Metolachlor stereoisomers: Enantioseparation, identification and chiral stability

Xie, Jianhua; Zhang, Lijuan; Zhao, Lu; Tang, Qiaozhi; Li, Kai; Liu, Weiping

doi:10.1016/j.chroma.2016.07.045

Cited by 15 publications

(12 citation statements)

References 13 publications

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Section: Resultsmentioning

confidence: 99%

“…The individual isomers remain unchanged upon storage in solution at 4 °C, C-chirality owing to tetrahedral nitrogen inversion was in thermal equilibrium, and atropisomerism depends on rotation about the phenyl-nitrogen bond whose energy barrier is relatively high, around 37 kcal/mol. 110 VCD was used to assign the stereochemistry of the 4 stereoisomers of a commercial sample of brivaracetam. The AC was confidently assigned as (2S,4'R)−239, (2S,4'S)−240, (2R,4'R)−241, and (2R,4'S)−242 ( Figure 66) without prior knowledge of their relative stereochemistry.…”

Section: Nitrogenated Compoundsmentioning

confidence: 99%

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Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Río

Joseph‐Nathan

2021

Natural Product Communications

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Although demonstrated in 1975, vibrational circular dichroism (VCD) finally started to popularize during this century as a reliable tool to determine the absolute configuration (AC) of organic molecules. This research field continues to be a very dynamic one, in particular for the study of natural products which are a unlimited source of chiral molecules. It therefore turns of interest to summarize the accomplishments published in recent years and to comment on some eventual difficulties that emerged in rare cases to complete the AC determination task. Therefore the aim of this review is to update VCD results for the AC assignment of natural products published from 2015 to 2019, a period in which VCD was reported in some 126 publications involving almost 300 molecules. They are organized according the type of studied metabolite allowing an easily search. The molecules correspond to 28 monoterpenes concerning 17 papers, to 42 sesquiterpenes in 14 papers, to 51 diterpenes in 19 publications, to 5 other terpenoids in three papers, to 48 aromatic molecules in 15 reports, to 20 polyketides in 10 publications, to 27 miscellaneous formulas also in 10 papers, and to 76 nitrogen containing compounds, which include alkaloids and their synthetic analogs, in 38 articles. The landscape of reviewed molecules is quite wide as it goes from simple monoterpenes, like borneol or camphor, to very relevant biological molecules like the alkaloid cocaine or tadalafil samples to distinguish genuine and counterfeit Cialis®. In addition, 5 natural products and a simple derivative published outside the reviewed period, were used to illustrate some aspects of density functional theory calculations.

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Section: Resultsmentioning

confidence: 99%

Section: Nitrogenated Compoundsmentioning

confidence: 99%

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Río

Joseph‐Nathan

2021

Natural Product Communications

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“…Metolachlor[(RS)-2-Chloro-N-(2-ethyl-6-methyl-phenyl)-N-(1-methoxypropan-2-yl)acetamide], has been used as a chloroacetanilide herbicide to control annual grass weeds and broadleaf weeds in corn, cotton, peanuts soybeans and beans [1]. It has the characteristics of strong inhibition and good safety.…”

Section: Introductionmentioning

confidence: 99%

Effect on the characterization of metolachlor polyurea microcapsules with urea instead of polyamines

Liu

Wang

et al. 2019

Designed Monomers and Polymers

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In this paper, a novel metolachlor microcapsules suspension (CS) was prepared by interfacial polymerization. Metolachlor polyurea microcapsules suspension was successfully prepared by urea instead of polyamines which could reduce the use of organic solvents and production costs. The synthesized microcapsules were characterized by Fourier Transform Infrared Spectrometer, Scanning Electron Microscope, Ultraviolet Spectrometry, Thermogravimetric analyses and particle size analyzer. In conclusion, the diameter of the urea microcapsules were the smallest (11.52 μm) and excellent encapsulation efficiency (81.45%). In addition, Urea microcapsules had compact microstructures and global shapes, which had a good thermal stability and metolachlor could be preserved better in the polyurea microcapsules. These results indicated that the prepared microcapsules by urea had better thermal storage properties and physicochemical property. The microcapsule suspension of metolachlor hasn’t been researched yet. Therefore, it is significant to prepare microcapsule suspension. More importantly, there is no use of organic solvents in the preparation of microcapsules suspension, which avoided the pollution of solvents to the ecological environment. It is hoped that this polyurea material will be applied in the field of pesticide synthesis and polymers.

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“…4,5 In comparison with HPLC, the low viscosity and high diffusivity of supercritical fluid allow much higher flow rates, thereby leading to shorter analysis time, lower solvent consumption, and higher efficiency. Chromatographic methods are most popular, including high-performance liquid chromatography (HPLC), gas chromatography, capillary electrochromatography, thin-layer chromatography, and supercritical fluid chromatography (SFC).…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] Among them, HPLC with different chiral stationary phases (CSPs) has become one of the most widely used method for today's enantioseparations because of various inherent advantages such as rapid analysis, reproducibility, and flexibility. 4,5 In comparison with HPLC, the low viscosity and high diffusivity of supercritical fluid allow much higher flow rates, thereby leading to shorter analysis time, lower solvent consumption, and higher efficiency. 6 SFC has emerged as a powerful alternative.…”

Section: Introductionmentioning

confidence: 99%

Enantioseparation of napropamide by supercritical fluid chromatography: Effects of the chromatographic conditions and separation mechanism

et al. 2018

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Supercritical fluid chromatography (SFC) is already used for enantioseparation in the pharmaceutical industry, but it is rarely used for the separation of chiral pesticides. Comparing with high performence liquid chromatography, SFC uses much more environmnetal friendly and economic mobile phase, supercritical CO . In our work, the enantioseparation of an amide herbicide, napropamide, using three different polysaccharide-type chiral stationary phases (CSPs) in SFC was investigated. By studying the effect of different CSPs, organic modifiers, temperature, back-pressure regulator pressures, and flow rates for the enantioseparation of napropamide, we established a rapid and green method for enantioseparation that takes less than 2 minutes: The column was CEL2, the mobile phase was CO with 20% 2-propanol, and the flow rate was 2.0 mL/min. We found that CEL2 demonstrated the strongest resolution capability. Acetonitrile was favored over alcoholic solvents when the CSP was amylose and 2-propanol was the best choice when using cellulose. When the concentration of the modifiers or the flow rate was decreased, resolutions and analysis times increased concurrently. The temperature and back-pressure regulator pressure exhibited only minor influences on the resolution and analysis time of the napropamide enantioseparations with these chiral columns. The molecular docking analysis provided a deeper insight into the interactions between the enantiomers and the CSPs at the atomic level and partly explained the reason for the different elution orders using the different chiral columns.

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Metolachlor stereoisomers: Enantioseparation, identification and chiral stability

Cited by 15 publications

References 13 publications

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Vibrational Circular Dichroism Absolute Configuration of Natural Products From 2015 to 2019

Effect on the characterization of metolachlor polyurea microcapsules with urea instead of polyamines

Enantioseparation of napropamide by supercritical fluid chromatography: Effects of the chromatographic conditions and separation mechanism

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