- Synthesis of enantiopure ABC-type triacylglycerols
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The synthesis of twelve enantiopure structured triacylglycerols (TAGs) of the ABC type possessing three different fatty acids is described by a six-step chemoenzymatic approach starting from (S)-solketal. Eight of the TAGs possess two different saturated fatty acyl groups located in the sn-1 and sn-2 positions with an unsaturated fatty acyl group in the remaining sn-3 position of the glycerol skeleton, whereas the remaining four possess two different saturated acyl groups in the terminal sn-1 and sn-3 positions with an unsaturated acyl group in the sn-2 position. The former group was synthesised by a six-step chemoenzymatic route involving a highly regioselective immobilised Candida antarctica lipase. The second group was prepared by a similar six-step approach, that required two separate lipase steps. Such enantiopure TAGs are strongly demanded as standards for enantiospecific analysis of intact TAGs in fats and oils.
- Gudmundsson, Haraldur G.,Linderborg, Kaisa M.,Kallio, Heikki,Yang, Baoru,Haraldsson, Gudmundur G.
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- Stereochemistry, lipid length and branching influences Mincle agonist activity of monoacylglycerides
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Herein, we report on the synthesis of a series of enantiomerically pure linear, iso-branched, and α-branched monoacyl glycerides (MAGs) in 63-72% overall yield. The ability of the MAGs to signal through human macrophage inducible C-type lectin (hMincle) using NFAT-GFP reporter cells was explored, as was the ability of the compounds to activate human monocytes. From these studies, MAGs with an acyl chain length ≥C22 were required for Mincle activation and the production of interleukin-8 (IL-8) by human monocytes. Moreover, the iso-branched MAGs led to a more pronounced immune response compared to linear MAGs, while an α-branched MAG containing a C-32 acyl chain activated cells to a higher degree than trehalose dibehenate (TDB), the prototypical Mincle agonist. Across the compound classes, the activity of the sn-1 substituted isomers was greater than the sn-3 counterparts. None of the representative compounds were cytotoxic, thus mitigating cytotoxicity as a potential mediator of cellular activity. Taken together, 6h (sn-1, iC26+1), 8a (sn-1, C32) and 8b (sn-3, C32) exhibited the best immunostimulatory properties and thus, have potential as vaccine adjuvants.
- Khan, Ayesha,Braganza, Chriselle D.,Kodar, Kristel,Timmer, Mattie S. M.,Stocker, Bridget L.
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supporting information
p. 425 - 430
(2020/02/03)
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- Synthesis and evaluation of immunostimulant plasmalogen lysophosphatidylethanolamine and analogues for natural killer T cells
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Plasmalogen lysophosphatidylethanolamine (pLPE) had been identified as a self antigen for natural killer T cells (NKT cells). It is very important in the development, maturation and activation of NKT cells in thymus. Besides, pLPE is a novel type of antigen for NKT cells. To evaluate the structure-activity relationship (SAR) of this new antigen, pLPE and its analogues referred to different aliphatic chains and linkages at the sn-1 position of the glycerol backbone were synthesized, and the biological activities of these analogues was characterized. It is discovered that the linkages between phosphate and lipid moiety are not important for the antigens' activities. The pLPE analogues 1, 3, 4, 7 and 9, which have additional double bonds on lipid parts, were identified as new NKT agonists. Moreover, the analogues 4, 7 and 9 were discovered as potent Th2 activators for NKT cells.
- Ni, Guanghui,Li, Zhiyuan,Liang, Kangjiang,Wu, Ting,De Libero, Gennaro,Xia, Chengfeng
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p. 2966 - 2973
(2014/05/20)
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- Synthesis of enantiopure structured triacylglycerols
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The synthesis of nine enantiopure structured triacylglycerols (TAGs) of the AAB type is described, all possessing the (S)-absolute configuration. Six of them possess one saturated and two identical unsaturated fatty acyl chains, whereas the remaining three possess two identical saturated fatty acids along with one unsaturated fatty acid. The former group was synthesized by a five-step chemoenzymatic route involving a highly regioselective immobilized Candida antarctica lipase, starting from enantiopure (R)-solketal. The second group was prepared by a fully chemical five-step approach based on the same chiral precursor. Such enantiopure TAGs are strongly required as standards for the enantiospecific analysis of intact TAGs in fats and oils.
- Kristinsson, Bjoern,Linderborg, Kaisa M.,Kallio, Heikki,Haraldsson, Gudmundur G.
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p. 125 - 132
(2014/02/14)
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- Pheromone synthesis. Part 253: Synthesis of the racemates and enantiomers of triglycerides of male Drosophila fruit flies with special emphasis on the preparation of enantiomerically pure 1-monoglycerides
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The racemates and enantiomers of triglycerides 1aee (2,3-ditigloyloxypropyl esters of palmitic, palmitoleic, stearic, oleic, and linoleic acids) of male Drosophila fruit flies were synthesized in three steps from the racemate and enantiomers of 2,3-acetoneglycerol (2) via 1-monoglycerides 4aee derived from the above fatty acids. Appropriate conditions were established for the preparation of enantiomerically pure 1-monoglycerides 4aee, and their enantiomeric purities were determined by NMR analysis of the corresponding bis-(R)-MTPA esters.
- Mori, Kenji
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p. 8441 - 8449
(2012/10/07)
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- Crystallization, polymorphism, and binary phase behavior of model enantiopure and racemic triacylglycerols
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Triacylglycerols (TAG) are the main component in fats and oils and a major component in many food and consumer products. These compounds are always asymmetric (about the sn-2 position), while many diacid and all triacid TAG are chiral. To understand what effect this has on their crystallization behavior, model enantiopure (1,2-bisdecanoyl-3-palmitoyl-sn-glycerol) and racemic (bisdecanoyl-1(3)-palmitoyl-rac-glycerol) TAG were prepared and characterized. In addition, a binary phase diagram was prepared to investigate their phase behavior and the racemate's crystalline tendency. For the subject compounds, infrared spectroscopy and X-ray powder diffraction data indicate the enantiopure TAG is β′-stable, whereas the racemic mixture is β-stable. In addition, based on the phase diagram, the high-melting form of the racemic mixture is a racemic compound (with a unit cell containing equal quantities of both enantiomers). Racemic (and nearracemic) mixtures also crystallize in a lower-melting metastable conglomerate β′ form. Thus, there are critical differences between the crystallization behavior of enantiopure and racemic TAG, and future investigations of these compounds should reflect these findings.
- Craven, R. John,Lencki, Robert W.
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experimental part
p. 1723 - 1732
(2012/04/17)
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- Total synthesis of three natural products: Decyl 8-hydroxyheptadecanoate, undecyl hexadecanoate and 2,3-dihydroxypropyl hexadecanoate
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First syntheses of decyl 8-hydroxyheptadecanoate 1 and undecyl hexadecanoate 2 via utilization of microwave energy and a new improved synthesis of 2,3-dihydroxypropyl hexadecanoate 3 have been accomplished from readily available starting compounds.
- Singh, Ashima,Sharma,Singh, Jasvinder
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p. 1648 - 1652
(2011/03/17)
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- PROCESS FOR REGIOSELECTIVE PREPARATION OF GLYCEROL, DERIVATIVE AND INTERMEDIATE THEREFOR
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Disclosed is a process for regioselective preparation of l-palmitoyl-2-linoleoyl-3-acetylglycerol which is known as having activities for proliferation of hematopoietic stem cells and megakaryocytes, and an intermediate for the same. The process for preparation of l-palmitoyl-2-linoleoyl-3-acetylglycerol includes the steps of obtaining (2-alkoxy-2-methyl-[l,3]-dioxolane-4-yl)methanol by reacting glycerol and trialkylorthoacetate; obtaining 1-acetyl glycerol by hydrolyzing (2-alkoxy-2-methyl-[l,3]-dioxolane-4-yl)methanol; obtaining l-palmitoyl-3-acetyl glycerol by reacting 1-acetyl glycerol and palmitic acid derivative; and reacting l-palmitoyl-3-acetyl glycerol and linoleic acid derivative. l-palmitoyl-2-linoleoyl-3-acetylglycerol can also be prepared by the steps of obtaining l-palmitoyl-3-acetyl glycerol by hydrolyzing palmitic acid (2-alkoxy-2-methyl-[l,3] dioxolane- 4-yl)methyl ester; and reacting l-palmitoyl-3-acetyl glycerol and linoleic acid derivative.
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Page/Page column 16
(2008/06/13)
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- A new approach to the synthesis of lysophosphatidylcholines and related derivatives
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A new stereospecific synthesis of lysophosphatidylcholines is reported. The sequence relies on orthogonal protection of hydroxyl groups derived from glyceric acid, using fluorenylmethylcarbonate versus tetrahydropyranyl ether functions, that allow regiospecific introduction of substituents to obtain the target phospholipid compound.
- Bibak, Niloufar,Hajdu, Joseph
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p. 5875 - 5877
(2007/10/03)
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- A mild approach to the synthesis of sn-glycerol 1,2-di-γ-linolenate 3-palmitate
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A synthetic approach comprising several studied modifications was applied to the preparation of sn-glycerol 1,2-di-γ-linolenate 3-palmitate (4). Thereby, a convenient and mild synthetic method was elaborated, affording 4 from 1,2-O-isopropylidene-sn-glycerol (1) in an average yield of 65-75% and analytically acceptable purity.
- Rejzek, Martin,Vacek, Miroslav,Wimmer, Zdenek
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p. 2756 - 2760
(2007/10/03)
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- Differential elimination of synthetic butyric triglycerides in vivo: A pharmacokinetic study
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New butyrate derivatives were synthesized to investigate the residence time of potent butyric acid in vivo. These derivatives were triglycerides in which one, two, or three butyric acid molecules were bound to glycerol or to mono- and dipalmitic esters of glycerol. Pharmacokinetic studies showed that a constant plasma level of each compound was maintained for a long time; all molecules had identical volumes of distribution, but differed about their mean residence time. Triesters in which palmitic acid was present displayed no toxicity and seemed to be even more stable in the organism; this may be due to their adsorption on the tissue. Other triglycerides constituted by butyric acid and various long fatty acids may be synthesized and useful in long-term clinical treatment.
- Planchon,Pouillart,Ronco,Villa,Pieri
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p. 1046 - 1048
(2007/10/02)
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- Nucleoside conjugates. 10. Synthesis and antitumor activity of 1-β-D-arabinofuranosylcytosine 5'-diphosphate-1,2-dipalmitins
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Three 1-β-D-arabinofuranosylcytosine 5'-diphosphate-1,2-dipalmitins from L-, D- and DL-α-dipalmitoylphosphatidic acids have been synthesized and their antitumor activity against two ara-C2 resistant L1210 lymphoid leukemia sublines in mice were evaluated. These new prodrugs of ara-C include ara-CDP-L-dipalmitin (1), ara-CDP-D-dipalmitin (2), and ara-CDP-DL-dipalmitin (3). The L and DL isomers produced significant increase in life span (>400%) and four to five long-term survivors (>45 days) out of six animals bearing ip implanted partially ara-C resistant L1210 subline [L1210/ara-C (I)], while the D isomer displayed a marginal activity (ILS 100-121%). In contrast, the L isomer was completely ineffective against deoxycytidine kinase deficient ara-C resistant L1210 subline [L1210/ara-C (II)]. However, the results demonstrate that the L and DL isomers of ara-CDP-dipalmitin are promising new prodrugs of ara-C with improved efficacy.
- Hong,An,Schliselfeld,Buchheit,Nechaev,Kirisits,West
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p. 1793 - 1798
(2007/10/02)
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- Asymmetric induction during carbonylation of an optically active organopalladium. A novel and versatile route to enantiomeric glycerides.
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In the course of carbonylation of optically active [η5-C5H5Feη5- CH5H3CH2NMe2PdCl]2 (1) in prochiral diols, the asymmetric induction of a newly developed chiral centre by a chiral plane has been performed. For 2-O-benzyl- glycerol, the extent of asymmetric induction, that means diastereoselectivity, was found to be about 36%. The protection of a free hydroxyl followed by hydrolysis of a ferrocenoyl derivative resulted in enantiomeric 2-O-benzyl-3-O-trityl-sn-glycerol (4) which can serve as a key intermediate in the synthesis of optically active mono-, di- and tri-substituted glycerides. This methodology has been illustrated by the detailed description of the preparation of 1-palmitoyl-sn-glycerol.
- Troitskaya,Sokolov
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p. 389 - 393
(2007/10/02)
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- ORD and CD studies of saturated glycerides.
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A convenient method for transforming 3-acyl-sn-glycerols into 1-acyl-2,3-diacyl'-sn-glycerols, antipodes of 1,2-diacyl'=3-acyl-sn-glycerols, of relatively high optical purity, via the 1,2-dimesyl-3-acyl-sn-glycerols has been worked out. ORD and CD curves of optically active triglycerides and also some mono- and diglycerides have been studied in detail. The curo 200 nm or below. A Cotton effect from the n yeilds ets* transtition of the ester chromophore was observed at 215-220 nm, which was negative for triglyceritical rotations could be observed in triglycerides with very small differences in chain length, such as 1,2-dilauroyl-3-myristoyl-sn-glycerol.
- Gronowitz,Herslof
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p. 174 - 188,178, 179, 186
(2007/10/07)
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