- Synthesis method of alpha-cyclocitral
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The invention discloses a synthesis method of alpha-cyclocitral. The method comprises the steps of (1) carrying out Diels-Alder reaction on 1,3-pentadiene and methylcrotonaldehyde under the catalysisof lewis acid to obtain a 2,6,6-trimethyl-3-cyclohexenyl formaldehyde crude product; (2) carrying out isomerization reaction on the 2,6,6-trimethyl-3-cyclohexenyl formaldehyde crude product obtained in step (1) under the catalysis of a catalyzer to generate an alpha-cyclocitral crude product. The method provided by the invention is easy to get reaction raw materials, mild in conditions, easy to control, free of generating byproducts, simple in process, favorable in industrial production, green and environmentally friendly.
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Paragraph 0021; 0050; 0051
(2018/06/26)
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- Method for preparing cyclocitral by micro-structural reactors
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The invention discloses a method for preparing cyclocitral by micro-structural reactors. The method comprises steps as follows: a liquid raw material citral and organic amine in a mole ratio being 1: (0.8-1.5) are simultaneously pumped into a tubular reactor or one micro-structural reactor for an amination reaction, the reaction temperature of the reactor is controlled in a range of 10-20 DEG C, a flow velocity of a reaction liquid is controlled, the reaction liquid is enabled to totally stay in the reactor for 0.1-25 min, and obtained aldimine and concentrated sulfuric acid are injected into another micro-structural reactor and subjected to a ring closing reaction; a reaction product is neutralized by a sodium hydroxide solution and is subjected to acidic hydrolysis, liquid separation, reduced pressure distillation and drying, and a pale yellow oily product, namely, cyclocitral, is obtained. According to the method, the reaction time is short, the reaction temperature is accurate and controllable, and product selectivity and yield are high. The method adopts simple steps, and is convenient to operate and high in practicability.
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- Synthesis of three putative kairomones of the beech leaf-mining weevil Orchestes fagi (L.)
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The beech leaf-mining weevil, Orchestes fagi (L.), also known as the beech flea weevil, is a common and widespread pest of beech, Fagus sylvatica L., in its native Europe. It now appears to be well established in Nova Scotia, Canada. We report a novel synthesis of 9-geranyl-p-cymene and syntheses of 9-geranyl-α-terpinene and 1,1-dimethyl-3-methylene-2-vinylcyclohexane, making partial use of known methods. All three of these compounds are found in beech leaf volatiles and/or wood and are putative kairomones of the beech leaf-mining weevil.
- Mayo,Silk,Abeysekera,MaGee
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supporting information
p. 1124 - 1132
(2016/07/21)
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- Nitriles and carbonyl groups as acceptors in titanocene-catalyzed radical cyclizations
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A catalytic approach to the titanocene-mediated radical cyclization of epoxy nitriles and epoxy carbonyl compounds to hydroxy ketones and diols is described. The reaction is sensitive to the substitution pattern of the catalyst and especially useful for the preparation of cyclobutanones. It can also be used for nitrile group transfer. Georg Thieme Verlag Stuttgart.
- Gansaeuer, Andreas,Piestert, Frederik,Huth, Inga,Lauterbach, Thorsten
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scheme or table
p. 3509 - 3515
(2009/05/26)
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- Improved synthesis of methyl 3-oxo-2,6,6-trimethylcyclohex-1-ene-1- carboxylate, an A-ring intermediate for (±)strigol
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Methyl 3-oxo-2,6,6-trimethylcyclohex-1-ene-1-carboxylate was synthesised over eight steps from the starting material of citral instead of α-ionone. KMnO4, HC(OEt)3 and O2/TEMPO/CuCl were substituted for NaIO4, CH3I and pyridinium chlorochromate, respectively. Every step was simplified and gave a 48% overall yield. The procedure is suitable for large scale production.
- Qianchao,Shiqing, Pi,Xinzhi, Chen
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p. 494 - 496
(2008/09/21)
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- Isolation, synthesis, and anti-tumor activities of a novel class of podocarpic diterpenes
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A novel unusual 17-carbon diterpenoid, named (+)-7-deoxynimbidiol, was isolated from the stalks of Celastrus hypoleucus (Oliv.) Warb. Its racemate and derivatives were synthesized, and the inhibitory activities of these compounds against four cultured human-tumor cell lines were evaluated. The structure-activity relationship was discussed.
- Xiong, Yi,Wang, Kuiwu,Pan, Yuanjiang,Sun, Hongxiang,Tu, Jue
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p. 786 - 789
(2007/10/03)
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- Synthesis of olivacene, a constituent of Archilejeunea olivacea
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A simple synthesis of olivacene 1, a naturally occurring sesquiterpenoid hydrocarbon isolated from Archilejeunea olivacea has been described.
- Kamat, Shrivallabh P.,D'Souza, Asha M.,Paknikar, Shashikumar K.
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p. 2662 - 2664
(2007/10/03)
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- γ-Pyronene, a synthon derived from saffron and intermediary precursor of synthesis of forskolin and strigol
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γ-Pyronene, a terpenic synthon available from myrcene, is an excellent raw material for the preparation of numerous intermediates used in the synthesis of perfumes, retinoids and biological derivatives such as forskolin or strigol.
- Boulin,Arreguy-San Miguel,Delmond
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p. 2753 - 2762
(2007/10/03)
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- Epoxy-pyronene: Obtention of cyclocitrals from ionones and precursor of new terpenic compounds
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The selective obtention of epoxy-pyronene from δ-pyronene has been realized using metachloroperbenzoic acid. The isomerization of this epoxidic compound with Lewis and protonic acids and on active alumina has been studied leading to cyclocitrals. Ionones are obtained from epoxy-pyronene by homologation with various C3 units, in the presence of paratoluenesulfonic acid in order to obtain β-cyclocitral in situ. New terpenic compounds with the cyclogeranyl skeleton were obtained from epoxy-pyronene by reduction followed by homologation.
- Marc,Soulet,Serramedan,Delmond
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p. 3381 - 3388
(2007/10/02)
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The selective obtention of epoxides from delta-pyronene has been realized using a peracid and a cyclodehydrohalogenation reaction. The isomerization of an epoxidic isomer with Lewis and protonic acids and on active alumina has been studied leading to cyclocitrals.
- Serramedan
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p. 4457 - 4460
(2007/10/02)
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- Reaction of Ester Enolates with Nucleophiles. Stereocontrolled Formation of Ketone and Aldehyde Enolates
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Lithium enolates of carboxylic and thiocarboxylic esters react with nucleophiles to afford ketone and aldehyde enolates and subsequently their enol silyl ethers diastereoselectively.This reaction is applied to the synthesis of γ-damascone, α-damascone, β-safranal, and artemisia ketone.
- Fehr, Charles,Galindo, Jose
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p. 1828 - 1830
(2007/10/02)
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- GRIGNARD AND HYDRIDE ADDITION TO A KETENE INTERMEDIATE: A NOVEL ACCESS TO α-DAMASCONE AND α-CYCLOCITRAL
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α-Damascone (1), a rose fragrance chemical, was synthesized by an allylmagnesium chloride addition to ketene 7 as key step.When the same ketene 7 was reduced by two different aluminium hydride reagents, α-cyclocitral was obtained.The presumed intermediates, enolates II and III, were first trapped as silyl enol ethers and then hydrolyzed with D2O to give the expected α-monodeuterated carbonyl compounds.Mixed aluminium hydride reduction of ketenes is recommended as a facile entry into the chemistry of aldehyde enolates.
- Naef, Ferdinand,Decorzant, Rene
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p. 3245 - 3250
(2007/10/02)
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- 175. The Synthesis of β,γ- and α,β-Unsaturated Aldehydes via Polyene Epoxides
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A substitute for the Darzens glycidic ester synthesis for converting unsaturated ketones or aldehydes into the homologated β,γ- or α,β-unsaturated aldehydes employing sulfur ylides is desribed.The carbonyl group is converted into the unsaturated oxirane which is then rearranged to the new aldehyde.High yields of isomerically pure aldehydes are available by this method and the process is of practical importance in the conversion of β-ionone into the β-C14-aldehyde, a key intermediate in the Isler synthesis of vitamin A.The efficient preparation of α- and β-cyclocitral by the novel process is also described.
- Rosenberger, Michael,Jackson, William,Saucy, Gabriel
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p. 1665 - 1674
(2007/10/02)
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