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Acylation
Kinds of Acylation Terms modified by Acylation Selected AbstractsLactone Kinetic Resolution by Acylation , Application to the Enantioselective Synthesis of Estrane DerivativesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2005Serge Wilmouth Abstract The acylation of an excess of racemic spirolactone 1 (6,9-divinyl-1-oxaspiro[4.4]nonan-2-one) enolate by protected methyl (S)-lactate or (,)-bornyl carbonate occurs with a kinetic resolution. The resulting lactones were alkylated with 1-iodobenzocyclobutenes to afford compounds that serve as precursors to nonracemic steroids such as 11,-alkyloxycarbonyl-11,,13,-(,-carbolactone)-17,-vinylgonatri-1,3,5(10)-enes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Acylation of lysophosphatidylcholine plays a key role in the response of monocytes to lipopolysaccharideFEBS JOURNAL, Issue 13 2003Bernhard Schmid Mononuclear phagocytes play a pivotal role in the progression of septic shock by producing tumor necrosis factor-, (TNF-,) and other inflammatory mediators in response to lipopolysaccharide (LPS) from Gram-negative bacteria. Our previous studies have shown monocyte and macrophage activation correlate with changes in membrane phospholipid composition, mediated by acyltransferases. Interferon-, (IFN-,), which activates and primes these cells for enhanced inflammatory responses to LPS, was found to selectively activate lysophosphatidylcholine acyltransferase (LPCAT) (P < 0.05) but not lysophosphatidic acid acyltransferase (LPAAT) activity. When used to prime the human monocytic cell line MonoMac 6, the production of TNF-, and interleukin-6 (IL-6) was approximately five times greater in cells primed with IFN-, than unprimed cells. Two LPCAT inhibitors SK&F 98625 (diethyl 7-(3,4,5-triphenyl-2-oxo2,3-dihydro-imidazole-1-yl)heptane phosphonate) and YM 50201 (3-hydroxyethyl 5,3,-thiophenyl pyridine) strongly inhibited (up to 90%) TNF-, and IL-6 production in response to LPS in both unprimed MonoMac-6 cells and in cells primed with IFN-,. In similar experiments, these inhibitors also substantially decreased the response of both primed and unprimed peripheral blood mononuclear cells to LPS. Sequence-based amplification methods showed that SK&F 98625 inhibited TNF-, production by decreasing TNF-, mRNA levels in MonoMac-6 cells. Taken together, the data from these studies suggest that LPCAT is a key enzyme in both the pathways of activation (priming) and the inflammatory response to LPS in monocytes. [source] Studies on organophosphorus compounds: Synthesis and reactions of [1,2,4,3]triaza-phospholo[4,5- a]quinoxaline derivativeHETEROATOM CHEMISTRY, Issue 5 2008Hassan M. Moustafa 2,4-Bis-(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawesson's reagent) (1) reacted with 2-hydrazino-3-methyl-quinoxaline (2) to give [1,2,4,3]-triazaphospholo[4,5- a]quinoxaline derivative 3. The Mannich reaction using different amines on compound 3 gave Mannich bases 4a,d. Also, compound 3 reacted with formaldehyde to give the corresponding 2-hydroxymethyl derivative 5, which upon reaction with thionyl chloride gave the corresponding chloromethyl derivative 6. Treatment of compound 6 with some thiols yielded the corresponding sulfides 7a,d. Acylation of compound 3 gave acylated compounds 8a,b. Compound 9, which was prepared through the reaction of compound 3 with ethyl cyanoacetate, was investigated as a starting material for the synthesis of some new heterocyclic systems 10,13. Also, reaction of compound 9 with carbon disulfide and 2 equivalents of methyl iodide in a one-pot reaction yielded the corresponding ketene-S,S-acetal 14, which in turn reacted with bidentates to give some new heterocycles 15,17. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:520,529, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20473 [source] Retro-ene reactions in heterocyclic synthesis. v. a novel synthetic method for 1,3,5-triazine-2,4(1H,3H)-dionesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2007The Late Kunio Ito N - t -Butylamidines 1 on heating with diphenyl carbonate (2) at 150-180° gave the 1,3,5-triazine-2,4(1H,3H)-dione derivatives 5. Acylation of amidines 1 and cyclocondensation of the resulting carbamates 3 gave [1,3,5,7]tetrazocine-2,6-dione derivatives 4, and subsequent retro-ene reaction and ring contraction afforded triazine derivatives 5. [source] Characterization of N -palmitoylated human growth hormone by in situ liquid,liquid extraction and MALDI tandem mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2007Emmanuelle Sachon Abstract Acylation is a common post-translational modification found in secreted proteins and membrane-associated proteins, including signal transducing and regulatory proteins. Acylation is also explored in the pharmaceutical and biotechnology industry to increase the stability and lifetime of protein-based products. The presence of acyl moieties in proteins and peptides affects the physico-chemical properties of these species, thereby modulating protein stability, function, localization and molecular interactions. Characterization of protein acylation is a challenging analytical task, which includes the precise definition of the acylation sites in proteins and determination of the identity and molecular heterogeneity of the acyl moiety at each individual site. In this study, we generated a chemically modified human growth hormone (hGH) by incorporation of a palmitoyl moiety on the N, group of a lysine residue. Monoacylation of the hGH protein was confirmed by determination of the intact molecular weight by mass spectrometry. Detailed analysis of protein acylation was achieved by analysis of peptides derived from hGH by protease treatment. However, peptide mass mapping by MALDI MS using trypsin and AspN proteases and standard sample preparation methods did not reveal any palmitoylated peptides. In contrast, in situ liquid,liquid extraction (LLE) performed directly on the MALDI MS metal target enabled detection of acylated peptide candidates by MALDI MS and demonstrated that hGH was N -palmitoylated at multiple lysine residues. MALDI MS and MS/MS analysis of the modified peptides mapped the N -palmitoylation sites to Lys158, Lys172 and Lys140 or Lys145. This study demonstrates the utility of LLE/MALDI MS/MS for mapping and characterization of acylation sites in proteins and peptides and the importance of optimizing sample preparation methods for mass spectrometry-based determination of substoichiometric, multi-site protein modifications. Copyright © 2007 John Wiley & Sons, Ltd. [source] Highly Selective Acylation of Dimethylamine Mediated by Oxygen Atoms on Metallic Gold Surfaces,ANGEWANDTE CHEMIE, Issue 2 2010Bingjun Xu Komplett gekuppelt: Die Acylierung von Dimethylamin durch Kupplung mit Formaldehyd gelingt mit fast kompletter Selektivität bei niedriger Aktivierungsenergie und niedrigen Bedeckungen mit adsorbierten O-Atomen auf metallischem Gold. Der Sauerstoff erzeugt die aktivierte Zwischenstufe (CH3)2N(a), die das Carbonyl-Kohlenstoffatom des Aldehyds angreift (siehe Bild). Ein allgemeiner Mechanismus für die effiziente und selektive Acylierung von Aminen durch Au wird vorgeschlagen. [source] An Inverse Substrate Orientation for the Regioselective Acylation of 3,,5,-Diaminonucleosides Catalyzed by Candida antarctica lipase B?CHEMBIOCHEM, Issue 8 2005Iván Lavandera Dr. Abstract Candida antarctica lipase B (CAL-B) catalyzes the regioselective acylation of natural thymidine with oxime esters and also the regioselective acylation of an analogue, 3,,5,-diamino-3,,5,-dideoxythymidine with nonactivated esters. In both cases, acylation favors the less hindered 5,-position over the 3,-position by upto 80-fold. Computer modeling of phosphonate transition-state analogues for the acylation of thymidine suggests that CAL-B favors acylation of the 5,-position because this orientation allows the thymine ring to bind in a hydrophobic pocket and forms stronger key hydrogen bonds than acylation of the 3,-position. On the other hand, computer modeling of phosphonamidate analogues of the transition states for acylation of either the 3,- or 5,-amino groups in 3,,5,-diamino-3,,5,-dideoxythymidine shows similar orientations and hydrogen bonds and, thus, does not explain the high regioselectivity. However, computer modeling of inverse structures, in which the acyl chain binds in the nucleophile pocket and vice versa, does rationalize the observed regioselectivity. The inverse structures fit the 5,-, but not the 3,-intermediate thymine ring, into the hydrophobic pocket, and form a weak new hydrogen bond between the O-2 carbonyl atom of the thymine and the nucleophile amine only for the 5,-intermediate. A water molecule might transfer a proton from the ammonium group to the active-site histidine. As a test of this inverse orientation, we compared the acylation of thymidine and 3,,5,-diamino-3,,5,-dideoxythymidine with butyryl acyl donors and with isosteric methoxyacetyl acyl donors. Both acyl donors reacted at equal rates with thymidine, but the methoxyacetyl acyl donor reacted four times faster than the butyryl acyl donor with 3,,5,-diamino-3,,5,-dideoxythymidine. This faster rate is consistent with an inverse orientation for 3,,5,-diamino-3,,5,-dideoxythymidine, in which the ether oxygen atom of the methoxyacetyl group can form a similar hydrogen bond to the nucleophilic amine. This combination of modeling and experiments suggests that such lipase-catalyzed reactions of apparently close substrate analogues like alcohols and amines might follow different pathways. [source] Enhancing Membrane Permeability by Fatty Acylation of Oligoarginine PeptidesCHEMBIOCHEM, Issue 8 2004Wellington Pham Dr. A systematic study of fatty acylated polyarginines as drug-delivery modules is described. A remarkable uptake was observed when a myristate moiety was incorporated with a 7-mer polyarginine (see scheme). Microscopic studies suggest that the fatty acylated peptide is internalized into the cytoplasm, not the nucleus, thus providing an alternative method for drug delivery. [source] Efficient Acylation of Anisole over Hierarchical Porous ZSM-5 StructureCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2010A. Padmanabhan Abstract Friedel-Crafts acylation is one of the most important methods to prepare aromatic ketones which are used in manufacturing fine and speciality chemicals, as well as pharmaceuticals. Herein, we report an efficient and convenient procedure for the acylation of anisole with acetic anhydride, using a hierarchical porous ZSM-5 catalyst. The hierarchical porous ZSM-5 catalyst was synthesized using styrene butadiene rubber (SBR) as macroporous template. The catalysts were characterized for their structural features by using XRD, SEM, and FT-IR analyses. The effect of temperature, molar ratio, and catalyst weight on the acylation of anisole was studied in detail. The reaction parameters such as anisole-to-acetic anhydride mole ratio, catalyst weight, and reaction temperature were optimized as 5:1, 0.2 g, and 70 °C, respectively. The method described here is environmentally benign and replaces the conventional catalyst by a highly active and reusable catalyst. [source] ChemInform Abstract: Palladium-Catalyzed Oxidative sp2 C,H Bond Acylation with Aldehydes.CHEMINFORM, Issue 38 2010Olivier Basle Abstract An efficient method to prepare aromatic, aliphatic, and optically active ketones is reported. [source] ChemInform Abstract: NHC Catalyzed Oxidations of Aldehydes to Esters: Chemoselective Acylation of Alcohols in Presence of Amines.CHEMINFORM, Issue 28 2010Suman De Sarkar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Enzyme Catalyzed Acylation of 7-Hydroxy-4-methyl-2H-chromene-2-one Using Microwave.CHEMINFORM, Issue 4 2010Mazaahir Kidwai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Novel Broensted Acid Catalyst for Friedel,Crafts Acylation.CHEMINFORM, Issue 18 2009Anna G. Posternak Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Thallium(III) Chloride: A Mild and Efficient Catalyst for Acylation of Alcohols, Phenols and Thiols, and for Geminal Diacylation of Aldehydes under Solvent-Free Conditions.CHEMINFORM, Issue 9 2009Santosh T. Kadam Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: New, Efficient, Selective, and One-Pot Method for Acylation of Amines.CHEMINFORM, Issue 6 2009Mahantesha Basanagouda Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Electrochemically Promoted Friedel,Crafts Acylation of Aromatic Compounds.CHEMINFORM, Issue 31 2008G. Karthik Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Efficient Reductive Acylation of 3-Nitroindoles.CHEMINFORM, Issue 24 2008Sujata Roy Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Silica Sulfuric Acid as an Efficient Solid Acid Catalyst for Friedel,Crafts Acylation Using Anhydrides.CHEMINFORM, Issue 10 2008A. Alizadeh Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: SO42- /SnO2: Efficient, Chemoselective, and Reusable Catalyst for Acylation of Alcohols, Phenols, and Amines at Room Temperature.CHEMINFORM, Issue 6 2008Jitendra R. Satam Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Acylation of Perimidine with 1,3,5-Triazines in Polyphosphoric Acid.CHEMINFORM, Issue 52 2007A. V. Aksenov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Tf2O as a Rapid and Efficient Promoter for the Dehydrative Friedel,Crafts Acylation of Aromatic Compounds with Carboxylic Acids.CHEMINFORM, Issue 39 2007Mohammd Mehdi Khodaei Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Acylation of Electrophilic Olefins Through Decatungstate-Photocatalyzed Activation of Aldehydes.CHEMINFORM, Issue 28 2007Silvia Esposti Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthesis of Mesoionic 4-(para-Substituted Phenyl-5-2,4-dichlorophenyl)-1,3,4-thiadiazolium-2-aminides by Direct Cyclization via Acylation of Thiosemicarbazides.CHEMINFORM, Issue 16 2007Marcelo Moreira Britto Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Acylation of Ambident Vinylogous Urethanes Exocyclic to Thiazolidines and Reduced Thiazines.CHEMINFORM, Issue 3 2007Anthony G. Avent Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Highly Selective Catalytic Friedel,Crafts Acylation and Sulfonylation of Activated Aromatic Compounds Using Indium Metal.CHEMINFORM, Issue 49 2006Doo Ok Jang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Three-Step ,-Acylation of (E)-Cinnamate Esters with Inversion of Stereochemistry Through Formation and Cleavage of Carbon,Pentamethylcyclopentadienyl Bonds.CHEMINFORM, Issue 35 2006Minoru Uemura Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthesis of New Bridged Biimidazoles by an Acylation,Dimerization Sequence.CHEMINFORM, Issue 22 2006Thomas Welzel Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] ,,,-Unsaturated ,-Diketones by Acylation of Ketones.CHEMINFORM, Issue 5 2006Alan R. Katritzky Abstract For Abstract see ChemInform Abstract in Full Text. [source] Acetonyltriphenylphosphonium Bromide (ATPB): A Versatile Reagent for the Acylation of Alcohols, Phenols, Thiols and Amines and for 1,1-Diacylation of Aldehydes under Solvent-Free Conditions.CHEMINFORM, Issue 43 2005Abu T. Khan No abstract is available for this article. [source] Metallophosphite-Induced Nucleophilic Acylation of ,,,-Unsaturated Amides: Facilitated Catalysis by a Diastereoselective Retro [1,4] Brook Rearrangement.CHEMINFORM, Issue 34 2005Mary R. Nahm Abstract For Abstract see ChemInform Abstract in Full Text. [source] | |||||||||||||||||||||||||||||||||||||