- Remarkable functions of sn-3 hydroxy and phosphocholine groups in 1,2-diacyl-sn-glycerolipids to induce clockwise (+)-helicity around the 1,2-diacyl moiety: Evidence from conformation analysis by 1H NMR spectroscopy
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Cell-membrane glycerolipids exhibit a common structural backbone of asymmetric 1,2-diacyl-sn-glycerol bearing polar head groups in the sn-3 position. In this study, the possible effects of sn-3 head groups on the helical conformational property around the 1,2-diacyl moiety in the solution state were examined. 1H NMR Karplus relation studies were carried out using a series of 1,2-dipalmitoyl-sn-glycerols bearing different sn-3 substituents (namely palmitoyl, benzyl, hydrogen, and phosphates). The 1H NMR analysis indicated that the helical property around the 1,2-diacyl moiety is considerably affected by these sn-3 substituents. The sn-3 hydroxy group induced a unique helical property, which was considerably dependent on the solvents used. In CDCl3 solution, three staggered conformers, namely gt(+), gg(?) and tg, were randomized, while in more polar solvents, the gt(+) conformer with (+)-helicity was amplified at the expense of gg(?) and tg conformers. The sn-3 phosphocholine in phosphatidylcholine exhibited a greater effect on the gt(+) conformer, which was independent of the solvents used. From the 1H NMR analysis, the helical conformational properties around the 1,2-diacyl moiety conformed to a simple empirical rule, which permitted the proposal of a conformational diagram for 1,2-dipalmitoyl-sn-glycerols in the solution states.
- Nishida, Yoshihiro,Yuan, Mengfei,Fukuda, Kazuo,Fujisawa, Kaito,Dohi, Hirofumi,Uzawa, Hirotaka
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supporting information
p. 1999 - 2009
(2017/10/16)
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- Efficient chemoenzymatic enantioselective synthesis of diacylglycerols (DAG)
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A new efficient chemoenzymatic methodology for the production of 3-O-benzyl-sn-glycerol and 1,2-O-dipalmitoyl-sn-glycerol has been developed. It starts from racemic 1-O-benzylglycerol and is based on the sequential enzymatic acylation-Mitsunobu inversion-enzymatic hydrolysis, which has been performed without isolation of the intermediates. In this way a 70-75% yield of 3-O-benzyl-sn-glycerol with 94-96% ee has been obtained.
- Guanti, Giuseppe,Banfi, Luca,Basso, Andrea,Bevilacqua, Elisabetta,Bondanza, Laura,Riva, Renata
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p. 2889 - 2892
(2007/10/03)
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- Baker's yeast mediated reduction of dihydroxyacetone derivatives
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Several monoprotected dihydroxyacetone derivatives 4a-d and their acetates 5a-d were prepared and subjected to biotransformation with baker's yeast. The simple chemical modification of the substrates (i.e. transforming the relatively small hydrophilic hyd
- Balint, Jozsef,Egri, Gabriella,Kolbert, Attila,Dianoczky, Csilla,Fogassy, Elemer,Novak, Lajos,Poppe, Laszlo
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p. 4017 - 4028
(2007/10/03)
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- Dispiroketals in synthesis. Part 24. Preparation and use of chiral 2,2′-bis(triisopropylsilyloxymethyl)bi(dihydropyran)s as new protecting and resolving agents for 1,2-diols
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C2 symmetric chiral 2,2′-bis(triisopropylsilyloxymethyl)bi(dihydropyran)s (S,S)-1 and (R,R)-1 were prepared from the corresponding glycidols and selectively reacted with 1,2-diols to give dispiroketals. The products of these reactions could be deprotected following treatment with fluoride, oxidation and reductive cleavage with samarium(II) iodide.
- Laine, Dramane,Fujita, Morifumi,Ley, Steven V.
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p. 1639 - 1645
(2007/10/03)
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- Structure and Synthesis of Petrosynes, New Acetylenic Enol Ether Glycerides from the Okinawan Marine Sponge of the Genus Petrosia
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Acetylenic enol ether glycerides, 1 and 3, were found in the Okinawan marine sponge of the genus Petrosia.The plane structures of these glycerides were deduced from spectroscopic analysis.Their complete structures were established by enantioselective total synthesis of all possible stereoisomers using (R)-1-O-benzylglycerol and its (S)-enantiomer, prepared from D-mannitol and L-ascorbic acid, respectively, as chiral building blocks.The synthesis involves the palladium(0)-catalyzed coupling reaction of bromo enol ether 9 with enediyne 21 as a key step.It became evident from the synthesis that the natural product 1 consisted of a mixture of (7R,2'S)-24 (petrosyne Ia) and (7S,2'S)-24 (petrosyne Ib), and the natural product 3 consisted of a mixture of (7R,2'S)-28 (petrosyne IIa) and (7S,2'S)-28 (petrosyne IIb).
- Iguchi, Kazuo,Kitade, Makoto,Kashiwagi, Toshihiko,Yamada, Yasuji
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p. 5690 - 5698
(2007/10/02)
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- Regio- and enantioselective esterifications of polyoxygenated compounds catalyzed by lipases
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The lipase catalyzed esterifications of derivatives of propane-1,2,3-triol and butane 1,2,4-triol in organic solvents have been studied. The influence of several factors (lipase source, organic solvent, additives and structural variations in the substrate
- Herradon,Cueto,Morcuende,Valverde
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p. 845 - 864
(2007/10/02)
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- NUCLEOPHILIC DISPLACEMENT REACTIONS OF THE METHANESULFONATES OF THE 1-O-BENZOYL-1,2-, -1,3-, AND -1,4-GLYCOLS
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Nucleophilic displacement reactions of the methanesulfonates (8a-c) of the 1-O-benzoyl-1,2-, -1,3-, and -1,4-glycols (7a-c) with potassium acetate in boiling acetic anhydride have been examined.Both benzoyloxy-group participation pathway (path A) and SN2 displacement pathway (path B) have been involved in the 1,2-(8a)- and 1,3-(8b)-substrates to give a mixture of the primary (10a,b) and the secondary (11a,b) acetates with complete inversion of chiralities.On the other hand, only SN2 displacement pathway (path B) has been involved in the 1,4-substrate (8c) to give the secondary acetate (11c) with inversion of the chirality.
- Takano, Seiichi,Hirama, Michiyasu,Seya, Kazuhiko,Ogasawara, Kunio
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p. 4233 - 4236
(2007/10/02)
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