- Insights into β-ketoacyl-chain recognition for β-ketoacyl-ACP utilizing AHL synthases
-
Beta-ketoacyl-ACP utilizing enzymes in fatty acid, polyketide and acyl-homoserine lactone biosynthetic pathways are important targets for developing antimicrobial, anticancer and antiparasitic compounds. Published reports on successful isolation of beta-ketoacyl-ACPs in a laboratory remain scarce to date and thus most beta-ketoacyl-ACP utilizing enzymes are routinely characterized using small molecule substrates in lieu of the bonafide 3-oxoacyl-ACPs. We report the systematic investigation into the electronic, geometric and spatial aspects of beta-ketoacyl-chain recognition to develop 3-oxoacyl-ACP substrate mimics for two beta-ketoacyl-ACP utilizing quorum signal synthases.
- Nhu Lam, Mila,Dudekula, Dastagiri,Durham, Bri,Collingwood, Noah,Brown, Eric C.,Nagarajan, Rajesh
-
-
Read Online
- Production and upgrading of 5-hydroxymethylfurfural using heterogeneous catalysts and biomass-derived solvents
-
High yields of HMF from glucose can be achieved using biomass-derived solvents and a combination of solid Lewis and Bronsted catalysts in a salt-free reaction system. The HMF produced in this system can be oxidized to FDCA or hydrogenated to DMF, both being high-value chemicals.
- Gallo, Jean Marcel R.,Alonso, David Martin,Mellmer, Max A.,Dumesic, James A.
-
-
Read Online
- Facile and Inexpensive Synthesis of 4-Oxoalkanoic Acids from Primary Nitroalkanes and Acrolein
-
4-Oxoalkanoic acids, useful organic compounds, are easily prepared by conjugate addition of primary aliphatic nitro compounds to acrolein on alumina surface, in the absence of a solvent, and subsequent oxidation with hydrogen peroxide/potassium carbonate.
- Ballini, Roberto,Petrini, Marino
-
-
Read Online
- Free-Radical Carbocyanation of Olefins
-
The free-radical three-component carbocyanation of electron-rich olefins was investigated with p-tosyl cyanide as cyanide source. The scope and limitations of the process were established by varying the nature of the alkene and radical precursor. Carbocyanation of chiral allylsilanes was shown to occur with high diastereocontrol, leading to syn β-silyl nitriles. The origin of the stereocontrol was rationalized by a Felkin–Anh-type transition-state model. Finally, a tin-free carbocyanation process was also devised, based on the use of a new alkylsulfonyl cyanide incorporating both carbon fragments to be added across the olefinic π system.
- Hassan, Haitham,Pirenne, Vincent,Wissing, Maren,Khiar, Chahinaz,Hussain, Ashique,Robert, Frédéric,Landais, Yannick
-
-
Read Online
- An Efficient Approach to β-Oxoadipate Derivatives and γ-Oxo Acids by the Reformatsky Reaction of Ethyl α-Bromoalkanoates with Succinic Anhydride
-
Ethyl 2-bromoalkanoates react with zinc and succinic anhydride in dimethylformamide forming 2-substituted 1-ethyl hydrogen 3-oxoadipates (hexanedioates) isolable in a yield of 56 - 78percent.When subjected to decarboxylative saponification, they afford 4-oxoalkanoic acids in overall yields of 50 - 72percent
- Schick, Hans,Ludwig, Ralf
-
-
Read Online
- A FACILE SYNTHESIS OF 4-OXO CARBOXYLIC ACIDS FROM γ-BUTYROLACTONE
-
An efficient, high-yield, three-step preparation of 4-oxo carboxylic acids from γ-butyrolactone via silylation and reaction with a Grignard reagent is presented.
- Fuentes, Lelia M.,Larson, Gerald L.
-
-
Read Online
- Asymmetric synthesis of 2-alkyl-substituted 2-hydroxyglutaric acid γ-lactones
-
3-Alkyl-1,2-cyclopentanediones 1 are transformed into 2-alkyl-2-hydroxyglutaric acid γ-lactones 3 in up to 83% isolated yields and up to 96% ee, affording a simple access to many bioactive compounds, including diacylglycerol lactones (DAG-lactones).
- Paju, Anne,Laos, Marit,J?gi, Artur,P?ri, Malle,J??laid, Raissa,Pehk, T?nis,Kanger, T?nis,Lopp, Margus
-
-
Read Online
- Chemoselective formation of cyclo-aliphatic and cyclo-olefinic 1,3-diolsviapressure hydrogenation of potentially biobased platform molecules using Kn?lker-type catalysts
-
The hydrogenative conversions of the biobased platform molecules 4-hydroxycyclopent-2-enone and cyclopentane-1,3-dione to their corresponding 1,3-diols are established using a pre-activated Kn?lker-type iron catalyst. The catalyst exhibits a high selectivity for ketone reduction, and does not induce dehydration. Moreover, by using different substituents of the ligand, thecis-transratio of the products can be affected substantially. A decent compatibility of this catalytic system with various structurally related substrates is demonstrated.
- Alsters, Paul L.,Chou, Khi Chhay,De Wildeman, Stefaan M. A.,Faber, Teresa,Hadavi, Darya,Han, Peiliang,Quaedflieg, Peter J. L. M.,Schwalb Freire, Alfonso J.,Verzijl, Gerard K. M.,van Slagmaat, Christian A. M. R.
-
supporting information
p. 10102 - 10112
(2021/08/03)
-
- Stereoselective Synthesis of Polysubstituted Tetrahydropyranones via Acid-Promoted Cyclization of β-Silyl-γ-ethylidene-γ-butyrolactones with Aldehydes and Ketones
-
β-Silyl-γ-ethylidene-γ-butyrolactone upon one-pot treatment with aldehydes and ketones in the presence of Lewis acids underwent a tandem Hosomi-Sakurai/Prins cyclization to give polysubstituted tetrahydropyranones stereoselectively. Various aldehydes and ketones can be used in this reaction to produce the corresponding tetrahydropyranones. The optical purity of the starting γ-butyrolactone was substantially retained in the resulting tetrahydropyranones.
- Ariyoshi, Shoma,Sakaguchi, Kazuhiko,Nishimura, Takahiro
-
p. 11884 - 11894
(2021/09/02)
-
- Palladium(II)-Catalyzed C(sp 3)-H Activation of N,O-Ketals towards a Method for the β-Functionalization of Ketones
-
A method for the formal β-functionalization of aliphatic ketones via a palladium-catalyzed sp 3 C-H activation pathway is reported. An N,O-ketal directs an aliphatic C-H carbonylation to form γ-lactams which upon hydrolysis generate γ-keto carb
- Ho, Danny K.H.,Calleja, Jonas,Gaunt, Matthew J.
-
p. 454 - 458
(2019/02/26)
-
- Aerobic cascade oxidation of substituted cyclopentane-1,2-diones using metalloporphyrin catalysts
-
A method for the aerobic cascade oxidation of cyclopentane-1,2-diones using metal porphyrins as catalysts, yielding hydroxydiacids 2, ketoacid 3 and diketoacids 4 which are the intermediates of important biologically active compounds is reported. This method is operationally simple and can be employed under ambient conditions.
- Maljutenko, Karolin,Borovkov, Victor,Kananovich, Dzmitry,J?rving, Ivar,Lopp, Margus
-
p. 661 - 664
(2018/01/05)
-
- Photolysis and photocatalysis of ibuprofen in aqueous medium: Characterization of by-products via liquid chromatography coupled to high-resolution mass spectrometry and assessment of their toxicities against Artemia Salina
-
The degradation of the pharmaceutical compound ibuprofen (IBP) in aqueous solution induced by direct photolysis (UV-A and UV-C radiation) and photocatalysis (TiO2/UV-A and TiO2/UV-C systems) was evaluated. Initially, we observed that whereas photocatalysis (both systems) and direct photolysis with UV-C radiation were able to cause an almost complete removal of IBP, the mineralization rates achieved for all the photodegradation processes were much smaller (the highest value being obtained for the TiO 2/UV-C system: 37.7%), even after an exposure time as long as 120 min. Chemical structures for the by-products formed under these oxidative conditions (11 of them were detected) were proposed based on the data from liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) analyses. Taking into account these results, an unprecedented route for the photodegradation of IBP could thus be proposed. Moreover, a fortunate result was achieved herein: tests against Artemia salina showed that the degradation products had no higher ecotoxicities than IBP, which possibly indicates that the photocatalytic (TiO2/UV-A and TiO2/UV-C systems) and photolytic (UV-C radiation) processes can be conveniently employed to deplete IBP in aqueous media. Copyright
- Da Silva, Julio Cesar Cardoso,Teodoro, Janaina Aparecida Reis,Afonso, Robson Jose De Cassia Franco,Aquino, Sergio Francisco,Augusti, Rodinei
-
p. 145 - 153
(2014/02/14)
-
- IMIDAZOPYRIDINE COMPOUND
-
The present invention provides an imidazopyridine compound represented by formula (I), wherein R1 and R2 each independently represent a C1-6 alkyl group et al; R3 and R4 each independently represent a hydrogen atom, a methyl et al; Ar1 is a divalent substituent representing a monocyclic or bicyclic, 3- to 8-membered aromatic or aliphatic heterocyclic group et al; Ar2 represents an aromatic carbocyclic group, or an aromatic heterocyclic group; W represents -(CH2)m et al, and m indicates an integer of from 0 to 10. This compound acts as a melanin concentrating hormone receptor antagonist, and is useful as treating agents for obesity.
- -
-
Page/Page column 58
(2008/06/13)
-
- A simple synthesis of α-methyl-γ-keto acids
-
The reaction of the anion derived from α-marpholinonitriles with methyl acrylate in excess of NaH in DMF gives γ-keto acids in high yield. This process is highly convenient for the synthesis of various α-substituted-γ-keto acids, which can be easily converted to naturally occurring α-substituted -γ-lactones.
- Pawar,Waghmare,Lokhande
-
p. 2549 - 2551
(2007/10/03)
-
- Superoxide ion induced oxidation of γ-lactones to γ-ketocarboxylic acids
-
γ-Ketocarboxylic acids have been achieved in reasonably good yield from their corresponding lactones under the significantly mild reaction conditions of in situ generated tetraethylammonium superoxide.
- Singh,Verma,Singh
-
p. 4471 - 4475
(2007/10/03)
-
- Method for preparing chiral diphosphines
-
The invention concerns a method for preparing a compound of formula (1) wherein: A represents naphthyl or phenyl optionally substituted; and Ar1, Ar2independently represent a saturated or aromatic carbocyclic group, optionally substituted.
- -
-
-
- A simple oxidation of γ- and δ-lactones to oxocarboxylic acids by buffered sodium hypochlorite
-
An efficient synthetic procedure is described for the preparation of 4- and 5-oxocarboxylic acids by reaction of the corresponding lactones with commercial bleach.
- D'Ambrosio, Michele,Guerriero, Antonio
-
p. 631 - 633
(2007/10/03)
-
- Asymmetric hydrogenation method of a ketonic compound and derivative
-
The present invention relates to a process for the asymmetric hydrogenation of a ketonic compound and derivative. The invention relates to the use of optically active metal complexes as catalysts for the asymmetric hydrogenation of a ketonic compound and derivative. The process for the asymmetric hydrogenation of a ketonic compound and derivative is characterized in that the asymmetric hydrogenation of said compound is carried out in the presence of an effective amount of a metal complex comprising as ligand an optically active diphosphine corresponding to one of the following formulae: STR1
- -
-
-
- Pheromone synthesis, CLXXVIII: Synthesis of (-)-exo-isobrevicomin and its (-)-endo isomer, the components of the male-produced volatiles of the mountain pine beetle, Dendroctonus ponderosae
-
(-)-exo-Isobrevicomin {(1S,5R,7S)-(-)-5-ethyl-7-methyl-6,8-dioxabicyclo[3.2.1]octane (1)} and its (-)-endo isomer [(1S,5R,7R)-2] were synthesized by employing the acetylenic acetal 7 as the common intermediate and by using the Sharpless asymmetric dihydro
- Mori, Kenji,Takikana, Hirosato,Nishimura, Yutaka,Horikiri, Hiromasa
-
p. 327 - 332
(2007/10/03)
-
- Process for preparation of 4- and 5-ketocarboxylic acids
-
This invention is a novel synthesis of 4-and 5-ketocarboxylic acids which includes the reaction of the appropriate delta- or gamma-lactone with a chromosulfuric acid solution and separating the 4- or 5-ketocarboxylic acid product from the reduced solution.
- -
-
-
- A one-pot synthesis of racemic and enantiomeric γ-butyrolactones
-
Borinate esters 4, derived from the hydroboration of homoallylic alcohols 2 were oxidized with chromic acid to provide a one-pot synthesis of the racemic and enantiomeric γ-butyrolactones (2-oxotetrahydrofurans) 3.
- Mandal,Mahajan
-
p. 311 - 313
(2007/10/02)
-
- Efficient Oxidation of Phenyl Groups to Carboxylic Acids with Ruthenium Tetraoxide. A Simple Synthesis of (R)-γ-Caprolactone, the Pheromone of Trogoderma granarium
-
The oxidation of aromatic rings to carboxylic acids with ruthenium tetraoxide is shown to be a very efficient and simple reaction using periodic acid as the stoichiometric oxidant in a biphasic solvent system (CCl4, CH3CN, H2O).The reaction can be very sensitive to the nature of the ring substituents when more than one aromatic ring is present.The procedure is compatible with other functional groups except for those that are quite acid sensitive.A simple synthesis of (R)-γ-caprolactone employs Sharpless asymmetric epoxidation and the presented oxidation procedure as key steps.
- Nunez, M. Teresa,Martin, Victor S.
-
p. 1928 - 1932
(2007/10/02)
-
- Regio- and Stereoselective Ring Opening of ω-Alkenyllactones Using Organocopper Reagents
-
New synthetic methods are described for the preparation of (E)-3, (E)-4, and (E)-5-alkenoic acids by the regio- and stereoselective ring opening of β, γ, and δ-lactones with unsaturated substituents at the ω-position using organocopper reagents such as halomagnesium diorganocuprates or Grignard reagents in the presence of copper(I) iodide.Both the organocopper reagents with primary, secondary, tertiary alkyl, and phenyl groups gave the corresponding carbon homologated alkenoic acids in good yields.Alkadienoic acids were also obtained in good yields by the reactions of ω-alkenyllactones with divinyl- and diallylcuprates.Utilizing the ring opening of β-isopropenyl-β-propiolactone, homoterpenoid carboxylic acids were easly obtained in good yields.The ring opening of β-(1-chlorovinyl)-β-propiolactone afforded 4-chloro-3-alkenoic acids which were easly transformed to 4-oxoalkanoic acids and 4-oxo-2-alkenoic acids.
- Kawashima, Masatoshi,Sato, Toshio,Fujisawa, Tamotsu
-
p. 3255 - 3264
(2007/10/02)
-
- A Synthesis of 4-Oxo Carboxylic Acids, 4-Oxo Aldehydes, and 1,4-Diketones from γ-Lactones
-
The α-methyldiphenylsilyl derivatives of γ-butyrolactone, γ-valerolactone, and the cis lactone of 2-hydroxycyclohexaneacetic acid have been reacted with Grignard reagents.The α-silylated lactones of γ-butyrolactone and γ-valerolactone react with a single equivalent of Grignard reagent to give a 2-substituted 4,5-dihydrofuran, which can be hydrolyzed and oxidized to 4-oxo carboxylic acids, 1,4-diketones, or 4-oxo aldehydes.The α-silylated fused lactone failed to react with ethylmagnesium bromide in refluxing tetrahydrofuran.An X-ray crystal structure of this silylated lactone indicated that this lack of reactivity is due to steric factors.
- Betancourt de Perez, Rosa M.,Fuentes, Lelia M.,Larson, Gerald L.,Barnes, Charles L.,Heeg, Mary Jane
-
p. 2039 - 2043
(2007/10/02)
-
- A CONVENIENT METHOD FOR THE SYNTHESIS OF 4-CHLORO-3-ALKENOIC ACID, A NEW USEFUL SYNTHETIC BLOCK FOR 4-OXOALKANOIC AND 4-OXO-2-ALKENOIC ACIDS
-
Easily available material, β-(1-chlorovinyl)-β-propiolactone reacted with organocopper reagents to afford 4-chloro-3-alkenoic acids in high yields.The acids were easily transformed into two kinds of useful carboxylic acids such as 4-oxoalkanoic and 4-oxo-(E)-2-alkenoic acids leading to various natural products.
- Kawashima, Masatoshi,Fujisawa, Tamotsu
-
p. 1851 - 1854
(2007/10/02)
-
- On the Oxygenation of Several Aromatic and Aliphatic Compounds with Aqueous Ferrous Ion-molecular Oxygen
-
Hydroxylation was shown to occur readily in the reactions of aromatic compounds siuch as benzoic acid, nitrobenzene, acetanilide, and phenol with ferrous ion-molecular oxygen in 0.5M phosphate buffer (pH 6.8) at 40 deg C for 3 h.The yields of hydroxylated products were higher than those obtained with other reported hydroxylation systems of transition metal-molecular oxygen.The NIH shift was not observed in the title reactions of C(4)-deuterioacetanilide and C(4)-deuteriobenzoic acid.This system was also demonstrated to oxygenate caproic acid to give a mixture of 3-, 4-, and 5-oxocaproic acids in 67percent total yield. Keywords ---- hydroxylation of aromatic compound; ferrous ion; molecular oxygen; benzoic acid; nitrobenzene; acetanilide; phenol; NIH shift; oxygenation of caproic acid; GC-MS of methyl oxocaproate
- Miura, Toshiaki,Shibata, Kunihiko,Adachi, Kenichi,Sawaya, Takuji,Kimura, Michiya
-
p. 100 - 105
(2007/10/02)
-
- Synthesis of Racemates and (+)-Enantiomers of γ-Caprolactone, γ-Dodecanolactone and δ-Hexadecanolactone, Lactonic Sex Pheromones of the Dermestid Beetle, Rove Beetle and Oriental Hornet
-
A simple method based on regioselective two-step alkylation of easily-available diethyl 3-oxoglutarate (2) is described for the synthesis of racemates of the lactonic pheromones, 1a, 1b, and 1c.Their (+)-enantiomers were also synthesized by means of microbiological reduction of the intermediary keto acids.
- Naoshima, Yoshinobu,Ozawa, Hiroshi,Kondo, Hirokiyo,Hayashi, Shuichi
-
p. 1431 - 1434
(2007/10/02)
-