- Enzymatic Regio- And Enantioselective C-H Oxyfunctionalization of Fatty Acids
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Directed evolution of a P450 hydroxylase (P450BSβ) achieves an engineered enzyme that is able to catalyze C-H oxyfunctionalization of fatty acids (FAs) in a highly regio- and enantioselective fashion (>20:1 Cβ/Cα and > 99% ee in all cases). The biocatalyst displays high reactivity (TON up to 1540), takes inexpensive H2O2 as oxidant, and converts C11-C18 saturated FAs as well as naturally derived unsaturated oleic and linoleic acids to optically pure β-hydroxy FAs. Merging biocatalysis with chemical transformation, we further offer a chemoenzymatic strategy to access valuable FA derivatives bearing 1,3-diol, β-amino, β-lactone, and β-lactam functionalities in either enantiomeric form. Molecular docking studies provide a rationale for the regio- and enantioselectivity of this reaction.
- Chen, Hao,Huang, Mengfei,Yan, Wenliang,Bai, Wen-Ju,Wang, Xiqing
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p. 10625 - 10630
(2021/09/02)
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- Structure of the unusual Sinorhizobium fredii HH103 lipopolysaccharide and its role in symbiosis
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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.
- 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
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p. 10969 - 10987
(2021/01/07)
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- Rhamnolipid inspired lipopeptides effective in preventing adhesion and biofilm formation of Candida albicans
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Rhamnolipids are biodegradable low toxic biosurfactants which exert antimicrobial and anti-biofilm properties. They have attracted much attention recently due to potential applications in areas of bioremediation, therapeutics, cosmetics and agriculture, however, the full potential of these versatile molecules is yet to be explored. Based on the facts that many naturally occurring lipopeptides are potent antimicrobials, our study aimed to explore the potential of replacing rhamnose in rhamnolipids with amino acids thus creating lipopeptides that would mimic or enhance properties of the parent molecule. This would allow not only for more economical and greener production but also, due to the availability of structurally different amino acids, facile manipulation of physico-chemical and biological properties. Our synthetic efforts produced a library of 43 lipopeptides revealing biologically more potent molecules. The structural changes significantly increased, in particular, anti-biofilm properties against Candida albicans, although surface activity of the parent molecule was almost completely abolished. Our findings show that the most active compounds are leucine derivatives of 3-hydroxy acids containing benzylic ester functionality. The SAR study demonstrated a further increase in activity with aliphatic chain elongation. The most promising lipopeptides 15, 23 and 36 at 12.5 μg/mL concentration allowed only 14.3%, 5.1% and 11.2% of biofilm formation, respectively after 24 h. These compounds inhibit biofilm formation by preventing adhesion of C. albicans to abiotic and biotic surfaces.
- Jovanovic, Milos,Radivojevic, Jelena,O'Connor, Kevin,Blagojevic, Stevan,Begovic, Biljana,Lukic, Vera,Nikodinovic-Runic, Jasmina,Savic, Vladimir
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supporting information
p. 209 - 217
(2019/03/23)
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- The synthesis of medium-chain-length β-hydroxy esters via the reformatsky reaction
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The synthesis of medium-chain-length β-hydroxy esters in good yield via the Reformatsky reaction is described. This work will be used as the basis for further investigation of hydroxyalkanoate polymers as potential feedstock for biofuel production.
- Sailer, Miloslav,Dubicki, Krystyn I.,Sorensen, John L.
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- ANTIMICROBIAL AGENT
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[Problem] To provide a novel antimicrobial agent that has excellent antimicrobial activity and which is prepared from an ester composed of propanediol and a β-hydroxycarboxylic acid. [Solution] An antimicrobial agent which is prepared from a propanediol mono-β-hydroxycarboxylic acid ester expressed by the following formula (1) or formula (2) (wherein R1 and R2 are both branched or unbranched, and saturated or unsaturated alkyl groups having 5 to 9 carbon atoms).
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Paragraph 0038
(2015/02/05)
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- Total synthesis of fellutamide b and deoxy-fellutamides B, C, and D
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The total syntheses of the marine-derived lipopeptide natural product fellutamide B and deoxy-fellutamides B, C, and D are reported. These compounds were accessed through a novel solid-phase synthetic strategy using Weinreb amide-derived resin. As part of the synthesis, a new enantioselective route to (3R)-hydroxy lauric acid was developed utilizing a Brown allylation reaction followed by an oxidative cleavage-oxidation sequence as the key steps. The activity of these natural products, and natural product analogues was also assessed against Mycobacterium tuberculosis in vitro.
- Giltrap, Andrew M.,Cergol, Katie M.,Pang, Angel,Britton, Warwick J.,Payne, Richard J.
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p. 2382 - 2397
(2013/08/23)
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- Asymmetric synthesis of long chain β-hydroxy fatty acid methyl esters as new elastase inhibitors
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Herein, β-hydroxy methyl esters with an even carbon chain length of 12-20 1b-5b were synthesized by three different asymmetric reduction methods I, II III from their corresponding β-keto methyl esters 1a-5a with the aim of determining their elastase activities. In method I, chiral catalyst A was prepared from chiral ligand (R)-binaphthol 1, while in method II, chiral catalyst B was synthesized from (2R,3R)-diisopropyl tartrate 2. Chiral catalyst B has not previously been used in asymmetric borane reductions or in the asymmetric synthesis of chiral β-hydroxy methyl esters. In method III, an asymmetric reduction was catalysed by (R)-Me-CBS oxazaborolidine 3. Hydride transfer was carried out in all of these methods by BH3· SMe2. Chiral hydroxy methyl esters with an (S)-configuration were synthesized by method I and with an (R)-configuration via methods II and III. The chiral hydroxy methyl esters obtained were analysed by chiral HPLC for their ee % values. Methods I, II and III were applied to long chain β-keto methyl esters for the first time. The reduction methods I, II and III were examined in terms of reaction yield and enantiomeric excess according to carbon chain length and the variable ratio of chiral catalysts to β-keto methyl ester. The highest enantiomeric excess of 90% ee was found in method III for 12 and 14 carbon numbers.
- Hasdemir, Belma,Onar, Huelya Elik,Yusufolu, Aye
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p. 1100 - 1105
(2012/11/07)
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- 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
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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.
- Braner, Markus,Zielonka, Stefan,Auras, Sylvia,Huettenhain, Stefan H.
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experimental part
p. 1019 - 1025
(2012/02/01)
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- Asymmetric synthesis of sphinganine and clavaminol H
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(Figure presented) An efficient enantioselective synthesis of sphinganine and clavaminol H is reported. These sphingoid-type bases were obtained from commercially available fatty acids using highly enantioselective Ru-catalyzed hydrogenation and organocatalytic electrophilic amination reactions to create the stereogenic centers.
- Ait-Youcef, Ramzi,Moreau, Xavier,Greck, Christine
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experimental part
p. 5312 - 5315
(2010/10/19)
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- Gas chromatography/electron-capture negative ion mass spectrometry for the quantitative determination of 2- and 3-hydroxy fatty acids in bovine milk fat
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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.
- Jenske, Ramona,Vetter, Walter
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experimental part
p. 5500 - 5505
(2010/03/25)
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- Polyhydroxyalkanoate and manufacturing method thereof
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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.
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Page/Page column 31
(2008/06/13)
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- Over 98% optical yield achieved by a heterogeneous catalysis. Substrate design and analysis of enantio-differentiating factors of tartaric acid-modified Raney nickel hydrogenation
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Tartaric acid-modified Raney nickel (TA-MRNi) is a chiral heterogeneous catalyst for the hydrogenation of prochiral ketones. An optical yield (OY) of 86% with methyl acetoacetate (1) as a substrate was improved to 94-96% by employing β-keto esters having a proper bulkiness at the γ-position. The γ-bulkiness effect contributes to a high intrinsic enantio-differentiating ability (factor-i) of the TA-MRNi catalysis. Through the study, we found the best substrate, γ-cyclopropyl-β-keto ester, the hydrogenation of which resulted in 98.6% OY. This further improvement in the OY was ascribed to a smaller contribution of non-enantio-differentiating hydrogenation (N-site catalysis) due to the substrate-specific activation of the enantio-differentiating hydrogenation by the chiral modifier. The OY of the hydrogenation of 1 was analyzed by comparing with well-behaved β-keto esters, and the contribution of the factor-i and the N-site to the OY value was evaluated to deduce the origin of the enantiodifferentiation.
- Sugimura, Takashi,Nakagawa, Satoshi,Tai, Akira
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p. 355 - 363
(2007/10/03)
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- ESTERS AND AMIDES AS PLA2 INHIBITORS
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The present invention relates to a novel fatty acid derivative of formula (I), wherein R1 is acyl group; R2 is acyl(lower)alkyl; R3 is hydrogen, aryl(lower)alkyl, etc.; R4 is acyl(lower)alkyl; and X is —O—, —NH—
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- Application of the Tethered Biginelli reaction for enantioselective synthesis of batzelladine alkaloids. Absolute configuration of the tricyclic guanidine portion of batzelladine B
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Tethered Biginelli condensation of enantioenriched hexahydropyrrolopyrimidines 8 with β-ketoesters provides efficient asymmetric access to tricyclic guanidines 9 having a syn relationship of the angular C2a and C8a hydrogens. This reaction was employed to realize the first practical enantioselective access to this fragment of batzelladine alkaloids B (2) and E (5). The efficiency of this strategy is illustrated in the synthesis of the dextrorotatory enantiomer of batzelladine B methanolysis product 10 in 10 steps and 25% overall yield from 2-nonanone and methyl acetoacetate. The asymmetric synthesis of 1.0 establishes that the absolute configuration of the tricyclic portion of batzelladine B (2) is 25aR,28S,30R. The 4-methyl-7-alkyl-1,2,2a,3,4,5,6,7,8,8a-decahydro-5,6,8b- triazaacenaphthalene-3-carboxylic acid subunit, e.g., 29, of batzelladine alkaloids A (1), D (4), F (6), and G was also prepared for the first time by catalytic hydrogenation of tricyclic guanidines 26 having the 2a,8a-anti stereochemistry.
- Franklin, Alison S.,Ly, Sylvie K.,Mackin, Gilbert H.,Overman, Larry E.,Shaka
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p. 1512 - 1519
(2007/10/03)
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- Chemistry of metapleural gland secretions of three attine ants, Atta sexdens rubropilosa, Atta cephalotes, and Acromyrmex octospinosus (Hymenoptera: Formicidae)
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The chemical composition of the secretions of the metapleural glands of workers and soldiers of two Atta species, atta sexdens rubropilosa and A. cephalotes, and workers of Acromyrmex oetospinoxus, has been studied. As indicated by infrared spectrometry and confirmed by the ninhydrin test, the secretions contain chiefly proteins. Of the volatile acidic portion, which is present as ionized salts, phenylacetic acid is the major component in workers and soldiers of A. s. rubropilosa and A. cephalotes. Both Atta species also contain 3 hydroxydecanoic acid and its homolog as minor components together with indoleacetic acid. While there are qualitative similarities in the acidic composition in the secretions of A. s. rubropilosa and A. cephalotes, they differ quantitatively. The secretion of Acromyrmex octospinosus contains 3-hydoxydecanoic and indoleacetic acids, but lacks phenylacetic acid The bactericidal and fungicidal actions of the three major substances have been confirmed.
- Do Nascimento, Ruth R.,Schoeters, Eric,Morgan, E. David,Billen, Johan,Stradling, David J.
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p. 987 - 1000
(2007/10/03)
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- An Improved Asymmetrically-Modified Nickel Catalyst Prepared from Ultrasonicated Raney Nickel
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The ultrasonic irradiation of Raney nickel catalyst in water followed by the removal of the resulting turbid supernatant gave an excellent nickel catalyst (RNi-U) which generated an asymmetrically-modified nickel catalyst.An EPMA (SEM-EDX) study indicated that RNi-U consisted of a fairly pure nickel surface of homogeneous size.Tartaric acid-NaBr-modified RNi-U (TA-NaBr-MRNi-U) showed a high enantio-differentiating ability as well as reactivity in the hydrogenation of prochiral ketones such as 1,3-diones and 3-oxoalkanoic acid esters.
- Tai, Akira,Kikukawa, Tadashi,Sugimura, Takashi,Inoue, Yoshihisa,Abe, Satoshi,et al.
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p. 2473 - 2477
(2007/10/02)
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- Total synthesis of arthrobacilin A
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Novel cyclic glycolipids, arthrobacilin A and its analogues, have been synthesized by means of unique DCC/DMAP·HCl promoted oligomerization/cyclization, zinc salt catalyzed β-selective glycosylation, and Noyori's BINAP/Ru catalyzed asymmetric reduction.
- Garcia, Dulce M.,Yamada, Hidetoshi,Hatakeyama, Susumi,Nishizawa, Mugio
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p. 3325 - 3328
(2007/10/02)
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- Highly Efficient Enantio-differentiating Hydrogenation over an Ultrasonicated Raney Nickel Catalyst Modified with Tartaric Acid
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A tartaric acid-NaBr-modified nickel catalyst prepared from ultrasonicated Raney nickel showed excellent enantio-differentiating and hydrogenating activity in the hydrogenation of a series of 3-oxoalkanoate and 1,3-diketones.
- Tai, Akira,Kikukawa, Tadasi,Sugimura, Takashi,Inoue, Yosihisa,Osawa, Tsutomu,Fujii, Satoshi
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p. 795 - 796
(2007/10/02)
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- Asymmetric Reduction of Aliphatic Short- to Long-Chain β-Keto Acids by Use of Fermenting Bakers' Yeast
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Eleven β-keto acids, ranging from 3-oxobutanoic to 3-oxooctanoic acids, were reduced with fermenting bakers' yeast to the corresponding optically active β-hydroxy acids, which were isolated as the methyl esters.In all cases, the (R)-hydroxy acids were obtained in >/=98percent ee, except for 3-oxobutanoic acid, which afforded the (S)-hydroxy acid in 86percent ee.Inhibition of fermentation was observed for 3-oxoundecanoic to 3-oxotetradecanoic acids, leading to no reduction.Lowering of the substrate concentration was found to be appreciably effective in avoiding inhibition.
- Utaka, Masanori,Watabu, Hisashi,Higashi, Hiroshi,Sakai, Takashi,Tsuboi, Sadao,Torii, Sigeru
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p. 3917 - 3921
(2007/10/02)
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- New potential immunoenhancing compounds. Synthesis and pharmacological evaluation of new long-chain 2-amido-2-deoxy-D-glucose derivatives
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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.
- Valcavi,Albertoni,Brandt,Corsi,Farina,Foresta,Pascucci,Ramacci
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p. 1190 - 1195
(2007/10/02)
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- The Preparation of Optically Pure 3-Hydroxyalkanoic Acid. The Enantioface-differentiating Hydrogenation of the C=O Double Bond with Modified Raney Nickel. XXXVII
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The enantioface-differentiating hydrogenation of methyl 3-oxoalkanoate (CH3(CH2)nCOCH2COOCH3, n=0, 6, 8, 10, 12) over the (R,R)-tartaric acid-NaBr-modified Raney nickel catalyst ((R,R)-TA-NaBr-MRNi) gave methyl (R)-3-hydroxyalkanoate (CH3(CH2)nCH(OH)CH2COOCH3, n=0, 6, 8, 10, 12) in an average optical yield of 85percent.After the methyl ester had been converted to dicyclohexylammonium salt of 3-hydroxyalkanoic acid, the salt was recrystallized three times from acetonitrile and then treated with acid to give optically pure (R)-3-hydroxyalkanoic acid (CH3(CH2)nCH(OH)CH2COOH, n=0, 6, 8, 10, 12) in a reasonable yield.From the hydrogenation product with (S,S)-TA-NaBr-MRNi, optically pure (S)-3-hydroxyalkanoic acid was obtained by the same process as above.
- Nakahata, Masaaki,Imaida, Motomasa,Ozaki, Hiroshi,Harada, Tadao,Tai, Akira
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p. 2186 - 2189
(2007/10/02)
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