5543-57-7Relevant academic research and scientific papers
Primary Amine Catalyzed Activation of Carbonyl Compounds: A Study on Reaction Pathways and Reactive Intermediates by Mass Spectrometry
Bencivenni, Giorgio,Calcaterra, Andrea,Ciogli, Alessia,Iazzetti, Antonia,Mazzoccanti, Giulia,Righi, Paolo,Villani, Claudio
supporting information, (2021/12/01)
The field of organocatalysis is expanding at a fast pace. Its growth is sustained by major stimuli, such as the effort toward an understanding of the mechanisms of reaction and catalytic processes in general, the elucidation of basic properties leading to stereocontrol and the search for broad applicability and scalability of the synthetic methodology. This paper reports a thorough study based on ESI-MS spectrometry of amino-organocatalyzed model reactions under different experimental conditions. Off-line reaction monitoring of mixtures containing different catalytic systems, by ESI-MSn showed the presence of several putative intermediate species, either in their protonated or sodiated forms. In addition, enantioselective chromatography of crude reactions provides the stereochemical outcome of asymmetric reactions. The bulk of the data collected offers a clue of the intricate pathways occurring in solution for the studied reactions.
Enantioseparation of mandelic acid on vancomycin column: Experimental and docking study
Shahnani, Mostafa,Sefidbakht, Yahya,Maghari, Shokoofeh,Mehdi, Ahmad,Rezadoost, Hassan,Ghassempour, Alireza
supporting information, p. 1289 - 1298 (2020/08/19)
So far, no detailed view has been expressed regarding the interactions between vancomycin and racemic compounds including mandelic acid. In the current study, a chiral stationary phase was prepared by using 3-aminopropyltriethoxysilane and succinic anhydride to graft carboxylated silica microspheres and subsequently by activating the carboxylic acid group for vancomycin immobilization. Characterization by elemental analysis, Fourier transform infrared spectroscopy, solid-state nuclear magnetic resonance, and thermogravimetric analysis demonstrated effective functionalization of the silica surface. R and S enantiomers of mandelic acid were separated by the synthetic vancomycin column. Finally, the interaction between vancomycin and R/S mandelic acid enantiomers was simulated by Auto-dock Vina. The binding energies of interactions between R and S enantiomers and vancomycin chiral stationary phase were different. In the most probable interaction, the difference in mandelic acid binding energy was approximately 0.2 kcal/mol. In addition, circular dichroism spectra of vancomycin interacting with R and S enantiomers showed different patterns. Therefore, R and S mandelic acid enantiomers may occupy various binding pockets and interact with different vancomycin functions. These observations emphasized the different retention of R and S mandelic acid enantiomers in vancomycin chiral column.
The Synthesis of Warfarin Using a Reconfigurable-Reactor Platform Integrated to a Multiple-Variable Optimization Tool
Bizarri, Nour,Kwak, Jee Seong,Mallik, Debasis,Organ, Michael G.,Sharif, Sepideh,Zhang, Wenyao Peter
supporting information, p. 15505 - 15508 (2020/11/30)
Optimization of the asymmetric synthesis of warfarin, an important anticoagulant, has been evaluated using a reconfigurable reaction platform capable of performing batch, continuous flow, and plug-flow synthesis. Further, this platform has been integrated with a novel, multidimensional, multiple variable analysis tool that can evaluate multiple critical quality attributes (CQA), percent conversion and enantiomeric excess in this case, from a single injection that is repeatedly recycled in a closed loop of chromatography columns, a detector and a heart-cut valve. Further, the new, integrated analysis system also facilitates validation of each QA, providing a high-level of confidence in analytical measurements, which are obtained without operator intervention.
Enantioselective Michael Addition Reaction Catalysed by Enantiopure Binuclear Nickel(II) Close-Ended Helicates
Arunachalam, Rajendran,Chinnaraja, Eswaran,Natarajan, Ramalingam,Samanta, Krishanu,Subramanian, Palani S.
, (2020/02/04)
The enantiopure Ni(II) helicates [Ni2L1RR.Cl2] (1), [Ni2L1SS.Cl2] (1′), [Ni2L2RR.Cl2] (2), [Ni2L2SS.Cl2] (2′) were synthesized by one-pot self-assembly technique from R-(+)- or S-(?)-1,1′-binaphthyl-2,2′-diamine, with 4-methyl-2,6-diformyl phenol or 4-tert-butyl-2,6-diformyl phenol and nickel salts. This binuclear double stranded Ni(II) helicates were characterized by ESI-MS, IR and single crystal X-ray structure wherever applicable. The extensive chiroptical studies suggest that the complexes are enantiopure in nature. The chirality transfer from ligand L1RR & L2RR to Ni(II) metal centre produced ΔΔ geometrical chirality, while their enantiomeric counterpart L1SS & L2SS produced ΛΛ chirality in their respective complexes.These enantiopure helicates were applied as catalysts in asymmetric Michael addition of 1,3-dicarbonyl compounds with β-nitrostyrene to produce nitroalkanes in good yield (96–98%) and ee (78–94%). (Figure presented.).
First aromatic amine organocatalysed activation of α,β-unsaturated ketones
Sonsona, Isaac G.,Marqués-López, Eugenia,Gimeno, M. Concepción,Herrera, Raquel P.
supporting information, p. 12233 - 12240 (2019/08/12)
This work provides an unprecedented example of a chiral aromatic amine used to activate α,β-unsaturated ketones in asymmetric aminocatalysis. Chiral aromatic diamine VII has been efficiently employed, as a proof of concept, in the Michael addition reaction between benzylideneacetones (1a-f) and coumarins (2a-d). The reaction gives rise to warfarin derivatives 3 with promising results using this family of catalysts for the first time. The additional studies performed supported the bifunctional mode of activation of the chiral catalyst VII and the covalent nature of the interactions between the catalyst VII and benzylideneacetones 1.
A Silica-Supported Catalyst Containing 9-Amino-9-deoxy-9-epi-quinine and a Benzoic Acid Derivative for Stereoselective Batch and Flow Heterogeneous Reactions
Ciogli, Alessia,Capitani, Donatella,Di Iorio, Nicola,Crotti, Simone,Bencivenni, Giorgio,Donzello, Maria Pia,Villani, Claudio
, p. 2020 - 2028 (2019/03/07)
A heterogeneous, silica-based catalyst containing 9-amino-9-deoxy-epi-quinine (or quinidine) and a derivative of benzoic acid was synthesized through radical thiol-ene click reaction. The acid component allows the in situ activation of cinchona amino group, acting as a bifunctional catalyst. The heterogenized catalysts efficiently promoted the reaction of ketones with trans-β-nitrostyrene, with diastereo- and enantioselectivity comparable to those of the homogeneous counterparts (dr up to 90:10 and 90 % ee). In addition, the catalyst retained a constant activity for at least four cycles. Finally, the supported catalyst (9-amino-9-deoxy-epi-quinine/achiral acid) was employed under continuous-flow conditions. Two enantioselective Michael reactions were in sequence performed with the same homemade packed-bed reactor. The addition of cyclohexanone to trans-β-nitrostyrene provided the evaluation of optimal residence time with high level of stereoselection (2 μL/min flow rate, 83 % ee). Furthermore, the flow reactor well performed in the preparation of warfarin (isolated yield 95 %, 78 % ee. in 16 h at room temperature). The dual (chiral amine/achiral acid) solid supported system, making an even easier work-out, represents a valuable tool for green chemistry and is attractive for large scale applications.
Diquats with Robust Chirality: Facile Resolution, Synthesis of Chiral Dyes, and Application as Selectors in Chiral Analysis
Talele, Harish R.,Koval, Du?an,Severa, Luká?,Reyes-Gutiérrez, Paul E.,Císa?ová, Ivana,Sázelová, Petra,?aman, David,Bednárová, Lucie,Ka?i?ka, Václav,Teply, Filip
supporting information, p. 7601 - 7604 (2018/06/11)
Diquats with extremely high racemization barriers with ΔG≠theor of 233 kJ mol?1 at 180 °C are described. Reported configurational robustness is due to a combination of two structural features: the rigid o-xylylene tether connecting the nitrogen atoms and the presence of two substituents in the bay region of the bipyridinium scaffold. The straightforward synthesis of diquats, plus facile resolution and derivatization make them attractive for chiral application studies. This is demonstrated by: 1) synthesis of the first non-racemic diquat dyes with pronounced chiroptical properties, and 2) capability of diquats to interact stereospecifically with chiral molecules. This suggests potential for diquat derivatives to be used as chiral selectors in separation methods.
A protein-based mixed selector chiral monolithic stationary phase in capillary electrochromatography
Xu, Shujuan,Wang, Yuying,Tang, Yixia,Ji, Yibing
, p. 13520 - 13528 (2018/08/21)
A new mixed selector chiral stationary phase (CSP) was prepared with co-immobilized human serum albumin and cellulase on a poly(glycidylmethacrylate-co-ethylene glycol dimethacrylate) (poly(GMA-co-EDMA)) monolith and the evaluation of its usefulness in chiral separation research was presented. For comparison, two single selector chiral stationary phases (CSPs) were also fabricated with the corresponding proteins. The enantioseparation ability of these CSPs was investigated by capillary electrochromatography (CEC) with various racemates. The mixed selector CSP exhibited a broader range of enantioselectivities than the single selectors and it could separate 10 chiral analytes while the two single selector CSPs resolved 3 and 8 respectively. Moreover, for (±)-warfarin, the enantioresolution was improved on the mixed selector CSP. Meanwhile, compared with the single selector CSPs, no additional preparation stage or reagent consumption was required in the simultaneous immobilization of different proteins, which is more favorable from economical and practical points of view. Consequently, by mixing HSA and cellulase together, the composite column combines the enantioselectivities of both individual proteins, thus expanding their application range practically.
Evaluation of the Edman degradation product of vancomycin bonded to core-shell particles as a new HPLC chiral stationary phase
Hellinghausen, Garrett,Lopez, Diego A.,Lee, Jauh T.,Wang, Yadi,Weatherly, Choyce A.,Portillo, Abiud E.,Berthod, Alain,Armstrong, Daniel W.
, p. 1067 - 1078 (2018/08/01)
A modified macrocyclic glycopeptide-based chiral stationary phase (CSP), prepared via Edman degradation of vancomycin, was evaluated as a chiral selector for the first time. Its applicability was compared with other macrocyclic glycopeptide-based CSPs: TeicoShell and VancoShell. In addition, another modified macrocyclic glycopeptide-based CSP, NicoShell, was further examined. Initial evaluation was focused on the complementary behavior with these glycopeptides. A screening procedure was used based on previous work for the enantiomeric separation of 50 chiral compounds including amino acids, pesticides, stimulants, and a variety of pharmaceuticals. Fast and efficient chiral separations resulted by using superficially porous (core-shell) particle supports. Overall, the vancomycin Edman degradation product (EDP) resembled TeicoShell with high enantioselectivity for acidic compounds in the polar ionic mode. The simultaneous enantiomeric separation of 5 racemic profens using liquid chromatography-mass spectrometry with EDP was performed in approximately 3?minutes. Other highlights include simultaneous liquid chromatography separations of rac-amphetamine and rac-methamphetamine with VancoShell, rac-pseudoephedrine and rac-ephedrine with NicoShell, and rac-dichlorprop and rac-haloxyfop with TeicoShell.
Green asymmetric synthesis of Warfarin and Coumachlor in pure water catalyzed by quinoline-derived 1,2-diamines
Kucherenko, Alexander S.,Kostenko, Alexey A.,Zhdankina, Galina M.,Kuznetsova, Olga Yu.,Zlotin, Sergei G.
supporting information, p. 754 - 759 (2018/02/14)
Simple enantiomerically pure C2-symmetric quinoline (isoquinoline)-derived 1,2-diamines were synthesized from the corresponding aldehydes via stereospecific diaza-Cope rearrangement with 2,2′-(1,2-diaminoethane-1,2-diyl)diphenol (HPEN). Efficient green synthesis of both enantiomers of the anticoagulant Warfarin and rodenticide Coumachlor was achieved in an aqueous medium via the asymmetric iminium-type Michael reaction in the presence of the catalysts 8e and (ent)-8e in combination with (R)- or (S)-mandelic acid, respectively. This procedure provides high enantioselectivity (up to 91% ee), which has never been attained for these bioactive compounds with the known catalysts under aqueous conditions. Nearly optically pure Warfarin (～99% ee) was prepared via a green isolation procedure, which included acidic precipitation of the crude product from a basic aqueous solution followed by single recrystallization. Furthermore, unlike the known primary amine-derived organocatalysts, the developed aqueous catalytic system does not produce parasitic byproducts and can be recovered and reused in the asymmetric reaction.
