- Synthesis of chlorins and bacteriochlorins from cycloaddition reactions with porphyrins
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Chlorins and bacteriochlorins are reduced porphyrin-type derivatives displaying characteristic structural, physical, and chemical features. Such features make chlorins and bacteriochlorins key “players” in several fields, and specifically in medicine as p
- Cavaleiro, José A. S.,Monteiro, Carlos J. P.,Moura, Nuno M. M.,P. M. S. Neves, M. Gra?a,Tomé, Augusto C.
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- Scalable synthesis of the aroma compounds d6-β-ionone and d6-β-cyclocitral for use as internal standards in stable isotope dilution assays
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C13 Norisoprenoids are important aroma compounds in wine, giving positive attributes to the overall wine aroma even when found at very low levels. β-Ionone is considered one of the most important aroma compounds giving violet, woody and raspberry aromas to wine, fruits and vegetables in which it is found. Due to its potent aroma at low levels, precise analytical methods are desired for its quantification. Stable isotope dilution assay (SIDA) is one of the most important of these methods but requires the use of isotopically labelled standards. Herein, we describe the scalable synthesis of d6-β-ionone and d6-β-cyclocitral, another aroma compound with smokey and fruity notes, starting from the relatively inexpensive deuterated starting material d6-acetone.
- Mosaferi, Shabnam,Jelley, Rebecca E.,Fedrizzi, Bruno,Barker, David
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- An unexpected generation of magnetically separable Se/Fe3O4 for catalytic degradation of polyene contaminants with molecular oxygen
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Selenization of Fe2O3 with NaHSe led to Se/Fe3O4. The unexpected generation of Fe3O4 attributed to the reduction conditions of the reaction, and the resulted magnetic features of the materi
- Chen, Xingyu,Mao, Jingfei,Liu, Chuang,Chen, Chao,Cao, Hongen,Yu, Lei
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supporting information
p. 3205 - 3208
(2020/08/12)
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- A Simple, Mild and General Oxidation of Alcohols to Aldehydes or Ketones by SO2F2/K2CO3 Using DMSO as Solvent and Oxidant
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A practical, general and mild oxidation of primary and secondary alcohols to carbonyl compounds proceeds in yields of up to 99% using SO2F2 as electrophile in DMSO as both the oxidant and the solvent at ambient temperature. No moisture- and oxygen-free conditions are required. Stoichiometric amount of inexpensive K2CO3, which generates easy to separate by-products, is used as the base. Thus, 5-gram scale runs proceeded in nearly quantitative yields by a simple filtration as the work-up. The use of a polar solvent such as DMSO, which usually promotes competing Pummerer rearrangement, is also noteworthy. This protocol is compatible with a variety of common N-, O-, and S-functional groups on (hetero)arene, alkene and alkyne substrates (68 examples). The protocol was applied (99% yield) to a formal synthesis of the important cholesterol-lowering drug Rosuvastatin. (Figure presented.).
- Zha, Gao-Feng,Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
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supporting information
p. 2262 - 2267
(2019/04/17)
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- Kinetics of β-Carotene Oxidation in the Presence of Highly Active Forms of μ-Carbido Diiron(IV) Tetraphenylporphyrinate
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Abstract: The oxidative destruction of β-carotene in the presence of highly oxidized forms of μ-carbido-bis[(5,10,15,20-tetraphenyl-21H,23H-porphyrinato)iron(IV)] (1 → 3) or its analog with axially coordinated imidazole (2 → 4) obtained under the action of tert-butyl hydroperoxide tBuOOH was studied by spectrophotometry. It was found that compound 3 is the oxo form of compound 1 singly oxidized at the macrocyclic ligand (π radical cation) under the action of which β-carotene is oxidized with a rate constant k = 3.3 L2 mol–2 s–1. A?conclusion is drawn that short-lived compound 4 has unique EAS and is capable of oxidizing tBuOOH to form O2, which makes it possible to consider it the model of peroxidase. The value of k for the reaction with the participation of β-carotene and compound 4 (k = 10.3 L2 mol–2 s–1) is three times higher than that with the participation of compound 3. If a new portion of β-carotene is added, the process of its oxidative destruction in the presence of compounds 3 or 4 occurs without additives of the dimeric complex and peroxide. A?possible nature of compound 4 is discussed, as well as the influence of N-base in the coordination sphere of the complex on the nature of active intermediates and the rate of β-carotene decomposition.
- Simonova,Zaitseva,Tyulyaeva, E. Yu.,Zdanovich,Koifman
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p. 2128 - 2134
(2018/10/24)
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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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- OZONOLYSIS OF AROMATICS AND/OR OLEFINS
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The invention pertains to a process for oxidizing unsaturated starting materials, comprising: (i) providing a liquid composition containing an olefin and/or aromatic starting compound, (ii) compressing an ozone-containing gas to a pressure of at least 5 bar absolute, (iii) introducing the compressed ozone-containing gas in one or more microreactors, bringing said gas into contact with said liquid composition (i), to obtain an ozonide, (iv) and optionally subjecting said ozonide to oxidative or reductive degradation. The use of compressed ozone makes it possible to mix large gas volumes with small liquid volumes, and achieve satisfactory contact between the gas and liquid reactants. This dramatically improves yields over conventional micro-reactor-driven ozonolysis.
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Page/Page column 12
(2010/04/03)
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- Generation of norisoprenoid flavors from carotenoids by fungal peroxidases
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To biotechnologlcally produce norisoprenoid flavor compounds, two extracellular peroxidases (MsP1 and MsP2) capable of degrading carotenoids were isolated from the culture supematants of the basidiomycete Marasmlus scorodonlus (garlic mushroom). The encod
- Zelena, Kateryna,Hardebusch, Bjoern,Huelsdau, Baerbel,Berger, Ralf G.,Zorn, Holger
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experimental part
p. 9951 - 9955
(2010/07/18)
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- β-ionone reactions with the nitrate radical: Rate constant and gas-phase products
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The bimolecular rate constant of script k signNO3+ β-ionone (9.4 ± 2.4 × 10-12 cm3 molecule-1 s-1 was measured using the relative rate technique for the reaction of the nitrate radical (NO3
- Harrison, Joel C.,Ham, Jason E.
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experimental part
p. 629 - 641
(2010/02/27)
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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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- Novel strategy for the synthesis of the butenolide moiety of peridinin
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Tartaric acid is the starting point for the stereoselective synthesis of the butenolide unit (see scheme)in peridinin, a marine carotenoid. Key steps were the desymmetrization of tartaric acid bis(Weinreb amide), an E-selective olefination by Ando-type bromophosphonates, and an anti-selective Mitsunobu elimination (for establishing the C1′=Cγ bond).
- Olpp, Thomas,Brueckner, Reinhard
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p. 1553 - 1557
(2007/10/03)
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- Synthesis of the 2-alkenyl-4-alkylidenebut-2-eno-4-lactone (=α-alkenyl-γ-alkylidenebutenolide) core structure of the carotenoid pyrrhoxanthin via the regioselective dihydroxylation of hepta-2,4-diene-5-ynoic acid esters
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A new strategy for the stereoselective synthesis of 4-alkylidenebut-2-eno- 4-lactones (= γ-alkylidenebutenolides) with (Z)-configuration of the exocyclic C=C bond at C(4) was developed. It is exemplified by the synthesis of 4-alkylidenebutenolactone 31 (Scheme 4), which constitutes a substructure of the carotenoids pyrrhoxanthin (1) and peridinin. The formation of the precursor 4-(1-hydroxyalkyl)butenolactone 29 was accomplished either by cyclocarbonylation of the prop-2-yn-1-ol moiety of 27 (→ 29) or by hydrostannylation of the isopropylidene-protected alkynoic acid ester 26 (->28) followed by transacetalization/transesterification (→ 30). The 4- alkylidenebutenolactone was formed by the ami-selective Mitsunobu dehydration 29 → 31.
- Schmidt-Leithoff, Joachim,Brueckner, Reinhard
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p. 1943 - 1959
(2007/10/03)
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- Novel domino reactions for diterpene synthesis
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New types of concerted domino acylation-cycloalkylation/alkylation- cycloacylation reactions have been described. These processes promoted by methanesulfonic acid-phosphorus pentoxide and concentrated H2SO 4, respectively, provide efficient, elegant, and expeditious routes for biologically active naturally occurring diterpenoids, namely (±)-ferruginol (1), (±)-nimbidiol (2), (±)-nimbiol (3), (±)-totarol (4), and ar-abietatriene (5).
- Bhar, Shanta S.,Ramana
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p. 8935 - 8937
(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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- Functionality of γ- and δ-pyrorenes. Synthesis and study of the reactivity of peroxide compounds
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The photooxygenation of γ- and δ-pyronenes, performed for the first time, affords, as expected, a hydroperoxide, a hydroperoxyperoxide, and an endoperoxide, respectively. The reactivity of these peroxides is studied. They lead to mono-, di- or trifunctional compounds. Most of them are new and could be useful to synthesize molecules with potential sweet-smelling or therapeutic properties.
- Campagnole, Monique,Bourgeois, Marie-Josèphe,Montaudon, Evelyne
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p. 1165 - 1171
(2007/10/03)
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- A conjugate addition-radical cyclisation approach to sesquiterpene-phenol natural products
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A conjugate addition-radical cyclization approach to sesquiterpenephenol natural products was discussed. The first step involved the conjugate addition of an organocopper species to a chromone-3-carboxylate which resulted in 2,2-disubstituted chroman-4-ones. The second step was the generation of a β-ketoester radical. The last step involved a stereoselective manganese(III) acetate-mediated radical cyclization reaction.
- Crombie, Barry S.,Smith, Colin,Varnavas, Christalla Z.,Wallace, Timothy W.
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p. 206 - 215
(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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- Ring A building blocks for taxoids and taxamycins
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The synthesis of a series of oxygenated cyclohexene ring A synthons 20, 22-27, 34, 36, and 37 that possess suitable functionality for further elaboration for taxoid synthesis are described. These compounds have been prepared from β-ionone by a series of oxidative and addition reactions or alternatively by Lewis acid catalyzed Diels-Alder cycloadditions with the oxygen-containing trimethyl substituted dienes 31 and 33. The syntheses of a series of oxygenated cyclohexene ring A synthons 20, 22-27, 34, 36, and 37 that possess suitable functionality for further elaboration for taxoid synthesis are described. These compounds have been prepared from β-ionone by a series of oxidative and addition reactions or alternatively by Lewis acid catalyzed Diels-Alder cycloadditions with the oxygen-containing trimethyl substituted dienes 31 and 33.
- Tjepkema, Michael W.,Wilson, Peter D.,Audrain, Helene,Fallis, Alex G.
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p. 1215 - 1224
(2007/10/03)
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δ-Pyronene, a terpenic synthon recently made industrially available from myrcene, has been characterized. It is an excellent raw material for the preparation of numerous intermediates used in the synthesis of perfumes and retinoids. Furthermore, new terpenic compounds including the cyclogeranyl skeleton have been prepared.
- Quirin, Marie Jeanne,Taran, Martine,Delmond, Bernard
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p. 1852 - 1856
(2007/10/03)
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- A facile method for the conversion of oximes to ketones and aldehydes by the use of activated MnO2
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Activated manganese dioxide (MnO2) was found to be an efficient oxidant in the conversion of oximes to carbonyl compounds. The utility of this method in synthesis was demonstrated by the conversion of galactose to its acyclic aldose derivative 5.
- Shinada, Tetsuro
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p. 6701 - 6704
(2007/10/02)
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- Synthesis of Functionalized Ring A Building Blocks for Taxoids
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The synthesis of a series of oxygenated cyclohexenes 1, 2, 11, 14, 18, and 19 that possess suitable functionality for further elaboration for taxoid synthesis is described.These compounds have been prepared from β-ionone by a series of oxidative and addition reactions or alternatively by a Lewis acid catalyzed intermolecular Diels-Alder reaction in which the A-ring is constructed directly.
- Tjepkema, Michael W.,Wilson, Peter D.,Wong, Timothy,Romero, Miguel A.,Audrain, Helene,Fallis, Alex G.
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p. 6039 - 6042
(2007/10/02)
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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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- Oxidative degradation of β-carotene and β-apo-8′-carotenal
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In the self-initiated oxidation of β-carotene with molecular oxygen the rate of oxygen uptake was shown to depend on the oxygen partial pressure. Epoxides, dihydrofurans, carbonyl compounds, carbon dioxide, oligomeric material, traces of alcohols, and probably carboxylic acids were formed. The main products in the early stage of the oxidation were shown to be 5,6-epoxy-β-carotene. 15,15′-epoxy-′-carotene, diepoxides, and a series of β-apo-carotenals and -carotenones. As the oxidation proceeded uncharacterised oligomeric material and the carbonyl compounds became more important and the epoxides degraded. In the final phase of the oxidation the longer chain β-apo-carotenals were themselves oxidized to shorter chain carbonyl compounds, particularly β-apo-13-carotenone, β-ionone, 5,6-epoxy-gb-ionone, dihydroactinidiolide and probably carboxylic acids. The effect of iron, copper and zinc stearates on the product composition and proportions was studied, as was the effect of light. The oxidation was inhibited by 2,6-di-t-butyl-4-methyphenol and α-tocopherol. The oxidations of β-apo-8′-carotenal and retinal under similar conditions were studied briefly, and the main products from the former compound were characterized. The initiation, the formation of the epoxides, the β-apo-carotenals and -carotenones, the successive chain shortening of the aldehydes to the ketones, and the formation of dihydroactinidiolide are explained in terms of free radical peroxidation chemistry.
- Mordi, Raphael C.,Walton, John C.,Burton, Graham W.,Hughes, Lise,Ingold U., Keith,Lindsay A., David,Moffatt J., Douglas
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p. 911 - 928
(2007/10/02)
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- The chemistry of thujone. XVI. Versatile and efficient routes to safronitrile, β-cyclogeranonitrile, β-cyclocitral, damascones, and their analogues
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Thujone, a waste by-product of the Canadian forest industry, has been utilized as a starting material to develop a versatile synthetic route to the damascones (rose oil ketones) and related analogues.The synthetic sequence provides a route to β-cyclocitral (45), the latter having been previously converted to β-damascone (2).In addition, thujone-drived intermediates are converted to β-damascenone (48) and to intermediates that can be utilized for the preparation of damascone analogues.In conjunction with the above, an efficient route to safronitrile (42), β-cyclogeranonitrile (43), and β-cyclocitral (45) from 2,6-dimethylcyclohexanone has been developed.In summary, these studies afford an attractive versatile route to these important perfumery materials.
- Kutney, James P.,Gunning, Philip J.,Clewley, Robin G.,Somerville, John,Rettig, Steven J.
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p. 2094 - 2114
(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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- A NEW, SPECIFIC SYNTHESIS OF β-CYCLOCITRAL
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A new specific synthesis of β-cyclocitral is presented.The key step is the dehydration of the trans 2.2.6-trimethylcyclohexanone cyanohydrin by thionyl chloride.
- Picard, Jean-Paul,Nzabamwita, Gaspard,Lacoste, Florence,Calas, Raymond,Dunogues, Jacques
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p. 135 - 140
(2007/10/02)
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- SYNTHESE TOTALE DU (+/-)POLIGODIAL, DE LA DRIMENINE ET DE COMPOSES APPARENTES A JONCTION DE CYCLE cis ET trans
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Isomerization by base under kinetic or thermodynamic control of the Diels-Alder adduct of 1,3,3-trimethyl-2-vinyl-1-cyclohexene with dimethyl acetylene dicarboxylate leads to two isomers which, after catalytic hydrogenation, give in high yield starting materials for synthesis of trans and cis drimanes.A short total synthesis of (+/-)-polygodial and (+/-)-drimenine from one of these isomers is desribed.
- Jalali-Naini, M.,Guillerm, D.,Lallemand, J-Y.
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p. 749 - 758
(2007/10/02)
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- Condensation of β-Cyclocitral with Benzaldehyde
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β-Cyclocitral 1b condenses with benzaldehyde in the presence of base catalysts giving the 2-benzopyrans 4, 5 and 6, and in the presence of acid catalysts giving exclusively the aldehyde 7.The cyclocitrals 1a and 1b are both isomerized by strong base anion exchange resin, but their aldehyde-protected derivatives 2 and 3 are not.Some tests used to characterize the aldehydes and their condensation products are described.
- Frank, Arlen W.
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p. 549 - 554
(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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- Process for preparing epoxide-cyclohexyl compound and resultant compound
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Homologation of α,β-polyene unsaturated aldehydes and ketones to form α,β-unsaturated aldehydes via epoxidation of the ketone or aldehyde and intermediates in this process such as β,γ-unsaturated polyene aldehydes.
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- Efficient oxidation of β?carotene in μ-carbido diiron octapropyltetraazaporphyrin–tBuOOH system
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The oxidative decomposition of β?carotene mediated by μ-carbido diiron octapropyltetraazaporphyrin ([FeOPrTAP]2C)–tBuOOH system was investigated in benzene. Interaction between tBuOOH and the binuclear complex resulted in the generation of powerful high-oxidized species those are capable of oxidizing the employed substrate within the limits of several minutes. The explanation for such reactivity behavior involves the existence of a mixture of reactive intermediates in the reaction medium: more stable singly oxidized at the macrocyclic ligand π-cation radical as well as much more reactive dication species that is more contributing to the reaction rate. The introduction of imidazole into the coordination sphere of the initial diiron complex accelerates the β?carotene destruction because of generation of a powerful high-oxidizing species, which is capable of oxidizing β?carotene as well as the applied organic peroxide resulting in dioxygen release. Catalytic behavior of all the observed active intermediates was supported by recycling of the reaction under carotene adding. The quantitative characteristics of reactivity of studied systems were obtained and the possible reaction mechanisms were proposed.
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