70630-17-0Relevant articles and documents
METHOD FOR SYNTHESIZING COMPOUND
-
Paragraph 0095-0103, (2021/03/23)
The compound of Chemical Formula 1 and the compound of Formula 2 are used to prepare the compound of Formula 3 (a). The present invention relates to a method for preparing a compound of Formula 3, comprising preparing a compound of Formula ROH and 4 (b) in (a) and Formula 4 obtained in the above step.
Synthesis of magnetic multiwall carbon nanotubes for enantioseparation of three pesticide residues in fruits and vegetables by chiral liquid chromatography
Lei, Shuo,Li, Xianhui,Wang, Yang,Sun, Lirong,Liu, Hao,Zhao, Longshan
, p. 1321 - 1329 (2018/11/03)
In this study, magnetic multiwalled carbon nanotubes (MMWCNTs) were synthesized and used as adsorbent for preconcentration of chiral pesticide residues (including epoxiconazole, tebuconazole, and metalaxyl) in lettuce, cabbage, and apple. Several parameters affecting the treatment efficiency were investigated, including extraction solvent and absorption solvent. Under the optimal conditions, all three chiral pesticides showed decent enantiomeric separation (Rs?>?1.48). The linearity of each target was good with the correlation coefficient (r2) being greater than 0.9923. The average recoveries of the three spiked levels were 73.4% to 110.9% with repeatability (RSDr) less than 7.6%, and the limit of quantification of the method was 0.10 to 0.25?mg·kg?1. The results indicated that MMWCNTs had a good purifying effect, which can be applied as an effective pretreatment tool for the determination of residual chiral pesticides in fruits and vegetables.
Nanocellulose derivative/silica hybrid core-shell chiral stationary phase: Preparation and enantioseparation performance
Zhang, Xiaoli,Wang, Litao,Dong, Shuqing,Zhang, Xia,Wu, Qi,Zhao, Liang,Shi, Yanping
, (2016/06/15)
Core-shell silica microspheres with a nanocellulose derivative in the hybrid shell were successfully prepared as a chiral stationary phase by a layer-by-layer self-assembly method. The hybrid shell assembled on the silica core was formed using a surfactant as template by the copolymerization reaction of tetraethyl orthosilicate and the nanocellulose derivative bearing triethoxysilyl and 3,5-dimethylphenyl groups. The resulting nanocellulose hybrid core-shell chiral packing materials (CPMs) were characterized and packed into columns, and their enantioseparation performance was evaluated by high performance liquid chromatography. The results showed that CPMs exhibited uniform surface morphology and core-shell structures. Various types of chiral compounds were efficiently separated under normal and reversed phase mode. Moreover, chloroform and tetrahydrofuran as mobile phase additives could obviously improve the resolution during the chiral separation processes. CPMs still have good chiral separation property when eluted with solvent systems with a high content of tetrahydrofuran and chloroform, which proved the high solvent resistance of this new material.
Chiral phosphine-phosphoramidite ligands for highly enantioselective hydrogenation of N-arylimines
Li, Qing,Hou, Chuan-Jin,Liu, Xiao-Ning,Huang, De-Zhi,Liu, Yan-Jun,Yang, Rui-Feng,Hu, Xiang-Ping
, p. 13702 - 13708 (2015/02/19)
The asymmetric hydrogenation of N-arylimines with the chiral phosphine-phosphoramidite ligand, (Sc,Sa)-PEAPhos 2b, has been developed. The results revealed that the presence of the substituents on the 3,3′-positions of the binaphthyl backbone significantly improved the enantioselectivity. The utility of this methodology was demonstrated in the synthesis of the chiral fungicide (R)-metalaxyl. This journal is
Enantiomerization and enantioselective bioaccumulation of metalaxyl in tenebrio molitor larvae
Gao, Yongxin,Wang, Huili,Qin, Fang,Xu, Peng,Lv, Xiaotian,Li, Jianzhong,Guo, Baoyuan
supporting information, p. 88 - 94 (2014/03/21)
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.
PROCESSES FOR THE PREPARATION OF SUBSTITUTED ANILINES
-
Page/Page column 8-10, (2011/06/11)
The invention relates to a process for the preparation of compounds of formula (III) wherein R1, R2, R3, R4 and R5 are independently selected from C1-6 alkyl or hydrogen, comprising reacting an aniline of formula (IV) with a carboxylic acid of formula (V) in the presence of a catalyst comprising silica.
Enzyme-catalyzed preparation of methyl (R)-N-(2,6-dimethylphenyl)alaninate: A key intermediate for (R)-metalaxyl
Park, Oh-Jin,Lee, Sang-Hyun,Park, Tae-Yoon,Lee, Sang-Who,Cho, Koon-Ho
, p. 1221 - 1225 (2007/10/03)
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.
Chiral ligands, transition-metal complexes thereof and uses thereof in asymmetric reactions
-
, (2008/06/13)
Chiral ligands and transition metal complexes based on such chiral ligands useful in asymmetric catalysis are disclosed. The chiral ligands include phospholanes, P,N ligands, N,N ligands, biphenols, and chelating phosphines. The ferrocene-based irridium (R,R)-f-binaphane complex reduces imines to the corresponding amines with 95-99.6% enantioselectivity and reduces β-substituted-α-arylenamides with 95% enantioselectivity. The transition metal complexes of the chiral ligands are useful in asymmetric reactions such as asymmetric hydrogenation of imines, asymmetric hydride transfer reactions, hydrosilylation, hydroboration, hydrovinylation, hydroformylation, allylic alkylation, cyclopropanation, Diels-Alder reaction, Heck reaction, isomerization, Aldol reaction, Michael addition and epoxidation reactions.
Amino Acids, 4 - Enantioselective Synthesis of N-Substituted α-Amino Carboxylic Acids from α-Hydroxy Carboxylic Acids
Effenberger, Franz,Burkard, Ulrike,Willfahrt, Joachim
, p. 314 - 333 (2007/10/02)
With primary and secondary amines, the (S)-α-(trifluoromethylsulfonyloxy) carboxylates (S)-3 afford in an SN2 reaction the N-substituted (R)-α-amino carboxylates (R)-5, (R)-9, and (R)-12, resp.The rates of α-substituted ethyl propionates decrease in the order of the substituents triflate (3a) >> bromide (8a) > mesylate (7a) >= tosylate (7b) > chloride (8b); in the reactions with amines, decreasing reactivity affords increasing racemisation and elimination as a consequence of the more drastic conditions which are required
