- Chiral ferrocene-imidazole diphosphine ligand as well as synthesis method and application thereof
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The invention relates to a chiral ferrocene-imidazole diphosphine ligand as well as a preparation method and application thereof. The synthesis method comprises the following steps: dissolving ferrocenyl chiral alcohol and N, N '-carbonyldiimidazole, whic
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Paragraph 0047-0051; 0060-0063
(2021/05/22)
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- Iridium/chiral diphosphine system catalyzed imine asymmetric hydrogenation method
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The invention discloses a method for catalyzing asymmetric hydrogenation of imines by an iridium/chiral diphosphine system, which comprises the following steps: reacting a chiral diphosphine ligand with a metal iridium precursor to prepare a complex in situ as a catalyst, and carrying out asymmetric hydrogenation on imines to prepare a chiral amine. The ligand is simple to prepare; catalyst dosage, simple operation, continuous operation can be realized, the preparation method is simple in process and suitable for large-scale preparation of chiral amine, the enantiomeric excess value of the product reaches 80% or above, and the preparation method has is excellent in effect when the S/C (2-ethyl-6-methylaniline/catalyst) rate is 500,000 during synthesis of the s-metolachlor intermediate, theyield reaches 95%, the enantioselectivity reaches 91%, and good industrial practicability is achieved.
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Paragraph 0060-0069; 0084-0089
(2019/12/25)
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- A Novel esterase from Pseudochrobactrum asaccharolyticum WZZ003: Enzymatic properties toward model substrate and catalytic performance in chiral fungicide intermediate synthesis
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Only a few esterases have been used for the synthesis of optically pure fungicide. For example, (R)-metalaxyl synthesized using esterase-involved bioreaction displays fungicide activity, whereas (S)-enantiomer is redundant. However, the biosynthesis of (R
- Cheng, Feng,Cheng, Feifei,Zheng, Jianyong,Wu, Guanzhong,Zhang, Yinjun,Wang, Zhao
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- Optimized Synthetic Route for Enantioselective Preparation of (S)-Metolachlor from Commercially Available (R)-Propylene Oxide
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An enantioselective preparation of (S)-metolachlor has been accomplished. The synthetic route featured the asymmetric preparation of chiral intermediates and the final (S)-metolachlor from commercially available (R)-propylene oxide and a key Fukuyama's process. The key steps, control points, separation purifications, and the whole process are optimized, and the target compound has been successfully prepared in five steps in 51-55% overall yield with excellent enantioselectivity (99% ee) up to a 30 g scale. By judicious choice of synthetic route and selection of starting materials and intermediates, no column chromatographic methods are needed for the separation and purification of the intermediates and the final products. The same strategy was extended as a general method for a series of pesticides and herbicide analogs of Metalaxyl-M and Dimethenamid-P.
- Yang, Peng,Wang, Xiao,Peng, Lin,Chen, Feng,Tian, Fang,Tang, Chao-Zhe,Wang, Li-Xin
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p. 1682 - 1688
(2017/10/25)
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- Enantiomerization and enantioselective bioaccumulation of metalaxyl in tenebrio molitor larvae
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The enantiomerization and enantioselective bioaccumulation of metalaxyl by a single dose of exposure to Tenebrio molitor larvae under laboratory condition were studied by high-performance liquid chromatography tandem mass spectroscopy (HPLC-MS/MS) based on a ChiralcelOD-3R [cellulosetris-tris-(3, 5-dichlorophenyl-carbamate)] column. Exposure of enantiopure R-metalaxyl and S-metalaxyl in Tenebrio molitor larvae exhibited significant enantiomerization, with formation of the R enantiomers from the S enantiomers, and vice versa, which might be attributed to the chiral pesticide catalyzed by a certain enzyme in Tenebrio molitor larvae. Enantiomerization was not observed in wheat bran during the period of 21 d. In addition, bioaccumulation of rac-metalaxyl in Tenebrio molitor larvae was enantioselective with a preferential accumulation of S-metalaxyl. These results showed that enantioselectivity was caused not only by actual degradation and metabolism but also by enantiomerization, which was an important process in the environmental fate and behavior of metalaxyl enantiomers.
- Gao, Yongxin,Wang, Huili,Qin, Fang,Xu, Peng,Lv, Xiaotian,Li, Jianzhong,Guo, Baoyuan
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- N-(Chloroacetyl)- and N-(dichloroacetyl)-N-(xylyl)alanine esters: Assignment of the absolute configurations and enantiodifferentiation by the dirhodium method
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Four chlorinated N-acylalanine methylesters (metalaxyl derivatives) containing either stereogenic centres alone as in 1 and 3 or stereogenic centres plus chiral axes as in 2 and 4 were investigated. The latter have been examined in terms of the absolute c
- Diaz Gomez, Edison,Jios, Jorge,Della Vedova, Carlos O.,March, Hugo D.,Di Loreto, Hector E.,Toth, Gabor,Simon, Andras,Albert, Dieter,Moeller, Stefan,Wartchow, Rudolf,Duddeck, Helmut
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p. 2285 - 2293
(2007/10/03)
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- Enzyme-catalyzed preparation of methyl (R)-N-(2,6-dimethylphenyl)alaninate: A key intermediate for (R)-metalaxyl
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A biocatalytic approach for the production of (R)-metalaxyl, mefenoxam, has been developed. A practical synthesis of methyl (R)-N-(2,6-dimethylphenyl) alaninate, a key intermediate for (R)-metalaxyl, has been developed by the use of lipase-catalyzed hydrolytic kinetic resolution and chemical racemization of the remaining ester. At high concentrations in aqueous media (300 g/L) lipases were stable and gave moderate to good conversions and excellent enantioselectivities (>98% ee). A simple extraction procedure was used to separate the acid product from the remaining ester and the acid was esterified with methanol to give methyl (R)-N-(2,6-dimethylphenyl)alaninate without any reduction in enantiomeric excess (>98% ee). Subsequent chemical coupling with methoxyacetyl chloride provided enantiomerically pure (R)-metalaxyl (>98% ee) without racemization.
- Park, Oh-Jin,Lee, Sang-Hyun,Park, Tae-Yoon,Lee, Sang-Who,Cho, Koon-Ho
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p. 1221 - 1225
(2007/10/03)
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- N-(1'-methyl-2'-methoxyethyl)-N-chloroacetyl-2,6-dimethylaniline as herbicide
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The optically active isomer of S(-)-N-(1'methyl-2'-methoxyethyl)-N-chloroacetyl-2,6-dimethylaniline has improved action against problem weeds over the racemic mixture of isomers.
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