- Comparison of enzymatic and acid hydrolysis of bound flavor compounds in model system and grapes
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Four synthesized terpenyl-β-D-glycopyranosides (geranyl, neryl, citronellyl, myrtenyl) were subjected to enzymatic (AR 2000, pH 5.5) and acid (citric buffer, pH 2.5) hydrolysis. Decrease of glycosides was measured by HPLC and the volatiles released - by comprehensive gas chromatography-mass spectrometry (GC x GC-ToF-MS). Enzymatic hydrolysis performed for 21 h yielded 100% degree of hydrolysis for all glycosides but citronellyl (97%). Degree of acid hydrolysis was highly dependent on type of aglycone and the conditions. The highest degree was achieved for geraniol, followed by citronellol and nerol. Myrtenylo-β-D-glycopyranoside was the most resistant glycoside to hydrolysis. Acid hydrolysis degree was also related to temperature/time combination, the highest being for 100 °C and 2 h. In a result of enzymatic hydrolysis 85-91% of total peak areas was terpene aglycone, whereas for acid hydrolysis the area of released terpene aglycone did not exceed 1.3% of total peak area indicating almost complete decomposition/transformation of terpenyl aglycone.
- Dziadas, Mariusz,Jeleń, Henryk H.
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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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- Synthesis of antimalarial yingzhaosu A analogues by the peroxidation of dienes with Co(II)/O2/Et3SiH
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Co(II)-catalyzed peroxidation of dienes including (S)-limonene in the presence of molecular oxygen and triethylsilane provided in each case the corresponding 2,3-dioxabicyclo[3.3.1]nonane derivatives via the intramolecular cyclization of the unsaturated peroxy radical intermediates. The product composition was remarkably influenced by the structure of the dienes, the nature of the solvents, and the concentration of the substrates and the catalyst. Some of the yingzhaosu A analogues obtained in this study showed notable antimalarial activities in vitro.
- Tokuyasu, Takahiro,Kunikawa, Shigeki,Abe, Manabu,Masuyama, Araki,Nojima, Masatomo,Kim, Hye-Sook,Begum, Khurshida,Wataya, Yusuke
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- Amine and thiazole substituted γ-butyrolactones from naturally occurring limonene
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Substituted γ-butyrolactones are important structural motifs in several natural products and pharmaceuticals. In this paper, we report the synthesis of novel γ-butyrolactone amine and thiazole derivatives from naturally occurring limonene. Regioselective bromination followed by nucleophilic substitution with different amines and thiourea gave desired products in moderate yield.
- Kaur, Pushpinder,Das, Pralay,Chaudhary, Abha,Singh, Bikram
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- 3'-KETOGLYCOSIDE COMPOUND FOR THE SLOW RELEASE OF A VOLATILE ALCOHOL
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The present invention relates to a 3'-ketoglycoside compound defined by formula (I) and its use for controlled release of alcohols, in particular alcohols showing an insect repellent effect. It relates also to a process for preparing the 3'-ketoglycoside compound of formula (I). It further relates to a composition comprising a 3'- ketoglycoside compound of formula (I). It relates also to the use of a 3'-ketoglycoside compound of formula (I) for the controlled release of alcohols. It related also to a method of use of such composition.
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Page/Page column 67-68
(2021/08/20)
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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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- Transition-Metal Catalyzed Autoxidation of cis- and trans-Pinane to a Mixture of Diastereoisomeric Pinanols
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Autoxidations of the pinanes, obtained after hydrogenation of naturally occurring Pinus elliottii oil, were performed with or without solvent, using the catalytic system Co(OAc)2/Mn(OAc)2/NH4Br in a 9:1:5 molar ratio, and dioxygen as the oxidant. The best selectivity for the pinanols was 71% (cis:trans ratio, 3:1) with 17% conversion. Autoxidations were also carried out in the absence of catalyst. The hydroperoxides formed with 17% conversion were decomposed with Na2SO3 and PPh3, resulting in 62% pinanols (cis:trans ratio, 5:1). The pyrolysis of the pinanols at 600°C and a contact time of 1.15 × 10-2 s/mol yielded 54% of linalool. The side products were mainly due to an "ene" reaction, giving diastereoisomeric 1,2-dimethyl-3-isopropenylcyclopentanols.
- Sercheli, Ricardo,Ferreira, Alfredo L. B.,Baptistella, Lúcia H. B.,Schuchardt, Ulf
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p. 1361 - 1364
(2007/10/03)
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- δ-Terpineol
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An improved and simple synthesis of crystalline δ-terpineol from β-pinene is reported.
- Bull, Steven D.,Carman, Raymond M.
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p. 2077 - 2081
(2007/10/02)
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- THE ENANTIOSELECTIVE BIOTRANSFORMATION OF α-TERPINEOL AND ITS ACETATE WITH THE CULTURED CELLS OF NICOTIANA TABACUM
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In the biotransformation of the enantiomers of p-ment-1-en-8-ol (α-terpineol) and 8-acetoxy-p-ment-1-ene (α-terpinyl acetate) with the cultured suspension cells of Nicotina tabacum, it was clarified that the cultured cells effected the hydroxylation at the 6-position of (4R)-(+)-enantiomer in preference to the (4S)-(-)-enantiomer, whereas the cells did the hydrolysis of the acetoxyl group and the hydroxylation of the ethylenic linkage of (4S)-(-)-α-terpinyl acetate in preference to the (4R)-(+)-enantiomer.
- Suga, Takayuki,Hirata, Toshifumi,Lee, Ym Sook
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p. 1595 - 1598
(2007/10/02)
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