- Facile syntheses of [8,9-2H2]- and [8-2H]-digeranyl
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[8,9-2H2]- and [8-2H]-(2E,6E,10E,14E)-2,6,11,15-tetramethyl-2,6,10,14-hexadecatetraene (digeranyl) (1 and 2) have been synthesized from geraniol by the condensation of geranyl p-tolylsulfone and reductive desulfonylation in the key steps.
- Nakagawa, Osamu,Shimoda, Kei,Izumi, Shunsuke,Hirata, Toshifumi
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- Vakuum UV Photolyses of Some Bichromophoric Alkenes Possesing Hydroxyl or Methoxycarbonyl Group
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The direct photolyses at 185 nm of some naturally occuring and related bichromophoric alkenes possesing hydroxyl or methoxycarbonyl group at an allylic, homoallylic, or remote position gave the geometrical isomers as the major photoproducts detectable on gas chromatography.The isomerization yield was highly sensitive to the functional group introduced and its position; allylic alkenols gave poor yields, while both functionalization at a remote position and esterification of the hydroxyl group improve the photoisomerization yield.
- Inoue, Yoshihisa,Goan, Kazuyoshi,Hakushi, Tadao
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- Alcoholyses and acetolyses of allylic and tertiary benzylic alcohols catalyzed by 2,3-dichloro-5,6-dicyanobenzoquinone
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Allylic and tertiary benzylic alcohols can be converted into their corresponding ethers and acetates selectively and efficiently in the presence of catalytic amounts of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ).
- Iranpoor,Mottaghinejad
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- The aphid sex pheromone cyclopentanoids: Synthesis in the elucidation of structure and biosynthetic pathways
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Identification of a range of aphid sex pheromones as comprising the cyclopentanoids (4aS,7S,7aR)-nepetalactone, (1R,4aS,7S,7aR)-nepetalactol and the (1S)- and (1R,4aR,7S,7aS)-nepetalactols required samples authenticated by 1H and 13C NMR. These and related compounds were provided by small scale synthesis and extraction from plants in the genus Nepeta (Lamiaceae). The subsequent discovery that the synthetic sex pheromones could attract males, and also parasitic wasps that attack aphids, has created a need for large scale syntheses of the cyclopentanoids. This is afforded by cyclisation of the 8-oxo-1-enamine of citronellal as originally developed by Schreiber and co-workers (1986). Investigation into the biosynthesis of the cyclopentanoids by plants for exploiting aphid sex pheromones in crop protection by means of molecular biology required synthesis of putative biosynthetic intermediates, some with radioactive isotopic labelling, particularly 8-oxidised monoterpene alcohols and aldehydes.
- Dawson, Glenn W.,Pickett, John A.,Smiley, Diane W. M.
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- Photoacylation of alcohols in neutral medium
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We report here conditions which allow the photoacylation of primary, secondary and tertiary alcohols with N-acetyl-5,7-dinitroindoline under exceptionally mild conditions, at wavelengths harmless to most functional groups, including otherwise photosensitive ones. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Debieux, Jean-Luc,Cosandey, Anne,Helgen, Celine,Bochet, Christian G.
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- Synthesis of monoterpene esters by alcoholysis reaction with Mucor miehei lipase in a solvent-free system
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The syntheses of geranyl acetate and citronellyl acetate by alcoholysis reaction catalyzed by immobilized lipase from Mucor miehei was studied for the first time in a solvent-free system. Reactions were carried out at a terpene alcohol/acyl donor molar ratio of 1:5 with Lipozyme at 10% of the total weight of the reactants in a solvent-free system. Incubations were carried out at 55 to 60 °C for ethyl and butyl acetates as acyl donors, whereas for methyl acetate the incubation temperature was 40 to 45 °C. Excess concentration of acyl donor increases the percentage of geranyl acetate and citronellyl acetate, while excess of terpene alcohol concentration decreases the same. Yields from 75 to 77% molar conversion (90 to 98% conversion, w/w) were obtained after 8 to 28 h of reaction time.
- Chatterjee,Bhattacharyya
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- Synthetic applications of homoiodo allylsilane II. Total syntheses of (-)-andrographolide and (+)-rostratone
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The first total synthesis of (-)-andrographolide (1), an ent-Labdane diterpenoid lactone from Asian medicinal herb Andrographis paniculata, was achieved via the biomimetic cyclization of an epoxy homoiodo allylsilane precursor 7. Asymmetric total synthesis of (+)-rostratone (25), an antipodal Labdane diterpenoid, was also accomplished via similar biomimetic cyclization of a readily accessible epoxy homoiodo allylsilane precursor 18.
- Gao, Hai-Tao,Wang, Bian-Lin,Li, Wei-Dong Z.
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- A simple method for the removal of organotin residues from acetates and a homoallylic alcohol prepared from organostannane reagents: Column chromatography using 10%-moist SiO2
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Simple column chromatography using 10%-moist silica gel enabled efficient removal of organotin residues from geranyl acetate, which was prepared by the acetylation of geraniol with vinyl acetate in the presence of a catalytic amount of a 1,3-dichloro-substituted tetrabutyldistannoxane. The desired acetate contained only 2.4 ppm of organotin residues. In sharp contrast to this, a similar purification method using dry silica as the stationary phase provided acetate containing ca. 5000 ppm of organotin residues.
- Nishida, Takanori,Matsuda, Daiki,Kasuga, Issei,Orita, Akihiro,Otera, Junzo
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- Continuous-Flow Chemo and Enzymatic Synthesis of Monoterpenic Esters with Integrated Purification
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Monoterpenic esters are very important flavor and fragrance compounds due to their organoleptic properties. Despite their importance, many drawbacks are found for the production of monoterpenic esters. Here in we report two different approach's (chemo and enzymatic) for the continuous production of monoterpenic esters with integrated purification arriving on the desired molecules with high yields (>95%) and short reaction times.
- Adarme, Carlos A.A.,Le?o, Raquel A.C.,de Souza, Stefania P.,Itabaiana, Ivaldo,de Souza, Rodrigo O.M.A.,Rezende, Claudia M.
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- Efficient synthesis and biological evaluation of ω-oxygenated analogues of vitamin K2: Study of modification and structure-activity relationship of vitamin K2 metabolites
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Novel ω-oxygenated vitamin K2 analogues, which are candidates for metabolites of vitamin K2 homologues, were efficiently synthesized and their apoptosis-inducing activity was evaluated. We revealed that some of those analogues were biologically active and the side-chain part played an important role in apoptosis-inducing activity. Our results can provide useful information to develop the structure-activity relationship of vitamin K2 analogues for new drugs based on vitamin K.
- Suhara, Yoshitomo,Murakami, Aya,Kamao, Maya,Mimatsu, Shino,Nakagawa, Kimie,Tsugawa, Naoko,Okano, Toshio
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- Synergistic factors ensue high expediency in the synthesis of menaquinone [K2] analogue MK-6: Application to access an efficient one-pot protocol to MK-9
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Here we report a practical and efficient method for the synthesis of menaquinone vitamin (K2) analog MK-6 in all trans forms through “1 + 5 convergent synthetic approach” of pentaprenyl chloride with monoprenyl menadione derivative. In the synergistic factors, less efficient leaving group/more efficient nucleophile (Cl) in the substrate makes it more prominent reaction by eliminating all Sn2’ side reaction products. Further, the addition of acetic acid in the last step (desulfonation) of reaction sequence removes the limitations of the reactions in terms of cyclized side product (multiple reactions of pentaprenyl alcohol with Et3B), byproduct (Et3B, incendiary compound) formations and their interruption in the tricky purification processes. The utility of this method was further extended to find an efficient one-pot synthesis to MK-9 to the gram scale synthesis. This approach is economical and efficient and avoids the awkward chromatographic separation processes.
- Yerramsetti, Nanaji,Dampanaboina, Lavanya,Mendu, Venugopal,Battula, Satyanarayana
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- Unravelling transition metal-catalyzed terpenic alcohol esterification: A straightforward process for the synthesis of fragrances
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Iron nitrate is a simple and commercially available Lewis acid and is demonstrated to be able to catalyze β-citronellol esterification with acetic acid, achieving high conversion and ester selectivity (ca. 80 and 70%, respectively), within shorter reaction times than those reported in the literature. To the best of our knowledge, this is the first report of a terpenic alcohol esterification reaction catalyzed by Fe(NO3)3. This process is an attractive alternative to the slow and expensive enzymatic processes commonly used in terpenic alcohol esterification. Moreover, it avoids the undesirable steps of neutralizing the products, which are always required in mineral acid-catalyzed reactions. We have performed a study of the activity of different metal Lewis acid catalysts, and found that their efficiency is directly linked to the ability of the metal cation to generate H+ ions from acetic acid ionization. The measurement of pH as well as the conversions achieved in the reactions allowed us to obtain the following trend: Fe(NO3)3 > Al(NO3)3 > Cu(NO3)2 > Ni(NO3)2 > Zn(NO3)2 > Mn(NO3)2 > Co(NO3)2 > LiNO3. The first three are recognized as stronger Lewis acids and they generate more acidic solutions. When we carried out reactions with different iron salts, it was possible to conclude that the type of anion affects the solubility of the catalyst, as well as the conversion and selectivity of the process. Fe2(SO4)3 and FeSO4 were insoluble and less active. Conversely, though they were equally soluble, Fe(NO3)3 was more selective for the formation of β-citronellyl acetate than FeCl3. We assessed the effects of the main reaction variables such as reactant stoichiometry, temperature, and catalyst concentration. In addition to citronellol, we investigated the efficiency of the iron(iii) catalyst in the solvent free esterification of several terpenic alcohols (geraniol, nerol, linalool, α-terpineol) as well as other carboxylic acids.
- Da Silva,Ayala
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- Synthesis of geranyl acetate in non-aqueous media using immobilized Pseudomonas cepacia lipase on biodegradable polymer film: Kinetic modelling and chain length effect study
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Pseudomonas cepacia lipase (PCL) was immobilized on ternary blend biodegradable polymer made up of polylactic acid (PLA), chitosan (CH), and polyvinyl alcohol (PVA). Immobilized biocatalyst was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), % water content, protein and lipase activity assay. The lipase activity assay showed enhanced activity of immobilized lipase than crude lipase. Higher half life time (t1/2) and lower deactivation rate constant (K d) was found for the n-hexane among various tested solvent. Influence of various reaction parameters on enzyme activity were studied in detail. When geraniol (1 mmol) and vinyl acetate (4 mmol) in toluene (3 mL) were reacted with 50 mg immobilized lipase at 55 °C; then 99% geraniol was converted to geranyl acetate after 3 h. Various kinetic parameters such as rmax, Ki(A), Km(A), Km(B) were determined using non-linear regression analysis for ternary-complex and Bi-Bi ping-pong mechanism. The kinetic study showed that reaction followed ternary-complex mechanism with inhibition by geraniol. Activation energy (Ea) was found to be lower for immobilized lipase (13.76 kCal/mol) than crude lipase (19.9 kCal/mol) indicating better catalytic efficiency of immobilized lipase. Immobilized biocatalyst demonstrated 4 fold increased catalytic activity than crude lipase and recycled five times.
- Badgujar, Kirtikumar C.,Bhanage, Bhalchandra M.
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- Total Synthesis of Isohericenone J via a Stille Coupling Reaction
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The first total synthesis of isohericenone J is reported. Key features of this synthetic strategy are a Friedel-Crafts reaction to construct the isobenzofuranone unit and a Pd-catalyzed Stille coupling reaction for the formation of the C5-C1′ bond, generating the natural product, as well as one of its isomers, in 6.0% overall yield in eight steps. This strategy provides a foundation for the synthesis of challenging isobenzofuranone and isoindolinone-type derivatives.
- Cao, Wei,Chen, Ping,Tang, Yu
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- Heteropoly acid catalysts for the synthesis of fragrance compounds from bio-renewables: Acetylation of nopol and terpenic alcohols
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The cesium salt of tungstophosphoric heteropoly acid, Cs2.5H0.5PW12O40, is an active and environmentally friendly heterogeneous catalyst for the liquid-phase acetylation of nopol and several biomass-derived terpenic alcohols (i.e., α-terpineol, nerol, geraniol, linalool, menthol, isoborneol, perillyl alcohol, carveol, isopulegol, carvacrol and nerolidol) with acetic anhydride. The resulting flavor and fragrance acetic esters, which are widely used in perfumery, household and food products, are obtained in good to excellent yields. The reactions occur at room temperature with low catalyst loadings without substantial catalyst leaching and can be performed with stoichiometric amounts of an acetylating agent in solvent free systems.
- Costa, Vinicius V.,Da Silva Rocha, Kelly A.,Oliveira, Luiz C. A.,Kozhevnikova, Elena F.,Kozhevnikov, Ivan V.,Gusevskaya, Elena V.
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- Identification of presumed pheromone blend from Australasian predaceous bug, Oechalia schellenbergii (Heteroptera: Pentatomidae)
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Oechalia schellenbergii is one of the most common predatory insects in Australia and the islands of the South Pacific. Adult males of this predaceous "true bug" collected during March near Gatton, Queensland, Australia, had a pair of enlarged exocrine glands opening underneath their wings that presumably produce an artractant pheromone. The two major components of the secretion are 3-methylenehexyl acetate and 9-hydroxygeranyl diacetate [2,6-dimethyl-2(E),6(E)-octadien-1,8-diol diacetate].
- Aldrich, Jeffrey R.,Oliver, James E.,Waite, Geoff K.,Moore, Chris,Waters, Rolland M.
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- Enzymatic synthesis of geranyl acetate by transesterification with acetic anhydride as acyl donor
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Pseudomonas sp. lipase (PS) was immobilized by adsorption technique onto glass beads and tested for its ability to synthesize geranyl acetate by transesterification with acetic anhydride as the acyl donor. Reactions were carried out in n-hexane containing 0.1 M geraniol, 0.1 M acetic anhydride, and 200 units of lipase PS. Enzyme load, effect of substrate concentration, added water, temperature, time course, organic solvent, pH memory, and enzyme reuse were studied. Yields of up to 96% were obtained with 200 units (approximately 11% w/w of reactants) of enzyme. Increasing amounts of geraniol inhibited lipase activity, while excess acyl donor concentration enhanced ester production. Yields as high as 97% were obtained at 50 °C, 24 h incubation, with no added water. Solvents with log P values ≥3.0 showed the highest conversion yields. Solvent-free samples also performed well. The pH range of 4-9 gave good yields (92-98.4%). Enzyme reuse studies showed the lipase remained active after 15 runs.
- Yee,Akoh
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- Design, synthesis, and biological evaluation of new (2E,6E)-10-(dimethylamino)-3,7-dimethyl-2,6-decadien-1-ol ethers as inhibitors of human and Trypanosoma cruzi oxidosqualene cyclase
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New dimethylamino truncated squalene ether derivatives containing a different aromatic moiety (phenyl, naphthyl, and biphenyl) or a simple alkyl (n-hexylic) group were synthesized as inhibitors of the oxidosqualene cyclase (OSC) and of the sterol biosynthetic pathway. The activity against human OSC was compared with the activity against the OSCs of pathogenic organisms such as Pneumocystis carinii and Trypanosoma cruzi. The phenyl derivative was the most potent inhibitor of T. cruzi OSC.
- Galli, Ubaldina,Oliaro-Bosso, Simonetta,Taramino, Silvia,Venegoni, Serena,Pastore, Emanuele,Tron, Gian Cesare,Balliano, Gianni,Viola, Franca,Sorba, Giovanni
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- Enzymatic synthesis of geranyl acetate in n-hexane with Candida antarctica lipases
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Geranyl acetate is an important flavor and fragrance compound. Two immobilized Candida antarctica lipases, SP382 and SP435, were investigated for their use in the synthesis of geranyl acetate by direct esterification. Yields between 95 and 99% molar conversion were obtained with 2 and 15% (w/w reactants) of SP435 and SP382 lipases, respectively. Optimum yields were obtained at 0.1 M acetic acid and 0.12 M geraniol after 16-h incubation. No inhibitory effect was observed at increasing concentrations of geraniol. Addition of 60% (w/w reactants) water led to 50 and 60% reduction in the esterification activity of SP382 and SP435 lipases, respectively. The best yields were obtained at added water contents between 0-5% (w/w reactants). Solvents with a log P value of 0.85 or more gave reaction yields of more than 80% molar conversion. Higher log P values did not necessarily lead to higher conversion yields. The immobilized lipase SP382 was still active after reusing ten times in the direct esterification reaction.
- Claon,Akoh
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- Isomerisation cis trans regioselective de doubles liaisons trisubstituees.
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At moderate temperatures aqueous sulphur dioxide equilibrates trisubstituted double bonds.
- Cuvigny,Herve du Penhoat,Julia
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- Terpene Cyclizations inside a Supramolecular Catalyst: Leaving-Group-Controlled Product Selectivity and Mechanistic Studies
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The tail-to-head terpene cyclization is arguably one of the most complex reactions found in nature. The hydrogen-bond-based resorcinarene capsule represents the first man-made enzyme-like catalyst that is capable of catalyzing this reaction. Based on noncovalent interactions between the capsule and the substrate, the product selectivity can be tuned by using different leaving groups. A detailed mechanistic investigation was performed to elucidate the reaction mechanism. For the cyclization of geranyl acetate, it was found that the cleavage of the leaving group is the rate-determining step. Furthermore, the studies revealed that trace amounts of acid are required as cocatalyst. A series of control experiments demonstrate that a synergistic interplay between the supramolecular capsule and the acid traces is required for catalytic activity.
- Zhang, Qi,Catti, Lorenzo,Pleiss, Jürgen,Tiefenbacher, Konrad
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- Selective allylic hydroxylation of acyclic terpenoids by CYP154E1 from Thermobifida fusca YX
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Allylic alcohols are valuable precursors in the synthesis of pharmaceutical intermediates, agrochemicals and natural products. Regioselective oxidation of parental alkenes is a challenging task for chemical catalysts and requires several steps including protection and deprotection. Many cytochrome P450 enzymes are known to catalyse selective allylic hydroxylation under mild conditions. Here, we describe CYP154E1 from Thermobifida fusca YX that enables this type of oxidation. Several acyclic terpenoids were tested as possible substrates for CYP154E1, and the regio- and chemoselectivity of their oxidation was investigated. Using a previously established bioinformatics approach we identified position 286 in the active site of CYP154E1 which is putatively involved in substrate binding and thereby might have an effect on enzyme selectivity. To tune regio- and chemoselectivity of the enzyme three mutants at position 286 were constructed and used for substrate oxidation. All formed products were analysed with GC-MS and identified using chemically synthesised authentic samples and known compounds as references. Best regioselectivity towards geraniol and nerol was observed with the wild type enzyme mainly leading to 8-hydroxy derivatives (8-hydroxygeraniol or 8-hydroxynerol) with high selectivity (100% and 96% respectively). Highest selectivities during the oxidation of geranylacetone and nerylacetone were observed with the following variants: V286F led mainly to 7-hydroxygeranylacetone (60% of the total product) and V286A produced predominantly 12-hydroxynerylacetone (75% of total product). Thus, CYP154E1 and its mutants expand the tool-box for allylic hydroxylation in synthetic chemistry.
- Bogazkaya, Anna M.,Von Buehler, Clemens J.,Kriening, Sebastian,Busch, Alexandrine,Seifert, Alexander,Pleiss, Juergen,Laschat, Sabine,Urlacher, Vlada B.
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- Design and synthesis of biologically active analogues of vitamin K2: Evaluation of their biological activities with cultured human cell lines
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Novel ω-oxygenated vitamin K2 analogues were efficiently synthesized and their biological activities were evaluated. Some were biologically active and the side-chain played an important role in γ-carboxylation and apoptosis-inducing activity. The results provide useful information on the structure-activity relationship of vitamin K2 analogues for the development of new drugs.
- Suhara, Yoshitomo,Hirota, Yoshihisa,Nakagawa, Kimie,Kamao, Maya,Tsugawa, Naoko,Okano, Toshio
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- Synthesis of Cembranoid Analogues through Ring-Closing Metathesis of Terpenoid Precursors: A Challenge Regarding Ring-Size Selectivity
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A systematic study on ring-closing metathesis with Grubbs II catalyst to cembranoid macrocycles is described. Acyclic terpenoids with a functional group X in the homoallylic position relative to an RCM active terminus and substituents R, R1 directly attached to the other terminal double bond were prepared from geraniol derived trienes and fragments that are based on bromoalkenes and dimethyl malonate. Such terpenoids were suitable precursors, despite the presence of competing double bonds in their framework. The size of R and R1 is crucial for successful macrocyclization. Whereas small alkyl substituents at the double bond directed the RCM towards six-membered ring formation, cross metathesis leading to dimers dominated for bulkier alkyl groups. A similar result was obtained for precursors without functional group X. In the case of unsymmetrically substituted terpenoid precursor (R=Et, R1=Me) with homoallylic OTBS or OMe group, the RCM could be controlled towards formation of macrocyclic cembranoids, which were isolated with excellent E-selectivity. The role of the substituents was further studied by quantum chemical calculations of simplified model substrates. Based on these results a mechanistic rationale is proposed.
- Heidt, Tanja,Baro, Angelika,K?hn, Andreas,Laschat, Sabine
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- BAKER'S YEAST HYDROGENATION OF CARBONYL ACTIVATED DOUBLE BONDS. ENANTIOSELECTIVE SYNTHESIS OF THE (S) -FORM OF THE DIHYDROTERPENEDIOL SECRETED BY DANAUS CHRYSIPPUS AND OF A PHEROMONE OF CALLOSOBRUCHUS CHINENSIS L.
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The (S)- forms of (E)-3,7-dimethyl-2-octene-1,8-diol (secreted by male danaid butterflies) and of (E)-3,7-dimethyl-2-octene-1,8-dioic acid (a pheromone of the azuki bean weevil) were synthesized via stereoselective hydrogenation by baker's yeast of the carbonyl activated double bond of achiral precursors.
- Gramatica, Paola,Giardina, Giuseppe,Speranza, Giovanna,Manitto, Paolo
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- Lithium perchlorate catalyzed acetylation of alcohols under mild reaction conditions
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Lithium perchlorate is found to efficiently catalyze the acetylation of alcohols and phenols with acetic anhydride in good to excellent yields.
- Nakae,Kusaki,Sato
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- Iridoid Sex Pheromone Biosynthesis in Aphids Mimics Iridoid-Producing Plants
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Biosynthesis of (1R,4aS,7S,7aR)-nepetalactol (1) and (4aS,7S,7aR)-nepetalactone (2) in plants involves iridoid synthase (ISY), an atypical reductive cyclase that catalyses the reduction of 8-oxogeranial into the reactive enol of (S)-8-oxocitronellal, and cyclization of this enol intermediate, either non-enzymatically or by a nepetalactol-related short chain dehydrogenase enzyme (NEPS) that yields the nepetalactols. In this study, we investigated the biosynthesis in vivo of 1 and 2 in the pea aphid, Acyrthosiphon pisum, using a library of isotopically-labelled monoterpenoids as molecular probes. Topical application of deuterium-labelled probes synthesized from geraniol and nerol resulted in production of 2H4?lactol 1 and 2H4?lactone 2. However, deuterium incorporation was not evident using labelled probes synthesized from (S)-citronellol. These results suggest that iridoid biosynthesis in animals, specifically aphids, may follow a broadly similar route to that characterised for plants.
- Partridge, Suzanne J.,Withall, David M.,Caulfield, John C.,Pickett, John A.,Stockman, Robert A.,Oldham, Neil J.,Birkett, Michael A.
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- Matteson Reaction under Flow Conditions: Iterative Homologations of Terpenes
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The Matteson reaction is ideally suited for flow chemistry since it allows iterative homologation of boronate esters. The present study provides accurate data on reaction times of the individual steps of the Matteson reaction, which occurs in less than 10 s in total. The protocol allows terpenes to be (per-)homologated in a controlled manner to yield homo-, bishomo-, and trishomo-terpenols after oxidative workup. The new terpene alcohols are validated with respect to their olfactoric properties.
- Kuhwald, Conrad,Kirschning, Andreas
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supporting information
p. 4300 - 4304
(2021/05/26)
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- Molybdenum-modified mesoporous SiO2as an efficient Lewis acid catalyst for the acetylation of alcohols
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A suitable, expeditious and well-organized approach for the acetylation of alcohols with acetic anhydride in the presence of 5%MoO3-SiO2 as an optimum environmentally benign heterogeneous catalyst was developed. The high surface area obtained for 5%MoO3-SiO2, 101 m2 g-1 compared to other catalysts, 22, 23, and 44 m2 g-1 for 5%WO3-ZrO2, 5%WO3-SiO2, and 5%MoO3-ZrO2, respectively, appears to be the driving force for better catalytic activity. Amongst the two dopants used, molybdenum oxide is the better dopant compared to its tungsten oxide counterpart. High yields of up to 86% were obtained with MoO3 doping while WO3 containing catalysts did not show any activity. Other reaction parameters such as reactor stirring speed, and solvent variation were studied and revealed that the optimum stirring speed is 400 rpm and cyclohexane is the best solvent. Thus, the utilization of affordable and nontoxic materials, short reaction times, reusability, and producibility of excellent yields of the desired products are the advantages of this procedure.
- Hlatshwayo, Xolani S.,Ndolomingo, Matumuene Joe,Bingwa, Ndzondelelo,Meijboom, Reinout
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p. 16468 - 16477
(2021/05/19)
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- Ring-Closing Metathesis of Aliphatic Ethers and Esterification of Terpene Alcohols Catalyzed by Functionalized Biochar
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Functionalized biochars, renewable carbon materials prepared from waste biomass, can catalyze transformations of a range of oxygen-containing substrates via hydrogen-bonding interactions. Good conversions (up to 75.2 %) to different O-heterocycles are obtained from ring-closing C?O/C?O metathesis reactions of different aliphatic ethers under optimized conditions using this heterogeneous, metal-free, and easy separable catalyst. The diversity in the sorts of O-containing feedstocks is further demonstrated by the utilization of functionalized biochar to promote the esterification of terpene alcohols, an important reaction in food and flavor industries. Under the optimized conditions, full conversions to various terpene esters are obtained. Moreover, both of the reactions studied herein are performed under neat conditions, thus increasing the overall sustainability of the process described.
- Kerton, Francesca M.,MacQuarrie, Stephanie L.,Vidal, Juliana L.,Wyper, Olivia M.
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supporting information
p. 6052 - 6056
(2021/12/10)
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- Allylic Amination of Alkenes with Iminothianthrenes to Afford Alkyl Allylamines
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Allylic C-H amination is currently accomplished with (sulfon)amides or carbamates. Here we show the first allylic amination that can directly afford alkyl allylamines, enabled by the reactivity of thianthrene-based nitrogen sources that can be prepared from primary amines in a single step.
- Chen, Junting,Cheng, Qiang,Lin, Songyun,Ritter, Tobias
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supporting information
p. 17287 - 17293
(2020/11/02)
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- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
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A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
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supporting information
p. 16702 - 16707
(2020/10/27)
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- Method for synthesizing acetate perfume
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The invention provides a method for synthesizing acetate by alcohol esterification, which comprises the following steps: by using enol acetate as an esterification reagent, esterifying a primary alcohol, secondary alcohol or tertiary alcohol substrate at high selectivity and high yield under the action of an acidic catalyst to obtain the corresponding acetate products. The method has the main advantages that the synthesis method is novel, enol acetate is used as an esterification reagent, reaction byproducts are micromolecular acetaldehyde or acetone and the like, and the micromolecular compounds do not show acidity and are low in boiling point, so that rearrangement side reaction of an alcohol substrate cannot be caused; and the small molecule byproduct can be conveniently removed from the reaction solution, so that the esterification reaction is promoted to be completely carried out, the reaction stability is good, and the yield is high.
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Paragraph 0051-0053; 0074-0076
(2021/01/15)
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- Synthesis method of geranyl acetate
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The invention relates to the technical field of preparation of flavors and fragrances, in particular to a synthesis method of geranyl acetate. The synthesis method of geranyl acetate comprises the following steps of: mixing acetic acid, geraniol and a polymerization inhibitor, heating the mixture to 60-140 DEG C, then adding a catalyst, and starting stirring; detecting the content of acetic acid in the reaction solution every 20-60 minutes, and stopping the reaction when the content of acetic acid is stable. According to the synthesis method of geranyl acetate, cation exchange resin is used asa catalyst, the catalytic activity and selectivity are excellent, other side reactions are not found, the reaction liquid is basically colorless, and geranyl acetate obtained through purification islighter in color and luster than geranyl acetate obtained through catalysis of concentrated sulfuric acid. Meanwhile, the catalytic system provided by the invention has the advantages of easiness in separation from a product, small corrosion to equipment, no environmental pollution, reusability and the like.
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Paragraph 0078-0103; 0108-0115
(2020/11/01)
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- Stereocontrolled synthesis and configurational assignment of (R)-all-trans-11,12-dihydro-3-hydroxyretinol
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The synthesis of (R)-all-trans-11,12-dihydro-3-hydroxyretinol and putative metabolites of the side-chain functional group has been achieved in a stereocontrolled manner via the Suzuki-Hiyama cross-coupling reaction of an enantiopure (hydroxycyclohexenyl)alkenyliodide and non-conjugated pinacolboranedienoate, which allowed the absolute configuration of this natural product to be confirmed.
- Rivas,Alvarez, Rosana,de Lera, Angel R.
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supporting information
(2019/08/07)
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- Preparing method and application of aminopyridine derivative
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The invention provides an aminopyridine derivative and a preparing method and application thereof. The structural formula of the aminopyridine derivative is shown in the description, wherein R represents substitute groups and is selected from one or more of alkyl groups of C1-C20, phenyl groups, naphthyls, methoxy groups, benzyloxy groups, fluorine, chlorine, bromine, trifluoromethyl, methoxycarbonyl groups. The preparing method comprises the steps of conducting benzylation on 4-aminopyridine and benzylic halides under action of an alkaline reagent. The aminopyridine derivative is used for catalyzing esterification reaction, and is especially suitable for catalyzing acetic acid esterification reaction with alcohol as the substrate; the reaction speed is high, the yield is high, and the reaction effect and the reaction speed are almost equal to those of 4-dimethylamino pyridine. The aminopyridine derivative has large molecular weight and a high boiling point and accordingly can be separated from primary products and auxiliary products through distillation or rectification and can be reused cyclically ten times or more, the cost of the catalyst is greatly reduced, and the aminopyridine derivative has good industrial application prospects.
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Paragraph 0101-0103; 0104; 0105; 0113
(2019/07/16)
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- Efficient Enzymatic Preparation of Flavor Esters in Water
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A straightforward biocatalytic method for the enzymatic preparation of different flavor esters starting from primary alcohols (e.g., isoamyl, n-hexyl, geranyl, cinnamyl, 2-phenethyl, and benzyl alcohols) and naturally available ethyl esters (e.g., formate, acetate, propionate, and butyrate) was developed. The biotransformations are catalyzed by an acyltransferase from Mycobacterium smegmatis (MsAcT) and proceeded with excellent yields (80-97%) and short reaction times (30-120 min), even when high substrate concentrations (up to 0.5 M) were used. This enzymatic strategy represents an efficient alternative to the application of lipases in organic solvents and a significant improvement compared with already known methods in terms of reduced use of organic solvents, paving the way to sustainable and efficient preparation of natural flavoring agents.
- Perdomo, Igor Chiarelli,Gianolio, Stefania,Pinto, Andrea,Romano, Diego,Contente, Martina Letizia,Paradisi, Francesca,Molinari, Francesco
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p. 6517 - 6522
(2019/06/20)
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- Exploiting the Synthetic Potential of Sesquiterpene Cyclases for Generating Unnatural Terpenoids
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The substrate flexibility of eight purified sesquiterpene cyclases was evaluated using six new heteroatom-modified farnesyl pyrophosphates, and the formation of six new heteroatom-modified macrocyclic and tricyclic sesquiterpenoids is described. GC-O analysis revealed that tricyclic tetrahydrofuran exhibits an ethereal, peppery, and camphor-like olfactoric scent.
- Oberhauser, Clara,Harms, Vanessa,Seidel, Katja,Schr?der, Benjamin,Ekramzadeh, Kimia,Beutel, Sascha,Winkler, Sven,Lauterbach, Lukas,Dickschat, Jeroen S.,Kirschning, Andreas
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supporting information
p. 11802 - 11806
(2018/09/10)
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- Isoprene oligomer, and method for producing isoprene oligomer
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The purpose of the present invention is to provide an isoprene oligomer and polyisoprene in which a modification has been added to the frame of the molecule. Also provided are a rubber composition obtained by blending the isoprene oligomer and/or polyisoprene, and a pneumatic tire in which the rubber composition is used for the members of the tire (for example, the tread or sidewalls). The presentinvention pertains to an isoprene oligomer obtained by being synthesized from an allylic diphosphoric acid represented by formula (X), and a compound represented by formula (Y). (In formula (X), n represents an integer 1 to 10. In formula (Y), R represents a group other than a methyl group.).
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Paragraph 0179
(2018/09/21)
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- Lipase-mediated selective acetylation of primary alcohols in ethyl acetate
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An environmental friendly process to selectively acetylate primary alcohols was demonstrated. The esterification process consists of treatment of a primary alcohol in the presence of immobilized C. antarctica lipase (Novozyme-435) in ethyl acetate at room temperature. Primary alcohols were acetylated in the presence of secondary alcohols and phenols.
- de Souza, Ernane C.,Romero-Ortega, Moises,Olivo, Horacio F.
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supporting information
p. 287 - 290
(2017/12/29)
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- Formyloxyacetoxyphenylmethane and 1,1-diacylals as versatile O-formylating and O-acylating reagents for alcohols
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Formyloxyacetoxyphenylmethane, symmetric 1,1-diacylals and mixed 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as moisture stable O-formylating and O-acylating reagents for primary and secondary alcohols, allylic alcohols and phenols under solvent/catalyst free conditions to afford their corresponding esters in good yield.
- Chapman, Robert S.L.,Francis, Molly,Lawrence, Ruth,Tibbetts, Joshua D.,Bull, Steven D.
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p. 6442 - 6452
(2018/10/02)
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- Nucleophilic Substitutions of Alcohols in High Levels of Catalytic Efficiency
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A practical method for the nucleophilic substitution (SN) of alcohols furnishing alkyl chlorides, bromides, and iodides under stereochemical inversion in high catalytic efficacy is introduced. The fusion of diethylcyclopropenone as a simple Lewis base organocatalyst and benzoyl chloride as a reagent allows notable turnover numbers up to 100. Moreover, the use of plain acetyl chloride as a stoichiometric promotor in an invertive SN-type transformation is demonstrated for the first time. The operationally straightforward protocol exhibits high levels of stereoselectivity and scalability and tolerates a variety of functional groups.
- Stach, Tanja,Dr?ger, Julia,Huy, Peter H.
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supporting information
p. 2980 - 2983
(2018/05/28)
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- Preparation of regio- and stereoisomeric di- and tetrahydrogeranylgeraniols and identification of esterifying groups in natural (bacterio)chlorophylls
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All regioisomeric di- and tetrahydrogeranylgeraniols possessing the C2[dbnd]C3 double bond were prepared as authentic samples. The synthetic C20-isoprenoid alcohols were separated well by gas chromatography. Based on the chromatographic analysis, the enzymatic reduction pathway of a geranylgeranyl group was investigated to identify the last stage of (bacterio)chlorophyll biosynthesis in phototrophs. The geranylgeranyl group was triply reduced to the phytyl group through the first regio- and stereospecific hydrogenation of C10[dbnd]C11 to C10H–C11(S)H, the second of C6[dbnd]C7 to C6H–C7(S)H, and the third of C14[dbnd]C15 to C14H–C15H. The identification of the reduction sequence completes the biosynthetic pathways for naturally occurring chlorophyll-a and bacteriochlorophyll-a bearing a phytyl group as the esterifying moiety in the 17-propionate residues.
- Tamiaki, Hitoshi,Nomura, Kota,Mizoguchi, Tadashi
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p. 6361 - 6370
(2017/11/16)
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- MANUFACTURING METHOD OF CARBOXYLIC ACID PRENYL AND PRENOL USING OXOVANADIUM COMPLEX
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PROBLEM TO BE SOLVED: To provide an industrially and economically advantageous manufacturing method of carboxylic acid prenyl and prenol in a high yield under a mild condition. SOLUTION: In a manufacturing method, allyl alcohol represented by the formula (1) is reacted with carboxylic acid anhydride represented by the formula (2) in a presence of an oxovanadium complex prepared by reacting trialkoxy oxovanadium and a pyridinecarboxylic acid derivative, thereby obtaining allyl ester represented by the formula (3). Further, carboxylic acid prenyl is subjected to solvolysis, thereby obtaining prenol represented by the formula (4). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPO&INPIT
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Paragraph 0069
(2017/10/07)
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- Method for preparing geranyl acetate under catalysis of acidic functionalized ionic liquid
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The invention discloses a method for preparing geranyl acetate under the catalysis of acidic functionalized ionic liquid. The method comprises the following steps: subjecting acetic acid and geraniol to esterification under the catalysis of the acidic functionalized ionic liquid; and after complete reaction, subjecting a reaction solution to after-treatment so as to obtain geranyl acetate. The structure of the acidic functionalized ionic liquid is as shown in a formula (II), i.e., [X(CH)SOH]Y. In the formula (II), X is R(R)(R)N-, and R, R and R are independently selected from C1-C5 alkyl groups; n is an integer in a range of 1 to 5; and Y is a hydrosulfate radical, a sulfonate radical, a methanesulfonate radical, a trifluoromethanesulfonate radical, a benzenesulfonate radical or a p-toluenesulfonate radical. The method provided by the invention is high in conversion rate, few in side reactions, high in product yield and purity and simple in after-treatment, and has important industrial application value.
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Paragraph 0028; 0029; 0030; 0031; 0032; 0033
(2017/08/30)
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- TiCl4/Et3N-Mediated Condensation of Acetate and Formate Esters: Direct Access to β-Alkoxy- and β-Aryloxyacrylates
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A methodology to build (E)-β-alkoxy- and (E)-β-aryloxyacrylate moieties from acetate and formate esters promoted by the TiCl4/Et3N system is presented. The reaction is compatible with a broad range of structural skeletons and elapses through an unusual condensation pathway. Taking into account the obtained results, we propose a plausible mechanism involving a bimetallic titanium intermediate for this type of transformation.
- álvarez-Calero, José María,Jorge, Zacarías D.,Massanet, Guillermo M.
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supporting information
p. 6344 - 6347
(2016/12/23)
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- Proton-gradient-transfer acid complexes and their catalytic performance for the synthesis of geranyl acetate
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Special proton-gradient-transfer acid complexes (PGTACs) in which the bonded protons are not equivalent and have gradients in transfer ability, acidity, and reactivity were reported. The acidity gradient of the protons gave the PGTACs excellent catalytic activity and selectivity in the esterification of terpenols. These PGTACs are “reaction-induced self-separation catalysts” and can be easily reused. The kinetics with PGTACs as catalyst in the esterification of geraniol were also studied for use in engineering design.
- Chen, Yongle,Ding, Shiya,Zheng, Wentao,Zhang, Yiyang,Wu, Youting,Hu, Xingbang
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p. 2114 - 2121
(2017/01/16)
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- Efficient O-Acylation of Alcohols and Phenol Using Cp2TiCl as a Reaction Promoter
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A method has been developed for the conversion of primary, secondary, and tertiary alcohols, and phenol, into the corresponding esters at room temperature. The method uses a titanium(III) species generated from a substoichiometric amount of titanocene dichloride together with manganese(0) as a reductant, as well as methylene diiodide. It involves a transesterification from an ethyl ester, or a reaction with an acyl chloride. A radical mechanism is proposed for these transformations.
- Durán-Pe?a, María Jesús,Botubol-Ares, José Manuel,Hanson, James R.,Hernández-Galán, Rosario,Collado, Isidro G.
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supporting information
p. 3584 - 3591
(2016/07/28)
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- Efficient acylation and transesterification catalyzed by dilithium tetra-tert-butylzincate at low temperatures
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The acylation and transesterification of alcohols with vinyl acetate and carboxylic esters were investigated in the presence of a catalytic amount (1-10 mol %) of dilithium tetra-tert-butylzincate (TBZL) as a catalyst. The acylation proceeded quantitatively at 0 °C within 1 h. The transesterification occurred for a wide range of combinations of esters and alcohols at 0 to -40 °C. To the best of our knowledge, this is the first successful transesterification at such low temperatures. The time-conversion plots for the transesterification show that the reaction reached equilibrium within 5 min at 0 °C. The reaction proceeded quantitatively by addition of molecular sieves 4A. In addition, the transesterification proceeded even in the presence of H2O and amines.
- Oshimura, Miyuki,Oda, Yuki,Kondoh, Keita,Hirano, Tomohiro,Ute, Koichi
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p. 2070 - 2073
(2016/04/26)
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- Transesterification Reactions Catalyzed by a Recyclable Heterogeneous Zinc/Imidazole Catalyst
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We report the development of a universal and recyclable heterogeneous zinc/imidazole catalyst. The catalyst is recoverable through simple filtration and can be reused at least five times, retaining its catalytic activity. Leached zinc species were not responsible for the observed catalysis based on the hot filtration test and ICP-MS analysis. The heterogeneous zinc catalyst also promotes chemoselective transesterification over amidation. (Figure presented.).
- Nakatake, Daiki,Yazaki, Ryo,Matsushima, Yoshimasa,Ohshima, Takashi
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supporting information
p. 2569 - 2574
(2016/08/16)
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- METHOD FOR PRODUCING PRENYL ESTERS AND PRENOLS
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PROBLEM TO BE SOLVED: To provide an industrially and economically advantageous method for geometrically selectively producing prenol under a mild condition. SOLUTION: Provided is a method for producing prenyl ester (3) in which allyl alcohol (1) is reacted with vinyl ester (2) under the presence of an oxovanadium complex and a hydrolytic enzyme. Further provided is a method for producing prenol (4) by hydrolyzing prenyl ester (3). SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0080
(2017/01/17)
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- Method for preparing natural geranyl acetate
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The invention discloses a method for preparing natural geranyl acetate. The natural geranyl acetate is made of geraniol and acetic anhydride. The method includes carrying out reaction on the geraniol and the acetic anhydride under the effects of a SO/TiOSiO solid superacid catalyst to obtain the natural geranyl acetate. The geraniol is natural geraniol, and the purity of the geraniol is 90-95%; the acetic anhydride is made of acetic acid generated by means of fermentation, and the purity of the acetic anhydride is higher than 99%. The method has the advantages that solid superacid is used as the catalyst, the reaction can be quickly carried out, the geranyl acetate is high in yield, and the method is nearly free of pollution byproducts; equipment cannot be corroded by the solid superacid, the solid superacid is easy to separate from liquid-phase reaction systems, and post-treatment is simple.
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Paragraph 0025
(2017/01/02)
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- Oxidative "reverse-esterification" of ethanol with benzyl/alkyl alcohols or aldehydes catalyzed by supported rhodium nanoparticles
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A very unusual role of polystyrene stabilized rhodium (Rh@PS) nanoparticles as a supported catalyst is described for "reverse-esterification" of ethanol with benzyl/alkyl alcohols or aldehydes. Faster and selective oxidation of ethanol to acetaldehyde and H2 under Rh@PS catalyzed conditions which restricted further oxidation of benzyl/alkyl alcohols and their in situ reaction gave the corresponding acetate esters following the dehydrogenative-coupling approach. A hitherto redox dehydrogenative-coupling of ethanol and aldehydes has also been explored for the same acetate ester synthesis under Rh@PS catalyzed conditions.
- Guha, Nitul Ranjan,Sharma, Saurabh,Bhattacherjee, Dhananjay,Thakur, Vandna,Bharti, Richa,Reddy, C. Bal,Das, Pralay
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supporting information
p. 1206 - 1211
(2016/03/09)
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- Ligand-controlled regiodivergent Ni-catalyzed reductive carboxylation of allyl esters with CO2
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A novel Ni-catalyzed regiodivergent reductive carboxylation of allyl esters with CO2 has been developed. This mild, user-friendly, and operationally simple method is characterized by an exquisite selectivity profile that is dictated by the ligand backbone.
- Moragas, Toni,Cornella, Josep,Martin, Ruben
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supporting information
p. 17702 - 17705
(2015/02/19)
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- Gd(OTf)3-catalyzed synthesis of geranyl esters for the intramolecular radical cyclization of their epoxides mediated by titanocene(III)
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A selective and mild method for the esterification of a variety of carboxylic acids with geraniol is developed. We demonstrated that the use of triphenylphosphine, I2, 2-methylimidazole or imidazole and a catalytic amount of Gd(OTf)3 resulted to be more active than the previous protocols, providing a 16-membered library of geranyl esters in higher yields and in shorter reaction times. The use of essential oil of palmarosa (Cymbopogon martinii), enriched with geraniol, as a raw material for the synthesis of the target compounds complemented and proved how sustainable and eco-friendly this protocol is. Finally, the selective 6,7-epoxidation of the obtained geranyl esters led us to study their regio-controlled radical cyclization mediated by titanocene(iii) for the synthesis of novel (8-hydroxy-9,9-dimethyl-5-methylene cyclohexyl)methyl esters in moderate yields and with excellent stereoselectivities.
- Garca Santos, William H.,Puerto Galvis, Carlos E.,Kouznetsov, Vladimir V.
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p. 1358 - 1366
(2015/02/05)
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- Green bioprocesses in sponge-like ionic liquids
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Abstract Ionic liquids (ILs) are a new class of liquid solvent, whose use has led to a green chemical revolution because of their unique array of physico-chemical properties, headed by their negligible vapour pressure and their exceptional ability to stabilize biocatalysts. Hydrophobic ILs based on cations with long alkyl side-chains, e.g. N,N,N,N-hexadecyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2]), are temperature switchable ionic liquid/solid phases that behave as sponge-like systems (sponge-like ionic liquid, SLILs). Based on this new property, SLILs have been used to develop straightforward and clean approaches for producing nearly pure synthetic compounds with added value (e.g. geranyl acetate, anisyl acetate, methyl oleate, etc.) in two steps: an enzymatic synthetic step as liquid phase, and then a product separation step involving simple centrifugation as a solid phase.
- Lozano, Pedro,Bernal, Juana M.,Gómez, Celia,García-Verdugo, Eduardo,Isabel Burguete,Sánchez, Gregorio,Vaultier, Michel,Luis, Santiago V.
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- Titanium carbenoid-mediated cyclopropanation of allylic alcohols: Selectivity and mechanism
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A new method for the chemo- and stereoselective conversion of allylic alcohols into the corresponding cyclopropane derivatives has been developed. The cyclopropanation reaction was carried out with an unprecedented titanium carbenoid generated in situ from Nugent's reagent, manganese and methylene diiodide. The reaction involving the participation of an allylic hydroxyl group, proceeded with conservation of the alkene geometry and in a high diastereomeric excess. The scope, limitations and mechanism of this metal-catalysed reaction are discussed. This journal is
- Durán-Pe?a,Botubol-Ares,Hanson,Hernández-Galán,Collado
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p. 6325 - 6332
(2015/06/08)
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- ISOPRENE OLIGOMER, POLYISOPRENE, PROCESSES FOR PRODUCING THESE MATERIALS, RUBBER COMPOSITION, AND PNEUMATIC TIRE
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The invention relates to an isoprene oligomer that contains a trans structural moiety and a cis structural moiety, which can be represented by the following formula (1), wherein at least 1 atom or group in the trans structural moiety is replaced by another atom or group. The invention also relates to a polyisoprene, which is biosynthesized using the isoprene oligomer and isopentenyl diphosphate. Further, this invention provides a rubber composition comprising the isoprene oligomer and/or the polyisoprene, and a pneumatic tire, including tire components (e.g., treads and sidewalls) formed from the rubber composition. wherein n represents an integer from 1 to 10; m represents an integer from 1 to 30; and Y represents a hydroxy group, a formyl group, a carboxy group, an ester group, a carbonyl group, or a group represented by the following formula (2):
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Paragraph 197-198
(2014/06/25)
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- Effect of acyclic monoterpene alcohols and their derivatives on TRP channels
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A series of thirty-six geraniol, nerol, citronellol, geranylamine, and nerylamine derivatives was synthesized and tested on TRPA1, TRPM8, and TRPV1 channels. Most of them acted as strong modulators of TRPA1 channels with EC50 and/or IC50 values 1 μM. None was able to significantly activate TRPM8 channels, while thirteen of them behaved as 'true' TRPM8 antagonists. Little or no effect was generally observed on TRPV1 channels. Some of the compounds examined, that is, compounds 1d,g,n, 2c,d,h,i,o, 3b,e exhibited an appreciable selectivity for TRPA1 subtype.
- Ortar, Giorgio,Schiano Moriello, Aniello,Morera, Enrico,Nalli, Marianna,Di Marzo, Vincenzo,De Petrocellis, Luciano
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p. 5507 - 5511
(2015/01/08)
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- Construction of the 1,2-dialkenylcyclohexane framework via ireland-claisen rearrangement and intramolecular barbier reaction: Application to the synthesis of ()-geijerone and a diastereoisomeric mixture with its 5-epimer
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The elemene-type terpenoids, which possess various biological activities, contain a syn- or anti-1,2-dialkenylcyclohexane framework. An efficient synthetic route to the syn- and anti-1,2-dialkenylcyclohexane core and its application in the synthesis of ()-geijerone and its diastereomer is reported. Construction of the syn- and anti-1,2-dialkenyl moiety was achieved via Ireland-Claisen rearrangement of the (E)-Allylic ester, and the cyclohexanone moiety was derived from the iodoaldehyde via intramolecular Barbier reaction. The synthetic strategy allows rapid access to various epimers and analogues of elemene-type products.
- Liang, Dawei,Gao, Nana,Liu, Wei,Dong, Jinhua
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p. 1238 - 1249
(2014/02/14)
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- Multi-target-directed design, syntheses, and characterization of fluorescent bisphosphonate derivatives as multifunctional enzyme inhibitors in mevalonate pathway
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Background Mevalonate pathway is an important cellular metabolic pathway present in all higher eukaryotes and many bacteria. Four enzymes in mevalonate pathway, including MVK, PMK, MDD, and FPPS, play important regulatory roles in cholesterol biosynthesis and cell proliferation. Methods The following methods were used: cloning, expression and purification of enzymes in mevalonate pathway, organic syntheses of multifunctional enzyme inhibitors, measurement of their IC50 values for above four enzymes, kinetic studies of enzyme inhibitions, molecular modeling studies, cell viability tests, and fluorescence microscopy. Results and conclusions We report our multi-target-directed design, syntheses, and characterization of two blue fluorescent bisphosphonate derivatives compounds 15 and 16 as multifunctional enzyme inhibitors in mevalonate pathway. These two compounds had good inhibition to all these four enzymes with their IC50 values at nanomolar to micromolar range. Kinetic and molecular modeling studies showed that these two compounds could bind to the active sites of all these four enzymes. The fluorescence microscopy indicated that these two compounds could easily get into cancer cells. General significance Multifunctional enzyme inhibitors are generally more effective than single enzyme inhibitors, with fewer side effects. Our results showed that these multifunctional inhibitors could become lead compounds for further development for the treatment of soft-tissue tumors and hypercholesteremia.
- Gao, Jinbo,Liu, Jinggong,Qiu, Yongge,Chu, Xiusheng,Qiao, Yuqin,Li, Ding
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p. 3635 - 3642
(2013/08/25)
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- Stereoselectivity of additions to N-methyl acetonitrilium fluorosulfonate
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Alkoxy-N-methyl-acetiminium salts were prepared by addition of CH 3OH and C2H5OH to N-methyl acetonitrilium fluorosulfonate at low temperature. Analysis of the 5JHH and 3J13C-H coupling constants in the NMR spectra showed an anti addition with a diastereoselectivity of >95%. Deprotonation of these salts with (Z)-configuration gave the corresponding N-methyl-alkoxyacetimines with very high (E)-configuration. Upon protonation at -78 °C, these iminoesters gave the corresponding alkoxy-N-methyl-acetiminium salts with (E)-configuration. Computational analyses of the iminoesters and the corresponding iminium cations including the conformations give insight into the relative stability. Nitrilium salts can be used as reagents, exemplified by some esterifications between simple acids and alcohols.
- Keese, Reinhart,Berdat, Fran?ois,MacChi, Piero
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p. 1965 - 1970
(2013/03/28)
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- A clean enzymatic process for producing flavour esters by direct esterification in switchable ionic liquid/solid phases
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A clean biocatalytic approach for producing flavour esters using switchable ionic liquid/solid phases as reaction/separation media has been developed. The phase behaviour of different IL/flavour acetyl ester (geranyl acetate, citronellyl acetate, neryl acetate and isoamyl acetate) mixtures was studied at several concentrations, resulting for all cases in fully homogeneous liquid media at 50 °C, and solid systems at room temperature. By using an iterative centrifugation protocol on the solid IL/flavour ester mixtures at controlled temperatures, the solid IL phase and the liquid flavour ester phase can be easily separated. The excellent suitability of an immobilized Candida antarctica lipase B (Novozym 435) catalyst in the esterification reaction between an aliphatic carboxylic acid (acetic, propionic, butyric or valeric) and a flavour alcohol (isoamyl alcohol, nerol, citronellol or geraniol) in N,N′,N′′,N′′′-hexadecyltrimethyl-ammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2])IL has been demonstrated, the product yield being improved up to 100% under appropriate reaction conditions (enzyme amount, dehydrating molecular sieves, etc.) at 50 °C. The enzymatic synthesis of sixteen different flavour esters was carried out in [C16tma][NTf2] by means of this approach, providing products of up to 0.757 g mL-1 concentration after IL separation. The residual activity of the enzyme/IL system during seven consecutive operation cycles was shown to be practically unchanged after reuse.
- Lozano, Pedro,Bernal, Juana M.,Navarro, Alicia
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p. 3026 - 3033
(2013/01/15)
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- PROCESS FOR THE PREPARATION OF VITAMIN K2
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A new process for making polyprenols is described as well as the use of these building blocks in the synthesis of Vitamin K2. The process involves reaction of a compound of formula (X) with a compound of formula (XI) in the presence of a base so as to form a compound of formula (XII) and conversion of that compound into a compound of formula (XIII).
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Page/Page column 30
(2011/10/13)
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- Hydroxy-group effect on the regioselectivity in a photochemical oxetane formation reaction (the Paterno-Buechi Reaction) of geraniol derivatives
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The Paterno-Buechi (PB) reaction of geraniol derivatives 1, which contain allylic alcohol functionality and unfunctionalized double bonds, with benzophenone was investigated to see the effect of the hydroxyl group on the regioselectivity of the oxetane formation, i.e., 2/3. At low concentration of geraniol (1a), oxetanes 2a and 3a were formed in a ratio of 2a/3a = ca. 50/50. The oxetane 2a is derived from the PB reaction at the allylic alcohol moiety, whereas the PB reaction at the unfunctionalized double bond produces the oxetane 3a. The PB reaction of the hydroxy-protected methyl ether 1b and acetate 1c gave selectively oxetanes 3b,c derived from the reaction at the more nucleophilic double bond, 2/3 ~ 15/85. The hydroxyl-group effect was found to be small, but apparently increased the formation of 2a in the PB reaction with geraniol (1a). The Royal Society of Chemistry and Owner Societies.
- Hisamoto, Ken,Hiraga, Yoshikazu,Abe, Manabu
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experimental part
p. 1469 - 1473
(2012/06/18)
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