2852-88-2Relevant 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.
Preparation method of R-(+)-2-(4-hydroxyphenoxy) propionic acid
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Paragraph 0066-0067; 0074-0075; 0079-0080, (2021/05/05)
The invention relates to the technical field of organic synthesis, in particular to a preparation method of R-(+)-2-(4-hydroxyphenoxy) propionic acid. The preparation method provided by the invention comprises the following steps that p-nitrophenol and (S)-(-)-2-chloropropionic acid are subjected to substitution reaction under an alkaline condition to obtain R-(+)-2-(4-nitrophenoxy) propionic acid; the R-(+)-2-(4-nitrophenoxy) propionic acid and H2 are subjected to a reduction reaction under the catalysis condition of a catalyst, and the R-(+)-2-(4-aminophenoxy) propionic acid is obtained; and the R-(+)-2-(4-aminophenoxy) propionic acid and sodium nitrite are subjected to a diazotization hydrolysis reaction under the acidic condition, and the R-(+)-2-(4-hydroxyphenoxy) propionic acid is obtained. The preparation method is simple, easy to obtain and low in cost, and the prepared R-(+)-2-(4-hydroxyphenoxy) propionic acid is high in yield and high in purity.
Preparation method of R-(+)-2-(4-hydroxyphenoxy) propionic acid
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Paragraph 0049-0050; 0053, (2020/12/30)
The invention provides a preparation method of R-(+)-2-(4-hydroxyphenoxy) propionic acid. The preparation method comprises the following steps: under the protection of inert gas, p-nitrophenol is usedas a starting raw material, and p-nitrophenoxy propionic acid is prepared through an etherification reaction; the p-nitrophenoxy propionic acid is reduced by adopting palladium on carbon to prepare p-aminophenoxy propionic acid; the optically pure R-(+)-2-(4-hydroxyphenoxy) propionic acid is prepared by diazotization and hydrolysis reaction of p-aminophenoxy propionic acid. The average yield of the preparation method of R-(+)-2-(4-hydroxyphenoxy) propionic acid is not lower than 85%, and the product purity is 99.5% or above.
Mutual Kinetic Resolution of Racemic 3,4-Dihydro-3-methyl-2H-[1,4]benzoxazines with Acyl Chlorides of Racemic O-Phenyllactic Acids and DFT Modelling of Transition States
Korolyova, Marina A.,Vakarov, Sergey A.,Kozhevnikov, Dmitry N.,Gruzdev, Dmitry A.,Levit, Galina L.,Krasnov, Victor P.
, p. 4577 - 4585 (2018/09/06)
The effect of the electronic nature of the para substituent on the aromatic ring of 2-aryloxypropionyl chlorides on the stereochemical outcome of the acylation of 3,4-dihydro-3-methyl-2H-[1,4]benzoxazine and its 7,8-difluoro-containing analogue has been studied. The geometries of the diastereoisomeric transition states and the corresponding Gibbs free enthalpies of activation were determined through DFT calculations at the COSMO-CH2Cl2-B3LYP-D3-gCP/def2-TZVP (or def2-SVP)//B3LYP-D3-gCP/def2-SVP level of theory. It has been found that a low-cost quantum chemical calculation at a chosen level of theory describes well the quantitative dependence of the selectivity of acylation on the structures of the reagents. The obtained results indicate that aromatic interactions between the reagents play a significant role in the process of stereodifferentiation, ensuring high selectivity of the acylation of benzoxazines with 2-aryloxyacyl chlorides.
Optical resolution of aryloxypropionic acids and their esters by HPLC on cellulose tris-3,5-dimethyl-triphenylcarbamate derivative
Azzolina,Collina,Ghislandi
, p. 1401 - 1416 (2007/10/02)
Chiral chromatographic resolution of a series of antiphlogistic 2- aryloxypropionic acids and their methyl and ethyl esters was performed using a Chiralcel OD column. The CSP selected resolved most of the acids and esters efficiently, the enantiomers being well separated without requiring time consuming analysis. Chromatographic separation of R enriched samples was performed to determine the correct elution order. Using eluting systems such as hexane and 2-propanol, or hexane, 2-propanol and formic acid, the S enantiomer of all acids and esters was always found to elute first. We also considered the role of electron-donating or electron-withdrawing substituents (at the aryloxylic moiety) on the chiral resolution. It was shown that the electronic features of the substituents have more influence on the chiral interactions between the solutes and the CSP than their steric hindrance. Finally we determined, by molecular models, the interaction between CSP and solutes. In this way were able to determine all the potential sites for interactions, which are compatible with the conformations of the compounds and the structure of the stationary phase, and point out those interactions which enable chiral resolution.
