88546-12-7

Upstream product

• 105962-57-0 (Z)-methyl 2-acetamido-3-(4-nitrophenyl)acrylate 
• 100-11-8 1-bromomethyl-4-nitro-benzene 
• 555-16-8 4-nitrobenzaldehdye 
• 78312-00-2 2-methyl-4-(4-nitrobenzylidene)oxazol-5(4H)-one 
• 66949-13-1 (Z)-2-methyl-4-(4-nitrobenzylidene)oxazol-5(4H)-one 
• 20877-15-0 ethyl 2-acetylamino-2-cyano-3-(4-nitrophenyl)propanoate 
• 109-21-7 butyl butyrate 
• 127090-51-1 2-acetylamino-3-(4-nitro-phenyl)-propionic acid methyl ester 
• 17193-40-7 (+)-Methyl 2-amino-3-(4-nitrophenyl)propionate hydrochloride 
• 66693-69-4 2-amino-3-(4-nitrophenyl)propionic acid hydrochloride 

Downstream Products

• 147065-06-3 (R)-4-nitrophenyl-alanine-hydrochloride 
• 780004-06-0 C₁₁H₁₄N₂O₄ 
• 6957-95-5 4-nitro-N,N-phthaloyl-D-phenylalanin-ethyl ester 
• 93942-39-3 C₂₃H₂₄Cl₂N₂O₄ 
• 93634-67-4 2(R)-acetylamino-3-(4-amino-phenyl)-propionic acid methyl ester 

Relevant academic research and scientific papers

Mechanistically Guided One Pot Synthesis of Phosphine-Phosphite and Its Implication in Asymmetric Hydrogenation

Although hybrid bidentate ligands are known to yield highly enantioselective products in asymmetric hydrogenation (AH), synthesis of these ligands is an arduous process. Herein, a one pot, atom-economic synthesis of a hybrid phosphine-phosphite (L1) is reported. After understanding the reactivity difference between an O-nucleophile versus C-nucleophile, one pot synthesis of Senphos (L1) was achieved (72 %). When L1 was treated with [Rh], 31P NMR revealed bidentate coordination to Rh. Senphos, in the presence of rhodium, catalyzes the AH of Methyl-2-acetamido-3-phenylacrylate and discloses an unprecedented turn over frequency of 2289, along with excellent enantio-selectivity (92 %). The generality is demonstrated by hydrogenating an array of alkenes. The AH operates under mild conditions of 1–2 bar H2 pressure, at room temperature. The practical relevance of L1 is demonstrated by scaling-up the reaction to 1 g and by synthesizing DOPA, a drug widely employed for the treatment of Parkinson's disease. Computational insights indicate that the R isomer is preferred by 3.8 kcal/mol over the S isomer.

Diaza-Crown Ether-Bridged Chiral Diphosphoramidite Ligands: Synthesis and Applications in Asymmetric Catalysis

A small library of diaza-crown ether-bridged chiral diphosphoramidite ligands was prepared. In the rhodium-catalyzed asymmetric hydrogenation and hydroformylation reactions, these ligands exhibited distinct properties in catalytic activity and/or enantioselectivity. Hydrogenated products with opposite absolute configurations could be obtained in high yields with excellent ee values by utilizing (S,S)-L1 and (S,S)-L3, respectively. Meanwhile, the addition of alkali metal cations caused variations in catalytic outcomes, showing the supramolecular tunability of these Rh/diphosphoramidite catalytic systems.

Melphalan intermediate and preparation method thereof

The invention discloses a Melphalan intermediate and a preparation method thereof. The Melphalan intermediate is prepared by acidifying a compound p-nitrobenzaldehyde under the action of methanol, a hydrochloric acid solvent, etc. The preparation method has a route with mild reaction conditions, is higher than an existing preparation method in yield, is economical and effective, and is suitable for large-scale industrial production. The synthesis route is as shown in the description.

A supramolecularly tunable chiral diphosphine ligand: Application to Rh and Ir-catalyzed enantioselective hydrogenation

A supramolecularly tunable chiral bisphosphine ligand bearing two pyridyl-containing crown ethers, (-) or (+)-Xyl-P16C6-Phos, was fabricated and utilized in the Rh-catalyzed asymmetric hydrogenation of α-dehydroamino acid esters and Ir-catalyzed asymmetric hydrogenation of quinolines in high yields with excellent enantioselectivities (90-99% ee). Up to a 22% enhancement in enantioselectivity was achieved by the addition of certain amounts of alkali ions (Li+, Na+ or K+), which could be selectively recognized and effectively complexed by the crown ethers on the chiral Xyl-P16C6-Phos.

Model containing pyridine base crown ether chiral bis-phosphorus ligand and its in asymmetric catalytic application of the catalyst in the reaction (by machine translation)

This invention relates to model containing pyridine base crown ether chiral bis-phosphorus ligand and its application of symmetrical catalytic reaction. Chiral bis-phosphorus ligand and intermediates containing pyridine base crown ether single phosphorus ligand the structural formula of (I) are respectively shown as the following formula, formula (I '). These chiral bis-phosphorus ligand of the transition metal complexes can be used as catalyst for asymmetric reactions, containing pyridine base crown ether of the invention the chiral bis-phosphorus ligand it is a kind of novel chiral ligand capable of regulating, by using different alkali metal ion, alkaline earth metal ion, rare-earth metal ion, ammonium salt or organic amine salt such as a crown ether, on the object with the ligand complex, the catalyst can be realized the space structure and electronic nature of the regulation and control. This kind of the alkali metal ion complexation assembled containing pyridine base crown ether chiral double-phosphorus ligand transition metal (Rh and Ir) complexes in catalytic hydrogenation reaction demonstrate excellent catalytic activity and good stereoselectivity. (by machine translation)

Temperature-controlled bidirectional enantioselectivity in a dynamic catalyst for asymmetric hydrogenation

Asymmetric catalysis using enantiomerically pure catalysts is one of the most widely used methods for the preparation of enantiomerically pure compounds. The separate synthesis of both enantiomerically pure compounds requires tedious and time-consuming pr

Asymmetric chemoenzymatic synthesis of N-acetyl-α-amino esters based on lipase-catalyzed kinetic resolutions through interesterification reactions

Several phenylalanine analogs have been synthesized through a four-step route starting from easily available ethyl acetamidocyanoacetate. In a first reaction, and making use of phase transfer catalysts, this compound reacted with several alkyl halides, being benzyltributylammonium chloride identified as the best one for the production of a series of quaternary amino acids in moderate to excellent yields (52-95%). Then, the corresponding N-acetyl-phenylalanine methyl and allyl ester derivatives were obtained through acidic hydrolysis, esterification, and N-acetylation. Rhizomucor miehei lipase was found as a versatile enzyme for the resolution of these amino esters, finding the best results through interesterification reactions with butyl butyrate in acetonitrile. A great influence in the stereoselectivity was found depending on the chemical structure of the compound, achieving for the non- or para-substituted in the phenyl ring excellent stereoselectivities, being moderate for the meta-nitro derivative, while the ortho-nitro amino ester did not react.

Highly modular P-OP ligands for asymmetric hydrogenation: Synthesis, catalytic activity, and mechanism

A library of enantiomerically pure P-OP ligands (phosphine-phosphite), straightforwardly available in two synthetic steps from enantiopure Sharpless epoxy ethers is reported. Both the alkyloxy and phosphite groups can be optimized for maximum enantioselectivity and catalytic activity. Their excellent performance in the Rhcatalyzed asymmetric hydrogenation of a wide variety of functionalized alkenes (26 examples) and modular design makes them attractive for future applications. The lead catalyst incorporates an (S)-BINOL-derived (BINOL= 1,1'bi-2-naphthol) phosphite group with computational studies revealing that this moiety has a dual effect on the behavior of our P-OP ligands. On one hand, the electronic properties of phosphite hinder the binding and reaction of the substrate in two out of the four possible manifolds. On the other hand, the steric effects of the BINOL allow for discrimination between the two remaining manifolds, thereby elucidating the high efficiency of these catalysts.

Modular synthesis of the ClickFerrophos ligand family and their use in rhodium- and ruthenium-catalyzed asymmetric hydrogenation

A series of diphosphine ClickFerrophos ligands (CF), based on a triazoleferrocene backbone, was synthesized in a four-step sequence via click chemistry methodology. In addition to the four previously synthesized ligands CF1, CF4, CF7 and CF10, six novel C

NEW PHOSPHINE-PHOSPHITE LIGANDS

The invention relates to new phosphine-phosphite ligands for the preparation of a catalyst for the asymmetric hydrogenation of unsaturated hydrocarbon compounds, methods for their preparation and use thereof.