55682-83-2Relevant articles and documents
1-Acetyl-3-[(3R)-hydroxyfatty acyl]glycerols: Lipid Compounds from Euphrasia rostkoviana Hayne and E. tetraquetra (Bréb.) Arrond
Lorenz, Peter,Knittel, Diana N.,Conrad, Jürgen,Lotter, Eva M.,Heilmann, J?rg,Stintzing, Florian C.,Kammerer, Dietmar R.
, p. 602 - 612 (2016)
Five homologous acetylated acylglycerols of 3-hydroxyfatty acids (chain lengths C(14) - C(18)), named euphrasianins A - E, were characterized for the first time in Euphrasia rostkoviana Hayne (Orobanchaceae) by gas chromatography/mass spectrometry (GC/MS) and high-performance liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (HPLC/APCI-MSn). In addition to mass spectrometric data, structures of euphrasianins were verified via a three-step total synthesis of one representative homologue (euphrasianin A). The structure of the latter was confirmed by 1D- and 2D-NMR experiments as well as high-resolution electrospray ionization-mass spectrometry (HR-ESI-MS). The absolute configuration of the 3-hydroxyfatty acid moiety at C(3) was found to be R in the natural euphrasianins, which was determined by alkaline hydrolysis and methylation of a purified fraction, followed by chiral GC analysis. Furthermore, in extracts of Euphrasia tetraquetra (Bréb.) Arrond. euphrasianins C and E were detected exclusively, indicating that this subclass of lipid constituents is possibly valuable for fingerprinting methods.
Dibromomethane as one-carbon source in organic synthesis: Formal total synthesis of (±)-nephrosteranic acid
Hon, Yung-Son,Hsieh, Cheng-Han,Chen, Hsien-Fan
, p. 1635 - 1651 (2007)
A diastereoselective formal total synthesis of (±)-nephrosteranic acid (10) is described. The key step is to introduce the α-methylene group by the ozonolysis of monosubstituted alkenes followed by reaction with a preheated mixture of CH2Br2-Et2NH. The α-methyl group of compound 10 was formed from the reduction of the corresponding α-methylene precursor. Copyright Taylor & Francis Group, LLC.
Systematic investigation of the kinetic resolution of 3-hydroxy fatty acid esters using Candida antarctica lipase B (CALB) and the influence of competing oligomerization on the enantiomeric ratios
Braner, Markus,Zielonka, Stefan,Auras, Sylvia,Huettenhain, Stefan H.
, p. 1019 - 1025 (2012)
The kinetic resolution of 3-hydroxy fatty acid esters C8:0 to C16:0 with Candida antarctica lipase B shows common plots of the enantiomeric excesses of the product and substrate, respectively, versus the conversion and an enantiomeric ratio E of 27 calculated from ee(p). Differences in E, either calculated from the products or the substrates, could be explained by competing oligomerization as a second substrate-consuming process. This reaction is slow compared to acylation, and the remaining enantiomer was oligomerized. Taylor & Francis Group, LLC.
Structure of the unusual Sinorhizobium fredii HH103 lipopolysaccharide and its role in symbiosis
Di Lorenzo, Flaviana,Speciale, Immacolata,Silipo, Alba,Alías-Villegas, Cynthia,Acosta-Jurado, Sebastián,Rodríguez-Carvajal, Miguel-ángel,Dardanelli, Marta S.,Palmigiano, Angelo,Garozzo, Domenico,Ruiz-Sainz, José-Enrique,Molinaro, Antonio,Vinardell, José-María
, p. 10969 - 10987 (2021/01/07)
Rhizobia are soil bacteria that form important symbiotic associations with legumes, and rhizobial surface polysaccharides, such as K-antigen polysaccharide (KPS) and lipopolysaccharide (LPS), might be important for symbiosis. Previously, we obtained a mutant of Sinorhizobium fredii HH103, rkpA, that does not produce KPS, a homopolysaccharide of a pseudaminic acid derivative, but whose LPS electrophoretic profile was indistinguishable from that of the WT strain. We also previously demonstrated that the HH103 rkpLMNOPQ operon is responsible for 5-acetamido-3,5,7,9-tetradeoxy-7-(3-hydroxybutyramido)-L-glyc-ero-L-manno-nonulosonic acid [Pse5NAc7(3OHBu)] production and is involved in HH103 KPS and LPS biosynthesis and that an HH103 rkpM mutant cannot produce KPS and displays an altered LPS structure. Here, we analyzed the LPS structure of HH103 rkpA, focusing on the carbohydrate portion, and found that it contains a highly heterogeneous lipid A and a peculiar core oligosaccharide composed of an unusually high number of hexuronic acids containing b-configured Pse5NAc7(3OHBu). This pseudaminic acid derivative, in its a-configuration, was the only structural component of the S. fredii HH103 KPS and, to the best of our knowledge, has never been reported from any other rhizobial LPS. We also show that Pse5NAc7(3OHBu) is the complete or partial epitope for a mAb, NB6-228.22, that can recognize the HH103 LPS, but not those of most of the S. fredii strains tested here. We also show that the LPS from HH103 rkpM is identical to that of HH103 rkpA but devoid of any Pse5NAc7(3OHBu) residues. Notably, this rkpM mutant was severely impaired in symbiosis with its host, Macroptilium atropurpureum.
Gas chromatography/electron-capture negative ion mass spectrometry for the quantitative determination of 2- and 3-hydroxy fatty acids in bovine milk fat
Jenske, Ramona,Vetter, Walter
experimental part, p. 5500 - 5505 (2010/03/25)
2- and 3-hydroxy fatty acids (2- and 3-OH-FAs) are bioactive substances reported in sphingolipids and bacteria. Little is known of their occurrence in food. For this reason, a method suitable for the determination of OH-FAs at trace levels in bovine milk fat was developed. OH-FAs (and conventional fatty acids in samples) were converted into methyl esters and the hydroxyl group was derivatized with pentafluorobenzoyl (PFBO) chloride to give PFBO-O-FA methyl esters. These derivatives with strong electron affinity were determined by gas chromatography interfaced to mass spectrometry using electron-capture negative ion in the selected ion monitoring mode (GC/ECNI-MS-SIM). This method proved to be highly sensitive and selective for PFBO-O-FA methyl esters. For the analysis of samples, two internal standards were used. For this purpose, 9,10-dideutero-2-OH-18:0 methyl ester (ISTD-1) from 2-OH-18:1(9c) methyl ester as well as the ethyl ester of 3-PFBO-O-12:0 (ISTD-2) was synthesized. ISTD-1 served as a recovery standard whereas ISTD-2 was used for GC/MS measurements. The whole-sample cleanup consisted of accelerated solvent extraction of dry bovine milk, addition of ISTD 1, saponification, conversion of fatty acids into methyl esters by use of boron trifluoride, separation of the methyl esters of OH-FAs from nonsubstituted FAs on activated silica, conversion of OH-FAs methyl esters into PFBO-O-FA methyl esters, addition of ISTD-2, and measurement by GC/ECNI-MS-SIM. By this method, ten OH-FAs were quantified in bovine milk fat with high precision in the range from 0.02 ± 0.00 to 4.49 ± 0.29 mg/100 g of milk fat.
Enantioselective synthesis of α-amino acids from N-tosyloxy β-lactams derived from β-keto esters
Durham, Timothy B.,Miller, Marvin J.
, p. 27 - 34 (2007/10/03)
A novel synthetic sequence has been developed to convert simple β-keto esters into enantiomerically enriched α-amino acids. The key features of this sequence include the addition of azide to the C3 position of β-keto ester derived N-tosyloxy-β-lactams through a concomitant nucleophilic addition/N-O bond reduction reaction, a mild CsF-induced N1 benzylation of α-azido monocyclic β-lactams, the preparation of α-keto-β-lactams through a novel four-step sequence from the corresponding 3-azido-1-benzyl-β-lactams, and TEMPO-mediated ring expansion of these compounds to the corresponding N-carboxy anhydrides (NCAs). In addition, the synthesis, isolation, and characterization of unusual 3-imino and 3-chloramino-β-lactams is reported.
Polyhydroxyalkanoate and manufacturing method thereof
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Page/Page column 43-44, (2008/06/13)
To provide a novel polyhydroxyalkanoate and a manufacturing method by a microorganism capable of substantially reducing unintended monomer units and obtaining the polyhydroxyalkanoate in a high yield. A microorganism capable of synthesizing a novel polyhydroxyalkanoate having 3-hydroxy-substituted benzoylalkanoic acid as a monomer unit using a substituted benzoylalkanoic acid as a material is cultured in the medium containing a substituted benzoylalkanoic acid, then the polyhydroxyalkanoate produced in the cultured bacteria is extracted and recovered.
New potential immunoenhancing compounds. Synthesis and pharmacological evaluation of new long-chain 2-amido-2-deoxy-D-glucose derivatives
Valcavi,Albertoni,Brandt,Corsi,Farina,Foresta,Pascucci,Ramacci
, p. 1190 - 1195 (2007/10/02)
A series of long-chain fatty acids and the corresponding 2-hydroxy, 2-oxo, 3-hydroxy acid glucosamides were evaluated as immunomodulating compounds. In a preliminary screening, 2-[(2-ethoxycarbonyloxy)tetradecanoyl-amino]-2-deoxy-D-glucose (2b) and 2-(3-hydroxydodecanoyl-amino)-2-deoxy-D-glucose (5a) resulted to be the most effective in enhancing the glucosamine activity. The findings of in vitro-ex vivo tests (unidirectional mixed lymphocyte culture reaction and primary antibody production) and in vivo tests (delayed type hypersensitivity, protection against bacterial or fungal infection and against Sarcoma 180 or Lewis lung carcinoma transplants) were very encouraging and allowed to assume for the two substances a protective activity, presumably through the ability of activating phagocytic and NK cells.
