- Catalytic enantioselective synthesis of β-amino alcohols by nitrene insertion
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Chiral β-amino alcohols are important building blocks for the synthesis of drugs, natural products, chiral auxiliaries, chiral ligands and chiral organocatalysts. The catalytic asymmetric β-amination of alcohols offers a direct strategy to access this class of molecules. Herein, we report a general intramolecular C(sp3)-H nitrene insertion method for the synthesis of chiral oxazolidin-2-ones as precursors of chiral β-amino alcohols. Specifically, the ring-closing C(sp3)-H amination of N-benzoyloxycarbamates with 2 mol% of a chiral ruthenium catalyst provides cyclic carbamates in up to 99% yield and with up to 99% ee. The method is applicable to benzylic, allylic, and propargylic C-H bonds and can even be applied to completely non-activated C (sp3)-H bonds, although with somewhat reduced yields and stereoselectivities. The obtained cyclic carbamates can subsequently be hydrolyzed to obtain chiral β-amino alcohols. The method is very practical as the catalyst can be easily synthesized on a gram scale and can be recycled after the reaction for further use. The synthetic value of the new method is demonstrated with the asymmetric synthesis of a chiral oxazolidin-2-one as intermediate for the synthesis of the natural product aurantioclavine and chiral β-amino alcohols that are intermediates for the synthesis of chiral amino acids, indane-derived chiral Box-ligands, and the natural products dihydrohamacanthin A and dragmacidin A.[Figure not available: see fulltext.].
- Zhou, Zijun,Tan, Yuqi,Shen, Xiang,Ivlev, Sergei,Meggers, Eric
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p. 452 - 458
(2020/12/31)
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- Stereoselective Synthesis of Enantiopure Oxazolidinones via Biocatalytic Asymmetric Aminohydroxylation of Alkenes
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Chiral oxazolidinones are of significance in both medicinal and synthetic chemistry, while preparing these compounds usually involves using expensive starting materials and harsh reaction conditions. Herein, a one-pot biocatalytic cascade process was developed for stereo- and regioselective aminohydroxylation of diverse alkenes by combining styrene monooxygenase and halohydrin dehalogenase, providing an approach to enantiopure oxazolidinones. (Figure presented.).
- Zhou, Xiao-Ying,Wan, Nan-Wei,Li, Ying-Na,Ma, Ran,Cui, Bao-Dong,Han, Wen-Yong,Chen, Yong-Zheng
-
supporting information
p. 4343 - 4348
(2021/08/03)
-
- Chiral separation materials based on derivatives of 6-amino-6-deoxyamylose
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In order to develop new type of chiral separation materials, in this study, 6-amino-6-deoxyamylose was used as chiral starting material with which 10 derivatives were synthesized. The amino group in 6-amino-6-deoxyamylose was selectively acylated and then the hydroxyl groups were carbamoylated yielding amylose 6-amido-6-deoxy-2,3-bis(phenylcarbamate)s, which were employed as chiral selectors (CSs) for chiral stationary phases of high-performance liquid chromatography. The resulted 6-amido-6-deoxyamyloses and amylose 6-amido-6-deoxy-2,3-bis(phenylcarbamate)s were characterized by IR, 1H NMR, and elemental analysis. Enantioseparation evaluations indicated that most of the CSs demonstrated a moderate chiral recognition capability. The 6-nonphenyl (6-nonPh) CS of amylose 6-cyclohexylformamido-6-deoxy-2,3-bis(3,5-dimethylphenylcarbamate) showed the highest enantioselectivity towards the tested chiral analytes; the phenyl-heterogeneous (Ph-hetero) CS of amylose 6-(4-methylbenzamido)-6-deoxy-2,3-bis(3,5-dimethylphenylcarbamate) baseline separated the most chiral analytes; the phenyl-homogeneous (Ph-homo) CS of amylose 6-(3,5-dimethylbenzamido)-6-deoxy-2,3-bis(3,5-dimethylphenylcarbamate) also exhibited a good enantioseparation capability among the developed CSs. Regarding Ph-hetero CSs, the enantioselectivity depended on the combination of the substituent at 6-position and that at 2- and 3-positions; as for Ph-homo CSs, the enantioselectivity was related to the substituent at 2-, 3-, and 6-positions; with respect to 6-nonPh CSs, the retention factor of most analytes on the corresponding CSPs was lower than that on Ph-hetero and Ph-homo CSPs in the same mobile phases, indicating π–π interactions did occur during enantioseparation. Although the substituent at 6-position could not provide π–π interactions, the 6-nonPh CSs demonstrated an equivalent or even higher enantioselectivity compared with the Ph-homo and Ph-hetero CSs.
- Gao, Ya-Ya,Zhang, Yu-Hang,Zhang, Shan,Chen, Wei,Bai, Zheng-Wu
-
supporting information
p. 899 - 914
(2021/10/07)
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- Asymmetric catalysis with a chiral-at-osmium complex
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The first example of a chiral osmium catalyst is reported in which the overall chirality originates exclusively from a stereogenic metal center (metal-centered chirality) with all coordinating ligands being achiral. The non-C2-symmetric chiral-at-metal complex contains two cyclometalated 7-methyl-1,7-phenanthrolinium heterocycles which can be described as two chelating pyridylidene remote N-heterocyclic carbene (rNHC) ligands. The octahedral coordination sphere is completed with one CO and one acetonitrile ligand. A monodentate chiral oxazoline ligand is used as a chiral auxiliary ligand to obtain enantiomerically pure chiral-at-osmium complexes (>99?:?1 e.r.). Finally, it is demonstrated that the developed chiral-at-osmium complex is suitable for ring-closing enantioselective C(sp3)-H aminations, including the first example of catalytic enantioselective cyclizations of azidoformates to chiral 2-oxazolidinones.
- Wang, Guanghui,Zhou, Zijun,Shen, Xiang,Ivlev, Sergei,Meggers, Eric
-
supporting information
p. 7714 - 7717
(2020/07/27)
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- Synthesis of Chiral 5-Aryl-2-oxazolidinones via Halohydrin Dehalogenase-Catalyzed Enantio- and Regioselective Ring-Opening of Styrene Oxides
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An efficient biocatalytic approach for enantio- and regioselective ring-opening of styrene oxides with cyanate was developed by using the halohydrin dehalogenase HheC from Agrobacterium radiobacter AD1, generating the corresponding chiral 5-aryl-2-oxazoli
- Wan, Nanwei,Zhou, Xiaoying,Ma, Ran,Tian, Jiawei,Wang, Huihui,Cui, Baodong,Han, Wenyong,Chen, Yongzheng
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p. 1201 - 1207
(2020/02/05)
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- Efficient Access to Chiral 2-Oxazolidinones via Ni-Catalyzed Asymmetric Hydrogenation: Scope Study, Mechanistic Explanation, and Origin of Enantioselectivity
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Cheap transition metal Ni-catalyzed asymmetric hydrogenation of 2-oxazolones was successfully developed, which provided an efficient synthetic strategy to prepare various chiral 2-oxazolidinones with 95%-99% yields and 97%->99% ee. The gram-scale hydrogenation could be proceeded well with >99% ee in the presence of low catalyst loading (up to 3350 TON). This Ni-catalyzed hydrogenation protocol demonstrated great synthetic utility, and the chiral 2-oxazolidinone product was easily converted to a variety of other important molecules in good yields and without loss of ee values, such as chiral dihydrothiophene-2(3H)-thione, amino alcohol, oxazoline ligand, and allenamide. Moreover, a series of deuterium labeling experiments, control experiments, and DFT calculations were conducted to illustrate a reasonable catalytic mechanism for this Ni-catalyzed asymmetric hydrogenation, which involved a tautomerization between the enamine and its isomer imine and then went through asymmetric 1,2-addition of Ni(II)-H to the preferred imine.
- Dong, Xiu-Qin,Liu, Yuanhua,Wang, Heng,Wang, Minyan,Yang, Xuanliang,Yi, Zhiyuan,Yin, Congcong,Zhang, Xumu
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p. 11153 - 11161
(2020/11/23)
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- Novel chiral stationary phases based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin combining cinchona alkaloid moiety
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Novel chiral selectors based on 3,5-dimethyl phenylcarbamoylated β-cyclodextrin connecting quinine (QN) or quinidine (QD) moiety were synthesized and immobilized on silica gel. Their chromatographic performances were investigated by comparing to the 3,5-dimethyl phenylcarbamoylated β-cyclodextrin (β-CD) chiral stationary phase (CSP) and 9-O-(tert-butylcarbamoyl)-QN-based CSP (QN-AX). Fmoc-protected amino acids, chiral drug cloprostenol (which has been successfully employed in veterinary medicine), and neutral chiral analytes were evaluated on CSPs, and the results showed that the novel CSPs characterized as both enantioseparation capabilities of CD-based CSP and QN/QD-based CSPs have broader application range than β-CD-based CSP or QN/QD-based CSPs. It was found that QN/QD moieties play a dominant role in the overall enantioseparation process of Fmoc-amino acids accompanied by the synergistic effect of β-CD moiety, which lead to the different enantioseparation of β-CD-QN-based CSP and β-CD-QD-based CSP. Furthermore, new CSPs retain extraordinary enantioseparation of cyclodextrin-based CSP for some neutral analytes on normal phase and even exhibit better enantioseparation than the corresponding β-CD-based CSP for certain samples.
- Zhu, Lunan,Zhu, Junchen,Sun, Xiaotong,Wu, Yaling,Wang, Huiying,Cheng, Lingping,Shen, Jiawei,Ke, Yanxiong
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p. 1080 - 1090
(2020/05/25)
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- Regioselective Ring-Opening of Styrene Oxide Derivatives Using Halohydrin Dehalogenase for Synthesis of 4-Aryloxazolidinones
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A biocatalytic approach towards a range of 4-aryloxazolidinones is developed using a halohydrin dehalogenase from Ilumatobacter coccineus (HheG) as biocatalyst. The method is based on the HheG-catalyzed α-position regioselective ring-opening of styrene oxide derivatives with cyanate as a nucleophile, producing the corresponding 4-aryloxazolidinones in moderate to good yields. Synthesis of enantiopure 4-aryloxazolidinones is also achievable using chiral epoxide materials. (Figure presented.).
- Wan, Nanwei,Tian, Jiawei,Zhou, Xiaoying,Wang, Huihui,Cui, Baodong,Han, Wenyong,Chen, Yongzheng
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p. 4651 - 4655
(2019/08/27)
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- A novel homochiral metal-organic framework with an expanded open cage based on (: R)-3,3′-bis(6-carboxy-2-naphthyl)-2,2′-dihydroxy-1,1′-binaphthyl: synthesis, X-ray structure and efficient HPLC enantiomer separation
-
A new homochiral metal-organic framework (MOF) with an expanded open cage based on the (R)-3,3′-bis(6-carboxy-2-naphthyl)-2,2′-dihydroxy-1,1′-binaphthyl ligand was synthesized and utilized as a novel chiral stationary phase for high-performance liquid chromatography. Twelve racemates including sec-alcohols, sulfoxides, epoxides, lactone, 1,3-dioxolan-2-one, and oxazolidinone were used as analytes for evaluating the separation properties of the chiral-MOF-packed column. Experimentally, the homochiral MOF offered good molecular recognition ability, which suggests good prospects for the application of chiral MOFs as stationary phases for enantioseparation.
- Tanaka, Koichi,Kawakita, Tomohiro,Morawiak, Maja,Urbanczyk-Lipkowska, Zofia
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p. 487 - 493
(2019/01/21)
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- Diastereoselective Electrophilic Trifluoromethylthiolation of Chiral Oxazolidinones: Access to Enantiopure α-SCF3 Alcohols
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Lithium imide enolates featuring Evans’ chiral oxazolidinone auxiliary were involved in diastereoselective α-trifluoromethylthiolation with electrophilic SCF3 donors. Diastereopure products were isolated and converted to enantiopure α-SCF3 alcohols without racemisation. (Figure presented.).
- Chachignon, Hélène,Kondrashov, Evgeniy V.,Cahard, Dominique
-
supporting information
p. 965 - 971
(2018/01/27)
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- A General Catalytic Method for Highly Cost- and Atom-Efficient Nucleophilic Substitutions
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A general formamide-catalyzed protocol for the efficient transformation of alcohols into alkyl chlorides, which is promoted by substoichiometric amounts (down to 34 mol %) of inexpensive trichlorotriazine (TCT), is introduced. This is the first example of a TCT-mediated dihydroxychlorination of an OH-containing substrate (e.g., alcohols and carboxylic acids) in which all three chlorine atoms of TCT are transferred to the starting material. The consequently enhanced atom economy facilitates a significantly improved waste balance (E-factors down to 4), cost efficiency, and scalability (>50 g). Furthermore, the current procedure is distinguished by high levels of functional-group compatibility and stereoselectivity, as only weakly acidic cyanuric acid is released as exclusive byproduct. Finally, a one-pot protocol for the preparation of amines, azides, ethers, and sulfides enabled the synthesis of the drug rivastigmine with twofold SN2 inversion, which demonstrates the high practical value of the presented method.
- Huy, Peter H.,Filbrich, Isabel
-
supporting information
p. 7410 - 7416
(2018/04/30)
-
- Synthesis of new C3 symmetric amino acid- and aminoalcohol-containing chiral stationary phases and application to HPLC enantioseparations
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We recently reported a new C3-symmetric (R)-phenylglycinol N-1,3,5-benzenetricarboxylic acid-derived chiral high-performance liquid chromatography (HPLC) stationary phase (CSP 1) that demonstrated better results as compared to a previously described N-3,5-dintrobenzoyl (DNB) (R)-phenylglycinol-derived CSP. Over a decade ago, (S)-leucinol, (R)-phenylglycine, and (S)-leucine derivatives were used as the starting materials of 3,5-DNB-based Pirkle-type CSPs for chiral separation. In this study, three new C3-symmetric CSPs (CSP 2, 3, and 4) were prepared by combining the ideas and results mentioned above. Here we describe the synthetic procedures and applications of the new C3-symmetric CSPs (CSP 2–CSP 4).
- Yu, Jeongjae,Armstrong, Daniel W.,Ryoo, Jae Jeong
-
-
- Evaluation of the Edman degradation product of vancomycin bonded to core-shell particles as a new HPLC chiral stationary phase
-
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.
- Hellinghausen, Garrett,Lopez, Diego A.,Lee, Jauh T.,Wang, Yadi,Weatherly, Choyce A.,Portillo, Abiud E.,Berthod, Alain,Armstrong, Daniel W.
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p. 1067 - 1078
(2018/08/01)
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- Continuous Flow Synthesis of Carbonylated Heterocycles via Pd-Catalyzed Oxidative Carbonylation Using CO and O2 at Elevated Temperatures and Pressures
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A continuous-flow Pd-catalyzed oxidative carbonylation protocol utilizing CO and O2 gas for the synthesis of carbonylated heterocycles is described. The optimization of temperature, pressure, CO/O2 ratio, catalyst loading, and reaction time resulted in process intensified conditions for this transformation. The optimized continuous flow conditions (120 °C, 20 bar pressure, 24 min residence time) were used to prepare a number of benzoxazolone, 2-benzoxazolidinone, and other biologically and synthetically important five- and six-membered carbonylated heterocycles in good overall yield and purity (14 examples). The continuous-flow process enables the safe and scalable oxidative carbonylation using CO/O2 under elevated pressures and temperatures.
- Chen, Yuesu,Hone, Christopher A.,Gutmann, Bernhard,Kappe, C. Oliver
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p. 1080 - 1087
(2017/07/26)
-
- Diastereoselective hydrogenation of α,β-unsaturated but-2-enamides to access the chiral 3-(p-tolyl) butanoic acids
-
An alternative methodology for the synthesis of chiral 3-(p-tolyl) butanoic acids is presented. This was accomplished through the diastereoselective hydrogenation reaction of different chiral N-3-(p-tolyl) but-2-enamides, using Pd/C in EtOH, to produce the corresponding chiral N-3-(p-tolyl) butanamides with high chemical yields and moderate diastereomeric ratios. Removal of the chiral auxiliary from N-3-(p-tolyl) butanamides gave the respective enantiomerically pure acids.
- Jiménez, Jacqueline,López, Mildred,Carranza, Vladimir,Mendoza, Angel,Varela, Jenaro,Sansinenea, Estibaliz,Ortiz, Aurelio
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p. 235 - 239
(2016/12/28)
-
- Efficient Routes to a Diverse Array of Amino Alcohol-Derived Chiral Fragments
-
Efficient syntheses of chiral fragments derived from chiral amino alcohols are described. Several unique scaffolds were readily accessed in 1-5 synthetic steps leading to 45 chiral fragments, including oxazolidinones, morpholinones, lactams, and sultams. These fragments have molecular weights ranging from 100 to 255 Da and are soluble in water (0.085 to >15 mM).
- Haftchenary, Sina,Nelson, Shawn D.,Furst, Laura,Dandapani, Sivaraman,Ferrara, Steven J.,Bo?kovi?, ?arko V.,Figueroa Lazú, Samuel,Guerrero, Adrian M.,Serrano, Juan C.,Crews, Demarcus K.,Brackeen, Cristina,Mowat, Jeffrey,Brumby, Thomas,Bauser, Marcus,Schreiber, Stuart L.,Phillips, Andrew J.
-
supporting information
p. 569 - 574
(2016/10/06)
-
- Computer-assisted design, synthesis, binding and cytotoxicity assessments of new 1-(4-(aryl(methyl)amino)butyl)-heterocyclic sigma 1 ligands
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In this work we applied a blend of computational and synthetic techniques with the aim to design, synthesize, and characterize new σ1 receptor (σ1R) ligands. Starting from the structure of previously reported, high-affinity benzoxazolone-based σ1 ligands, the three-dimensional homology model of the σ1R was exploited for retrieving the molecular determinants to fulfill the optimal pharmacophore requirements. Accordingly, the benzoxazolone moiety was replaced by other heterocyclic scaffolds, the relevant conformational space in the σ1R binding cavity was explored, and the effect on σ1R binding affinity was ultimately assessed. Next, the compounds designed in silico were synthesized, and their affinity and selectivity toward σ1and σ2receptors were tested. Finally, a representative series of best σ1R binders were assayed for cytotoxic activity on the SH-SY5Y human neuroblastoma cell line. Specifically, the new 4-phenyloxazolidin-2-one derivatives 2b (i.e., (R)-2b and (S)-2b) emerged as potential leads for further development as σ1R agents, as they were found endowed with the highest σ1R affinity (Kiσ1 values in the range 0.95–9.3?nM), and showed minimal cytotoxic levels exhibited in the selected, cell-based test, in line with a σ1R agonist behavior.
- Zampieri, Daniele,Vio, Luciano,Fermeglia, Maurizio,Pricl, Sabrina,Wünsch, Bernhard,Schepmann, Dirk,Romano, Maurizio,Mamolo, Maria Grazia,Laurini, Erik
-
p. 712 - 726
(2016/07/06)
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- (Enantio)selective Hydrogen Autotransfer: Ruthenium-Catalyzed Synthesis of Oxazolidin-2-ones from Urea and Diols
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A novel strategy for the synthesis of oxazolidin-2-ones from vicinal diols and urea is described. In this heterocycle synthesis, two different C?O and C?N bonds are sequentially formed in a domino process consisting of nucleophilic substitution and alcohol amination. The use of readily available starting materials and the good atom economy render this process environmentally benign. While this transformation is already highly chemo- and regioselective, we also developed the first asymmetric version of this method using (R)-(+)-MeO-BIPHEP as the chiral ligand.
- Pe?a-López, Miguel,Neumann, Helfried,Beller, Matthias
-
supporting information
p. 7826 - 7830
(2016/07/07)
-
- New synthetic strategy for chiral 2-oxazolidinones derivatives via rhodium-catalyzed asymmetric hydrogenation
-
Asymmetric hydrogenation of 4-substituted cyclic enamido esters catalyzed by a rhodium-TangPhos complex provides an efficient method for the synthesis of chiral 4-substituted oxazolinones with excellent yields and good enantioselectivities. The products are valuable chiral building blocks and the applications as chiral auxiliaries and pharmaceuticals are well-known.
- Wang, Qingli,Tan, Xuefeng,Zhu, Ziyue,Dong, Xiu-Qin,Zhang, Xumu
-
supporting information
p. 658 - 662
(2016/01/26)
-
- Eluent tolerance and enantioseparation recovery of chiral packing materials based on chitosan bis(phenylcarbamate)-(n-octyl urea)s for high performance liquid chromatography
-
The goal of the present work was to study the influence of the swelling of chitosan derivatives on the enantioseparation and the separation performance recovery of chiral stationary phases (CSPs) based on these derivatives. Therefore, six chitosan bis(phenylcarbamate)-(n-octyl urea)s were synthesized, which were coated on macroporous 3-aminopropyl silica gel affording new CSPs. Most of the CSPs demonstrated strong enantioseparation capability for the tested chiral compounds. The swelling capacity of the chitosan bis(phenylcarbamate)-(n-octyl urea)s in ethyl acetate, acetone and tetrahydrofuran (THF) was evaluated. Among the chitosan derivatives, the chitosan bis(3,5-dichlorophenylcarbamate)-(n-octyl urea) polymer showed the highest swelling capacity in ethyl acetate and THF. The polymer-based CSPs could be utilized with pure ethyl acetate and a normal phase containing 70% THF, but was damaged by pure THF. On the other hand, the separation performance of the damaged CSP could be recovered after it was allowed to stand for a period of time. The observations are important for the development and application of polysaccharide derivative-based CSPs.
- Wang, Jing,Huang, Shao-Hua,Chen, Wei,Bai, Zheng-Wu
-
supporting information
(2016/12/02)
-
- Catalytic Oxidative Carbonylation of Amino Moieties to Ureas, Oxamides, 2-Oxazolidinones, and Benzoxazolones
-
The direct syntheses of ureas, oxamides, 2-oxazolidinones, and benzoxazolones by the oxidative carbonylation of amines, β-amino alcohols, and 2-aminophenols allows us to obtain high value added molecules, which have a large number of important applications in several fields, from very simple building blocks. We have found that it is possible to perform these transformations using the PdI2/KI catalytic system in an ionic liquid, such as 1-butyl-3-methylimidazolium tetrafluoroborate, as the solvent, the solvent/catalyst system can be recycled several times with only a slight loss of activity, and the product can be recovered easily by crystallization.
- Mancuso, Raffaella,Raut, Dnyaneshwar S.,Della Ca, Nicola,Fini, Francesco,Carfagna, Carla,Gabriele, Bartolo
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p. 2204 - 2211
(2015/07/15)
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- Dehydrative synthesis of chiral oxazolidinones catalyzed by alkali metal carbonates under low pressure of CO2
-
Dehydrative synthesis of oxazolidinones from amino alcohols and CO 2 was achieved in the presence of alkali metal carbonates such as Cs2CO3 as catalyst. It is noteworthy that 1 atm of CO 2 is enough for the reaction to proceed and no special dehydrating agent is required in this system. A mechanstic study showed that the OH of amino alcohol acts as nucleophile and the OH in the carbamic acid moiety is liberated during the cyclization process.
- Foo, Siong Wan,Takada, Yuki,Yamazaki, Yusuke,Saito, Susumu
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supporting information
p. 4717 - 4720
(2013/08/23)
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- SUBSTITUTED N-PENTANAMIDE COMPOUNDS, PREPARATION METHODS AND USES THEREOF
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The present invention relates to a (2R, 3R)-3-(3-substituted phenyl)-2-methyl n-pentanamide compounds as shown in the formula I and the preparation method thereof, wherein, the substituents are as defined in the specification, the present invention further relates to a use of the above compounds for the preparation of tapentadol II or its pharmaceutically acceptable salt, and the intermediates involved in the preparation process.
- -
-
Paragraph 0090; 0091
(2014/01/08)
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- Ethyl imidazole-1-carboxylate (EImC) as a carbonylating agent: Efficient synthesis of oxazolidin-2-ones from amino alcohols
-
Various substituted oxazolidin-2-ones were synthesized from the corresponding amino alcohols using ethyl imidazole- 1-carboxylate (EImC). Highly substituted and sterically hindered amino alcohols and amino alcohols having a free hydroxy group were cyclized to oxazolidin-2-ones efficiently. This method is simple and produces oxazolidin-2-ones in very good yield.
- Veeraswamy,Reddy, K. Indrasena,Ragavan, R. Venkat,Yennam, Satyanarayana,Jayashree
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p. 109 - 111
(2013/03/14)
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- Catalytic, enantioselective N-acylation of lactams and thiolactams using amidine-based catalysts
-
In contrast to alcohols and amines, racemic lactams and thiolactams cannot be resolved directly via enzymatic acylation or classical resolution. Asymmetric N-acylation promoted by amidine-based catalysts, particularly Cl-PIQ 2 and BTM 3, provides a convenient method for the kinetic resolution of these valuable compounds and often achieves excellent levels of enantioselectivity in this process. Density functional theory calculations indicate that the reaction occurs via N-acylation of the lactim tautomer and that cation-π interactions play a key role in the chiral recognition of lactam substrates.
- Yang, Xing,Bumbu, Valentina D.,Liu, Peng,Li, Ximin,Jiang, Hui,Uffman, Eric W.,Guo, Lei,Zhang, Wei,Jiang, Xuntian,Houk,Birman, Vladimir B.
-
supporting information
p. 17605 - 17612
(2013/01/15)
-
- Desulfurization-oxygenation of chiral 1,3-thiazolidine-2-thiones and 1,3-oxazolidine-2-thiones using propylene oxide and microwave irradiation
-
An efficient method for the desulfurization-oxygenation of 1,3-thiazolidine-2-thiones and 1,3-oxazolidine-2-thiones using propylene oxide and employing microwave irradiation is described. This strategy of oxygenation of the thiocarbonyl group provides an attractive methodology to prepare chiral 1,3-thiazolidin-2-ones and 1,3-oxazolidin-2-ones from the corresponding precursors in good yields. Copyright
- Minor-Villar, Leticia,Tello-Aburto, Rodolfo,Olivo, Horacio F.,Fuentes, Aydee,Romero-Ortega, Moises
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p. 2835 - 2839
(2013/02/21)
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- Synthesis of cyanoacetyl oxazolidinones
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Carefully controlled displacement of chiral chloroacetyl imides with cyanide afforded previously unreported cyanoacetimides in good overall yield. Knoevenagel condensation of the cyanoacetimides to furnish acrylonitriles was also demonstrated. Georg Thiem
- Weeber, Kaitlyn M.,Schwarz, Jacob B.
-
experimental part
p. 1993 - 1996
(2012/09/07)
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- Efficient parallel resolution of pentafluorophenyl active esters using quasi-enantiomeric combinations of oxazolidin-2-ones
-
The parallel resolution of racemic pentafluorophenyl 2-aryl/ phenylpropanoates and butanoates using an equimolar combination of quasi-enantiomeric Evans oxazolidin-2-ones is discussed. The levels of diastereoselectivity were excellent (>90% de) leading to separable quasi-enantiomeric oxazolidin-2-ones in good yield. This methodology was used to resolve a series of structurally related 2-aryl/phenylpropanoic and butanoic acids.
- Shaye, Najla Al,Chavda, Sameer,Coulbeck, Elliot,Eames, Jason,Yohannes, Yonas
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experimental part
p. 439 - 463
(2011/06/17)
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- Development of bifunctional aza-bis(oxazoline) copper catalysts for enantioselective henry reaction
-
Base-functionalized aza-bis(oxazoline) ligands were prepared to explore the concept of dual activation through the Lewis acid and a tethered tertiary amine base. The catalytic activity of the Cu complex was evaluated for the asymmetric Henry reaction. Compared with a corresponding unfunctionalized copper complex with external 1-benzyl-4-ethylpiperazine base, the ethylpiperazine- functionalized aza-bis(oxazoline) copper catalyst resulted in rate acceleration (2.5 times) as well as improved enantioselectivity (72% ee vs 92% ee).
- Lang, Kai,Park, Jongwoo,Hong, Sukwon
-
supporting information; experimental part
p. 6424 - 6435
(2010/12/19)
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- Carbon dioxide as a carbonylating agent in the synthesis of 2-oxazolidinones, 2-oxazinones, and cyclic ureas: Scope and limitations
-
Carbon dioxide can be used as a convenient carbonylating agent in the synthesis of 2-oxazolidinones, 2-oxazinones, and cyclic ureas. The transient carbamate anion generated by treating a primary or secondary amine group in basic media can be activated with phosphorylating agents such as Diphenylphosphoryl azide (DPPA) and Diphenyl chlorophosphate (DPPCl) but also with other types of electrophiles such as SOCl2, TsCl, or AcCl. The intramolecular trapping of the activated carbamate by a hydroxyl group leads to the formation of 2-oxazolidinones or 2-oxazinones in good to excellent yields. This methodology was successfully applied to the synthesis of cyclic ureas up to 7-membered rings from the corresponding diamines.
- Paz, Jairo,Perez-Balado, Carlos,Iglesias, Beatriz,Munoz, Luis
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experimental part
p. 3037 - 3046
(2010/07/15)
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- Resolution of pentafluorophenyl esters using oxazolidin-2-ones
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A series of structurally related racemic pentafluorophenyl active esters were resolved using an equimolar amount of (S)-4-phenyloxazolidin-2-one. The levels of diastereocontrol were found to be excellent (80-96% de) at ～40% conversion.
- Al Shaye, Najla,Eames, Jason
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scheme or table
p. 5892 - 5895
(2010/11/18)
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- Parallel kinetic resolution of D-labelled 2-aryl-propionic and butanoic acids using quasi-enantiomeric combinations of oxazolidin-2-ones
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The parallel kinetic resolution of racemic 2-aryl-2-deuterio-propionic and butanoic acids using an equimolar combination of quasi-enantiomeric oxazolidin-2-ones is discussed. The levels of diastereoselectivity were high leading to enantiomerically pure D-
- Coulbeck, Elliot,Dingjan, Marco,Eames, Jason
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experimental part
p. 193 - 205
(2010/11/18)
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- Carbonylation with CO2 and phosphorus electrophiles: A convenient method for the synthesis of 2-oxazolidinones from 1,2-amino alcohols
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2-Oxazolidinones were prepared in good yields from 1,2-amino alcohols and CO2 in the presence of tetramethyl-phenylguanidine (PhTMG) as a base and a variety of phosphorus electrophiles under mild conditions. This procedure is advantageous over previous methodologies and relies on a novel carbonylation procedure that utilizes nontoxic CO2 and phosphorus electrophiles. Georg Thieme Verlag Stuttgart.
- Paz, Jairo,Pérez-Balado, Carlos,Iglesias, Beatriz,Mu?oz, Luis
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scheme or table
p. 395 - 398
(2009/08/09)
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- Asymmetric synthesis of amlnocyclopropanes and N-cyclopropylamino alcohols through direct amidocyclopropanation of alkenes using chiral organozinc carbenoids
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Chiral N-(diethoxymethyl)oxazolidinones, prepared from the corresponding oxazolidinones by heating in trielhyl orthoformate, can be used as organozinc carbenoid precursors for the direct enantioselective amidocyclopropanation of alkenes. The reaction is successful with a wide range of oxazolidinones and alkenes and proceeds with moderate to excellent yield and stereoselectivity. In most cases the trans/exo amidocyclopropane product, is favoured, although certain cyclic alkenes such as indene favour the formation of the endo cyclopropane. The products can be readily elaborated to produce cyclopropylamino alcohols and amino acids. Wiley-VCH Verlag GmbH & Co. KGaA.
- Begis, Guillaume,Cladingboel, David E.,Jerome, Laure,Motherwell, William B.,Sheppard, Tom D.
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experimental part
p. 1532 - 1548
(2009/09/08)
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- Configurational flexibility of epimeric β-aminothioether-chelated ruthenium(II) η6-arene complex salts
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Five chiral β-aminothioethers were obtained via different routes orientated on literature protocols. Three of these β-aminothioethers were reacted with two di-μ-chloro-bis{chloro[η6-arene]- ruthenium(II)} derivatives, resulting in the title complex salts. The complex cations exhibit three stereocenters, viz. ruthenium and sulfur atoms and the chiral benzylic carbon atom of the chelate ligand backbone. Both, ruthenium and sulfur stereocenters epimerize into a mixture of four NMR distinguishable diastereomers in equilibrium, but the designed chiral benzylic carbon atom is stable under all conditions applied so far. The relative diastereomer concentrations in solution depend mainly on the spatial requirements of the η6-arene ligand rather than on the thioether moiety. Diastereomer ratios and the absolute configurations in solution were studied by NMR and CD spectroscopy. The spectroscopic results fit to the absolute X-ray crystal structure parameters determined for the diastereomers present in the crystalline state.
- Weber, Immo,Heinemann, Frank W.,Bauer, Walter,Zenneck, Ulrich
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experimental part
p. 123 - 140
(2009/04/11)
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- Reactive intermediates from DMDO oxidation of ynamides. Trapping of a de novo chiral push-pull carbene via cyclopropanation
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The reaction profile of DMDO oxidations of ynamides is described. This work illustrates the first examples of highly diastereoseiective intramolecular cyclopropanations of a push-pull carbene derived from alkyne oxidation. In addition, the ynamide oxidati
- Al-Rashid, Ziyad F.,Hsung, Richard P.
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p. 661 - 663
(2008/09/17)
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- Catalysts for use in enantioselective synthesis
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Disclosed are compounds having the following formula: in which Z11 is selected from a substituted or unsubstituted saturated adamantyl or other polycyclic group and a substituted or unsubstituted branched acyclic group containing at least 5 carbon atoms at least one of which is a tertiary carbon; and in which Z12 is a cyclic imide. Methods of using these compounds as chiral catalysts for carbenoid reactions and for enantioselective C—H aminations are also described.
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Page/Page column 60; 65
(2008/12/05)
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- Parallel kinetic resolution of active esters using designer oxazolidin-2-ones derived from phenylglycine
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The parallel kinetic resolution of racemic pentafluorophenyl 2-phenylpropionate using an equimolar combination of quasi-enantiomeric oxazolidin-2-ones is discussed. The levels of diastereoselectivity were excellent (>90% de) leading to separable quasi-enantiomeric oxazolidin-2-one adducts in good yield. This methodology was subsequently used to resolve a series of 2-aryl propionic and butanoic acids.
- Chavda, Sameer,Coulbeck, Elliot,Dingjan, Marco,Eames, Jason,Flinn, Anthony,Northen, Julian
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p. 1536 - 1548
(2008/12/21)
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- Probing the parallel resolution of Mosher's acid using a combination of quasi-enantiomeric oxazolidin-2-ones
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Mosher's acid (2-methoxy-2-phenyl-2-trifluoromethylacetic acid) was resolved by parallel resolution of its corresponding pentafluorophenyl active ester using a quasi-enantiomeric combination of oxazolidin-2-ones.
- Chavda, Sameer,Coulbeck, Elliot,Dingjan, Marco,Eames, Jason,Motevalli, Majid
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p. 1274 - 1284
(2008/12/20)
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- Enantioselective amination of silylketene acetals with (N-arylsulfonylimino)phenyliodinanes catalyzed by chiral dirhodium(II) carboxylates: asymmetric synthesis of phenylglycine derivatives
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The first catalytic enantioselective amination of silylketene acetals with (N-arylsulfonylimino)phenyliodinanes is described. The reaction of silylketene acetals derived from methyl phenylacetates with [N-(2-nitrophenylsulfonyl)imino]phenyliodinane (NsN =
- Tanaka, Masahiko,Kurosaki, Yasunobu,Washio, Takuya,Anada, Masahiro,Hashimoto, Shunichi
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p. 8799 - 8802
(2008/03/18)
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- Dirhodium tetracarboxylates derived from adamantylglycine as chiral catalysts for enantioselective C-H aminations
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(Chemical Equation Presented) The dirhodium tetracarboxylate, Rh 2(S-TCPTAD)4, derived from adamantylglycine, is an effective chiral catalyst for both inter- and intramolecular C-H aminations.
- Reddy, Ravisekhara P.,Davies, Huw M. L.
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p. 5013 - 5016
(2007/10/03)
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- Pd(OAc)2-catalyzed carbonylation of amines
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A phosphine-free catalytic system [Pd(OAc)2-Cu(OAc) 2-air] induced a substrate-specific carbonylation of amines in boiling toluene under CO gas (1 atm). Symmetrical N,N′-dialkylureas were obtained by the carbonylation of primary amines. N,N,N′-Trialkylureas were selectively formed by addition of a secondary amine to the above reaction vessel. Secondary amines did not give tetraalkylureas. However, dialkylamines with a phenyl group on their alkyl chains, such as N-monoalkylated benzylic amine or phenethylamine derivatives, underwent a direct aromatic carbonylation to afford five- or six-membered benzolactams. In the carbonylation, the chelation effect or steric repulsion between Pd(II) and the meta-substituent in the ortho-palladation and the ring sizes of cyclopalladation products that were formed prior to carbonylation were found to generate good site selectivity and increase the reaction rate. In contrast, carbonylation of ω- arylalkylamines with a hydroxyl group gave neither ureas nor benzolactams but instead produced 1,3-oxazolidinones smoothly. Hydrochlorides of amines also underwent carbonylation to afford the corresponding amides under the conditions used. This procedure made it possible to prepare ureas of amino acid esters and N-alkylcarbamates in practical yields.
- Orito, Kazuhiko,Miyazawa, Mamoru,Nakamura, Takatoshi,Horibata, Akiyoshi,Ushito, Harumi,Nagasaki, Hideo,Yuguchi, Motoki,Yamashita, Satoshi,Yamazaki, Tetsuro,Tokuda, Masao
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p. 5951 - 5958
(2007/10/03)
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- Kinetic resolution of 2-oxazolidinones via catalytic, enantioselective N-acylation
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Kinetic resolution of racemic 2-oxazolidinones via catalytic, enantioselective N-acylation has been achieved for the first time and with outstanding selectivities. Copyright
- Birman, Vladimir B.,Jiang, Hui,Li, Ximin,Guo, Lei,Uffman, Eric W.
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p. 6536 - 6537
(2007/10/03)
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- Design and synthesis of a new generation of 'NH'-Ni(II) complexes of glycine Schiff bases and their unprecedented C-H vs. N-H chemoselectivity in alkyl halide alkylations and Michael addition reactions
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Within this manuscript the synthesis of a new generation of Ni(II) complexes that contain a secondary rather than a tertiary amino group, as well as the unusual chemoselectivity, was demonstrated in alkyl halide alkylations and Michael addition reactions. The complete C-H chemoselectivity observed in these reactions suggests that coordination of nitrogen to a metal has a significant synthetic potential as protecting a group without the need of introducing a transient N-C substituent. These new complexes have also proven highly synthetically useful nucleophilic glycine equivalents for the simple and highly diastereoselective synthesis of β-substituted pyroglutamic acids via their reactions with chiral Michael acceptors. Georg Thieme Verlag Stuttgart.
- Ellis, Trevor K.,Soloshonok, Vadim A.
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p. 533 - 538
(2007/10/03)
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- Stereoselective electrochemical carboxylation: 2-phenylsuccinates from chiral cinnamic acid derivatives
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Chiral 2-phenyl succinic ester derivatives have been obtained under mild conditions, in short times and with satisfactory yields by electrochemical reduction of chiral cinnamic acid derivatives under a CO2 atmosphere. When 4R-(diphenylmethyl)-o
- Orsini, Monica,Feroci, Marts,Sotgiu, Giovanni,Inesi, Achille
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p. 1202 - 1208
(2007/10/03)
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- Chemically modified mutant serine hydrolases show improved catalytic activity and chiral selectivity
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This invention provides novel chemically modified mutant serine hydrolases that catalyze a transamidation and/or a transpeptidation and/or a transesterification reaction. The modified serine hydrolases have one or more amino acid residues in a subsite replaced with a cysteine, wherein the cysteine is modified by replacing the thiol hydrogen in the cysteine with a substituent group providing a thiol side chain comprising a moiety selected from the group consisting of a polar aromatic substituent, an alkyl amino group with a positive charge, and a glycoside. In particularly preferred embodiments, the substitutents include an oxazolidinone, a C1 to C15 alkyl amino group with a positive charge, or a glycoside.
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- Modified Mg: Al hydrotalcite in the synthesis of oxazolidin-2-ones
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The modified Mg: Al (3: 1) hydrotalcite has been found to be an efficient catalyst in the conversion of carbamates into oxazolidin-2-ones under mild reaction conditions. A wide variety of oxazolidin-2-ones were obtained with excellent chemical yield. The Royal Society of Chemistry 2005.
- Cwik, Agnieszka,Fuchs, Aliz,Hell, Zoltan,Boejtoes, Ildiko,Halmai, Dora,Bombicz, Petra
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p. 967 - 969
(2007/10/03)
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- Enantioselective acyl transfer catalysts and their use in kinetic resolution of alcohols and desymmetrization of meso-diols
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Novel enantioselective acylation catalysts comprising chiral derivatives of DHIP and DHIQ, having the following representative general structures are disclosed: These new compounds are useful for resolving racemates or further enhancing the enantiomeric excess of an enantiomerically enriched composition and for desymmetrizing meso compounds.
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Page/Page column 20
(2008/06/13)
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- MONOCYCLIC ANILIDE SPIROHYDANTOIN CGRP RECEPTOR ANTAGONISTS
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The present invention is directed to compounds that are antagonists of CGRP receptors and that are useful in the treatment or prevention of diseases in which the CGRP is involved, such as headache, migraine and cluster headache. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the prevention or treatment of such diseases in which CGRP is involved.
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