- Enantioselective synthesis of 1-aminoindene derivativesviaasymmetric Br?nsted acid catalysis
-
We describe a catalytic asymmetric iminium ion cyclization reaction of simple 2-alkenylbenzaldimines using a BINOL-derived chiralN-triflyl phosphoramide. The corresponding 1-aminoindenes and tetracyclic 1-aminoindanes are formed in good yields and high enantioselectivities. Further, the chemical utility of the obtained enantiopure 1-aminoindene is demonstrated for the asymmetric synthesis of (S)-rasagiline.
- Ding, Du,Jiang, Hua-Jie,Wang, Tao,Wu, Xiang,Zhang, Ying,Zhao, Li-Ping
-
supporting information
p. 9680 - 9683
(2021/09/30)
-
- Engineering the large pocket of an (S)-selective transaminase for asymmetric synthesis of (S)-1-amino-1-phenylpropane
-
Amine transaminases offer an environmentally benign chiral amine asymmetric synthesis route. However, their catalytic efficiency towards bulky chiral amine asymmetric synthesis is limited by the natural geometric structure of the small pocket, representing a great challenge for industrial applications. Here, we rationally engineered the large binding pocket of an (S)-selective ?-transaminase BPTA fromParaburkholderia phymatumto relieve the inherent restriction caused by the small pocket and efficiently transform the prochiral aryl alkyl ketone 1-propiophenone with a small substituent larger than the methyl group. Based on combined molecular docking and dynamic simulation analyses, we identified a non-classical substrate conformation, located in the active site with steric hindrance and undesired interactions, to be responsible for the low catalytic efficiency. By relieving the steric barrier with W82A, we improved the specific activity by 14-times compared to WT. A p-p stacking interaction was then introduced by M78F and I284F to strengthen the binding affinity with a large binding pocket to balance the undesired interactions generated by F44. T440Q further enhanced the substrate affinity by providing a more hydrophobic and flexible environment close to the active site entry. Finally, we constructed a quadruple variant M78F/W82A/I284F/T440Q to generate the most productive substrate conformation. The 1-propiophenone catalytic efficiency of the mutant was enhanced by more than 470-times in terms ofkcat/KM, and the conversion increased from 1.3 to 94.4% compared with that of WT, without any stereoselectivity loss (ee > 99.9%). Meanwhile, the obtained mutant also showed significant activity improvements towards various aryl alkyl ketones with a small substituent larger than the methyl group ranging between 104- and 230-fold, demonstrating great potential for the efficient synthesis of enantiopure aryl alkyl amines with steric hindrance in the small binding pocket.
- Liu, He,Wang, Hualei,Wei, Dongzhi,Xie, Youyu,Xu, Feng,Xu, Xiangyang,Yang, Lin
-
p. 2461 - 2470
(2021/04/22)
-
- Enzymatic Primary Amination of Benzylic and Allylic C(sp3)-H Bonds
-
Aliphatic primary amines are prevalent in natural products, pharmaceuticals, and functional materials. While a plethora of processes are reported for their synthesis, methods that directly install a free amine group into C(sp3)-H bonds remain unprecedented. Here, we report a set of new-to-nature enzymes that catalyze the direct primary amination of C(sp3)-H bonds with excellent chemo-, regio-, and enantioselectivity, using a readily available hydroxylamine derivative as the nitrogen source. Directed evolution of genetically encoded cytochrome P411 enzymes (P450s whose Cys axial ligand to the heme iron has been replaced with Ser) generated variants that selectively functionalize benzylic and allylic C-H bonds, affording a broad scope of enantioenriched primary amines. This biocatalytic process is efficient and selective (up to 3930 TTN and 96percent ee), and can be performed on preparative scale.
- Jia, Zhi-Jun,Gao, Shilong,Arnold, Frances H.
-
supporting information
p. 10279 - 10283
(2020/07/27)
-
- Kinetic Resolution of Racemic Primary Amines Using Geobacillus stearothermophilus Amine Dehydrogenase Variant
-
A NADH-dependent engineered amine dehydrogenase from Geobacillus stearothermophilus (LE-AmDH-v1) was applied together with a NADH-oxidase from Streptococcus mutans (NOx) for the kinetic resolution of pharmaceutically relevant racemic α-chiral primary amines. The reaction conditions (e. g., pH, temperature, type of buffer) were optimised to yield S-configured amines with up to >99 % ee.
- Tseliou, Vasilis,Knaus, Tanja,Vilím, Jan,Masman, Marcelo F.,Mutti, Francesco G.
-
p. 2184 - 2188
(2020/03/11)
-
- Chemoenzymatic Synthesis of a Chiral Ozanimod Key Intermediate Starting from Naphthalene as Cheap Petrochemical Feedstock
-
Ozanimod represents a recently developed, promising active pharmaceutical ingredient (API) molecule in combating multiple sclerosis. Addressing the goal of a scalable, economically attractive, and technically feasible process for the manufacture of this drug, a novel alternative synthetic approach toward (S)-4-cyano-1-aminoindane as a chiral key intermediate for ozanimod has been developed. The total synthesis of this intermediate is based on the utilization of naphthalene as a readily accessible, economically attractive, and thus favorable petrochemical starting material. At first, naphthalene is transformed into 4-carboxy-indanone within a four-step process by means of an initial Birch reduction, followed by an isomerization of the C=C double bond, oxidative C=C cleavage, and intramolecular Friedel-Crafts acylation. The transformation of the 4-carboxy-indanone into (S)-4-cyano-1-aminoindane then represents the key step for introducing the chirality and the desired absolute S configuration. When evaluating complementary biocatalytic approaches based on the use of a lipase and transaminase, respectively, the combination of a chemical reductive amination of the 4-carboxyindanone followed by a subsequent lipase-catalyzed resolution turned out to be the most efficient route, leading to the desired key intermediate (S)-4-cyano-1-aminoindane in satisfactory yield and with excellent enantiomeric excess of 99%.
- Uthoff, Florian,L?we, Jana,Harms, Christina,Donsbach, Kai,Gr?ger, Harald
-
p. 4856 - 4866
(2019/05/02)
-
- Kinetic Resolution and Deracemization of Racemic Amines Using a Reductive Aminase
-
The NADP(H)-dependent reductive aminase from Aspergillus oryzae (AspRedAm) was combined with an NADPH oxidase (NOX) to develop a redox system that recycles the co-factor. The AspRedAm-NOX system was applied initially for the kinetic resolution of a variety of racemic secondary and primary amines to yield S-configured amines with enantiomeric excess (ee) values up to 99 %. The addition of ammonia borane to this system enabled the efficient deracemization of racemic amines, including the pharmaceutical drug rasagiline and the natural product salsolidine, with conversions up to >98 % and >99 % ee Furthermore, by using the AspRedAm W210A variant it was possible to generate the opposite R enantiomers with efficiency comparable to, or even better than, the wildtype AspRedAm.
- Aleku, Godwin A.,Mangas-Sanchez, Juan,Citoler, Joan,France, Scott P.,Montgomery, Sarah L.,Heath, Rachel S.,Thompson, Matthew P.,Turner, Nicholas J.
-
p. 515 - 519
(2018/02/15)
-
- A stereoselective, catalytic strategy for the in-flow synthesis of advanced precursors of rasagiline and tamsulosin
-
The diastereoselective, trichlorosilane-mediate reduction of imines, bearing different and removable chiral auxiliaries, in combination either with achiral bases or catalytic amounts of chiral Lewis bases, was investigated to afford immediate precursors of chiral APIs (Active Pharmaceutical Ingredients). The carbon-nitrogen double bond reduction was successfully performed in batch and in flow mode, in high yields and almost complete stereocontrol. By this metal-free approach, the formal synthesis of rasagiline and tamsulosin was successfully accomplished in micro(meso) flow reactors, under continuous flow conditions. The results of these explorative studies represent a new, important step towards the development of automated processes for the preparation of enantiopure biologically active compounds.
- Brenna, Davide,Pirola, Margherita,Raimondi, Laura,Burke, Anthony J.,Benaglia, Maurizio
-
supporting information
p. 6242 - 6247
(2017/09/30)
-
- Dynamic power learning split preparation (S)- 1 - amino indane
-
The invention relates to a preparation method of optically pure (S)-1-aminoindane. The preparation method comprises steps as follows: 1-aminoindane is taken as a raw material, a solvent, Candida rugose lipase, an acyl donor L-(+)-O-acetyl mandelic acid and a racemization catalyst KT-02 are added to a high pressure kettle in proportion, hydrogen is introduced, all components react for a period of time, and then 1-aminoindane can be completely converted into an acetyl compound of (S)-1-aminoindane. A product is purified and subjected to acid hydrolysis and alkali free operation, (S)-1-aminoindane is obtained, and an ee value of a final product is larger than 99%. The preparation method has the characteristics that the operation is simple, the racemization catalyst is cheap and available, the raw material is completely utilized, the optical purity of the product is high and the like; the preparation method has great guidance and application value in the aspect of production and preparation of (S)-1-aminoindane.
- -
-
Paragraph 0014; 0019; 0020
(2017/07/04)
-
- Simultaneous engineering of an enzyme's entrance tunnel and active site: The case of monoamine oxidase MAO-N
-
A new directed evolution approach is presented to enhance the activity of an enzyme and to manipulate stereoselectivity by focusing iterative saturation mutagenesis (ISM) simultaneously on residues lining the entrance tunnel and the binding pocket. This combined mutagenesis strategy was applied successfully to the monoamine oxidase from Aspergillus Niger (MAO-N) in the reaction of sterically demanding substrates which are of interest in the synthesis of chiral pharmaceuticals based on the benzo-piperidine scaffold. Reversal of enantioselectivity of Turner-type deracemization was achieved in the synthesis of (S)-1,2,3,4-tetrahydro-1-methyl-isoquinoline, (S)-1,2,3,4-tetrahydro-1-ethylisoquinoline and (S)-1,2,3,4-tetrahydro-1-isopropylisoquinoline. Extensive molecular dynamics simulations indicate that the altered catalytic profile is due to increased hydrophobicity of the entrance tunnel acting in concert with the altered shape of the binding pocket.
- Li, Guangyue,Yao, Peiyuan,Gong, Rui,Li, Jinlong,Liu, Pi,Lonsdale, Richard,Wu, Qiaqing,Lin, Jianping,Zhu, Dunming,Reetz, Manfred T.
-
p. 4093 - 4099
(2017/07/10)
-
- Asymmetric hydrogenation of 2,3-dihydro-1H-inden-1-one oxime and derivatives
-
Asymmetric hydrogenation of 2,3-dihydro-1H-inden-1-one oxime and derivatives to produce the corresponding optically active amine has been performed in the presence of rhodium and iridium catalysts. The optimization of neutral rhodium based catalytic syste
- Maj, Anna M.,Suisse, Isabelle,Agbossou-Niedercorn, Francine
-
p. 268 - 273
(2017/03/01)
-
- But-2-ene-1,4-diamine and But-2-ene-1,4-diol as Donors for Thermodynamically Favored Transaminase- and Alcohol Dehydrogenase-Catalyzed Processes
-
Both cis- and trans-but-2-ene-1,4-diamines have been prepared and efficiently applied as sacrificial cosubstrates in enzymatic transamination reactions. The best results were obtained with the cis-diamine. The thermodynamic equilibrium of the stereoselective transamination process is shifted to the amine formation due to tautomerization of 5H-pyrrole into 1H-pyrrole, achieving high conversions (78–99%) and enantiomeric excess (up to >99%) by using a small excess of the amine donor. Furthermore, when the reaction proceeded, a strong coloration was observed due to polymerization of 1H-pyrrole. A structurally related compound, cis-but-2-ene-1,4-diol, has been utilized as cosubstrate in different alcohol dehydrogenase (ADH)-mediated bioreductions. In this case, high conversions (91–99%) were observed due to a lactonization process. Both strategies are convenient from both synthetic and atom economy points of view in the production of valuable optically active products. (Figure presented.).
- Martínez-Montero, Lía,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
-
supporting information
p. 1618 - 1624
(2016/10/13)
-
- PROCESS AND INTERMEDIATES FOR THE RACEMIZATION OF ENANTIOMERICALLY ENRICHED 1-AMINOINDANE
-
The present invention relates to an improved process for the racemization of (S) -1-aminoindane. (S) -1-aminoindane is formed as a side product in the process of preparation (R) -1-aminoindane by enantiomeric resolution of racemic 1-aminoindane. (R) -aminoindane is a valuable intermediate in the process of preparation of rasagiline.
- -
-
Page/Page column 26
(2016/08/17)
-
- (R)- SELECTIVE AMINATION
-
The present invention relates to a method for the enzymatic synthesis of enantiomerically enriched (R)-amines of general formula [1][c] from the corresponding ketones of the general formula [1][a] by using novel transaminases. These novel transaminases are selected from two different groups: either from a group of some 20 proteins with sequences as specified herein, or from a group of proteins having transaminase activity and isolated from a microorganism selected from the group of organisms consisting of Rahnella aquatilis, Ochrobactrum anthropi, Ochrobactrum tritici, Sinorhizobium morelense, Curtobacterium pusiffium, Paecilomyces lilacinus, Microbacterium ginsengisoli, Microbacterium trichothecenolyticum, Pseudomonas citronellolis, Yersinia kristensenii, Achromobacter spanius, Achromobacter insolitus, Mycobacterium fortuitum, Mycobacterium frederiksbergense, Mycobacterium sacrum, Mycobacterium fluoranthenivorans, Burkhoideria sp., Burkhoideria tropica, Cosmospora episphaeria, and Fusarium oxysporum.
- -
-
Paragraph 0120; 0121; 0122
(2016/03/22)
-
- Mechanism-Guided Engineering of ω-Transaminase to Accelerate Reductive Amination of Ketones
-
Asymmetric reductive amination of ketones using ω-transaminases (ω-TAs) offers a promising alternative to the chemocatalytic synthesis of chiral amines. One fundamental challenge to the biocatalytic strategy is the very low enzyme activities for most ketones compared with native substrates (i.e., cat/KM for acetophenone). The W58L mutant afforded an efficient synthesis of enantiopure amines (i.e., >99% ee) using isopropylamine as an amino donor.
- Han, Sang-Woo,Park, Eul-Soo,Dong, Joo-Young,Shin, Jong-Shik
-
p. 1732 - 1740
(2015/06/02)
-
- Chiral amine synthesis using ω-transaminases: An amine donor that displaces equilibria and enables high-throughput screening
-
The widespread application of ω-transaminases as biocatalysts for chiral amine synthesis has been hampered by fundamental challenges, including unfavorable equilibrium positions and product inhibition. Herein, an efficient process that allows reactions to proceed in high conversion in the absence of by-product removal using only one equivalent of a diamine donor (ortho-xylylenediamine) is reported. This operationally simple method is compatible with the most widely used (R)- and (S)-selective ω-TAs and is particularly suitable for the conversion of substrates with unfavorable equilibrium positions (e.g., 1-indanone). Significantly, spontaneous polymerization of the isoindole by-product generates colored derivatives, providing a high-throughput screening platform to identify desired ω-TA activity. ω-Transaminases (ω-TA) have been employed as biocatalysts in a simple and efficient process for the synthesis of chiral amines. A dual-function diamine donor (ortho-xylylenediamine) serves to displace challenging reaction equilibria towards product formation whilst generating intensely colored by-products, which have allowed the development of liquid-phase and colony-based assays.
- Green, Anthony P.,Turner, Nicholas J.,O'Reilly, Elaine
-
supporting information
p. 10714 - 10717
(2015/05/13)
-
- Substrate profile of an ω-transaminase from Burkholderia vietnamiensis and its potential for the production of optically pure amines and unnatural amino acids
-
A new (S)-enantioselective ω-transaminase (ω-TA) gene from Burkholderia vietnamiensis G4 was functionally expressed in Escherichia coli BL21 (DE3), and the purified recombinant N-terminal His-tagged ω-TA (HBV-ω-TA) had a dimeric structure with optimum pH and temperature of 8.4 and 40 C, respectively. The enzyme showed higher activities toward aromatic amines than aliphatic amines and (S)-1-methylbenzylamine ((S)-α-MBA) was the most active amino donor. For amino acceptor, keto acids, keto esters and aldehydes were more reactive than ketones with pyruvate ethyl ester being most active. Several chiral amines and unnatural amino acids or esters were synthesized using HBV-ω-TA as the catalyst and isopropylamine or (S)-α-MBA as amino donor. Notably, HBV-ω-TA catalyzed the amino transfer to β-keto esters to give optically pure β-amino acid esters. In addition, glyoxylate was used as amino acceptor for the first time in the kinetic resolution of racemic amines and optically pure amines, such as (R)-1-methylbenzylamine, (R)-1-phenylpropylamine, (R)-2-amino-4-phenylbutane and (R)-1-aminotetraline, were obtained.
- Jiang, Jinju,Chen, Xi,Feng, Jinhui,Wu, Qiaqing,Zhu, Dunming
-
-
- Reusable ω-transaminase sol-gel catalyst for the preparation of amine enantiomers
-
Heterogeneous ω-transaminase sol-gel catalysts were prepared and characterized in terms of immobilization degree, loading capacity and catalytic behavior in the kinetic resolution of racemic 1-phenylethylamine (a model compound) with sodium pyruvate in phosphate buffer (pH 7.5). The catalyst obtained when ω-transaminase from Arthrobacter sp. was encapsulated from the aqueous solution of the enzyme, isopropyl alcohol and polyvinyl alcohol in the sol-gel matrices, consisting of the 1:5 mixture of tetramethoxysilane and methyltrialkoxysilane, proved to be optimal including the reuse and storage stabilities of the catalyst. The optimized immobilizate was shown to perform well in the kinetic resolution of four structurally different aromatic primary amines in aqueous DMSO (10, v/v-%). The enzyme preparation showed synthetic potential by enabling the catalyst reuse in five consecutive preparative scale kinetic resolutions using 100 mM 1-phenylethylamine in aqueous DMSO (10, v/v-%). It was typical to fresh catalyst preparations that the kinetic resolution tended to exceed 50% before the reaction stopped leaving the (S)-amine unreacted while thereafter in reuse the reactions stopped at 50% conversion as expectable to highly enantioselective reactions.
- P?ivi?, Mari,Kanerva, Liisa T.
-
p. 1488 - 1494
(2013/09/24)
-
- Investigation of one-enzyme systems in the ω-transaminase-catalyzed synthesis of chiral amines
-
ω-Transaminase (TA) catalyzed asymmetric syntheses of amines were carried out in the one enzyme systems with wild-type enzymes (S)-TA from Pseudomonas aeruginosa, (S)-TA from Paracoccus denitrificans and (R)-TA from Aspergillus terreus. The scope of amine donors and aromatic carbonyl substrates was thoroughly explored. Among the range of potential amino donors, 2-propylamine, 2-butylamine and 1-phenylethylamine were found as promising candidates, which gave superior conversions in the amination reactions compared to other donors. Various prochiral aromatic ketones were accepted as substrates by the investigated enzymes. In most cases, good to excellent conversions (up to 98%) to the amine products with excellent e.e.-values (>99.9% for (S) or (R)) were obtained by the action of a single enzyme and an appropriate amino donor. (S)-TA from Paracoccus denitrificans was found to accept bulky ketones, e.g. 1-indanone, α- and β-tetralone or 2-acetonaphthone, in the asymmetric amination. In some cases the enantiomeric excesses in the amination reactions were dependent on the amino donor. More-over, the influence of the pH, temperature and cosolvents on the outcome of reactions was additionally investigated.
- Fesko, Kateryna,Steiner, Kerstin,Breinbauer, Rolf,Schwab, Helmut,Schuermann, Martin,Strohmeier, Gernot A.
-
p. 103 - 110
(2013/10/22)
-
- Enantioselective reduction of ketoxime ethers with borane-oxazaborolidines and synthesis of the key intermediate leading to (S)-rivastigmine
-
The reduction of representative alkyl aryl (E)-ketoxime O-benzyl ethers with borane catalyzed by terpene oxazaborolidines, derived from (1R)-nopinone and (1R)-camphor, gave the corresponding amines with 82-99% ee. Oxazaborolidines derived from (1S)-2-carene and (1S)-3-carene were less selective. (S)-1-(3-Methoxyphenyl)ethanamine (94% ee) the key intermediate in the synthesis of (S)-rivastigmine, was obtained by the reduction of (E)-1-(3-methoxyphenyl) ethanone O-benzyl oxime with borane/oxazaborolidine generated from (S)-valinol.
- Pakulski, Marcin M.,Mahato, Sanjit K.,Bosiak, Mariusz J.,Krzeminski, Marek P.,Zaidlewicz, Marek
-
p. 716 - 721
(2012/09/21)
-
- N-octanoyldimethylglycine trifluoroethyl ester, an acyl donor leading to highly enantioselective protease-catalysed kinetic resolution of amines
-
The use of N-octanoyldimethylglycine trifluoroethyl ester as acyl donor in the kinetic resolution of aliphatic amines catalysed by proteases led to enantiomeric ratios >200 in most cases. The resolutions mediated by Protex 6L were shown to be much faster
- Queyroy, Severine,Vanthuyne, Nicolas,Gastaldi, Stephane,Bertrand, Michele P.,Gil, Gerard
-
supporting information; experimental part
p. 1759 - 1764
(2012/08/08)
-
- Solvent-free kinetic resolution of primary amines catalyzed by Candida antarctica lipase B: Effect of immobilization and recycling stability
-
Highly enantioselective (E >200) N-acylation of nine racemic primary amines with isopropyl methoxyacetate in the presence of Candida antarctica lipase B (Novozym 435) has been reported to yield the unreacted (S)-amines (ee ≥98%) and produced the (R)-amides (ee ≥95%) at 50% conversion under solvent-free conditions. One of the amines and the acyl donor have been used in an equimolar ratio at room temperature (23 °C). Under the reaction conditions, the reuse stability of Novozym 435 with 1-phenylethylamine (as a model compound) has been shown to be poor while somewhat improved stability has been observed with an in-house prepared sol-gel CAL-B catalyst.
- Paeivioe, Mari,Perkioe, Paeivi,Kanerva, Liisa T.
-
experimental part
p. 230 - 236
(2012/06/15)
-
- 3,3′-diaryl-BINOL phosphoric acids as enantioselective extractants of benzylic primary amines
-
We report that 3,3′-diaryl-BINOL phosphoric acids are effective enantioselective extractants in chiral separation methods based on reactive liquid-liquid extraction. These new extractants are capable of separating racemic benzylic primary amine substrates. The effect of the nature of the substituents at the 3,3′-positions of the host were examined as well as the structure of the substrate, together with important parameters such as the organic solvent, the pH of the aqueous phase, and the host stoichiometry. Titration of the substrate with the host was monitored by FTIR, NMR, UV-Vis, and CD spectroscopy, which provided insight into the structure of the host-guest complex involved in extraction.
- Verkuijl, Bastiaan J.V.,De Vries, Johannes G.,Feringa, Ben L.
-
experimental part
p. 34 - 43
(2011/10/08)
-
- COMPOSITIONS AND METHODS FOR CYCLOFRUCTANS AS SEPARATION AGENTS
-
The present invention relates to derivatized cyclofructan compounds, compositions comprising derivatized cyclofructan compounds, and methods of using compositions comprising derivatized cyclofructan compounds for chromatographic separations of chemical species, including enantiomers. Said compositions may comprise a solid support and/or polymers comprising derivatized cyclofructan compounds.
- -
-
Page/Page column 44-45
(2010/12/31)
-
- Development of new HPLC chiral stationary phases based on native and derivatized cyclofructans
-
An unusual class of chiral selectors, cyclofructans, is introduced for the first time as bonded chiral stationary phases. Compared to native cyclofructans (CFs), which have rather limited capabilities as chiral selectors, aliphatic-and aromatic-functionalized CF6s possess unique and very different enantiomeric selectivities. Indeed, they are shown to separate a very broad range of racemic compounds. In particular, aliphatic-derivatized CF6s with a low substitution degree baseline separate all tested chiral primary amines. It appears that partial derivatization on the CF6 molecule disrupts the molecular internal hydrogen bonding, thereby making the core of the molecule more accessible. In contrast, highly aromaticfunctionalized CF6 stationary phases lose most of the enantioselective capabilities toward primary amines, however they gain broad selectivity for most other types of analytes. This class of stationary phases also demonstrates high "loadability" and therefore has great potential for preparative separations. The variations in enantiomeric selectivity often can be correlated with distinct structural features of the selector. The separations occur predominantly in the presence of organic solvents.
- Sun, Ping,Wang, Chunlei,Breitbach, Zachary S.,Zhang, Ying,Armstrong, Daniel W.
-
experimental part
p. 10215 - 10226
(2010/05/01)
-
- Optically active amines by enzyme-catalyzed kinetic resolution
-
Chiral amines are resolved by an enzyme-catalyzed kinetic resolution. Key steps are the selective acylation of one enantiomer with isopropyl methoxyacetate, separation of the resulting amide from the unreacted antipode, and finally amide hydrolysis. The p
- Ditrich, Klaus
-
experimental part
p. 2283 - 2287
(2009/04/06)
-
- Highly selective enzymatic kinetic resolution of primary amines at 80°C: A comparative study of carboxylic acids and their ethyl esters as acyl donors
-
(Chemical Equation Presented) Optimization of the kinetic resolution of 2-amino-4-phenyl-butane was achieved at 80°C using CAL-B-catalyzed aminolysis of carboxylic acids and their ethyl esters. The reactions carried out with long chain esters and the corresponding acids as acyl donors proceeded with remarkably high enantioselectivity. The use of carboxylic acids as acylating agents led to a marked acceleration of the reaction rate compared to their ester counterparts. Laurie acid led to enantiomeric excesses superior to 99.5% for both the remaining amine and the corresponding lauramide at 50% conversion (reached in 3 h). These optimized conditions were applied to the resolution of a series of aliphatic and benzylic amines.
- Nechab, Malek,Azzi, Nadia,Vanthuyne, Nicolas,Bertrand, Michele,Gastaldi, Stephane,Gil, Gerard
-
p. 6918 - 6923
(2008/02/11)
-
- Asymmetric synthesis of primary amines via the spiroborate-catalyzed borane reduction of oxime ethers
-
The enantioselective borane reduction of O-benzyloxime ethers to primary amines was studied under catalytic conditions using the spiroborate esters 5-10 derived from nonracemic 1,2-amino alcohols and ethylene glycol. Effective catalytic conditions were achieved using only 10% of catalyst 5 derived from diphenylvalinol in dioxane at 0°C resulting in complete conversion to the corresponding primary amine in up to 99% ee.
- Huang, Xiaogen,Ortiz-Marciales, Margarita,Huang, Kun,Stepanenko, Viatcheslav,Merced, Francisco G.,Ayala, Angel M.,Correa, Wildeliz,De Jesus, Melvin
-
p. 1793 - 1795
(2008/02/02)
-
- Synthesis of enantiomerically pure amino-substituted fused bicyclic rings
-
This invention describes various processes for synthesis and resolution of racemic amino-substituted fused bicyclic ring systems. One process utilizes selective hydrogenation of an amino-substituted fused bicyclic aromatic ring system. An alternative process prepares the racemic amino-substituted fused bicyclic ring system via nitrosation. In addition, the present invention describes the enzymatic resolution of a racemic mixture to produce the (R)- and (S)-forms of amino-substituted fused bicyclic rings as well as a racemization process to recycle the unpreferred enantioner. Further provided by this invention is an asymmetric synthesis of the (R)- or (S)-enantiomer of primary amino-substituted fused bicyclic ring systems.
- -
-
-
- (S)-1-aminoindane: Synthesis by chirality transfer using (R)-phenylglycine amide as chiral auxiliary
-
A practical asymmetric synthesis of nearly enantiomerically pure (S)-1-aminoindane has been developed. The key step involves the diastereoselective heterogeneous metal-catalyzed reduction of the ketimine of 1-indanone with the chiral auxiliary (R)-phenylglycine amide. The selectivity of the asymmetric hydrogenation step was optimized with regard to metal catalyst, solvent and catalyst loading. The chiral auxiliary was removed by means of a novel non-reductive procedure. Thus, (S)-1-aminoindane with an ee of 96% was prepared in 58% overall yield from (R)-phenylglycine amide in an effective three-step procedure.
- Uiterweerd, Patrick G.H.,Van Der Sluis, Marcel,Kaptein, Bernard,De Lange, Ben,Kellogg, Richard M.,Broxterman, Quirinus B.
-
p. 3479 - 3485
(2007/10/03)
-
- Asymmetric synthesis of two new conformationally constrained lysine derivatives
-
The asymmetric synthesis of the conformationally constrained L- and D-lysine derivatives methyl (1S,8S)-1-amino-8-tert-butoxycarbonylamino-1,2,3,4,5,6,7, 8-octahydroanthracene-1-carboxylate (4) and methyl (1R,8S)-1-amino-8-tert-butoxycarbonylamino-1,2,3,4,5,6,7, 8-octahydroanthracene-1-carboxylate (5), respectively are described. Application of the Bucherer hydantoin synthesis to the carbonyl group of 2′,3′,4′,5′,6′,7′-hexahydrospiro[1, 3-ethylenedithiole-2,1′-anthracen]-8′-one (18), which was prepared from 1,8-dichloroanthraquinone (14) in nine steps and the deprotection of the masked second ketone of 18 yields rac-21. The latter is the precursor for a novel asymmetric reductive amination protocol using (R)-phenylglycinol as a chiral amino auxiliary and NaBH(OAc)3 as a reducing agent. Using this procedure, the asymmetric reductive amination of α-tetralone derivatives and indanone proceeds with >95% de. Lower diastereomeric excesses are observed for benzosuberone (16.7% de) and acetophenone (27.3% de). rac-21 gave (1′S,8′S,1(R)-25a (38% yield) and (1′R,8′S,1(R)-25b (44.5% yield) with greater than 52 and 78% de, respectively. Cleavage of the amino auxiliary of (1′S,8′S,1(R)-25a and of (1′R,8′S,1(R)-25b with lead(IV) tetraacetate and hydrolysis of the hydantoin ring yields the unprotected analogs of 4 and 5. The latter are transformed into the selectively protected target molecules 4 and 5 through standard protection procedures. The overall yield of the 17- and 18-step synthesis starting from 13 was 0.3% yield for each constrained lysine derivative.
- Stalker, Robert A,Munsch, Tamara E,Tran, Jacquelyn D,Nie, Xiaoping,Warmuth, Ralf,Beatty, Alicia,Aaker?y, Christer B
-
p. 4837 - 4849
(2007/10/03)
-
- Comparison of the ω-transaminases from different microorganisms and application to production of chiral amines
-
Microorganisms that are capable of (S)-enantioselective transamination of chiral amines were isolated from soil samples by selective enrichment using (S)-α-methylbenzylamine ((S)-α-MBA) as a sole nitrogen source. Among them, Klebsiella pneumoniae JS2F, Bacillus thuringiensis JS64, and Vibrio fluvialis JS17 showed good ω-transaminase (ω-TA) activities and the properties of the ω-TAs were investigated. The induction level of the enzyme was strongly dependent on the nitrogen source for the strains, except for V. fluvialis JS17. All the ω-TAs showed high enantioselectivity (E>50) toward (S)-α-MBA and broad amino donor specificities for arylic and aliphatic chiral amines. Besides pyruvate, aldehydes such as propionaldehyde and butyraldehyde showed good amino acceptor reactivities. All the ω-TAs showed substrate inhibition by (S)-α-MBA above 200 mM. Moreover, substrate inhibition by pyruvate above 10 mM was observed for ω-TA from V. fluvialis JS17. In the case of product inhibition, acetophenone showed much greater inhibitions than L-alanine for all ω-TAs. Comparison of the enzyme properties indicates that ω-transaminase from V. fluvialis JS17 is the best one for both kinetic resolution and asymmetric synthesis to produce enantiomerically pure chiral amines. Kinetic resolution of sec-butylamine (20 mM) was done under reduced pressure (150 Torr) to selectively remove an inhibitory product (2-butanone) using the enzyme from V. fluvialis JS17. Enantiomeric excess of (R)-sec-butylamine reached 94.7% after 12 h of reaction.
- Shin, Jong-Shik,Kim, Byung-Gee
-
p. 1782 - 1788
(2007/10/03)
-
- Enantioselective borohydride reduction of N-diphenylphosphinyl imines using optically active cobalt(II) complex catalysts
-
The enantioselective borohydride reduction using optically active cobalt(II) complex catalysts was successfully applied to various aryl N-diphenylphosphinyl imines, and the corresponding reduced products were obtained in good yields with high enantiomeric excesses (up to 99% ee). The optically active primary amines were obtained by the successive hydrolysis under mild conditions.
- Sugi, Kiyoaki D.,Nagata, Takushi,Yamada, Tohru,Mukaiyama, Teruaki
-
p. 493 - 494
(2007/10/03)
-
- Catalytic asymmetric hydroboration-amination
-
A one-pot asymmetric synthesis of primary amines from vinylarenes via catalytic hydroboration is described.
- Fernandez, Elena,Hooper, Mark W.,Knight, Frances I.,Brown, John M.
-
p. 173 - 174
(2007/10/03)
-
- N6-(1- and 2-benzocycloalkyl) adenosines
-
N6 -(1 and 2-Benzocycloalkyl)adenosines and pharmaceutically acceptable acid addition salts having highly desirable central nervous system and cardiovascular properties, process for their manufacture, pharmaceutical compositions and methods for using said compounds and compositions are described.
- -
-
-
