5856-63-3Relevant academic research and scientific papers
Biochemical and Structural Characterization of an (R)-Selective Transaminase in the Asymmetric Synthesis of Chiral Hydroxy Amines
Li, Fulong,Liang, Youxiang,Wei, Yuwen,Zheng, Yukun,Du, Yan,Yu, Huimin
supporting information, p. 4582 - 4589 (2021/08/07)
An (R)-selective transaminase RbTA with excellent stereoselectivity (>99% ee) in the asymmetric amination of hydroxy ketones was identified. Biochemical characterization showed that RbTA exhibited the highest activity toward 4-hydroxy-2-butanone among reported enzymes, and that it has broad substrate specificity, including for aliphatic, aromatic, and alicyclic ketones. Crystallization of RbTA were performed, as were molecular docking and mutagenesis studies. Residue Tyr125 plays a key role in substrate recognition by forming a hydrogen bond with hydroxy ketone. The applicability of the enzyme was determined in preparative-scale synthesis of (R)-3-amino-1-butanol, demonstrating the potential of RbTA as a green biocatalyst for production of value-added chiral hydroxy amines. This study provides an efficient tool for enzymatic synthesis of chiral hydroxy amines, as well as structural insight into substrate recognition by transaminases in the asymmetric amination of hydroxy ketones. (Figure presented.).
Design, Synthesis, Fungicidal Activity, and Unexpected Docking Model of the First Chiral Boscalid Analogues Containing Oxazolines
Li, Shengkun,Li, Dangdang,Xiao, Taifeng,Zhang, Shasha,Song, Zehua,Ma, Hongyu
, p. 8927 - 8934 (2016/12/07)
Chirality greatly influences the biological and pharmacological properties of a pesticide and will contribute to unnecessary environmental loading and undesired ecological impact. No structure and activity relationship (SAR) of enantiopure succinate dehydrogenase inhibitors (SDHIs) was documented during the structure optimization of boscalids. On the basis of commercial SDHIs, oxazoline natural products, and versatile oxazoline ligands in organic synthesis, the first effort was devoted to explore the chiral SDHIs and the preliminary mechanism thereof. Fine-tuning furnished chiral nicotinamides 4ag as a more promising fungicidal candidate against Rhizoctonia solani, Botrytis cinerea, and Sclerotinia sclerotiorum, with EC50 values of 0.58, 0.42, and 2.10 mg/L, respectively. In vivo bioassay and molecular docking were investigated to explore the potential in practical application and plausible novelty in action mechanism, respectively. The unexpected molecular docking model showed the different chiral effects on the binding site with the amino acid residues. This chiral nicotinamide also featured easy synthesis and cost-efficacy. It will provide a powerful complement to the commercial SDHI fungicides with the introduction of chirality.
Efficient continuous kinetic resolution of racemic 2-aminobutanol over immobilized penicillin G acylase
Wang, Jianxin,Liu, Na,Cheng, Xiaobo,Chen, Ligong
supporting information, p. 956 - 962 (2016/07/07)
In this paper, an efficient method was established for continuous kinetic resolution of racemic 2-aminobutanol by selective hydrolysis of N-phenylacetyl (±)-2-aminobutanol over immobilized penicillin G acylase (PGA) in a fixed-bed reactor. Several N-acylated derivatives of 2-aminobutanol were screened in batch experiments, and it was found that the hydrolysis of N-phenylacetyl (±)-2-aminobutanol proceeded smoothly in the presence of immobilized penicillin G acylase with satisfied enantioselectivity. Thus, the reaction parameters were optimized in a fixed-bed reactor. Under the optimized conditions, 39.3% conversion of N-phenylacetyl (±)-2-aminobutanol and 98.2% ee value of S-2-aminobutanol were obtained. This fixed-bed system was operated continuously for 40?h without significant decrease of enzyme activity. It has been demonstrated to be more efficient compared to the batch experiments.
Preparation, characterization and performance evaluation of separation of alcohol using crosslinked membrane materials
Ingole, Pravin G.,Thakare, Neha R.,Kim, Keehong,Bajaj, Hari C.,Singh, Kripal,Lee, Hyungkeun
, p. 4018 - 4024 (2013/12/04)
In the present study the glutaraldehyde-crosslinked chitosan membrane (GXCM) was prepared and chiral resolution of (R,S)-2-amino-1-butanol (2A1B) was performed. The membrane was analyzed by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) for its chemical composition. The morphology of the membrane was studied by Scanning Electron Microscopy (SEM) and correlated with membrane performance. The performance of the GXCM membrane was quantified by performing chiral resolution of (R,S)-2-amino-1-butanol in pressure driven separation and the influences of permeation parameters such as operating pressure, concentration of feed solutions, concentration of copper(ii) ions were investigated to understand the chiral selectivity of the membrane. The optical resolution of (R,S)-2-amino-1-butanol racemic mixture, 92% of enantiomeric excess (% ee) was achieved. The separation ability of the above crosslinked membrane was also investigated, and a separation factor of up to 5.6 was achieved.
Synthesis of imidacloprid derivatives with a chiral alkylated imidazolidine ring and evaluation of their insecticidal activity and affinity to the nicotinic acetylcholine receptor
Nishiwaki, Hisashi,Kuriyama, Mituhiro,Nagaoka, Hikaru,Kato, Akira,Yamauchi, Satoshi,Shuto, Yoshihiro,Akamatsu, Miki
, p. 6305 - 6312,8 (2012/12/11)
A series of imidacloprid (IMI) derivatives with an alkylated imidazolidine ring were asymmetrically synthesized to evaluate their insecticidal activity against adult female housefly, Musca domestica, and affinity to the nicotinic acetylcholine receptor of the flies. The bulkier the alkyl group, the lower was the receptor affinity, but the derivatives methylated and ethylated at the R-5-position of the imidazolidine ring were equipotent to the unsubstituted compound. Quantitative structure-activity relationship (QSAR) analysis of the receptor affinity demonstrated that the introduction of a substituent into the imidazolidine ring was fundamentally disadvantageous, but the introduction of a substituent at the R-5-position was permissible in the case of its small size. The binding model of the synthesized derivatives with the receptor supported the QSAR analysis, indicating the existence of space for a short alkyl group around the R-5-position in the ligand-binding site. In addition, positive correlation was observed between the insecticidal activity and receptor affinity, suggesting that the receptor affinity was the primary factor in influencing the insecticidal activity even if the imidazolidine ring was modified.
A mild and highly efficient synthesis of chiral N-dichloroacetyl-4-ethyl-1, 3-oxazolidines
Zhao, Li-Xia,Fu, Ying,Ye, Fei,Gao, Shuang
, p. 943 - 946 (2012/11/07)
Chiral 2-amino-butanols (4 and 5) were obtained via the isolation of diastereomeric salt. Then, chiral compounds (6-9) were synthesized by a sequential procedure involving condensation of chiral 2-amino-butanol with ketone and dichloroacetyl chloride. All the compounds were characterized by IR, 1H NMR, 13C NMR, and element analysis. The absolute configurations of (S)-8 was determined by X-ray crystallography.
Enantiopure cyclic O-substituted phenylphosphonothioic acid: Synthesis and chirality-recognition ability
Ribeiro, Nigel,Kobayashi, Yuka,Maeda, Jin,Saigo, Kazuhiko
experimental part, p. 438 - 448 (2012/01/02)
As a new acidic selector (resolving agent), we synthesized an enantiopure O-alkyl phenylphosphonothioic acid with a seven-membered ring ((R)-5), which was designed on the basis of the results for the enantioseparation of 1-arylethylamine derivatives with acyclic O-ethyl phenylphosphonothioic acid (I). The phosphonothioic acid (R)-5 showed unique chirality-recognition ability in the enantioseparation of 1-naphthylethylamine derivatives, aliphatic secondary amines, and amino alcohols; the ability was complementary to that of I. The X-ray crystallographic analyses of the less- and more-soluble diastereomeric salts showed that hydrogen-bonding networks in the salt crystals are 21-column-type with a single exception which is cluster-type. In the cases of the 21-column-type crystals, stability of the crystals is firstly governed by hydrogen bonds to form a 21-column and secondly determined by intra-columnar T-shaped CH/π interaction(s), intra-columnar hydrogen bond(s), inter-columnar van der Waals interaction and/or inter-columnar T-shaped CH/π interaction(s). In contrast, the cluster-type salt crystal is stabilized by the assistance of inter-cluster T-shaped CH/π and van der Waals interactions. To realize still more numbers of intra- and inter-columnar and -cluster T-shaped CH/π interactions, the seven-membered ring of (R)-5 plays a considerable role. Copyright
COMPOSITIONS AND METHODS FOR CYCLOFRUCTANS AS SEPARATION AGENTS
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Page/Page column 45-49; 59, (2010/12/31)
The present invention relates to derivatized cyclofructan compounds, compositions comprising derivatized cyclofructan compounds, and methods of using compositions comprising derivatized cyclofructan compounds for chromatographic separations of chemical species, including enantiomers. Said compositions may comprise a solid support and/or polymers comprising derivatized cyclofructan compounds.
Optical resolution reagent and manufacturing method of optically active amines that uses it
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Page/Page column 20-21, (2008/06/13)
PROBLEM TO BE SOLVEDTo provide an effective reagent for optical resolution which produce an optically active amines by resolving the (+/-)-amines and the method for producing the optically active amines characterized by using the same reagent. SOLUTION The O-alkylthiophosphoric acid represented as the following formula (1) is effective for the optical resolution of various amines.
Direct Organocatalytic Asymmetric α-Chlorination of Aldehydes
Halland, Nis,Braunton, Alan,Bachmann, Stephan,Marigo, Mauro,Jorgensen, Karl Anker
, p. 4790 - 4791 (2007/10/03)
The direct organocatalytic enantioselective α-chlorination of aldehydes has been developed. The reaction proceeds for a series of different aldehydes with NCS as the chlorine source using easily available catalysts such as L-proline amide and (2R,5R)-diphenylpyrrolidine. The α-chloro aldehydes are obtained in up to 99% yield and up to 95% ee. The synthetic utility of the enantioselective α-chlorination of aldehydes is demonstrated by transformation of the α-chloro aldehydes to the corresponding α-chloro alcohols (>90% yield) by standard reduction and further transformation to both a terminal epoxide and amino alcohol, both obtained without loss of optical purity. Oxidation of the α-chloro aldehydes followed by esterification gave optically active α-chloro esters without loss of optical purity. It is demonstrated that these optically active α-chloro esters can be converted into nonproteinogenic amino acids in overall high yields, maintaining the enantiomeric excess obtained in the catalytic enantioselective α-chlorination step. Copyright
