![4-hydroxy[1]benzopyran-2-one](/Databaselist/images/loading.webp)
81-81-2Relevant academic research and scientific papers
Ionic liquids: Efficient media for the lipase-catalyzed Michael addition
Fan, Yunchang,Cai, Dongxu,Wang, Xin,Yang, Lei
, (2018)
Recently, ionic liquids (ILs) have been regarded as ideal media for non-aqueous bio-catalysis. In this work, the synthesis of warfarin by the lipase-catalyzed Michael addition in IL media and the parameters that affected the warfarin yield were investigated. Experimental results demonstrated that the chemical structures of the ILs were a major factor for influencing the warfarin yield. The ILs containing the NTf2– anion were suitable reaction media due to the high chemical stability of this anion. The incorporation of the hydroxyl group on the IL cation significantly improved the lipase activity due to the H2O-mimicking property of this group. The lipase activity decreased by increasing the alkyl chain length on the IL cation due to the non-polar domain formation of the IL cation at the active site entrance of lipase. The ILs and lipase could be reused no less than five times without reduction in the warfarin yield.
Enzyme-catalyzed Michael addition for the synthesis of warfarin and its determination via fluorescence quenching of L-tryptophan
Yuan, Yusheng,Yang, Liu,Liu, Shaopu,Yang, Jidong,Zhang, Hui,Yan, Jingjing,Hu, Xiaoli
, p. 183 - 188 (2017)
A sensitive fluorescence sensor for warfarin was proposed via quenching the fluorescence of L-tryptophan due to the interaction between warfarin and L-tryptophan. Warfarin, as one of the most effective anticoagulants, was designed and synthesized via lipase from porcine pancreas (PPL) as a biocatalyst to catalyze the Michael addition of 4-hydroxycoumarin to α, β-unsaturated enones in organic medium in the presence of water. Furthermore, the spectrofluorometry was used to detect the concentration of warfarin with a linear range and detection limit (3σ/k) of 0.04–12.0?μmol?L??1 (R2?=?0.994) and 0.01?μmol?L??1, respectively. Herein, this was the first application of bio-catalytic synthesis and fluorescence for the determination of warfarin. The proposed method was applied to determine warfarin of the drug in tablets with satisfactory results.
Hypervalent Iodine(III)-Mediated Tosyloxylation of 4-Hydroxycoumarins
Xu, Bowen,Gao, Yiping,Han, Jianwei,Xing, Zejing,Zhao, Sihan,Zhang, Ziyang,Ren, Runlin,Wang, Limin
, p. 10136 - 10144 (2019)
An efficient approach was developed for synthesis of 3-tosyloxy-4-hydroxycoumarins under mild conditions by using Koser's reagents. The reaction tolerated various functional groups, and the products served as useful aromatic building blocks. Additionally, a plausible mechanism via iodonium ylide was proposed, and the oral anticoagulant Warfarin was synthesized in good yield.
Spectral assignments and structural studies of a warfarin derivative stereoselectively formed by tandem cyclization
Velayutham Pillai,Rajeswari,Vidhyasagar
, p. 447 - 454 (2015)
Abstract The structural elucidation of a Mannich condensation product of rac-Warfarin with benzaldehyde and methyl amine was carried out using IR, Mass, 1H NMR, 13C NMR, 1H-1H COSY, 1H-13C COSY, DEPT-135, HMBC, NOESY spectra and single crystal X-ray diffraction. Formation of a new pyran ring via a tandem cyclization in the presence of methyl amine was observed. The optimized geometry and HOMO-LUMO energy gap along with other important physical parameters were found by Gaussian 09 program using HF 6-31G (d, p) and B3YLP/DFT 6-31G (d, p) level of theory. The preferred conformation of the piperidine ring in solution state was found to be chair from the NMR spectra. Single crystal X-ray diffraction and optimized geometry (by theoretical study) also confirms the chair conformation in the solid state.
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.
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.).
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.
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.
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.
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.
