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1.
Perchloric acid-acetic acid reagent system has been found to be an efficient reagent for deprotection of p-methyl benzene sulfonyl (tosyl) derivatives of primary aromatic amines, secondary aromatic amines and chiral aminoketones. 相似文献
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A novel chiral N-mesyloxycarbamate to perform rhodium-catalyzed stereoselective C-H amination reactions is reported. Chiral benzylic and propargylic amines are produced in good yields and selectivities using ethyl acetate as solvent. The corresponding free amines are easily obtained by cleavage of the chiral reagent, which could also be recovered. 相似文献
4.
Enantiomeric discrimination of chiral primary amines was performed by both reversed-phase HPLC and normal-phase HPLC after labeling with a chiral fluorescent derivatization reagent, (1R,2R)- and (1S,2S)-trans-2-(2,3-anthracenedicarboximido)cyclohexanecarbonyl chloride. Use of HPLC permits separation of diastereomeric derivatives of amines up to C30 which have a primary amino group at the middle of the alkyl chain. The derivatives of primary amines having an anteiso alkyl chain, which has a chiral branched-methyl at the n-3 position of the alkyl chain, were also separated by HPLC, and it was also possible to separate niphatesine D by reversed-phase HPLC after derivatization. 相似文献
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A solid-phase reaction technique is described for improved derivatization of aliphatic amines, amino alcohols and amino acids. A polymeric activated ester is used for the immobilization of the 3,5-dinitrobenzoyl group, which can then be used for derivatizations of strong or weak nucleophiles, while avoiding solution-phase derivatization conditions. The reagent is easily prepared and can be regenerated after use to attain its original reactivity. The resulting chromatograms are free of system peaks due to excess derivatizing reagent, and sample handling is kept to a minimum. The reagent can be used in conjunction with both reversed- and normal-phase chromatography and can be used for off-line gas chromatographic or high-performance liquid chromatographic (HPLC) derivatizations. In addition, the reagent can be used on-line for derivatization in HPLC. Since the labelling reagent is a strong pi-acid, chiral substrates can be derivatized and separated on a Pirkle-type pi-donor column. The confirmation and quantitation of amphetamine in urine was accomplished using a polymer containing two labelling moieties, p-nitrobenzoyl and 3,5-dinitrobenzoyl. The derivatization and separation of chiral and achiral amines, amino alcohols and amino acids is described. 相似文献
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Catalytic Enantioselective Amination of Alcohols by the Use of Borrowing Hydrogen Methodology: Cooperative Catalysis by Iridium and a Chiral Phosphoric Acid 下载免费PDF全文
Dr. Yao Zhang Ching‐Si Lim Derek Sui Boon Sim Hui‐Jie Pan Prof. Yu Zhao 《Angewandte Chemie (International ed. in English)》2014,53(5):1399-1403
The catalytic asymmetric reduction of ketimines has been explored extensively for the synthesis of chiral amines, with reductants ranging from Hantzsch esters, silanes, and formic acid to H2 gas. Alternatively, the amination of alcohols by the use of borrowing hydrogen methodology has proven a highly atom economical and green method for the production of amines without an external reductant, as the alcohol substrate serves as the H2 donor. A catalytic enantioselective variant of this process for the synthesis of chiral amines, however, was not known. We have examined various transition‐metal complexes supported by chiral ligands known for asymmetric hydrogenation reactions, in combination with chiral Brønsted acids, which proved essential for the formation of the imine intermediate and the transfer‐hydrogenation step. Our studies led to an asymmetric amination of alcohols to provide access to a wide range of chiral amines with good to excellent enantioselectivity. 相似文献
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《Tetrahedron》2019,75(43):130591
Fluorenylethylchoroformate (FLEC) is a valuable chiral derivatisation reagent that is used for the resolution of a wide variety of chiral amines. Herein, we describe an improved preparation of (S)-(−)-FLEC using an efficient asymmetric catalytic transfer hydrogenation as the key step. We also demonstrate the application of FLEC as a chiral Fmoc equivalent for chiral resolution, with facile deprotection, of tetrahydroquinaldines, and its capacity for inducing regioselective outcomes in nitration reactions. 相似文献
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A simple method for the synthesis of amines by the reduction of imines, anils and enamines, including some chiral substrates, with the MCl2/NaBH4/CH3OH reagent (M = Co, Ni) in 64–82% yields is described. 相似文献
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合成了用于气相色谱(GC)的手性衍生化试剂N-七氟丁酰基-L-脯氨酰氯(N-HFB-L-PCl)。各种特性试验表明,N-HFB-L-PCl是灵敏的GC手性衍生化试剂,可直接于水相拆分微量的手性胺对映体。 相似文献
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Toshiki Mochizuki Sayuri TaniguchiHaruhito Tsutsui Jun Zhe MinKoichi Inoue Kenichiro TodorokiToshimasa Toyo’oka 《Analytica chimica acta》2013
l-Pyroglutamic acid (l-PGA) was evaluated as a chiral labeling reagent for the enantioseparation of chiral amines in terms of separation efficiency by reversed-phase chromatography and detection sensitivity by ESI-MS/MS. Several amines and amino acid methyl esters were used as typical representatives of the chiral amines. Both enantiomers of the chiral amines were easily labeled with l-PGAs at room temperature for 60 min in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and 1-hydroxy-1H-benzotriazole as the activation reagents. The resulting diastereomers were completely separated by reversed-phase chromatography using the small particle (1.7 μm) ODS column (Rs = 1.6–6.8). A highly sensitive detection at a low-fmol level (1–4 fmol) was also obtained from the multiple reaction monitoring (MRM) chromatograms. Therefore, a high-throughput determination was achieved by the present UPLC–ESI-MS/MS method. 相似文献
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Perfluoro-2-propoxypropionic acid, which was prepared by the anionic dimerization of hexafluoro-1,2-epoxypropane, was optically resolved via diastereomeric salt formation with chiral amines. The optically pure (+) and (?) perfluoro-2-propoxypropionic acids thus obtained were found to be a convenient chiral reagent for determining enantiomeric compositions of α-amino acids by means of 19F nmr analysis. 相似文献
12.
《Tetrahedron: Asymmetry》1999,10(15):2997-3002
(S)-O-Acetyllactyl chloride is used as a versatile chiral derivatizing agent for the chromatographic determination of the enantiomeric excesses of alcohols or amines. However, some precautions must be taken to avoid its racemization during preparation and use. In addition, the racemic counterpart of this reagent can be used to determine the best analytical separation conditions. 相似文献
13.
Monique Calmes Jacques Daunis Ahmad Hanouneh Robert Jacquier 《Tetrahedron: Asymmetry》1993,4(12):2437-2440
1-Fluoro-2,4-dinitrophenyl-5-(S)-alanine amide (Marfey's reagent) was used as a chiral derivatizing agent for benzylic amines in order to determine optical purities. 相似文献
14.
The synthesis of a polymer-supported Mukaiyama reagent is described. This preparation was thoroughly optimized using a DoE approach to achieve optimum loading, and the procedure was successfully applied to prepare the supported reagent on a 10 g scale. This reagent proved to be effective for the formation of carbodiimides through the dehydration of thioureas and for a one-pot guanylation of primary amines. 相似文献
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Nobuo Ishikawa 《Journal of fluorine chemistry》1984,25(1):17-20
The usefulness of optically active (+),(?)-perfluoropropoxy- and perfluoroisopropoxypropionic acids as derivatives for the analysis of chiral amines and alcohols is mentioned. Lanthanide chelates of (+),(?)-di(perfluoropropoxypropionyl)methane behaved as a useful shift reagent for the pmr analysis of optically active compounds. 相似文献
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The chiral amination reagent (?)- was prepared from (?)-ephedrine, configurationally determined by X-ray structure analysis and reacted with carbon nucleophiles to yield the optically active amines with up to 44% ee. 相似文献
18.
Extraction-derivatisation techniques have been developed for the unambiguous identification of biogenic amines, and their putative amino acid precursors and metabolites (both major and minor), in single ventral thoracic nerve cords of the locust. Schistocerca gregaria, by the use of gas chromatography-negative-ion chemical ionisation mass spectrometry with selected ion monitoring. In addition the configuration of that enantiomer of p-octopamine present in the thoracid nervous system of the locust was established as R using the chiral derivatisation reagent, (-)-heptafluorobutyrylphenylalanyl chloride. 相似文献
19.
Yuan Gao Zhijun Wang Xinyu Zhang Min Zhao Dr. Shuai Zhang Prof. Dr. Chao Wang Prof. Dr. Liang Xu Prof. Dr. Pengfei Li 《Angewandte Chemie (International ed. in English)》2023,62(31):e202303709
Chiral amines are broadly used compounds in pharmaceutical industry and organic synthesis, and reductive amination reactions have been the most appreciated methods for their syntheses. However, one-step transfer hydrogenative direct asymmetric reductive amination (THDARA) that could expand the scope, simplify the operation and eliminate the use of additives has been challenging. In this work, based on the Xiao's racemic transfer hydrogenative reductive amination in 2010 and our recent work in novel chiral pyridine ligands, chiral half-sandwich iridium catalysts were rationally designed and synthesized. Using the optimized catalyst and azeotropic mixture of formic acid and triethylamine as the hydrogen source, a broad range of α-chiral (hetero)aryl amines, including various polar functional groups and heterocycles, were prepared in generally high yield and enantioselectivity under mild and operationally simple conditions. Density functional theory (DFT) calculation of the catalytically active Ir−H species and the key hydride transfer step supported the chiral pyridine-induced stereospecific generation of the iridium center, and the enantioselection by taming the highly flexible key transition structure with multiple attractive non-covalent interactions. This work introduced a type of effective chiral catalysts for simplified approach to medicinally important chiral amines, as well as a rare example of robust enantioselective transition-metal catalysis. 相似文献
20.
《Tetrahedron: Asymmetry》2000,11(9):2033-2036
Treatment of enantiomerically pure (S)-4-alkyl-5,5-diphenyl-oxazolidinones, themselves derived from appropriate amino acids, with HF–pyridine (Olah's reagent) generated a range of (S)-α-(fluorodiphenylmethyl)alkylamines. These compounds represent a novel range of fluorinated chiral amines. 相似文献