|
| ||
|
|
||
Acid Esters (acid + ester)
Kinds of Acid Esters Selected AbstractsComparative Reactivity of Hypervalent Iodine Oxidants in Metalloporphyrin-Catalyzed Oxygenation of Hydrocarbons: Iodosylbenzene Sulfate and 2-Iodylbenzoic Acid Ester as Safe and Convenient Alternatives to IodosylbenzeneADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2009Abstract A comparative study of the reactivity of 2-iodylbenzoic acid isopropyl ester (IBX-ester), oligomeric iodosylbenzene sulfate [(PhIO)3,SO3]n, and iodosylbenzene in the oxygenation of anthracene in the presence of metal porphyrin or phthalocyanine complexes is reported. Results of this study demonstrate that oligomeric iodosylbenzene sulfate and the IBX-ester are the most reactive oxygenating reagents that can be used as a safe and convenient alternative to the thermally unstable and potentially explosive iodosylbenzene. [source] Efficient, Rhodium-Catalyzed Hydrogenation of ,-Dehydroamino Acid Esters with Chiral Monodentate Aminophosphanes Bearing Two Binaphthyl GroupsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2007Luc Eberhardt Abstract All four stereoisomers of 4-{4,5-dihydro-3H -dinaphtho[2,1- c:1,,2,- e]azepin-4-yl}dinaphtho[2,1- d:1,,2,- f][1,3,2]dioxaphosphepine have been prepared from (R or S)-1,1,-binaphthyl-2,2,-diyl chlorophosphite and the appropriate dinaphtho-azepine. When reacted with [Rh(1,5-cyclooctadiene)2]BF4, highly active catalysts for the hydrogenation of ,-dehydroamino acid esters were obtained. The highest enantioselectivities (up to 99,% ee) were achieved with the phosphoramidites having two chiral binaphthyl groups with opposite configurations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Reactions of Polycyclic Ketones with Dimethoxycarbene; a Convenient Route for a ,One-Pot' Preparation of Some , -Hydroxycarboxylic Acid EstersHELVETICA CHIMICA ACTA, Issue 7 2007Jaros, aw Roma Abstract Polycyclic ,cage' ketones, such as pentacyclo[5.4.0.02,6.03,10.05,9]undecan-8-one (10), pentacyclo[5.4.0.02,6.03,10.05,9]undecane-8,11-dione (11), and adamantan-2-one (16) were treated with the nucleophilic dimethoxycarbene (DMC; 1), which was generated thermally from 2,5-dihydro-2,2-dimethoxy-5,5-dimethyl-1,3,4-oxadiazole (4a) in boiling toluene. In this ,one-pot' procedure, the , -hydroxycarboxylic acid ester 12 or a corresponding derivative 15 or 17 was obtained (Schemes,4,7). Additionally, ,cage' thione 21 was treated with DMC under the same conditions yielding dimethoxythiirane 22 (Scheme,8). Subsequent hydrolysis or desulfurization (followed by hydrolysis on silica gel) of 22 gave , -mercaptocarboxylate 25 and the corresponding desulfurized ester 24, respectively. In all cases, the addition of DMC occurred stereoselectively, and the addition from the exo -face is postulated to explain the structures of the isolated products. [source] DPPH (=,2,2-Diphenyl-1-picrylhydrazyl,=,2,2-Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl) Radical-Scavenging Reaction of Protocatechuic Acid Esters (=,3,4-Dihydroxybenzoates) in Alcohols: Formation of Bis-alcohol AdductHELVETICA CHIMICA ACTA, Issue 4 2006Shizuka Saito Abstract Protocatechuic acid esters (=,3,4-dihydroxybenzoates) scavenge ca. 5,equiv. of radical in alcoholic solvents, whereas they consume only 2,equiv. of radical in nonalcoholic solvents. While the high radical-scavenging activity of protocatechuic acid esters in alcoholic solvents as compared to that in nonalcoholic solvents is due to a nucleophilic addition of an alcohol molecule at C(2) of an intermediate o -quinone structure, thus regenerating a catechol (=,benzene-1,2-diol) structure, it is still unclear why protocatechuic acid esters scavenge more than 4,equiv. of radical (C(2) refers to the protocatechuic acid numbering). Therefore, to elucidate the oxidation mechanism beyond the formation of the C(2) alcohol adduct, 3,4-dihydroxy-2-methoxybenzoic acid methyl ester (4), the C(2) MeOH adduct, which is an oxidation product of methyl protocatechuate (1) in MeOH, was oxidized by the DPPH radical (=,2,2-diphenyl-1-picrylhydrazyl) or o -chloranil (=,3,4,5,6-tetrachlorocyclohexa-3,5-diene-1,2-dione) in CD3OD/(D6)acetone 3,:,1). The oxidation mixtures were directly analyzed by NMR. Oxidation with both the DPPH radical and o -chloranil produced a C(2),C(6) bis-methanol adduct (7), which could scavenge additional 2,equiv. of radical. Calculations of LUMO electron densities of o -quinones corroborated the regioselective nucleophilic addition of alcohol molecules with o -quinones. Our results strongly suggest that the regeneration of a catechol structure via a nucleophilic addition of an alcohol molecule with a o -quinone is a key reaction for the high radical-scavenging activity of protocatechuic acid esters in alcoholic solvents. [source] Magnetic Nanoparticle Supported Second Generation Hoveyda,Grubbs Catalyst for Metathesis of Unsaturated Fatty Acid EstersADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 16 2009Zhu Yinghuai Abstract The Hoveyda,Grubbs catalyst has been successfully immobilized on surface-modified magnetic nanoparticles with a loading amount of 0.28,mmol ruthenium/g (magnetic support). The supported catalysts were active for the self-metathesis of methyl oleate and macro-monomer in a quantitative conversion, respectively. In addition, the catalyst can be easily separated by using a magnet and reused several times with sustained activity. [source] Synthesis of N-Heteroaryl(trifluoromethyl)hydroxyalkanoic Acid Esters by Highly Efficient Solid Acid-Catalyzed Hydroxyalkylation of Indoles and Pyrroles with Activated Trifluoromethyl KetonesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14 2005Mohammed Abid Abstract The synthesis of N-heteroaryl(trifluoromethyl)hydroxyalkanoic acid esters by solid acid-catalyzed Friedel,Crafts hydroxyalkylation of indoles and pyrroles with ethyl 3,3,3-trifluoropyruvate and ethyl 4,4,4-trifluoroacetoacetate is described. The inexpensive and readily available K-10 montmorillonite is found to be an efficient catalyst for the synthesis of a wide variety of trifluoromethylated indol-3-yl- and pyrrol-2-yl-hydroxypropionic and -butanoic acid esters. Using a series of substituted indoles and pyrroles the corresponding products were isolated in excellent yield (up to 98%) and 100% selectivity under mild experimental conditions, during very short reaction times. Beyond these, the ease of product isolation, catalyst stability and handling make this process an attractive, environmentally benign alternative for the synthesis of the target compounds. [source] New 5-Aminolevulinic Acid Esters,Efficient Protoporphyrin Precursors for Photodetection and Photodynamic Therapy,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2003H. Brunner ABSTRACT Photodetection (PD) and photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA),induced protoporphyrin IX (PPIX) accumulation are approaches to detect and treat dysplasia and early cancer in the gastrointestinal tract and in the urinary bladder. Because ALA-induced PPIX production is limited, we synthesized ALA ester hydrochlorides 3,22 and tested them in two different in vitro models (gastrointestinal tract: HT29,CCD18; urinary bladder: J82,UROTSA). PPIX accumulation after incubation with 0.12 mmol/L for 3 h and PPIX accumulation as a function of different incubation times were measured using flow cytometry. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were performed to check cellular dark toxicity. Phototoxicity after irradiation was tested. ALA nonafluorohexylester hydrochloride 11, ALA thiohexylester hydrochloride 13 and ALA dibenzyldiester dihydrochloride 19 induced appreciably increased PPIX levels and showed improved phototoxicity compared with the references ALA hydrochloride 1, ALA hexylester hydrochloride 3 and ALA benzylester hydrochloride 4. Thus, the new compounds 11, 13 and 19 are promising compounds for PD and PDT. [source] The Effects of 5-Aminolevulinic Acid Esters on Protoporphyrin IX Production in Human Adenocarcinoma Cell Lines,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2001H. Brunner ABSTRACT Photodynamic diagnosis (PDD) and photodynamic therapy (PDT) using 5-aminolevulinic acid (ALA),induced protoporphyrin IX (PPIX) is an interesting approach to detect and treat dysplasia and early cancers in the gastrointestinal tract. Because of low lipophilicity resulting in poor penetration across cell membranes, high doses of ALA should be administered in order to reach clinically relevant levels of PPIX. One way of increasing PPIX accumulation is derivatization of ALA into a more lipophilic molecule. In our in vitro study, different esterifications of ALA were investigated to analyze the effects on PPIX accumulation in human adenocarcinoma cell lines. For systematic analysis of cell type,specific PPIX accumulation, three human adenocarcinoma cell lines (SW480, HT29 and CaCo2) and a fibroblast cell line (CCD18) were tested. 3-(4,5-Dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) assays were performed to ensure that the ALA esters showed no cellular dark toxicity. Different concentrations (ranging from 0.012 to 0.6 mmol/L, 3 h) and incubation times (5, 10, 30, 180 min; 0.12 mmol/L) were examined. PPIX accumulation was measured using flow cytometry. ALA esters, especially ALA-hexylester and ALA-benzylester, induced significant higher PPIX levels in adenocarcinoma cell lines when compared with ALA and may be promising candidates for PDT and PDD. [source] ChemInform Abstract: Regioselective Addition of Organomagnesium Reagents to N-Silyl Activated Nicotinic Acid Esters , A Convenient Method for the Synthesis of 4,4-Disubstituted 1,4-Dihydronicotinates.CHEMINFORM, Issue 46 2009Christian A. Sperger 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: Synthesis of Chiral Tetraaminophosphonium Chlorides from N-Boc ,-Amino Acid Esters.CHEMINFORM, Issue 18 2009Daisuke Uraguchi 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: Synthesis and Selected Transformations of 1H-Imidazole 3-Oxides Derived from Amino Acid Esters.CHEMINFORM, Issue 9 2009Marcin Jasinski 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: Reaction of ,-Nitrocinnamic Acid Esters with Pyrrole.CHEMINFORM, Issue 4 2009L. V. Baichurina 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: Rh-Catalyzed Asymmetric Hydrogenation of ,-Phthalimido-Substituted ,,,-Unsaturated Carboxylic Acid Esters: An Efficient Enantioselective Synthesis of ,-Aryl-,-amino Acids.CHEMINFORM, Issue 14 2008Jun Deng 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] Synthesis of New Pyrido[2,3-d]pyrimidine Derivatives by Three-Component Condensation of 5-Acetyl-4-aminopyrimidines, Cyclohexane-1,3-diones, and Orthocarboxylic Acid Esters.CHEMINFORM, Issue 36 2007A. V. Komkov 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] Reaction of 2-(2-Oxo-2,3-dihydro-1H-indol-3-ylidene)acetic Acid Esters with Benzene-1,2-diamine and 2-Aminobenzenethiol.CHEMINFORM, Issue 28 2007V. O. Koz'minykh 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] Reaction of Hydrazine and Hydroxylamine Derivatives with Pyrimidinoacetic Acid Esters and Lactones.CHEMINFORM, Issue 20 2007Sergei I. Filimonov 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] Intermolecular One-Pot Cyclization of Formyl-Pyrroles of Amino Acid Esters with Norephedrine: Stereoselective Routes to New Tricyclic Pyrrole,Pyrazine,Oxazole Fused Structures.CHEMINFORM, Issue 11 2007Ayhan S. Demir 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] Enantioselective Equilibration , Access to Chiral Aldol Adducts of Mandelic Acid Esters.CHEMINFORM, Issue 10 2007Stefan Scholtis 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] Regioselective Addition of Aromatic Amines at the Exocyclic C=C Bond of 2-(2-Oxo-2,3-dihydro-1H-indol-3-ylidene)acetic Acid Esters.CHEMINFORM, Issue 9 2007V. O. Koz'minykh 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] Enantio- and Diastereoselective Hydrogenation via Dynamic Kinetic Resolution by a Cationic Iridium Complex in the Synthesis of ,-Hydroxy-,-amino Acid Esters.CHEMINFORM, Issue 3 2007Kazuishi Makino 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] DABCO Catalyzed Reaction of Various Nucleophiles with Activated Alkynes (I) Leading to the Formation of Alkenoic Acid Esters, e.g. (III)/(IV), 1,4-Dioxane (XI), Morpholine (XIII), and Piperazinone Derivatives (XVII).CHEMINFORM, Issue 44 2006Ming-Jin Fan 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] Novel Approach to Arylhydrazones, the Precursor for Fischer Indole Synthesis, via Diazo Esters Derived from ,-Amino Acid Esters.CHEMINFORM, Issue 17 2006Eiko Yasui 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] An Unusual Reaction of (2-Oxo-1,2-dihydro-3H-indol-3-ylidene)acetic Acid Esters with Hydrazine.CHEMINFORM, Issue 11 2006V. O. Kozminykh 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] Unexpected Formation of Polysubstituted 1-Azabutadienes and 1,3-Dioxanes from the Reaction of 3-Fluoroalkyl-3-arylaminoacrylic Acid Esters with Formaldehyde.CHEMINFORM, Issue 42 2005Fu-Lu Zhao Abstract For Abstract see ChemInform Abstract in Full Text. [source] Reductive Alkylation of Perfluorocarboxylic Acid Esters with CCl3F or CCl4 and Synthesis of Higher Linear Perfluoroketones.CHEMINFORM, Issue 16 2005Yu. V. Zeifman No abstract is available for this article. [source] Reactions of Polyfluorinated 2-Arylhydrazono-3-oxocarboxylic Acid Esters with o-Phenylenediamine.CHEMINFORM, Issue 8 2005O. G. Khudina Abstract For Abstract see ChemInform Abstract in Full Text. [source] Cinnamic Acid Esters as Potent Inhibitors of Fungal 17,-Hydroxysteroid Dehydrogenase , A Model Enzyme of the Short-Chain Dehydrogenase/Reductase SuperfamilyCHEMINFORM, Issue 46 2004Stanislav Gobec Abstract For Abstract see ChemInform Abstract in Full Text. [source] An Efficient Synthesis of Aryloxyacetic Acid and Arylthioacetic Acid Esters.CHEMINFORM, Issue 45 2004Ji-Tai Li Abstract For Abstract see ChemInform Abstract in Full Text. [source] An Efficient Synthesis of 1H-Pyrazole-4-carboxylic Acid Esters with Vilsmeier Reagent under Neat Conditions.CHEMINFORM, Issue 44 2004R. Sridhar Abstract For Abstract see ChemInform Abstract in Full Text. [source] Synthesis of Cyclic ,-Amino Acid Esters from Methionine, Allylglycine, and Serine.CHEMINFORM, Issue 37 2004James Gardiner Abstract For Abstract see ChemInform Abstract in Full Text. [source] | ||||||||||||||||||||||||||||||||||||||||