- Preparation method of 4AA
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The invention discloses a preparation method of 4AA. The preparation method comprises the following steps: S1, preparing a first intermediate from benzamide and a formaldehyde aqueous solution; S2, preparing a second intermediate from the first intermediate, thionyl chloride, toluene and n-heptane; S3, preparing a third intermediate from the second intermediate, methyl acetoacetate, sodium methoxide, toluene, diluted hydrochloric acid and isopropanol; S4, preparing a fourth intermediate from the third intermediate, reductase, ethyl acetate, saturated sodium bicarbonate and saturated salt water; S5, preparing a fifth intermediate from the fourth intermediate, imidazole, TBSCL and methylbenzene; S6, preparing a sixth intermediate from the fifth intermediate, ethanolamine, methanol and n-heptane; S7, preparing a seventh intermediate by using the sixth intermediate, a Grignard reagent and n-heptane; and S8, preparing 4AA from the seventh intermediate, ruthenium trichloride, potassium acetate, ethyl acetate, acetic acid and a peracetic acid solution.
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- Preparation method of (2S,3R)-2-acylaminomethyl-3-hydroxybutyrate
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The invention provides a preparation method of (2S,3R)-2-acylaminomethyl-3-hydroxybutyrate, which adopts a catalytic system composed of a bivalent ruthenium complex and a C3*-Tunephos series C2 axisymmetric bidentate phosphine ligand to carry out an asymmetric reduction reaction in a hydrogen atmosphere. The preparation method provided by the invention has the characteristics of high atom economy,greenness, no pollution, single selectivity, high production efficiency and the like, and the catalyst is easy to synthesize and low in production cost and has a good industrial application prospect.
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Paragraph 0047-0063; 0070-0075
(2020/08/22)
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- Asymmetric synthesis of optically active methyl-2-benzamido-methyl-3-hydroxy-butyrate by robust short-chain alcohol dehydrogenases from Burkholderia gladioli
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Three short-chain alcohol dehydrogenases from Burkholderia gladioli were discovered for their great potential in the dynamic kinetic asymmetric transformation of methyl 2-benzamido-methyl-3-oxobutanoate, and their screening against varied organic solvents and substrates. This is the first report of recombinant enzymes capable of achieving this reaction with the highest enantio- and diastereo-selectivity.
- Chen, Xiang,Liu, Zhi-Qiang,Huang, Jian-Feng,Lin, Chao-Ping,Zheng, Yu-Guo
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supporting information
p. 12328 - 12331
(2015/07/27)
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- Process for preparing optically active oxazolidinone derivative
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Disclosed is a process for preparing an optically active oxazolidinone derivative comprising allowing hydrazine to react on an optically active ester having a hydroxyl group at the 3-position which is represented by formula (II): wherein R1represents a lower alkyl group having 1 to 4 carbon atoms, a phenyl group, a methoxymethyl group, a benzyloxymethyl group, a benzyloxycarbonylaminomethyl group which may have a substituent or substituents on the benzene ring thereof, an acylaminomethyl group having 3 to 10 carbon atoms, or an alkyloxycarbonylaminomethyl group having 3 to 6 carbon atoms; R2and R3, which may be the same or different, each represent a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, a phenyl group, an acetylaminomethyl group, a benzoylaminomethyl group, or a benzyl group; and * indicates an asymmetric carbon atom, and subjecting the resulting hydrazide to Curtius rearrangement.
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- New Chiral Diphosphine Ligands Designed to Have a Narrow Dihedral Angle in the Biaryl Backbone
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A series of novel optically active diphosphine ligands, (4,4′-bi-1,3-benzodioxole)-5,5′-diylbis(diarylphosphine)s (6), which are called SEGPHOS, has been designed and synthesized with dihedral angles in the Ru complexes being less than that in the corresponding BINAP-Ru complex. The stereorecognition abilities of SEGPHOS-Ru complex catalysts in the asymmetric catalytic hydrogenation of a wide variety of carbonyl compounds are superior to those observed with BINAP-Ru complex catalysts.
- Saito, Takao,Yokozawa, Tohru,Ishizaki, Takero,Moroi, Takashi,Sayo, Noboru,Miura, Takashi,Kumobayashi, Hidenori
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p. 264 - 267
(2007/10/03)
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- Method of preparing a derivative of optically active azetidin-2-one
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To prepare the compound (1'R,3S)-3-(1'-tri-substituted silyloxyethyl)azetidin-2-one, (2S,3R)-2-aminomethyl-3-hydroxybutyric acid is reacted with an alcohol in the presence of at least one compound chosen from the group consisting of thionyl chloride, hydrogen chloride and p-toluene sulfonic acid, thereby obtaining a salt of the corresponding ester. The salt is reacted with a tri-substituted silane in the presence of a metallic catalyst, thereby protecting the hydroxy group of the ester and then reacted with a base, thereby obtaining an ester of (2S,3R)-2-aminomethyl-3-(tri-substituted silyloxy)butyric acid. Subsequently, the ester is transformed into lactam in the presence of a Grignard reagent or a metal amide, thereby obtaining (1'R,3S)-3-(1'-tri-substituted silyloxyethyl)azetidin-2-one. This compound provides a useful base for preparing β-lactam type antimicrobial agents such as carbapenem type agents.
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- Synthesis of Partially Hydrogenated 2,2'-Bis(diphenylphosphenyl)-1,1'-binaphthyl (BINAP) Ligands and Their Application to Catalytic Asymmetric Hydrogenation
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Three pairs of new axially dissymmetric bisphosphane ligands, (R)-(-)- and (S)-(+)-2,2'-bis(dicyclohexylphosphanyl)-1,1'-binaphthyl , (R)-(+)- and (S)-(-)-2,2'-bis(diphenylphosphanyl)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl and (R)-(-)- and (S)-(+)-2,2'-bis(dicyclohexylphosphanyl)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl , have been synthesized.The absolute configurations of the isomers 2 were determined by single-crystal X-ray diffraction of the linear 1:1 polymeric complex of (S)-(+)-2,2'-bis(dicyclohexylphosphinoyl)-1,1'-binaphthyl and (2R,3R)-(-)-di-O-benzoyltartaric acid , and those of the isomers 3 and 4 were established on the basis of CD spectra of the phosphanes and their bisoxides.X-Ray crystallographic studies of two cationic RhI complexes, (cod)>ClO4 and (cod)>ClO4 , revealed that complex (S)-17 possesses a dissymmetric structure, while complex (S)-18 has a pseudo-C2-symmetry and shows a significantly large dihedral angle between the two phenyl rings .The potentiality of ligand 3 for asymmetric catalysis was demonstrated in RuII-catalysed stereoselective hydrogenations of methyl 2-(benzamidomethyl)-3-oxobutanoate (21, in up to 92percent d.e. and 99percent e.e.) and geraniol (22, in 98percent optical purity).
- Zhang, Xiaoyong,Mashima, Kazushi,Koyano, Kinko,Sayo, Noboru,Kumobayashi, Hidenori,et al.
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p. 2309 - 2322
(2007/10/02)
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- Cationic BINAP-Ru(II) Halide Complexes: Highly Efficient Catalysts for Stereoselective Asymmetric Hydrogenation of α- and β-Functionalized Ketones
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Cationic ruthenium-BINAP complexes 5, 7, and 10 of the formula Y, where X = Cl, Br, I; Y = Cl, Br, I, BF4, B(C6H5)4; arene = benzene, p-cymene, ethyl benzoate, and their enantiomers have been prepared by the reaction of arene-ruthenium halide complexes 4, 6, and 9 with (S)-BINAP or (R)-BINAP.Structures of the complexes were established by spectroscopy, conductivity, and a single-crystal X-ray analysis (5d: orthorhombic, P21212; a=20.141(2) Angstroem, b=18.504(1) Angstroem, c=12.241(1) Angstroem, V=4562.0(7) Angstroem3, Z=4, R=0.078 for unique 4177 reflections).BINAP derivatives with various substituents at the para and meta positions of four phenyl rings on phosphorus atoms and their cationic Ru(II) complexes have also been synthesized.These BINAP-Ru(II) complexes have been used as catalysts for the asymmetric hydrogenation of various unsaturated organic compounds such as α- and β-keto esters, allylic alcohols, and α,β-unsaturated carboxylic acids in excellent diastereo- and/or enantioselectivities.Catalytic activities and stereoselectivities depend highly on reaction conditions such as solvent, temperature, and additives.Variation of halogen ligands bound to ruthenium atom and substituents on four phenyl rings of BINAP also have exerted remarkable effects on the efficiency of the catalysis.Asymmetric hydrogenation of methyl (+/-)-2-(benzamidomethyl)-3-oxobutanoate catalyzed by the species derived from 9c and 3,5-(t-Bu)2-BINAP afforded the corresponding syn-(2S,3R)-17 in 98percent de and 99percent ee.
- Mashima, Kazushi,Kusano, Koh-hei,Sato, Naomasa,Matsumura, Yoh-ichi,Nozaki, Kyoko,et al.
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p. 3064 - 3076
(2007/10/02)
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- Ruthenium catalyzed process for preparing 4-acetoxyazetidinones
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A simplified process for preparing 4-acetoxyazetidinones of formula (I): STR1 wherein Z is a hydrogen atom, a lower alkyl group or a hydroxyethyl group which may or may not be protected is disclosed. According to the invention, azetidinones of formula (II): STR2 wherein Z has the same meaning as defined above and Y is a hydrogen atom or a carboxyl group is reacted with acetic acid and an oxidizing agent in the presence of a ruthenium compound represented by the formula [Ru(B)2 (L)]m wherein B is Cl, Br or l, m is a positive integer, and L is 1,5-cyclooctadiene, norbornadiene, cycloheptatriene, cyclooctatetraene or benzene which may or may not have a lower alkyl group as a substituent, as a catalyst.
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- Process for preparing optically active 3-hydroxybutanoic acid
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A process for preparing an optically active 3-hydroxybutanoic acid represented by formula (I): STR1 wherein: R1 represents a protective group of carboxylic acid, and R2 represents a hydrogen atom; a lower alkyl group which may be substituted with a halogen atom; a lower alkoxy group; a phenyl group which may be substituted with a lower alkyl group or a lower alkoxy group; or a benzyloxy group which may be substituted with a lower alkyl group or a lower alkoxy group, is disclosed, comprising asymmetrically hydrogenating a 3-oxobutanoic acid ester represented by formula (II): STR2 wherein R1 and R2 are as defined above, in the presence of a ruthenium-optically active phosphine complex as a catalyst. The compound of formula (I) which is useful for synthesizing a 4-acetoxyazetidin-2-one derivative, a useful intermediate for obtaining penem antibiotics, can be prepared economically.
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- Highly Stereoselective Asymmetric Hydrogenation of 2-Benzamidomethyl-3-oxobutanoate catalysed by Cationic binap-Ruthenium(II) Complexes
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Highly diastereoselective hydrogenation of methyl 2-benzamidomethyl-3-oxobutanoate has been accomplished by using (p-cymene)>I and corresponding complexes of derivatives of binap as catalyst, giving methyl (2S,3R)-2-benzamidomethyl-3-hydroxybutanoate, a versatile intermediate for the synthesis of β-lactam antibiotics, in up to 98percent diastereoisomeric excess and 99percent enantiomeric excess.
- Mashima, Kazushi,Matsumura, Yoh-ichi,Kusano, Koh-hei,Kumobayashi, Hidenori,Sayo, Noboru,et al.
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p. 609 - 610
(2007/10/02)
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