16484-77-8Relevant academic research and scientific papers
HPLC separation of 2-aryloxycarboxylic acid enantiomers on chiral stationary phases
Charushin, V. N.,Chulakov, E. N.,Krasnov, V. P.,Levit, G. L.,Sadretdinova, L. Sh.,Tumashov, A. A.,Vakarov, S. A.
, p. 900 - 907 (2021/06/07)
The possibility for separating enantiomers of a number of practically significant 2-aryloxycarboxylic acids was studied by normal- and reversed-phase HPLC on popular chiral stationary phases. The best separation parameters were achieved on the chiral phases with the polysaccharide base Chiralcel OD-H and Chiralpack AD under the normal-phase HPLC conditions. The (S)- and (R)-enantiomers of 2-(1-naphthyloxy)- and 2-(2-iodophenoxy)propionic acids with enantiomeric excess ee >99% were isolated using preparative chiral HPLC.
Evaluation of the Edman degradation product of vancomycin bonded to core-shell particles as a new HPLC chiral stationary phase
Hellinghausen, Garrett,Lopez, Diego A.,Lee, Jauh T.,Wang, Yadi,Weatherly, Choyce A.,Portillo, Abiud E.,Berthod, Alain,Armstrong, Daniel W.
, p. 1067 - 1078 (2018/08/01)
A modified macrocyclic glycopeptide-based chiral stationary phase (CSP), prepared via Edman degradation of vancomycin, was evaluated as a chiral selector for the first time. Its applicability was compared with other macrocyclic glycopeptide-based CSPs: TeicoShell and VancoShell. In addition, another modified macrocyclic glycopeptide-based CSP, NicoShell, was further examined. Initial evaluation was focused on the complementary behavior with these glycopeptides. A screening procedure was used based on previous work for the enantiomeric separation of 50 chiral compounds including amino acids, pesticides, stimulants, and a variety of pharmaceuticals. Fast and efficient chiral separations resulted by using superficially porous (core-shell) particle supports. Overall, the vancomycin Edman degradation product (EDP) resembled TeicoShell with high enantioselectivity for acidic compounds in the polar ionic mode. The simultaneous enantiomeric separation of 5 racemic profens using liquid chromatography-mass spectrometry with EDP was performed in approximately 3?minutes. Other highlights include simultaneous liquid chromatography separations of rac-amphetamine and rac-methamphetamine with VancoShell, rac-pseudoephedrine and rac-ephedrine with NicoShell, and rac-dichlorprop and rac-haloxyfop with TeicoShell.
A new method for production of chiral 2-aryloxypropanoic acids using effective kinetic resolution of racemic 2-aryloxycarboxylic acids
Tengeiji, Atsushi,Nakata, Kenya,Ono, Keisuke,Shiina, Isamu
, p. 1227 - 1252 (2013/08/23)
We report a novel method for the preparation of 2-aryloxypropanoic acids by kinetic resolution of racemic 2-aryloxypropanoic acids using enantioselective esterification. The usage of pivalic anhydride (Piv2O) as an activating agent, bis(a-naphthyl)methanol ((α-Np)2CHOH) as an achiral alcohol, and (+)-benzotetramisole ((+)-BTM) as a chiral acyl-transfer catalyst enables the effective separation of various racemic 2-aryloxypropanoic acids to afford optically active carboxylic acids and the corresponding esters with high enantioselectivities. Furthermore, theoretical calculations of the transition states required to form the chiral esters successfully proved the enantiomer recognition mechanism of the asymmetric esterification.
Separation of the phenoxy acid herbicides and their enantiomers by capillary zone electrophoresis in presence of highly sulphated cyclodextrins
Malik, Ashok Kumar,Aulakh, Jatinder Singh,Fekete, Agnes,Philippe, Schmitt-Kopplin
experimental part, p. 1163 - 1167 (2010/08/20)
The study of the chiral compounds and their fate in the environment is receiving an increasing attention - enantiomeric ratios are being measured and enantioselective degradation processes are being reported. It is particularly important with the toxic compounds like the pesticides, which are being freely used in the environment to control the harmful pests. Capillary zone electrophoresis was used for the chiral and mutual separation of four phenoxy acid herbicides using highly sulphated cyclodextrins (HSCD) in the buffer. The CE runs were performed with reverse polarity (anode in the outlet vial) using the acidic ammonium formate buffer (20 mmol, pH 3). Under these conditions of suppressed the electroendoosmotic flow (EOF), the analytes are mobilized to the anode by entering into host guest relation with the migrating negatively charged sulphated cyclodextrin. The phenoxy acid herbicides selected for the purpose were fenoprop, dicloprop, mecoprop and 2,4-DB. The α-HSCD and β-HSCD have been tested as resolving agents in the CE for the separation of the enantiomers of the herbicides. Though the chiral separation of the dicloprop and mecoprop were achieved with α-HSCD but it was not able to resolve fenoprop. With β-HSCD the required base line separation was achieved. Potential difference selected was 10 kV. The limit of detection (S/N=3) achieved in present case is 0.15 ppm for fenoprop, 0.14 ppm for dicloprop and mecoprop and 0.11 ppm for 2,4-DB.
π-deficient 2-(arylsulfonyl)ethyl esters as protecting groups for carboxylic acids
Alonso, Diego A.,Nájera, Carmen,Varea, Montserrat
, p. 277 - 287 (2007/10/03)
Several π-deficient 2-(arylsulfonyl)ethyl groups have been studied as carboxylic acid protecting groups. The 2-[3,5-bis(trifluoromethyl)phenylsulfonyl]ethyl group is the most easily removed protecting group for acids under mild basic conditions using aqueous NaHCO3.
Conversion of a hydroxy group in certain alcohols into a fluorosulfonate ester or a trifluoromethylsulfonate ester
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Page column 10, (2010/02/05)
The present invention provides a method of converting a hydroxy group in alcohols containing an electron withdrawing group into perfluoroalkane sulfonate and fluorosulfonate esters, which are good leaving groups, with inversion of configuration where the hydroxyl-bearing carbon is chiral. The method consists of converting an alcohol to an O—N,N-dialkylsulfamate ester and reacting it with a perfluoroalkansulfonic or fluorosulfonic acid. The method has applications in the synthesis of pharmaceutical and agrochemical compounds.
Carboxylic acids and skeletal muscle chloride channel conductance: Effects on the biological activity induced by the introduction of methyl groups on the aromatic ring of chiral α-(4-chloro-phenoxy)alkanoic acids
Ferorelli, Savina,Loiodice, Fulvio,Tortorella, Vincenzo,Conte-Camerino, Diana,De Luca, Anna Maria
, p. 239 - 246 (2007/10/03)
One or two methyl groups have been introduced on the aromatic ring of two chiral clofibric acid analogs, 2-(4-chloro-phenoxy)propanoic and 2-(4-chloro-phenoxy)butanoic acids. The biological activity of the derivatives obtained (3-6) has been evaluated on the skeletal muscle chloride conductance (gCl). The results confirm the hypothesis of two different sites modulating chloride channel function, an excitatory site that increases channel activity and an inhibitory site that produces a channel block. In fact, this chemical modification strongly reduces the blocking activity of the (R)-and (S)-enantiomers in comparison with the parent compounds, but does not markedly affect the ability of the (R)-enantiomers to increase chloride channel conductance.
(R)- and (S)-3-hydroxy-4,4-dimethyl-1-phenyl-2-pyrrolidinone as chiral auxiliaries in the enantioselective preparation of α-aryloxypropanoic acid herbicides and α-chlorocarboxylic acids
Camps, Pelayo,Perez, Francesc,Soldevilla, Nuria
, p. 2065 - 2079 (2007/10/03)
rac-α-Chlorocarboxylic acids, rac-9a-e, were formally deracemized by reaction of the corresponding acyl chlorides with the chiral auxiliaries (R)- and (S)-3-hydroxy-4,4-dimethyl-1-phenyl-2-pyrrolidinone, (R)- and (S)-4, followed by mild alkaline hydrolysis. The highest o.p. (99%) was obtained in the case of (S)-α-chloropropanoic acid, a known precursor for the synthesis of (R)-α-aryloxypropanoic acid herbicides such as dichlorprop-P, (R)-3a, or mecoprop-P, (R)-3b, which, together with their enantiomers, were also obtained in moderate e.e.s by dynamic kinetic resolution from (αRS,3S)-4,4- dimethyl-2-oxo-l-phenylpyrrolidin-3-yl α-bromopropanoate, (αRS,3S)-6, by reaction with the corresponding phenoxide followed by mild acid hydrolysis.
Enzymatic enantioselective ester hydrolysis by carboxylesterase NP
Smeets, J. W. H.,Kieboom, A. P. G.
, p. 490 - 495 (2007/10/02)
The enzymatic hydrolysis of a series of carboxylic esters by carboxylesterase NP has been investigated in order to determine the scope and limitations of this enzyme. 2-Substituted propionates were hydrolyzed with high enantioselectivity when an aromatic moiety was part of the 2-substituent.Enantioselective hydrolysis could be accomplished with several 2-arypropionates, 2-(aryloxy)propionates and N-arylalanine esters.The propionate esters yielded propionic acids as (S) enantiomers, whereas the alanine esters yielded the (R) enantiomers.Without a 2-aryl substituent, the enzymatic hydrolysis of the propionates occurred at a lower rate without acceptable enantioselectivity.In addition to 2-substituted propionates, only a few other esters were hydrolyzed with high enantioselectivity by carboxylesterase NP, such as some prochiral disubstituted malonates. 1-Phenylethylacetate was the only substrate with chirality in the alcohol part of the ester that was found to be hydrolyzed enantioselectively.Carboxylesterase NP proved to be a powerful enzyme for kinetic resolution of propionate esters with an aromatic ring containing a 2-substituent.
Enantioselective Hydrolysis of Aryloxypropionic Esters by Bovine Serum Albumin: Enhancement in Selectivity by β-Cyclodextrin
Kamal, Ahmed,Ramalingam, T.,Venugopal, N.
, p. 39 - 42 (2007/10/02)
Bovine serum albumin catalyzed hydrolysis of racemic aryloxypropionic esters affords appreciable enantioselectivity.The effect of β-cyclodextrin this process of hydrolysis has been studied.
