19403-80-6Relevant academic research and scientific papers
Hydroxypyridyl Imines: Enhancing Chromatographic Separation and Stereochemical Analysis of Chiral Amines via Circular Dichroism
Joyce, Leo A.,Regalado, Erik L.,Welch, Christopher J.
, p. 8199 - 8205 (2016)
Imine-bond formation between chiral amines and commercially available 3-hydroxypyridine-2-carboxaldehyde (HCA) was exploited for rapid determination of stereochemical composition. Chiral supercritical fluid chromatography (SFC) screening of the derivatized imine compounds led to the elucidation of multiple combinations of mobile and stationary phases that gave resolution of all members of a series of chiral amines. The first eluting enantiomer was generally the derivative of the (R)-amine enantiomer across the series that was studied, indicating that the imine formed from the (S)-amine has more favorable interaction with the chiral stationary phase of the column. These conditions were then applied to more challenging compounds, namely amino alcohols and diastereomers possessing more than one stereocenter. The approach was utilized to monitor stereoselective biocatalytic transamination and assign the absolute configuration of the enantiomeric products. Finally, hydrolysis of the imine bond of the derivative was shown to generate enantiopure amine starting materials without racemization. This further highlights the value of this approach for creating readily reversed derivatives that enhance chromatographic separation and aid in the determination of absolute configuration.
Heteroleptic enantiopure Pd(ii)-complexes derived from halogen-substituted Schiff bases and 2-picolylamine: Synthesis, experimental and computational characterization and investigation of the influence of chirality and halogen atoms on the anticancer acti
Kordestani, Nazanin,Amiri Rudbari, Hadi,Correia, Isabel,Valente, Andreia,C?rte-Real, Leonor,Islam, Mohammad Khairul,Micale, Nicola,Braun, Jason D.,Herbert, David E.,Tumanov, Nikolay,Wouters, Johan,Enamullah, Mohammed
, p. 9163 - 9180 (2021/06/06)
Seven enantiomeric pairs of palladium complexes, [Pd(pic)(R or S)-N-1-(phenyl)ethyl-2,4-X1,X2-salicylaldiminate)]NO3, [Pd(pic)(R or S)]NO3 (X1 = X2 = Cl, Br, I, H; X1/X2 = Br/Cl), were synthesized by the reaction of enantiopure halogen-substituted Schiff
Aggregation-induced emission enhancement of chiral boranils
Vaz, Patrícia A. A. M.,Rocha, Jo?o,Silva, Artur M. S.,Guieu, Samuel
, p. 18166 - 18171 (2018/11/23)
New boranils based on chiral benzylamines have been synthesized and their photophysical properties studied. These BF2-complexes exhibit a bright blue fluorescence in solution and in the solid state, and exhibit aggregation-induced emission enhancement. The chirality of the ligand, even if it is not directly located at the boron center, has consequences on the circular dichroism of the complexes.
Synthesis, characterization and crystal structures of ruthenium complexes with bidentate chiral salicylaldiminato ligands
Tang, Li-Hua,Chen, Xin,Jia, Ai-Quan,Xin, Zhi-Feng,Zhang, Qian-Feng
, p. 120 - 127 (2018/05/09)
Condensations of salicylaldehyde and 4-chlorosalicylaldehyde with (R)-α-methylbenzylamine in refluxing ethanol afforded the chiral Schiff base ligands (R)-N-(1-phenylethyl)salicylidene (HL1?) and (R)-N-(1-phenylethyl)(4-chlorosalicylidene) (HL2?), respectively. Similarly, reaction of 3,5-di-tert-butylsalicylaldehyde and (S)-2-amino-3-methylbutan-1-ol gave the chiral Schiff base ligand (S)-N-(1-hydroxymethylisobutyl)(3,5-di-tert-butylsalicylidene) (HL3?). Treatment of (Et4N)[RuCl4(MeCN)2] and [RuCl3(NO)(PPh3)2] with HL1? in the presence of triethylamine afforded an anionic ruthenium(III) complex (R,R)-(Et4N)[Ru(κ2-N,O-L1?)2Cl2] (1) and a neutral ruthenium(II) nitrosyl complex (R)-[Ru(κ2-N,O-L1?)(NO)Cl2(PPh3)] (2), respectively. Interaction of [RuCl2(PPh3)3] and 2 equiv. HL2? led to isolation of a ruthenium(III) complex (R,R)-[Ru(κ2-N,O-L2?)2Cl(PPh3)] (3). Reaction of [Ru(NO)Cl3·xH2O] and HL3? gave an anionic ruthenium(II) nitrosyl complex (S)-(Et3NH)[Ru(κ2-N,O-L3?)(NO)Cl3] (4). The molecular structures of ligands HL1? HL2? and ruthenium complexes 1–4 have been determined by single-crystal X-ray crystallography.
A Practical Electrophilic Nitrogen Source for the Synthesis of Chiral Primary Amines by Copper-Catalyzed Hydroamination
Guo, Sheng,Yang, Jeffrey C.,Buchwald, Stephen L.
, p. 15976 - 15984 (2018/11/23)
A mild and practical method for the catalytic installation of the amino group across alkenes and alkynes has long been recognized as a significant challenge in synthetic chemistry. As the direct hydroamination of olefins using ammonia requires harsh conditions, the development of suitable electrophilic aminating reagents for formal hydroamination methods is of importance. Herein, we describe the use of 1,2-benzisoxazole as a practical electrophilic primary amine source. Using this heterocycle as a new amino group delivery agent, a mild and general protocol for the copper-hydride-catalyzed hydroamination of alkenes and alkynes to form primary amines was developed. This method provides access to a broad range of chiral α-branched primary amines and linear primary amines, as demonstrated by the efficient synthesis of the antiretroviral drug maraviroc and the formal synthesis of several other pharmaceutical agents.
Asymmetric induction in the addition of enantiomerically pure H-phosphinate to chiral aldimines: diastereoselective generation of α-amino phosphinates with P,C-stereogenic centers
Yang, Meng,Xu, Hao,Zhou, Zhong-Yang,Zhang, He,Liu, Li-Juan,Sun, Yong-Ming,Nie, Shao-Zhen,Zhao, Chang-Qiu
supporting information, p. 815 - 822 (2016/09/02)
α-Amino phosphinates with P,C-stereogenic centers were prepared from a P-retained addition of (RP)-(?)-menthyl H-phenylphosphinate to (R)-aldimines with up to 86:14 dr under catalyst and solvent free condition at ambient temperature; the single
An efficient microwave method for the synthesis of imines
Border, Emily C.,Blair, Victoria L.,Andrews, Philip C.
, p. 844 - 848 (2015/05/20)
A large variety of aryl and heterocyclic chiral and achiral imines can be generated simply, efficiently, and cleanly through the use of microwave irradiation and the use of a small amount of molecular sieve. Reactions are rapid and complete in a matter of minutes, and can be quantitative, reducing significantly the time and amount of solvents used in compound isolation and purification.
Stereoselective addition of dialkyl phosphites to di-salicylaldimines bearing the (R,R)-1,2-diaminocyclohexane moiety
Lewkowski, Jaros?aw,Tokarz, Pawe?,Lis, Tadeusz,?lepokura, Katarzyna
, p. 810 - 816 (2014/01/23)
The addition of dialkyl phosphites to the azomethine bond of N,N′-disalicylidene-1,2-diaminocyclohexane imines, catalyzed by sodium hydride led to bis-aminophosphonates in a high diastereoselectivity. One of the bis-aminophosphonates was analyzed by X-ray
Chiroptical inversion induced by rotation of a carbon-carbon single bond: An experimental and theoretical study
Lu, Wei,Du, Ganhong,Liu, Keyuan,Jiang, Liming,Ling, Jun,Shen, Zhiquan
, p. 283 - 292 (2014/02/14)
We propose a new strategy to construct chiral molecular switches with highly reversible and sensitive chiroptical responses to variations in the external environment. Its fundamental concept involves a stimuli-triggered exchange of two conformations presenting significantly different chiroptical properties through the rotation of a carbon-carbon single bond, as demonstrated by chiral Schiff bases s-1, s-2, and a salicylamide analogue s-3. Upon addition of base in solution, the circular dichroism (CD) spectra of these molecular switches displayed unique changes featuring an inversion of the Cotton effect's signs, and the original CD profiles can be recoverd by acidification. Various spectroscopic studies as well as the conformational analysis combining with TDDFT computations allowed clear elucidation of the chiroptical inversion mechanism. It is expected that this kind of chiroptical switches is of great interest for molecular recognition, chemosensing, and the construction of molecular-scale devices. Furthermore, the present study indicates that the use of the conformational transition about a single bond may serve as the basis for designing chiroptical inversion systems.
Design of chiral sulfoxide-Schiff base hybrids and their application in Cu-catalyzed asymmetric Henry reactions
Cheng, Hong-Gang,Lu, Liang-Qiu,Wang, Tao,Chen, Jia-Rong,Xiao, Wen-Jing
supporting information; experimental part, p. 5596 - 5598 (2012/07/03)
A new class of chiral sulfoxide-Schiff base ligands has been developed by the rational combination of two privileged chiral backbones. These sulfoxide-Schiff base ligands were found to be highly efficient for Cu-catalyzed asymmetric Henry reactions (up to
