22818-40-2Relevant articles and documents
A Facile Method for the Production of D-p-Hydroxyphenylglycine. Asymmetric Transformation of DL-p-Hydroxyphenylglycine Using (+)-1-Phenylethanesulfonic Acid
Yoshioka, Ryuzo,Tohyama, Masanori,Yamada, Shigeki,Ohtsuki, Osamu,Chibata, Ichiro
, p. 4321 - 4324 (1987)
A practical method for the production of D-p-hydroxyphenylglycine, useful as a starting material for preparing semisynthetic penicillins or cephalosporins, has been developed.The diastereomeric salts of DL-p-hydroxyphenylglycine with (+)-1-phenylethanesulfonic acid as a resolving agent, were efficiently resolved into less soluble D-p-hydroxyphenylglycine (+)-1-phenylethanesulfonate and soluble L-HPG * (+)-PES by the fractional crystallization of its salts in aqueous solution.The soluble L-HPG * (+)-PES could be easily epimerized into DL-HPG * (+)-PES by heating it with water containing a 0.1 molar equivalent of free DL-HPG in an autoclave.When the fractional crystallization of DL-HPG with (+)-PES was simultaneously carried out under the epimerizing conditions, the DL-HPG * (+)-PES was transformed into D-HPG * (+)-PES in up to 90percent yield.The present asymmetric transformation should be a suitable method for preparing D-HPG in a large scale.
The Optical Resolution and Asymmetric Transformation of DL-p-Hydroxyphenylglycine with (+)-1-Phenylethanesulfonic Acid
Yoshioka, Ryuzo,Tohyama, Masanori,Ohtsuki, Osamu,Yamada, Shigeki,Chibata, Ichiro
, p. 649 - 652 (1987)
Optically active 1-phenylethanesulfonic acid was found to be an efficient resolving agent for the optical resolution and asymmetric transformation of DL-p-hydroxyphenylglycine.When DL-p-hydroxyphenylglycine was resolved by the fractional crystallization of its diastereomeric salt with (+)-1-phenylethanesulfonic acid, less soluble D-p-hydroxyphenylglycine (+)-1-phenylethanesulfonate was obtained in a good yield.Soluble L-HPG*(+)-PES was easily epimerized into DL-HPG*(+)-PES by heating it at 100 deg C in glacial acetic acid in the presence of a small amount of salicylaldehyde.Under such epimerizing conditions, the asymmetric transformation of DL-HPG*(+)-PES was attempted by simultaneously combining the fractional crystallization of the less soluble D-HPG*(+)-PES and the epimerization of the soluble L-HPG*(+)-PES.This asymmetric tranformation was achieved succesfully; that is, 80percent of the DL-HPG used as the starting material was converted into D-HPG.
RETRACTED ARTICLE: Chemoenzymatic Method for Enantioselective Synthesis of (R)-2-Phenylglycine and (R)-2-Phenylglycine Amide from Benzaldehyde and KCN Using Difference of Enzyme Affinity to the Enantiomers
Kawahara, Nobuhiro,Asano, Yasuhisa
, p. 5014 - 5020 (2018)
In general, enzymatic and chemoenzymatic methods for asymmetric synthesis of α-amino acids are performed using highly enantioselective enzymes. The enzymatic reactions using α-aminonitrile as a starting material have been performed using reaction conditions apart from the chemical Strecker synthesis. We developed a new chemoenzymatic method for the asymmetric synthesis of α-amino acids from aldehydes and KCN by performing Strecker synthesis and nitrilase reaction in the same reaction mixture. Nitrilase AY487533 that showed rather low enantioselectivity in hydrolysis of 2-phenylglycinonitrile (2PGN) to 2-phenylglycine (2PG) was utilized in the hydrolysis of aminonitrile formed from benzaldehyde and KCN via 2PGN by Strecker synthesis, preferentially synthesizing (R)-2PG with more than 95 % yield and enantiomeric excess (ee). The method was also utilized for the synthesis of (R)-2-phenylglycine amide ((R)-2PGNH2) from benzaldehyde and KCN by the chemoenzymatic reaction in the presence of a mutated nitrilase AY487533W186A, which catalyzes the conversion of 2PGN to 2PGNH2.
Highly Stable Zr(IV)-Based Metal-Organic Frameworks for Chiral Separation in Reversed-Phase Liquid Chromatography
Jiang, Hong,Yang, Kuiwei,Zhao, Xiangxiang,Zhang, Wenqiang,Liu, Yan,Jiang, Jianwen,Cui, Yong
supporting information, p. 390 - 398 (2021/01/13)
Separation of racemic mixtures is of great importance and interest in chemistry and pharmacology. Porous materials including metal-organic frameworks (MOFs) have been widely explored as chiral stationary phases (CSPs) in chiral resolution. However, it remains a challenge to develop new CSPs for reversed-phase high-performance liquid chromatography (RP-HPLC), which is the most popular chromatographic mode and accounts for over 90% of all separations. Here we demonstrated for the first time that highly stable Zr-based MOFs can be efficient CSPs for RP-HPLC. By elaborately designing and synthesizing three tetracarboxylate ligands of enantiopure 1,1′-biphenyl-20-crown-6, we prepared three chiral porous Zr(IV)-MOFs with the framework formula [Zr6O4(OH)8(H2O)4(L)2]. They share the same flu topological structure but channels of different sizes and display excellent tolerance to water, acid, and base. Chiral crown ether moieties are periodically aligned within the framework channels, allowing for stereoselective recognition of guest molecules via supramolecular interactions. Under acidic aqueous eluent conditions, the Zr-MOF-packed HPLC columns provide high resolution, selectivity, and durability for the separation of a variety of model racemates, including unprotected and protected amino acids and N-containing drugs, which are comparable to or even superior to several commercial chiral columns for HPLC separation. DFT calculations suggest that the Zr-MOF provides a confined microenvironment for chiral crown ethers that dictates the separation selectivity.
Efficient synthesis of cefadroxil in [Bmim][NTf2]-phosphate cosolvent by magnetic immobilized penicillin G acylase
Zhaoyu, Zheng,Chunmiao, Hu,Chuanhu, Du,Ping, Xue,Weiwei, Zhang
, p. 1649 - 1657 (2019/11/03)
For the first time, cefadroxil was synthesized from 7-Amino-3-desacetoxycephalosporanic acid and d-hydroxyphenylglycine methyl ester in [Bmim][NTf2]-phosphate cosolvent capable of dissolving the substrates using the penicillin G acylase (PGA) immobilized on the micrometer-size magnetic polymer microspheres having high activity of 2,083 U/g. The high synthesis/hydrolysis (S/H) ratio of 1.12 was achieved with 79.0% yield, where only the S/H ratio of 0.19 and yield of 20.0% was obtained using free PGA under the identical optimum reaction conditions. Cefadroxil had been synthesized efficiently in [Bmim][NTf2]-phosphate cosolvent by the magnetic immobilized PGA, which illuminated that there are two very critical and essential designs, that is, effective support and suitable solvent system by PGA, in enzymatic synthesis of cefadroxil. Obviously, there is great potential for the magnetic immobilized PGA and ionic liquid solvent in application to biocatalysis.
