- Two-step continuous flow synthesis of α-terpineol
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α-Terpineol is a naturally occurring monoterpene present in essential oils, of high value on the market as it is widely used as flavoring in the cosmetics and food industry. This study aims to produce α-terpineol by two different synthetic strategies, using both batch and continuous flow systems, focusing on the optimization of the process, improving the reaction conversion and selectivity. The first strategy adopted was a one-stage hydration reaction of (+)-α-pinene by an aqueous solution of chloroacetic acid (molar ratio 1:1 between pinene and the acid) in continuous flow conditions. This reaction was carried out at 80 °C with a residence time of 15 min, obtaining good conversion (72%) and selectivity (76%), and productivity of 0.53 kg.day?1. The second strategy accomplished was a two-step cascade reaction with (+)-limonene as starting material, where the first step is a chemospecific double bond addition using trifluoroacetic acid, and the second step is the basic hydrolysis of the ester promoted by a solution of sodium hydroxide (2.25 M) in methanol (1:1). This reaction was adapted to a continuous flow condition, where all steps involved a residence time of 40 min, at 25 °C, with no quenching between steps required, with 97% conversion, 81% selectivity and up to 0.14 kg.day?1.
- Aguillon, Anderson R.,Le?o, Raquel A. C.,de Carvalho, Beatriz L. C.,de Souza, Rodrigo O. M. A.
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supporting information
(2021/08/23)
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- Synthesis of Aristoquinoline Enantiomers and Their Evaluation at the α3β4 Nicotinic Acetylcholine Receptor
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The first synthesis of aristoquinoline (1), a naturally occurring nicotinic acetylcholine receptor (nAChR) antagonist, was accomplished using two different approaches. Comparison of the synthetic material's spectroscopic data to that of the isolated alkaloid identified a previously misassigned stereogenic center. An evaluation of each enantiomer's activity at the α3β4 nAChR revealed that (+)-1 is significantly more potent than (-)-1. This unexpected finding suggests that naturally occurring 1 possesses the opposite absolute configuration from indole-containing Aristotelia alkaloids.
- Argade, Malaika D.,Straub, Carolyn J.,Rusali, Lisa E.,Santarsiero, Bernard D.,Riley, Andrew P.
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supporting information
p. 7693 - 7697
(2021/08/16)
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- Stolonidiol: Synthesis, Target Identification, and Mechanism for Choline Acetyltransferase Activation
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Stolonidiol, a marine natural product, has been reported to potentiate the activity of choline acetyltransferase (ChAT), the enzyme that produces the neurotransmitter acetylcholine. Here we report the total synthesis of stolonidiol starting from (R)-(+)-limonene. To identify the mechanism by which ChAT activity is increased, we sought to identify the biological target of stolonidiol. We show that stolonidiol binds to the phorbol ester binding site of protein kinase C (PKC), induces translocation of PKC to the cell membrane, and activates kinase activity. Furthermore, we confirmed the increase in ChAT activity observed upon treatment of cells with stolonidiol and show that this effect is mediated by PKC. Collectively, our data strongly suggest that PKC activation by stolonidiol is responsible for the resulting potentiation of ChAT activity.
- Mason, Jeremy W.,Schmid, Cullen L.,Bohn, Laura M.,Roush, William R.
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supporting information
p. 5865 - 5869
(2017/05/04)
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- Comparative study of the bioconversion process using R-(+)- and S-(-)-limonene as substrates for Fusarium oxysporum 152B
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This study compared the bioconversion process of S-(-)-limonene into limonene-1,2-diol with the already established biotransformation of R-(+)-limonene into α-terpineol using the same biocatalyst in both processes, Fusarium oxysporum 152B. The bioconversion of the S-(-)-isomer was tested on cell permeabilisation under anaerobic conditions and using a biphasic system. When submitted to permeabilisation trials, this biocatalyst has shown a relatively high resistance; still, no production of limonene-1,2-diol and a loss of activity of the biocatalyst were observed after intense cell treatment, indicating a complete loss of cell viability. Furthermore, the results showed that this process can be characterised as an aerobic system that was catalysed by limonene-1,2-epoxide hydrolase, had an intracellular nature and was cofactor-dependent because the final product was not detected by an anaerobic process. Finally, this is the first report to characterise the bioconversion of R-(+)- and S-(-)-limonene by cellular detoxification using ultra-structural analysis.
- Molina, Gustavo,Bution, Murillo L.,Bicas, Juliano L.,Dolder, Mary Anne Heidi,Pastore, Glucia M.
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p. 606 - 613
(2015/04/16)
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- A practical synthesis of d-α-terpineol via Markovnikov addition of d-limonene using trifluoroacetic acid
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d-α-Terpineol (1), which is a useful flavor and fragrance compound, has been synthesized from d-limonene by Markovnikov addition using trifluoroacetic acid, followed by hydrolysis in 76% yield with 98% purity.
- Yuasa, Yoshifumi,Yuasa, Yoko
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p. 1231 - 1232
(2012/12/23)
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- Enantioselective synthesis of α-terpineol and nephthenol by intramolecular acyloxazolidinone enolate alkylations
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Enolate anions generated from norterpenyl bromides bearing oxazolidinone chiral auxiliaries at the chain termini underwent efficient, stereo-biased cyclizations to form 6- and 14-membered rings in novel synthetic routes to α-terpineol and nephthenol enantiomers. The Royal Society of Chemistry 2006.
- Jin, Yinghua,Coates, Robert M.
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p. 2902 - 2904
(2008/09/18)
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- The 3-hydroxycineoles
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Data concerning the 3-hydroxycineoles 1 and 2 are provided to enable the ready identification of these metabolites and to determine their enantiomeric excess in mixtures. An unusual SN2-type inversion at a tertiary center is observed during one synthetic approach. CSIRO 2005.
- Carman, Raymond M.,Robinson, Ward T.,Wallis, Craig J.
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p. 785 - 791
(2007/10/03)
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- Galloylglucosides from berries of Pimenta dioica
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Three new galloylglucosides, (4S)-α-terpineol 8-O-β-D-(6-O- galloyl)glucopyranoside (1); (4R)-α-terpineol 8-O-β-D-(6-O- galloyl)glucopyranoside (2), and 3-(4-hydroxy-3-methoxyphenyl)propane-1,2- diol 2-O-β-D-(6-O-galloyl)glucopyranoside (3), were isolated from the berries of Pimenta dioica together with three known compounds, gallic acid (4), pimentol (5), and eugenol 4-O-β-D-(6-O-galloyl)glucopyranoside (6). The structures of 1-3 were elucidated on the basis of MS and NMR spectral data and enzymatic hydrolysis. These galloylglucosides (1-3, 5, and 6) showed radical-scavenging activity nearly equivalent to that of gallic acid (4) against 1,1-diphenyl-2-picrylhydrazyl radical.
- Kikuzaki, Hiroe,Sato, Akemi,Mayahara, Yoko,Nakatani, Nobuji
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p. 749 - 752
(2007/10/03)
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- Selective Deoxygenation of Allylic Alcohols and Acetates by Lithium Perchlorate Promoted Triethylsilane Reduction
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A series of cyclic secondary allylic alcohols and acetates was deoxygenated using triethylsilane in the presence of ethereal lithium perchlorate.Under these conditions the allylic oxygen functionality was selectively removed in the presence of esters, isolated olefins, ketals and tertiary alcohols.Primary allylic alcohols were not deoxygenated under these conditions.
- Wustrow, David J.,Smith, William J.,Wise, Lawrence D.
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- Solvomercuration-Demercuration of Limonene with Hg(BF4)2; A Chemo- and Regiospecific Route to 8-Substituted p-Menthenes
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Solvomercuration-demercuration of limonene with equimolar Hg(BF4)2 and excess nucleophile (-20 deg C) functionalizes the acyclic double bond and provides specifically 8-substituted p-menthenes.Key words: limonene; mercuration-demercuration; α-terpineol; mercuric tetrafluoroborate; p-menthenes
- Mattos, Marcio C.S. de,Kover, W. Bruce,Aznar, Fernando,Barluenga, Jose
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p. 4863 - 4866
(2007/10/02)
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- 1,8-Diazabicycloundec-7-ene as a Mild Deprotective Agent for Acetyl Groups
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A simple acetyl cleavage is described.The method showed selective acetyl deprotection of polyfunctionalized molecules.
- Baptistella, Lucia Helena B.,Santos, Jose Fernando dos,Ballabio, Karin Cristina,Marsaioli, Anita Jocelyne
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p. 436 - 438
(2007/10/02)
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- PHOTOCHEMICAL TRANSFORMATIONS-IV. OXYFUNCTIONALIZATION OF SOME SATURATED HYDROCARBONS WITH HYDROXYL RADICALS
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It is shown that hydroxylation of saturated hydrocarbons by hydrogen peroxide occurs under the influence of light.This reaction has been investigated on acyclic, monocyclic and bicyclic hydrocarbons.These reactions were also studied using performic acid as the source of hydroxyl radicals and results compared with those obtained with peracetic acid.As expected, the preferred attack was on tertiary centres, followed by secondary and then primary.
- Sharma, S. N.,Sonawane, H. R.,Dev, Sukh
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p. 2483 - 2492
(2007/10/02)
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- Rearrangement of Pinane Derivatives. Part 8. Deamination of 2αH-Pinan-3α-ylamine
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Solvolysis of 2αH-pinan-3α-yl toluene-p-sulphonate has been shown to proceed with concomitant 1,2-hydride shift to give the pinan-2-yl carbocation.Contrary to earlier reports, this species reacts normally to give, in good yield, pinan-2-yl substitution products.In contrast the pinan-3-ylamines react via a similar route, but give much smaller amounts of pinan-2-yl products.The usual reasons for differences between solvolysis and deamination (i.e. the intermediacy of diazonium ions and/or high-energy ions) can be discounted, and possible reasons for the differences in behaviour are discussed.
- Giddings, Rodney M.,Jones-Parry, Richard,Salmon, J. Roger,Whittaker, David
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p. 725 - 728
(2007/10/02)
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