A new selective reduction of nitroalkenes into enamides

Laso, Nieves M.; Quiclet‐Sire, Béatrice; Zard, Samir Z.

doi:10.1016/0040-4039(96)00078-0

Cited by 41 publications

(20 citation statements)

References 21 publications

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“…To introduce bifunctionality in the Schiff base chelating system, optically active p ‐NO 2 phenylalanine was used as a precursor to render a linking group in the system. Specificity can be generated by direct reduction of nitro group in the presence of iron powder and acetic acid by selective reduction as reported elsewhere (22) followed by conjugation of biomolecule and vanadium complexation.…”

Section: Discussionmentioning

confidence: 99%

Synthesis of Oxovanadium(IV) Schiff base Complexes derived from C‐substituted Diamines and Pyridoxal‐5‐Phosphate as Antitumor Agents

et al. 2012

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Oxovanadium (IV) complexes of N,N¢-bispyridoxyl-5, 5¢-bis (phosphate) ethylenediimine (L1) and N,N¢-bis(pyridoxyl)-5,5¢-bis(phosphate)-1¢¢-(p-nitrobenzyl)ethylenediimine (L2) were synthesized by condensation of optically active C-substituted diamines and pyridoxal-5-phosphate. Oxovanadium (IV) complexes derived from L1 and L2 were evaluated as DNA cleavage agent (cleavage of supercoiled plasmid pBR322 DNA). Interestingly, both the oxovanadium (IV) complexes exhibited DNA nuclease activity, and the extent of oxidation of DNA by these vanadyl complexes was superior to VOSO 4 . The significant reduction in primary tumor and increased delay in tumor growth of 15 days was seen in the tumor regression analysis with oxovanadium (IV) complex of L1. With the preliminary studies performed with the pyridoxal-5-phosphate -based salen derivatives including the cytotoxicity and tumor regression, it is evident that the salen bifunctional chelating agent has obtained therapeutic potential if conjugated to a gene-specific targeting molecule for the oxidation of guanine residue.

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Section: Discussionmentioning

confidence: 99%

Synthesis of Oxovanadium(IV) Schiff base Complexes derived from C‐substituted Diamines and Pyridoxal‐5‐Phosphate as Antitumor Agents

et al. 2012

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“…19 More efficient catalytic systems need to be developed for asymmetric hydrogenation of (E)-β-arylenamides, which can be readily prepared from aldehydes through nitroaldol and reductive acylation. 20,21 WingPhos was found to be an efficient ligand for asymmetric hydrogenation of both (E)-β-arylenamides and cyclic β-arylenamides. A series of chiral β-arylisopropylamines, 2-aminotetralines, and 3-aminochromans can be easily accessed by using this method With this method, several key chiral intermediates for therapeutic agents such as the β 2 -agonist arformoterol, 22a α-blocker tamsulosin, 22b dopamine agonist rotigotine, 22c and α 1 -adrenoceptor antagonist silodosin, 22d can be efficiently synthesized by asymmetric hydrogenation (Scheme 4).…”

Section: Scheme 1 Hydrogenation Of α-Arylenamidementioning

confidence: 99%

Search for Ideal P-Chiral Phosphorus Ligands for Practical Asymmetric Hydrogenation and Asymmetric Suzuki–Miyaura Coupling

Liu

Luo

et al. 2013

Synlett

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The synthesis of P-chiral phosphorus ligands with novel structures is important for the development of efficient asymmetric catalytic transformations. Here, we describe the development of Pchiral phosphorus ligands such as BIBOP, WingPhos, BI-DIME, and 8 in our laboratory. Conformational rigidity, high tunability of electronic and steric properties, and convenient physical properties are the main features of our ligand design. Progress in developing practical asymmetric hydrogenation and asymmetric cross-coupling reactions are discussed.One of most challenging tasks for current organic chemists is to develop highly efficient, selective, and green chemical processes from readily available starting materials under mild and operationally convenient conditions with minimum environmental impact. 1 Among the various approaches used to construct chiral molecules including chiral resolution of racemic compounds, chiral pools, and chiral auxiliaries, catalytic asymmetric transformation is the most appealing method. The field of asymmetric catalysis has progressed dramatically in the last several decades with the emergence of numerous asymmetric catalytic reactions. Nevertheless, most of these methods are far from ideal from the practical point of view with respect to meeting the increasing demand of chiral building blocks, drugs, and agrochemicals. Only a few asymmetric catalytic methods are sufficiently practical in terms of both reactivity (turnover numbers) and enantioselectivity. The development of practical asymmetric catalytic methods therefore remains a significant challenge. Chiral catalysts and ligands play a central role in determining the efficiency of asymmetric catalytic reactions. 2 The search for efficient chiral ligands is thus of great importance for the development of effective asymmetric catalytic processes. Since Knowles 3 developed CAMP and DIPAMP for asymmetric hydrogenation almost half a century ago, P-chiral phosphorus ligands have been broadly applied in asymmetric catalysis. The advantages of these ligands are two-fold: (1) the three substituents on the phosphorus center dictate the electronic and steric properties of the ligands. Variation of any substituents could dramatically alter its catalytic performance; (2) the P-chiral centers are in close proximity to the metal center, providing a close chiral environment for substrate coordination. However, the development of P-chiral phosphorus ligands was slow for a long period of time. It was not until the late 1990s that exploration of P-chiral phosphorus ligands accelerated, leading to the development of a series of now well-known P-chiral ligands such as BisP*, 4 MiniPhos, 5 TangPhos, 6 TCF-Phos, 7 DuanPhos, 8 and QuinoxP* 9 among others (Figure 1). The successful applications of these ligands in asymmetric hydrogenation and many other reactions have clearly demonstrated the Dr. Guodu Liu (middle left)

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“…Reductive acylation of ketoximes have been frequently applied in the synthesis of α-arylenamides. 8,12 However, this method has not been successfully employed for stereoselective synthesis of β-arylenamides. We herein report the reductive acylation of ketoximes 2, which can be easily prepared from nitroalkenes 1, to form (E)-β-arylenamides stereoselectively with up to 16:1 E/Z ratios.…”

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confidence: 99%

“…A number of methods have been reported for the syntheses of β-arylenamides including: (1) the reduction of nitro alkenes; 8 (2) the direct condensation of a ketone with an amide; 5,9 (3) Beckmann rearrangement of ketoximes; 6,10 and (4) the palladium-catalyzed cross coupling between vinyl triflates and amides. 11 Unfortunately, most of them suffered from low yields or E/Z selectivities (Scheme 1).…”

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confidence: 99%

Practical Syntheses of N-Acetyl (E)-β-Arylenamides

et al. 2013

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A facile and practical method for the preparation of (E)-β-arylenamides [(E)-N-(1-arylprop-1-en-2-yl]acetamides] has been developed by reductive acetylation of the corresponding oximes with iron(II) acetate as the reducing reagent. Employment of hexamethylphosphoramide as the solvent was found to be critical for the high E/Z selectivity. The methodology has been applied in efficient syntheses of a key chiral intermediate of tamsulosin by asymmetric hydrogenation.

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A new selective reduction of nitroalkenes into enamides

Cited by 41 publications

References 21 publications

Synthesis of Oxovanadium(IV) Schiff base Complexes derived from C‐substituted Diamines and Pyridoxal‐5‐Phosphate as Antitumor Agents

Synthesis of Oxovanadium(IV) Schiff base Complexes derived from C‐substituted Diamines and Pyridoxal‐5‐Phosphate as Antitumor Agents

Search for Ideal P-Chiral Phosphorus Ligands for Practical Asymmetric Hydrogenation and Asymmetric Suzuki–Miyaura Coupling

Practical Syntheses of N-Acetyl (E)-β-Arylenamides

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