangement of epoxy ketone 10 on treatment with BF 3 · Et 2 O under anhydrous conditions. Intermediate 10 was available from the known enone 8, either via direct epoxidation (60% H 2 O 2 , NaOH, MeOH; yield 50%), or via reduction to the corresponding allylic alcohol 14 (LiAlH 4 , THF), followed by epoxidation ([VO(acac) 2 ], t BuOOH) and reoxidation under Swern conditions, in 37% total yield.

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“…2 ) Cyc10tene (1), CT, a principal component of coffee aroma 3 ) and maple flavor,4) is widely applied as a caramel-like flavoring in food. Since CT exists in the stable, chemically active enol form within the five-membered ring rather than as the unstable a-diketone, it was expected that CT could be utilized as a convenient starting material for the synthesis of biologically active compounds containing a five-membered ring in their skeleton.…”

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confidence: 99%