cas 5303-65-1, ETHYL 3-AMINOBUTYRATE | Articles data

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Parallel interconnected kinetic asymmetric transformation (PIKAT) with an immobilized ω-transaminase in neat organic solvent
Comprising approximately 40% of the commercially available optically active drugs, α-chiral amines are pivotal for pharmaceutical manufacture. In this context, the enzymatic asymmetric amination of ketones represents a more sustainable alternative than traditional chemical procedures for chiral amine synthesis. Notable advantages are higher atom-economy and selectivity, shorter synthesis routes, milder reaction conditions and the elimination of toxic catalysts. A parallel interconnected kinetic asymmetric transformation (PIKAT) is a cascade in which one or two enzymes use the same cofactor to convert two reagents into more useful products. Herein, we describe a PIKAT catalyzed by an immobilized ω-transaminase (ωTA) in neat toluene, which concurrently combines an asymmetric transamination of a ketone with an anti-parallel kinetic resolution of an amine racemate. The applicability of the PIKAT was tested on a set of prochiral ketones and racemic α-chiral amines in a 1:2 molar ratio, which yielded elevated conversions (up to >99%) and enantiomeric excess (ee, up to >99%) for the desired products. The progress of the conversion and ee was also monitored in a selected case. This is the first report of a PIKAT using an immobilized ωTA in a non-aqueous environment.
B?hmer, Wesley,Koenekoop, Lucien,Mutti, Francesco G.,Simon, Timothée
(2020/05/25)

Structural analysis of the dual-function thioesterase SAV606 unravels the mechanism of Michael addition of glycine to an α,β-unsaturated thioester
Thioesterases catalyze hydrolysis of acyl thioesters to release carboxylic acid or macrocyclization to produce the corresponding macrocycle in the biosynthesis of fatty acids, polyketides, or nonribosomal peptides. Recently, we reported that the thioesterase CmiS1 from Streptomyces sp. MJ635-86F5 catalyzes the Michael addition of glycine to an α,β-unsaturated fatty acyl thioester followed by thioester hydrolysis in the biosynthesis of the macrolactam antibiotic cremimycin. However, the molecular mechanisms of CmiS1-catalyzed reactions are unclear. Here, we report on the functional and structural characterization of the CmiS1 homolog SAV606 from Streptomyces avermitilis MA-4680. In vitro analysis indicated that SAV606 catalyzes the Michael addition of glycine to crotonic acid thioester and subsequent hydrolysis yielding (R)-N-carboxymethyl-3-aminobutyric acid. We also determined the crystal structures of SAV606 both in ligand-free form at 2.4 ? resolution and in complex with (R)-N-car-boxymethyl-3-aminobutyric acid at 2.0 ? resolution. We found that SAV606 adopts an α/β hotdog fold and has an active site at the dimeric interface. Examining the complexed structure, we noted that the substrate-binding loop comprising Tyr-53–Asn-61 recognizes the glycine moiety of (R)-N-carboxymethyl-3-aminobutyric acid. Moreover, we found that SAV606 does not contain an acidic residue at the active site, which is distinct from canonical hotdog thioesterases. Site-directed mutagenesis experiments revealed that His-59 plays a crucial role in both the Michael addition and hydrolysis via a water molecule. These results allow us to propose the reaction mechanism of the SAV606-catalyzed Michael addition and thioester hydrolysis and provide new insight into the multiple functions of a thioesterase family enzyme.
Chisuga, Taichi,Miyanaga, Akimasa,Kudo, Fumitaka,Eguchi, Tadashi
p. 10926 - 10937
(2017/07/06)

Chiral Phosphinyl Enamines and Their Asymmetric Reduction through Group-Assisted Purification Chemistry Leading to Enantiopure β-Amino Esters/Amides
A series of new chiral N -phosphinyl β-enamino esters and amides were successfully prepared with excellent Z -stereoselectivity (Z / E > 99:1 in nearly all cases). Group-assisted purification chemistry proved to be an efficient method for the asymmetric reduction of the resulting β-enamino esters/amides to give enantiopure β-amino esters/amides. The asymmetric reduction can be controlled efficiently by using a combination of sodium cyanoborohydride and acetic acid.
Qiao, Shuo,Wu, Jianbin,Mo, Junming,Spigener, Preston T.,Zhao, Brian Nlong,Jiang, Bo,Li, Guigen
p. 2483 - 2488
(2017/10/06)

QUINOLINONE PYRIMIDINES COMPOSITIONS AS MUTANT-ISOCITRATE DEHYDROGENASE INHIBITORS
The invention relates to inhibitors of mutant isocitrate dehydrogenase (mt-IDH) proteins with neomorphic activity useful in the treatment of cell-proliferation disorders and cancers, having the Formula: where A, B, W1, W2, W3, and R1-R6 are described herein.
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Paragraph 0619; 0624; 0625

(2016/04/19)

Catalytic Promiscuity of Transaminases: Preparation of Enantioenriched β-Fluoroamines by Formal Tandem Hydrodefluorination/Deamination
Transaminases are valuable enzymes for industrial biocatalysis and enable the preparation of optically pure amines. For these transformations they require either an amine donor (amination of ketones) or an amine acceptor (deamination of racemic amines). Herein transaminases are shown to react with aromatic β-fluoroamines, thus leading to simultaneous enantioselective dehalogenation and deamination to form the corresponding acetophenone derivatives in the absence of an amine acceptor. A series of racemic β-fluoroamines was resolved in a kinetic resolution by tandem hydrodefluorination/deamination, thus giving the corresponding amines with up to greater than 99 % ee. This protocol is the first example of exploiting the catalytic promiscuity of transaminases as a tool for novel transformations.
Cuetos, Aníbal,García-Ramos, Marina,Fischereder, Eva-Maria,Díaz-Rodríguez, Alba,Grogan, Gideon,Gotor, Vicente,Kroutil, Wolfgang,Lavandera, Iván
supporting information
p. 3144 - 3147
(2016/03/12)

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
p. 32 - 39
(2014/01/06)

Synthesis of oxazolidin-2-ones and imidazolidin-2-ones directly from 1,3-diols or 3-amino alcohols using iodobenzene dichloride and sodium azide
A general and efficient method for the synthesis of oxazolidin-2-ones and imidazolidin-2-ones directly from 1,3-diols and 3-amino alcohols has been developed using the same reagent combination of iodobenzene dichloride (PhICl2) and sodium azide (NaN3).
He, Tian,Gao, Wen-Chao,Wang, Wei-Kun,Zhang, Chi
supporting information
p. 1113 - 1118
(2014/04/03)

Expanding dynamic kinetic protocols: Transaminase-catalyzed synthesis of α-substituted β-amino ester derivatives
Several α-alkylated β-amino esters have been obtained via DKR processes employing a kit of transaminases and isopropylamine as an amino donor in aqueous medium under mild conditions. Thus, while acyclic α-alkyl-β-keto esters afforded excellent conversions and enantioselectivities, although usually low diastereoselectivities, using more constrained cyclic β-keto esters high to excellent inductions were obtained.
Cuetos, Anibal,Lavandera, Ivan,Gotor, Vicente
supporting information
p. 10688 - 10690
(2013/11/06)

Amination of ketones by employing two new (S)-selective ω-transaminases and the his-tagged ω-TA from Vibrio fluvialis
Two recently identified (S)-selective ω-transaminases (ω-TAs) that originate from Paracoccus denitrificans (Strep-PD-ωTA, cloned with an N-terminal Strep-tag II) and Pseudomonas fluorescens (PF-ωTA) were employed for the asymmetric amination of selected prochiral ketones. The substrates tested were transformed into optically pure amines (>99 % ee) with high conversion (up to >99 %). The ω-TAs led to higher conversion in the absence of dimethyl sulfoxide as a cosolvent than in its presence (15 %, v/v). Additionally, it was shown that a His-tagged recombinant transaminase from Vibrio fluvialis (His-VF-ωTA, cloned with an N-terminal His 6-tag) showed for a single substrate, ethyl acetoacetate, significantly higher stereoselectivity for the amination compared to the corresponding commercial enzyme preparation (>99 vs. 50 %). The (S)-selective ω-transaminases (ω-TAs) from Paracoccus denitrificans and Pseudomonas fluorescens transformed various ketones into optically pure amines (>99 % ee). These enzymes extend the substrate spectrum of highly (S)-stereoselective ω-TAs. Copyright
Mutti, Francesco G.,Fuchs, Christine S.,Pressnitz, Desiree,Turrini, Nikolaus G.,Sattler, Johann H.,Lerchner, Alexandra,Skerra, Arne,Kroutil, Wolfgang
experimental part
p. 1003 - 1007
(2012/04/04)

Asymmetric bio-amination of ketones in organic solvents
ω-Transaminases, employed as a lyophilised crude cell-free extract, were successfully employed in organic solvent for the asymmetric amination of ketones without the need for immobilisation. Best activity was found for methyl tert-butyl ether (MTBE) at a water activity of 0.6. The ω-transaminases (9 different enzymes) accepted efficiently 2-propylamine as amine donor when used in the solvent, which is not the case when they are used in aqueous solution. The bio-amination in organic solvent showed several advantages such as higher reaction rates (up to 17-fold), general acceptance of 2-propylamine as amine donor, simple work-up procedure (i.e., no basification and extraction required), easy recycling of the catalyst and lack of substrate inhibition. The biocatalysts maintained their excellent stereoselectivity in MTBE allowing the preparation of optically pure amines (ee >99%) with up to >99% conversion.
Mutti, Francesco G.,Kroutil, Wolfgang
supporting information
p. 3409 - 3413
(2013/02/25)

Stereoselectivity of four (R)-selective transaminases for the asymmetric amination of ketones
Four (R)-ω-transaminases originating from Hyphomonas neptunium (HN-ωTA), Aspergillus terreus (AT-ωTA) and Arthrobacter sp. (ArR-ωTA), as well as an evolved transaminase (ArRmut11-ωTA) were successfully employed for the amination of prochiral ketones leading to optically pure (R)-amines. The first three transaminases displayed perfect stereoselectivity for the amination of all substrates tested (ee >99%). Furthermore, the transaminase AT-ωTA led in most cases to better conversion than ArR-ωTA and HN-ωTA using D-alanine as amine donor. α-Tetralone, which was the only substrate not accepted by HN-ωTA, ArR-ωTA, and AT-ωTA, was successfully transformed with perfect enantioselectivity (ee >99%) into the corresponding optically pure amine employing the variant ArRmut11-ωTA. Copyright
Mutti, Francesco G.,Fuchs, Christine S.,Pressnitz, Desiree,Sattler, Johann H.,Kroutil, Wolfgang
experimental part
p. 3227 - 3233
(2012/01/03)

Formation and hydrolysis of amide bonds by lipase A from Candida antarctica; Exceptional features
Various commercial lyophilized and immobilized preparations of lipase A from Candida antarctica (CAL-A) were studied for their ability to catalyze the hydrolysis of amide bonds in N-acylated α-amino acids, 3-butanamidobutanoic acid (β-amino acid) and its ethyl ester. The activity toward amide bonds is highly untypical of lipases, despite the close mechanistic analogy to amidases which normally catalyze the corresponding reactions. Most CAL-A preparations cleaved amide bonds of various substrates with high enantioselectivity, although high variations in substrate selectivity and catalytic rates were detected. The possible role of contaminant protein species on the hydrolytic activity toward these bonds was studied by fractionation and analysis of the commercial lyophilized preparation of CAL-A (Cat#ICR-112, Codexis). In addition to minor impurities, two equally abundant proteins were detected, migrating on SDS-PAGE a few kDa apart around the calculated size of CAL-A. Based on peptide fragment analysis and sequence comparison both bands shared substantial sequence coverage with CAL-A. However, peptides at the C-terminal end constituting a motile domain described as an active-site flap were not identified in the smaller fragment. Separated gel filtration fractions of the two forms of CAL-A both catalyzed the amide bond hydrolysis of ethyl 3-butanamidobutanoate as well as the N-acylation of methyl pipecolinate. Hydrolytic activity towards N-acetylmethionine was, however, solely confined to the fractions containing the truncated form of CAL-A. These fractions were also found to contain a trace enzyme impurity identified in sequence analysis as a serine carboxypeptidase. The possible role of catalytic impurities versus the function of CAL-A in amide bond hydrolysis is further discussed in the paper. The Royal Society of Chemistry 2010.
Liljeblad, Arto,Kallio, Pauli,Vainio, Marita,Niemi, Jarmo,Kanerva, Liisa T.
scheme or table
p. 886 - 895
(2010/06/20)

Asymmetric synthesis of optically pure pharmacologically relevant amines employing ω-transaminases
Various ω-transaminases were tested for the synthesis of enantiomerically pure amines from the corresponding ketones employing D- or L-alanine as amino donor and lactate dehydrogenase to remove the side-product pyruvate to shift the unfavourable reaction equilibrium to the product side. Both enantiomers, (R)- and (S)-amines, could be prepared with up to 99% ee and >99% conversions within 24 h at 50 mM substrate concentration. The activity and stereoselectivity of the amination reaction depended on the ω-transaminase and substrate employed; furthermore the co-solvent significantly influenced both the stereoselectivity and activity of the transaminases. Best results were obtained by employing ATA-117 to obtain the (R)-enantiomer and ATA-113 or ATA-103 to access the (S)-enantiomer with 15% v v-1 DMSO.
Koszelewski, Dominik,Lavandera, Ivan,Clay, Dorina,Rozzell, David,Kroutil, Wolfgang
scheme or table
p. 2761 - 2766
(2009/10/06)

Formal asymmetric biocatalytic reductive amination
All for one: A combination of three biocatalysts (ω-transaminase, alanine dehydrogenase, and an enzyme such as formate dehydrogenase for cofactor recycling) catalyze a cascade to achieve the asymmetric transformation of a ketone into a primary α-chiral unprotected amine through a formal stereoselective reductive amination (see scheme). Only ammonia and the reducing agent (formate) are consumed during this reaction. (Chemical Equation Presented).
Koszelewski, Dominik,Lavandera, Ivan,Clay, Dorina,Guebitz, Georg M.,Rozzell, David,Kroutil, Wolfgang
supporting information; experimental part
p. 9337 - 9340
(2009/05/15)

METHOD FOR SYNTHESIS OF KETO ACID OR AMINO ACID BY HYDRATION OF ACETHYLENE COMPOUND
An object of the present invention is to provide a method for synthesis of keto acids by hydration of an acetylene compound (acetylene-carboxylic acids) under mild conditions free from harmful mercury catalysts and a method for synthesis of amino acids from acetylene-carboxylic acids in a single container (one-pot or tandem synthesis). In one embodiment of the method according to the present invention for synthesis of keto acids, acetylene-carboxylic acids is hydrated in the presence of a metal salt represented by General Formula (1), where M1 represents an element in Group VIII, IX, or X of the periodic table, and X1, X2, or X3 ligand represents halogen, H2O, or a solvent molecule, and k represents a valence of a cation species, and Y represents an anion species, and L represents a valence of the anion species, and each of K and L independently represents 1 or 2, and k × m = L × n.
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Page/Page column 25; 26; 27

(2008/12/06)

Process for preparing optically active 3-azidocarboxylic acid derivatives and 3-aminocarboxylic acid derivatives
A process for enantioselectively preparing 3-azidocarboxylic acid derivatives comprises reacting 3-sulfonatocarboxylic acid derivatives with an alkali metal azide in a solvent selected from the group comprising certain carboxamides; a solvent mixture which comprises such carboxamides; a solvent mixture of water and a solvent miscible homogeneously with water; water with the proviso that the addition of a phase transfer catalyst is not used in the reaction in water; and DMSO. The resulting products are optionally reduced to 3-aminocarboxylic acid derivatives.
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Page/Page column 10-11

(2008/06/13)

PROCESS FOR THE PREPARATION OF CHIRAL AMINES
The invention relates to a process for the preparation of a chiral amine, whereby a ketone or aldehyde is contacted with an enantiomerically enriched phenylglycine amide to give an imine, whereby the imine is subsequently contacted with a Reformatsky reagent and the formed compound is subsequently converted into a chiral amine by means of hydrogenolysis, oxidation or a retro Strecker method.
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Page/Page column 14-15

(2008/06/13)

Discovery of Novel 2,8-Diazaspiro[4.5]decanes as Orally Active Glycoprotein IIb-IIIa Antagonists
In our efforts to develop orally active GPIIb-IIIa antagonists with improved pharmaceutical properties, we have utilized a novel 2,8-diazaspiro[4.5]decane scaffold as a template. We describe here our investigation of a variety of templates including spiropiperidinyl-γ -lactams, spiropiperidinylimide, spiropiperidinylureas, and spiropiperidinylhydantoins. With the appropriate acidic and basic pharmacophores in place, each template yielded analogues with potent GPIIb-IIIa inhibitory activity. One of the compounds, 59 (CT50787), was also used to demonstrate for the first time the use of a pharmacological agent which is αIIbβ3 specific to display biological activity in a lower species such as mouse and to extend bleeding times. Evaluation of the pharmacokinetic properties of selected compounds from each series in rat, dog, and cynomolgus monkey has led to the identification of 22 (CT51464), a double prodrug, with excellent pharmacokinetic properties. It exhibited good pharmacokinetic profile across species (F% = 33 (Cyno), 73 (dog), 22 (rat); t1/2β = 14. 2 h (Cyno), 8.97 h (dog), 1.81 h (rat)). The biologically active form, 23 (CT50728), displayed inhibition of platelet aggregation in platelet rich plasma (PRP) with an IC50 value of 53 nM in citrate buffer, 110 nM in PPACK anticoagulated PRP, and 4 nM in solid-phase GPIIb-IIIa competition binding assay (ELISA). Both 23 and 22 were stable in human liver microsomes, did not inhibit the P450 3A4 isozyme, and had low protein binding (18.22% for 23) and a desirable log P (0.45 ± 0.06 for 22, and -0.91 ± 0.32 for 23). It is predicted that the high oral bioavailability for these compounds in multiple species should translate into lower intra- and intersubject variability in man. The long plasma half-life of the lead is consistent with once or twice daily administration for chronic therapy. Analogue 22 (CT51464) thus appears to be a promising oral GPIIb-IIIa inhibitor with significantly improved pharmacokinetic properties over the previously described clinical candidates and may be found useful in the treatment of arterial occlusive disorders.
Mehrotra, Mukund M.,Heath, Julie A.,Smyth, Mark S.,Pandey, Anjali,Rose, Jack W.,Seroogy, Joseph M.,Volkots, Deborah L.,Nannizzi-Alaimo, Lisa,Park, Gary L.,Lambing, Joseph L.,Hollenbach, Stanley J.,Scarborough, Robert M.
p. 2037 - 2061
(2007/10/03)

Method of introducing amino group and method of synthesizing amino acid compound
The present invention relates to a method for introducing an amino group into an organic acid or an organic ester by reacting an organic salt or an organic ester and ammonia under high-temperature and high-pressure water conditions, a method for synthesizing an amino acid or an amino ester by the above method, and a method for manufacturing an amino acid compound by synthesizing an amino acid or an amino ester by the above method and separating and refining it with an ion exchange resin.
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Page 9

(2008/06/13)

Synthesis of N-Methyl-N-{(1S)-1-[(3R)-pyrrolidin-3-yl]ethyl} amine
N-Methyl-N-{(1S)-1-[(3R)-pyrrolidin-3-yl]ethyl} amine (1)1 is a key intermediate in the preparation of premafloxacin (2), which was under development as an antibiotic for use against pathogens of veterinary importance. This paper describes the development of a practical, efficient, and stereoselective process for the preparation of 1 from isobutyl (3S)-3-{methyl[(1S)-1-phenylethyl]-amino}butanoate (5c). The key steps in the synthetic sequence are an asymmetric Michael addition, which yields 5c, and a stereoselective alkylation, which yields (3S,4S)-3-allyl-1,4-dimethylazetidin-2-one (17).
Fleck, Thomas J.,McWhorter Jr., William W.,DeKam, Richard N.,Pearlman, Bruce A.
p. 9612 - 9617
(2007/10/03)

Structural effects on chemo- and enantioselectivity of Candida antarctica lipase B - Resolution of β-amino esters
The Candida antarctica lipase B-catalyzed reactions of five β-amino esters with neat butyl butanoate and with 2,2,2-trifluoroethyl butanoate in diisopropyl ether were studied, as were the reactions of the same β-amino esters and their N-butanamides with neat butanol. The possibility for sequential resolution, where the amino and ester functions of the substrate both react with an achiral butanoate, became less likely with increasing size of the substrate from ethyl 3-aminobutanoate (1a) to pentanoate (1b) or larger. On the other hand, the alcoholyses of N-acylated β-amino esters successfully proceeded in butanol with E > 100. Gram-scale resolution of the N-butanoylated 1a was performed to demonstrate the usefulness of the method.
Gedey, Szilvia,Liljeblad, Arto,Lazar, Laszlo,Fueloep, Ferenc,Kanerva, Liisa T.
p. 565 - 570
(2007/10/03)

Preparation of optically active β-amino acids from microbial polyester polyhydroxyalkanoates
An efficient method for the preparation of optically active ethyl β-aminobutyrate from the biopolymer, poly-(R)-(-)-3-hydroxybutyrate (PHB) obtained from bacterial cells has been established using chemical transforamtions: simple recovery of PHB from bacterial cells followed by acidic alcoholysis, tosylation, nucleophilic substitution by azide, and an indium mediated reduction.
Park, Sang Hyun,Lee, Seung Hwan,Lee, Sang Yup
p. 498 - 499
(2007/10/03)

Bispiperidines as antithrombotic agents
Novel compounds which are inhibitors of the binding of fibrinogen to the Gp IIb/IIIa platelet receptors, and which can be used therepeutically as antithrombotic agents
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(2008/06/13)

A facile procedure for reduction of azides to amines with aluminium triiodide
It has been demonstrated that a wide variety of aromatic and aliphatic azides can be efficiently reduced to the corresponding amines in good yields with freshly prepared aluminium triiodide. Other functional groups such as ether, ester, nitro and halides remain uneffected.
Barua, Apurba,Bez, Ghanashyam,Barua, Nabin C.
p. 128 - 129
(2007/10/03)

Enantioselective acylation of β-aminoesters using penicillin G acylase in organic solvents
The resolution of racemic β-aminoesters has been achieved through selective acylation catalyzed by Penicillin G Acylase (ChiroCLEC(TM)-EC). The method has been optimized using three different phenylacetyl donors, and the effect of solvents on the rate of reaction is described. The efficiency of our method is illustrated by the synthesis of five different β-aminoesters with high enantiomeric purities.
Roche, Didier,Prasad, Kapa,Repic, Oljan
p. 3665 - 3668
(2007/10/03)

Sequential resolution of ethyl 3-aminobutyrate with carboxylic acid esters by Candida antarctica lipase B
The reactions of ethyl 3-aminobutyrate 1 with carboxylic acid esters, catalyzed by lipases from Candida antarctica, Pseudomonas cepacia and Pseudomonas fluorescens, have been studied. The reactions take place on the amino and ester functions of the substrate provided that the alkyl group of the achiral ester differs from ethyl. This property has been exploited for the Candida antarctica lipase B-catalyzed resolution of 1 in butyl butyrate, leading to the unreacted enantiomer (S)-1 and butyl 3-aminobutyrate, and to the butanamide of butyl (R)-3-aminobutyrate.
Gedey, Szilvia,Liljeblad, Arto,Fueloep, Ferenc,Kanerva, Liisa T.
p. 2573 - 2581
(2007/10/03)

Commercial synthesis of 2,5-dimethylpiperid-4-one
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Murzagulova,Akhmedova,Yablokov,Mezentseva,Sharifkanov,Praliev,Turmukhanova
p. 507 - 508
(2007/10/03)

Candida antarctica lipase catalyzed resolution of ethyl (±)-3-aminobutyrate
Candida antarctica lipase efficiently catalyzes acetylation and hydrolysis of ethyl (±)-3-aminobutyrate.
Sanchez, Victor M.,Rebolledo, Francisca,Gotor, Vicente
p. 37 - 40
(2007/10/03)

A practical stereoselective synthesis of (2S, 4S)-4-tert-butoxycarbonylamino-2-methylpyrrolidine
Two practical syntheses of (2S, 4S)-4-tert-butoxycarbonylamino-2-methylpyrrolidine, an important intermediate for quinolone antibacterial agents, have been developed through the combination of diastereo and enantioselective reactions starting from ethyl crotonate and L-alanine, respectively.
Qun, Li,Chu, Daniel T. W.,Raye, Kathleen,Claiborne, Akiyo,Seif, Louis,Macri, Bryan,Plattner, Jacob J.
p. 8391 - 8394
(2007/10/02)

Chemo- and diastereoselective reduction of β-enamino esters: A convenient synthesis of both cis- and trans-γ-amino alcohols and β-amino esters
Convenient procedures for the chemo- and diastereoselective reduction of b-enamino esters 1 are described. Both cis- and trans-γ-amino alcohols 2 or b-amino esters 3 can be prepared by reduction of b-enamino esters 1, readily available starting materials, with the use of inexpensive reagents Na/i-PrOH or NaHB(OAc)3/AcOH, respectively, and the appropriate reduction conditions. The mechanisms and diastereoselectivities for the reductions are discussed. The relative configurations and conformations of the diastereoisomeric γ-amino alcohols 2 and β-amino esters 3 obtained are established by 1H and 13C NMR study and unequivocally set by their cyclic derivatives tetrahydro-1,3-oxazines 4.
Bartoli,Cimarelli,Marcantoni,Palmieri,Petrini
p. 5328 - 5335
(2007/10/02)

Chiral quinolone intermediates
Chiral compounds having the formulae STR1 useful in the synthesis of quinolone intermediates.
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(2008/06/13)

Stereoselective ring opening of chiral oxazolidines by reformatsky reagents: An enantioselective entry to β-amino esters
Chiral oxazolidines obtained by condensation of aldehydes with (-).(R)- or (+).(S)-N-benzylphenylglycinol react with the Reformatsky reagent derived from ethyl bromoacetate, in mild reaction conditions (Et2O or CH2Cl2, 0°C, 15-60 min), leading to ethyl β-amino carboxylates in moderate to good diastereomeric excess (60-92%). These ring opening products are transformed into primary β-aminoesters, in one step, by debenzylation with H2/Pd on carbon without loss of their stereochemical integrity. In this way, ethyl β-amino carboxylates can be obtained in both enantiomeric forms, with chemical yields ranging 55-76% and moderate to good e.e. (60-92%).
Andres, Celia,Gonzalez, Alfonso,Pedrosa, Rafael,Perez-Encabo, Alfonso
p. 2895 - 2898
(2007/10/02)

GABA-uptake inhibitors: Construction of a general pharmacophore model and successful prediction of a new representative
A model for the pharmacophore of GABA-uptake inhibitors was established using published structure-activity data and molecular modeling. The model accounted for the activities of different classes of GABA-uptake inhibitors. Analogues of guvacine substituted at position 6 were synthesized in order to confirm the model. 6-(3,3-Diphenylpropyl)guvacine (30f), which fit well with the pharmacophore, had an in vitro IC50 of 0.1 μM. This value is as good as those of the best GABA-uptake inhibitors known today.
N'Goka,Schlewer,Linget,Chambon,Wermuth
p. 2547 - 2557
(2007/10/02)

A NEW CHIRAL HOST COMPOUND 10,10'-DIHYDROXY-9,9'-BIPHENANTHRYL. OPTICAL RESOLUTION OF PROPIONIC ACID DERIVATIVES, BUTYRIC ACID DERIVATIVES, AND 4-HYDROXYCYCLOPENT-2-EN-1-ONE DERIVATIVES BY COMPLEXATION
Optically active 10,10'-dihydroxy-9,9'-biphenanthryl was designed as a new chiral host compound for optical resolution of guest compounds, and was found to be wery effective for resolution of the title guest compounds.
Toda, Fumio,Tanaka, Koichi
p. 1807 - 1810
(2007/10/02)

ENANTIOSELECTIVE HYDROLYSIS BY BAKER'S YEAST - II. ESTERS OF N-ACETYL AMINO ACIDS
D-N-Acetyl amino acid esters were obtained via enantioselective hydrolysis of their racemates by use of fermenting yeast.Evidence is given that proteinases are the enzymes involved.
Glaenzer, B. I.,Faber, K.,Griengl, H.
p. 771 - 778
(2007/10/02)

THIOCARBONYL OLEFINATION III: A NEW SYNTHESIS OF β-AMINOACIDS FROM N-THIOACYLURETHANES.
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Slopianka, M.,Gossauer, A.
p. 95 - 100
(2007/10/02)

Thiocarbonyl Olefination, IV. - Preparation of β-Amino Acids from N-(Acetyl)thioamides; Total Synthesis of Iturinic Acid
A new method for the synthesis of β-amino acids is described whose key step consists in the regioselective thiocarbonyl olefination of N-(acetyl)thioamides with methyl (triphenylphosphoranylidene)acetate.By this procedure, a straightforward synthesis of iturinic acid has been carried out for the first time.
Slopianka, Marion,Gossauer, Albert
p. 2258 - 2265
(2007/10/02)