- Asymmetric Synthesis. Metal Complex Mediated Synthesis of Chiral Glycine by Enantioselective Proton Exchange
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The complex (1+), a species containing a chiral tridentate triamine ligand, (S,S)-proam, and a tridentate ligand incorporating a glycine residue, picgly, has been prepared.The α-protons of the coordinated glycine residue exchange at different rates in basic D2O solutions.The difference in rate was found to be 7.8:1 in favor of the pro-S proton at pD 11.2 at 25 deg C with a NaHCO3/Na2CO3 buffer.It is proposed that the origins of this enantiosection arise from both steric and hydrogen-bonding effects as inferred from the determined crystal structure of the complex.A kinetic analysis of the exchange process shows that the system is essentially that of an asymmetric synthesis (CH2 -> CHD) followed by a reinforced kinetic resolution (CHD -> CD2).As such, the optical purity of the chiral glycine (NH2CHDCO2H) continuously increases with the extent of reaction.This was confirmed.It is suggested that the present kinetic relationships are representative of the majority of asymmetric syntheses involving enantiotopic atoms or groups, and it follows that, for such systems, quoting an enantiomeric excess has meaning only when the extent of reaction is specified.
- Dokuzovic, Zdravko,Roberts, Nicholas K.,Sawyer, Jeffery F.,Whelan, John,Bosnich, B.
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Read Online
- Chiral recognition of amino acid derivatives by 1,1′-binaphthalene-8,8′-diol
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Optically active 1,1′-binaphthalene-8,8′-diol is found to bind a variety of amines in CDCl3 or C6D6 solution. Significant chiral recognition (ΔΔGo = ～1.2 kcal/mol) was observed in the valine derivative 4. A three-point binding motif is assumed. Copyright
- Kawabata, Takeo,Kuroda, Akio,Nakata, Eizo,Takasu, Kiyosei,Fuji, Kaoru
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Read Online
- London Dispersion Interactions Rather than Steric Hindrance Determine the Enantioselectivity of the Corey–Bakshi–Shibata Reduction
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The well-known Corey–Bakshi–Shibata (CBS) reduction is a powerful method for the asymmetric synthesis of alcohols from prochiral ketones, often featuring high yields and excellent selectivities. While steric repulsion has been regarded as the key director of the observed high enantioselectivity for many years, we show that London dispersion (LD) interactions are at least as important for enantiodiscrimination. We exemplify this through a combination of detailed computational and experimental studies for a series of modified CBS catalysts equipped with dispersion energy donors (DEDs) in the catalysts and the substrates. Our results demonstrate that attractive LD interactions between the catalyst and the substrate, rather than steric repulsion, determine the selectivity. As a key outcome of our study, we were able to improve the catalyst design for some challenging CBS reductions.
- Eschmann, Christian,Song, Lijuan,Schreiner, Peter R.
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supporting information
p. 4823 - 4832
(2021/02/01)
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- l -Proline as a Valuable Scaffold for the Synthesis of Novel Enantiopure Neonicotinoids Analogs
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In this research, six neonicotinoid analogs derived from l-proline were synthesized, characterized, and evaluated as insecticides against Xyleborus affinis. Most of the target compounds showed good to excellent insecticidal activity. To the best of our knowledge, this is the first report dealing with the use of enantiopure l-proline to get neonicotinoids. These results highlighted the compound 9 as an excellent candidate used as the lead chiral insecticide for future development. Additionally, molecular docking with the receptor and compound 9 was carried out to gain insight into its high activity when compared to dinotefuran. Finally, the neurotoxic evaluation of compound 9 showed lower toxicity than the classic neonicotinoid dinotefuran.
- Bonilla-Landa, Israel,Cuapio-Mu?oz, Ulises,Luna-Hernández, Axel,Reyes-Luna, Alfonso,Rodríguez-Hernández, Alfredo,Ibarra-Juarez, Arturo,Suarez-Mendez, Gabriel,Barrera-Méndez, Felipe,Caram-Salas, Nadia,Enríquez-Medrano, J. Francisco,Díaz De León, Ramón E.,Olivares-Romero, José Luis
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p. 1455 - 1465
(2021/02/16)
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- Understanding the Alkylation Mechanism of 3-Chloropiperidines – NMR Kinetic Studies and Isolation of Bicyclic Aziridinium Ions
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The present study describes the kinetic analysis of the 3-chloropiperidine alkylation mechanism. These nitrogen mustard-based compounds are expected to react via a highly electrophilic bicyclic aziridinium ion, which is readily attacked by nucleophiles. Halide abstraction using silver salts with weakly coordinating anions lead to the isolation of these proposed intermediates, whereas their structure was confirmed by single crystal XRD. Kinetic studies of the aziridinium ions also revealed notable reactivity differences of the C5 gem-methylated compounds and their unmethylated counterparts. The observed reactivity trends were also reflected by NMR studies in aqueous solution and DNA alkylation experiments of the related 3-chloropiperidines. Therefore, the underlying Thorpe-Ingold effect might be considered as another option to adjust the alkylation activity of these compounds.
- Helbing, Tim,Georg, Mats,St?hr, Fabian,Carraro, Caterina,Becker, Jonathan,Gatto, Barbara,G?ttlich, Richard
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p. 5905 - 5913
(2021/10/29)
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- Production of professional linoleic, complex metal compounds and manufacturing method thereof
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[A] a method of manufacturing a novel professional linoleic. Also, suitable for producing a professional linoleic, complex metal compound and its manufacturing method. The manufacturing method of the present invention [a] professional linoleic, selected from Rh metal or Pt, selected from the group consisting of one or more metal oxide Mo and 1 is supported by a carrier in the presence of a composite metal compound, by reacting with hydrogen containing proline. The present invention is a composite metal compound, or a metal selected from Rh Pt, selected from the group consisting of one or more metal oxide Mo and 1 compound, Al2 O3 Carried by the carrier. Figure 3 [drawing]
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Paragraph 0081-0085
(2021/11/26)
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- Selective hydrogenation of primary amides and cyclic di-peptides under Ru-catalysis
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A ruthenium(II)-catalyzed selective hydrogenation of challenging primary amides and cyclic di-peptides to their corresponding primary alcohols and amino alcohols, respectively, is reported. The hydrogenation reaction operates under mild and eco-benign conditions and can be scaled-up.
- Subaramanian, Murugan,Sivakumar, Ganesan,Babu, Jessin K.,Balaraman, Ekambaram
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supporting information
p. 12411 - 12414
(2020/10/30)
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- Basicities and Nucleophilicities of Pyrrolidines and Imidazolidinones Used as Organocatalysts
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The Br?nsted basicities pKaH (i.e., pKa of the conjugate acids) of 32 pyrrolidines and imidazolidinones, commonly used in organocatalytic reactions, have been determined photometrically in acetonitrile solution using CH acids as indicators. Most investigated pyrrolidines have basicities in the range 16 aH aH aH 12.6) and the 2-imidazoliummethyl-substituted pyrrolidine A21 (pKaH 11.1) are outside the typical range for pyrrolidines with basicities comparable to those of imidazolidinones. Kinetics of the reactions of these 32 organocatalysts with benzhydrylium ions (Ar2CH+) and structurally related quinone methides, common reference electrophiles for quantifying nucleophilic reactivities, have been measured photometrically. Most reactions followed second-order kinetics, first order in amine and first order in electrophile. More complex kinetics were observed for the reactions of imidazolidinones and several pyrrolidines carrying bulky 2-substituents, due to reversibility of the initial attack of the amines at the electrophiles followed by rate-determining deprotonation of the intermediate ammonium ions. In the presence of 2,4,6-collidine or 2,6-di-tert-butyl-4-methyl-pyridine, the deprotonation of the initial adducts became faster, which allowed the rate of the attack of the amines at the electrophiles to be determined. The resulting second-order rate constants k2 followed the correlation log?k2(20 °C) = sN(N + E), where electrophiles are characterized by one parameter (E) and nucleophiles are characterized by the two solvent-dependent parameters N and sN. In this way, the organocatalysts A1-A32 were integrated in our comprehensive nucleophilicity scale, which compares n-, -, and σ-nucleophiles. The nucleophilic reactivities of the title compounds correlate only poorly with their Br?nsted basicities.
- An, Feng,Maji, Biplab,Min, Elizabeth,Ofial, Armin R.,Mayr, Herbert
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supporting information
p. 1526 - 1547
(2020/02/04)
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- Behind the Mirror: Chirality Tunes the Reactivity and Cytotoxicity of Chloropiperidines as Potential Anticancer Agents
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The pressing demand for sustainable antitumor drugs prompted us to investigate 3-chloropiperidines as potential mustard-based anticancer agents. In this study, an explorative set of variously decorated monofunctional 3-chloropiperidines (M-CePs) was efficiently synthesized through a fast and affordable route providing high yields of pure racemates and enantiomers. Consistently with their reactivity, M-CePs were demonstrated to alkylate DNA in vitro. On a panel of carcinoma cell lines, M-CePs exhibited low nanomolar cytotoxicity indexes, which showed their remarkable activity against pancreatic cancer cells and in all cases performed strikingly better than the chlorambucil control. Very interestingly, stereochemistry modulated the activity of M-CePs in unexpected ways, pointing to additional molecular mechanisms of action beyond the direct damage of genomic DNA. This encouraging combination of efficacy and sustainability suggests they are valid candidates for anticancer agent development.
- Carraro, Caterina,Francke, Alexander,Sosic, Alice,Kohl, Franziska,Helbing, Tim,De Franco, Michele,Fabris, Daniele,G?ttlich, Richard,Gatto, Barbara
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supporting information
p. 552 - 557
(2019/03/07)
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- Pyrrolidine-Oxadiazolone Conjugates as Organocatalysts in Asymmetric Michael Reaction
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Pyrrolidine-oxadiazolone based organocatalysts are envisaged, synthesized, and utilized for asymmetric Michael reactions. Results of the investigations suggest that some of the catalysts are indeed efficient for stereoselective 1,4-conjugated Michael additions (dr: >97:3, ee up to 99%) in high chemical yields (up to 97%) often in short reaction time. As an extension, one enantiopure Michael adduct has been utilized to synthesize optically active octahydroindole.
- Mahato, Chandan K.,Mukherjee, Sayan,Kundu, Mrinalkanti,Pramanik, Animesh
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p. 1053 - 1063
(2019/01/14)
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- Novel chiral amine oxide ligand and preparation method thereof
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The invention provides a novel chiral amine oxide ligand and a preparation method thereof. The method uses a simple amino acid or an amino acid derivative as a raw material, the raw material is modified, the modified material reacts with substances such as a coupling agent and an alkali, and therefore the pincher configuration chiral ligand compound is obtained, that is, the chiral amine oxide ligand. The chiral amine oxide ligand provided by the invention has a structure of a non-simple linear chain, has a soft skeleton in the molecular structure, contains a recognition gene containing heteroatoms such as oxygen or nitrogen, and can well coordinate with a series of metals and realize high enantioselectivity and high reactivity in a non-symmetric reaction; and the preparation method is simple, the steps are few, and the raw materials are cheap and easy to obtain.
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- Isosteric expansion of the structural diversity of chiral ligands: Design and application of proline-based N,N′-dioxide ligands for copper-catalyzed enantioselective Henry reactions
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Chiral N,N′-dioxide catalysts were designed based on isosteric approach. Using L-Proline as the starting material, a variety of chiral N,N′-dioxide ligands were obtained via conventional functional group transformations and were utilized in asymmetric Henry reactions between nitromethane and aromatic aldehydes. Using the N,N′-dioxide-copper(II) complexes as the catalysts, asymmetric Henry reaction produced the corresponding β-nitroalcohols in up to 66% yields and up to 83% ee's under mild conditions. The reactions were easy to carry out, and special care such as air or moisture-free conditions was not required.
- Gao, En,Li, Meng,Duan, Lili,Li, Lin,Li, Yue-Ming
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- Catalytic Mechanism Study on the 1,2- and 1,4-Transfer Hydrogenation of Ketimines and β-Enamino Esters Catalyzed by Axially Chiral Biscarboline-Based Alcohols
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Axial N-O alcohols, which have two large carboline moieties connected to the axis were synthesized and used in catalytic enantioselective 1,2- and 1,4-transfer hydrogenations of total 26 ketimines and β-enamino esters. Excellent levels of enantioselectivity ranging from 91% to 99% were achieved by using catalyst (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide. Interestingly, a mixture of (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide and (aR)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide was also able to provide high enantioselectivities up to 95% that is the same as that using pure (aS)-(S)-3,3′-bis((S)-2-(hydroxymethyl)pyrrolidine-1-carbonyl)-9,9′-dimethyl-9H,9′H-[1,1′-bipyrido[3,4-b]indole] 2-oxide. A plausible catalytic mechanism was suggested and total four kinds of transition states (TS) including almost 60 TS structures were investigated using density functional theory (DFT) with different basis sets such as 6-311G(2d,p). The predicted activation energy data are consistent with the experimental results. (Figure presented.).
- Dong, Mengxian,Wang, Jie,Wu, Shijie,Zhao, Yang,Ma, Yangyang,Xing, Yongfei,Cao, Fei,Li, Longfei,Li, Zhenqiu,Zhu, Huajie
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supporting information
p. 4602 - 4610
(2019/08/30)
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- A synthesis method of the dried meat ammonia is mellow L -
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The invention discloses an L-prolinol synthetic method. The method comprises the following steps that 1, ethyl alcohol is added in a reaction kettle, thionyl chloride is dropwise added at 10-15 DEG C, then, L-prolinol is added, the temperature is increased to 40 DEG C, a heat-preservation reaction is carried out for 10-12 h, the mixture is concentrated to be thick liquid after the reaction is finished, ethyl acetate is added for dissolution, the pH value is adjusted through triethylamine to be 7-8, and salt is filtered away to obtain L-proline ethyl ester; 2, the L-proline ethyl ester is in a methyl alcohol system, lithium chloride is added at 5-10 DEG C, the sodium borohydride is added many times, a heat-preservation reaction is carried out at 20-25 DEG C for 2-2.5 h, hydrochloric acid is added, heat-preservation hydrolysis is carried out for 2 h, methyl alcohol is recycled, the pH value is adjusted through 25% sodium hydroxide to be 12, a product is extracted through dichloromethane, anhydrous sodium sulfate drying is carried out, and filtering is carried out; 3, dichloromethane is recycled from mother liquid at 30-40 DEG C and normal pressure, oily matter is obtained, pressure reduction and distillation are carried out, and therefore the pure L-prolinol is obtained. According to the L-prolinol synthetic method, the reaction temperature is mild, the safety coefficient is low, no solid waste is produced, and environmental protection is achieved.
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Paragraph 0016; 0020-0022
(2018/07/06)
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- Ionic Liquids Derived from Proline: Application as Surfactants
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Ionic liquids derived from prolinium esters, previously described as fully green and stable, were found to decompose in the presence of water by ester hydrolysis. To avoid this problem, a new family of these biodegradable salts incorporating an alcohol instead of the ester group is proposed. From this family, two novel ionic liquids that incorporate the prolinolium cation [HOPro] and the [DS] or [DBS] anion were selected (DS=dodecylsulfate; DBS=dodecylbenzenesulfonate). Both salts are liquid at room temperature, a property not usually found in ionic surfactants, and are also chemically and thermally stable. Moreover, they are more effective in reducing the surface tension of water than the corresponding traditional surfactants in the form of sodium salts, being useful for applications related to their aggregation capacity. They were tested for surfactant enhanced oil recovery and an optimal formulation for reservoirs at high salinity and temperature, able to produce ultra-low interfacial tension, was found with [HOPro][DBS].
- Fernández-Stefanuto, Verónica,Corchero, Raquel,Rodríguez-Escontrela, Iria,Soto, Ana,Tojo, Emilia
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p. 2885 - 2893
(2018/09/10)
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- Method for synthesizing D-proline
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The invention belongs to the technical field of synthesis of chiral organic compounds, and especially relates to a method for synthesizing D-proline. The method comprises the following steps: taking pyrrolidine-2-carbaldehyde, dissolving the pyrrolidine-2-carbaldehyde in an organic solvent, adding a catalyst and an organic alkali potassium t-butoxide, and carrying out an asymmetric catalysis hydrogenation reaction to obtain an intermediate II; and carrying out an oxidation reaction on the intermediate II and an oxidant to obtain the product D-proline III. The method for synthesizing D-prolinehas the following advantages: the use amount of the catalyst is small, and the catalyst can be used repeatedly, so the cost is saved; the solvent used in the synthesis process is a common solvent, sothe method has the characteristics of low cost, non-toxicity, no pollution, greenness and environmental protection; and the synthesis method has a simple process, the yield in the invention is higherthan the yield in the prior art, and the optical purity of the obtained product is high, so the method is suitable for industrial production.
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Paragraph 0026-0029; 0035
(2018/07/30)
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- Preparation method of L-prolinol
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The invention relates to a preparation method of L-prolinol, which is prepared from cheap L-pyroglutamic acid as a raw material by high-pressure hydrogenation reduction with a transition metal atom-modified ruthenium-carbon catalyst. The catalytic activity of the modified ruthenium-carbon catalyst is significantly higher than that of the existing commercial ruthenium-carbon catalyst, so that the lactam hydrogenation reaction of L-pyroglutamic acid, which is difficult to implement, can be smoothly carried out. The preparation method of L-prolinol provided by the invention has the following benefits: the process route is short, the yield is high (up to about 90%), the post-treatment is simple, the catalyst can be reused for more than 20 times, acid water can be recycled after distillation, green synthesis is basically realized, no waste water and waste residues are generated, a large amount of solid waste and waste water generated by reduction of hydroborate and lithium aluminum hydride are avoided, and the method is suitable for large-scale industrial production.
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Paragraph 0057-0060; 0064; 0067; 0072; 0074; 0080; 0082
(2017/08/29)
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- Enantioselective Synthesis of 6,6-Disubstituted Pentafulvenes Containing a Chiral Pendant Hydroxy Group
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Simple enantioselective synthesis of 6,6-disubstituted pentafulvenes bearing chiral pendant hydroxy groups are attained by cascade reactivity using commercially available proline-based organocatalysts. Condensation of cyclopentadiene with the acetyl function of a 1,2-formylacetophenone, followed by cyclization of a resulting fulvene-stabilized carbanion with the formyl group, generates bicyclic chiral alcohols with initial er values up to 94:6. Exceptional enantio-enrichment of the resultant alcohols results upon crystallization—even near racemic samples spontaneously de-racemize. This enables new families of substituted cyclopentadienes that are both enantiomerically and diastereomerically pure to be rapidly attained.
- Nouch, Ryan,Cini, Melchior,Magre, Marc,Abid, Mohammed,Diéguez, Montserrat,Pàmies, Oscar,Woodward, Simon,Lewis, William
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supporting information
p. 17195 - 17198
(2017/11/27)
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- Solvent free, fast and asymmetric Michael additions of ketones to nitroolefins using chiral pyrrolidine–pyridone conjugate bases as organocatalysts
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New chiral organocatalysts are envisaged based on a pyrrolidine–pyridone conjugate and synthesized from commercially available proline employing standard protocols. These catalysts were found to be useful for asymmetric Michael additions of ketones to nitroolefins to afford the desired products in very good yields (up to 98%) with excellent diastereo- and enantioselectivities (>97:3 syn/anti and up to 98% ee) in very short reaction time compared with the existing reports.
- Mahato, Chandan K.,Kundu, Mrinalkanti,Pramanik, Animesh
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p. 511 - 515
(2017/04/28)
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- Zinc-Catalyzed Esterification of N-β-Hydroxyethylamides: Removal of Directing Groups under Mild Conditions
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Amide transformations involving C–N bond cleavage are recognized as difficult reactions owing to the inert nature of amides resulting from resonance. Accordingly, a strong inductive effect and geometrical distortion reasonably decrease the resonance stabilization to attenuate the C–N linkage. Although the conversion of such activated amides has been studied intensively, reaction systems for “unactivated” amides are underdeveloped. We herein report that a zinc(II) trifluoromethanesulfonate [Zn(OTf)2] catalyst achieves the esterification of a wide range of unactivated tertiary amides with the assistance of intramolecular acyl rearrangement. The reaction was applied to the one-pot removal of various amide-based directing groups under mild reaction conditions to afford the corresponding esters in high yields.
- Nishii, Yuji,Hirai, Takahiro,Fernandez, Sarah,Knochel, Paul,Mashima, Kazushi
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supporting information
p. 5010 - 5014
(2017/09/21)
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- Synthesis of Enantiomerically Pure N-Acyl Amino Nitriles via Catalytic Dehydration of Oximes and Application in a de Novo Synthesis of Vildagliptin
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An alternative route toward enantiomerically highly enriched N-acyl amino nitriles based on the Cu(OAc)2-catalyzed dehydration of aldoximes, which are readily available from N-acyl l- or d-α-amino aldehydes through condensation with hydroxylamine, has been developed. The desired products were obtained with high conversion and in enantiomeric excesses of 97-99% ee. Furthermore, this method has been applied in the synthesis of an N-chloroacetylated 2-cyanopyrrolidine, which represents a building block for the synthesis of Vildagliptin.
- Rommelmann, Philipp,Betke, Tobias,Gr?ger, Harald
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supporting information
p. 1521 - 1527
(2017/10/25)
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- Amino alcohol-derived chiral ionic liquids: structural investigations toward chiral recognition
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From tentative beginnings, chiral ionic liquids have emerged into functionalized and tailor-made materials that provide novel input in classical asymmetric synthesis and separations. However, despite this broad application range the prediction of any chiral ionic liquids' performance is difficult. We present a systematic study toward the chiral recognition properties of novel ionic liquids with an amino alcohol sub-structure derived from the chiral pool precursors ephedrine, prolinol, and phenylalaninol. The influence of different ionic head groups and core structures on the diastereomeric interactions between racemic Mosher's acid carboxylate and enantiopure chiral ionic liquids was systematically investigated to provide insight into their recognition properties prior to application of these chiral ionic liquids in various fields.
- Vasiloiu, Maria,Cervenka, Isabella,Gaertner, Peter,Weil, Matthias,Schr?der, Christian,Bica, Katharina
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p. 1069 - 1082
(2015/10/19)
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- Diastereoselective desymmetrization of diarylphosphinous acid-borane amides under Birch reduction
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Treatment of diarylphosphinous acid-borane amides possessing chiral amido functionality with an alkali metal solution in liquid ammonia induced a preferential dearomatization of one aryl substituent at phosphorus leading to the formation of non-equimolar amounts of diastereomers. Diastereoselectivity of dearomatization depends strongly on the structure of a chiral auxiliary.
- Stankevi?, Marek
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p. 6082 - 6102
(2015/06/08)
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- Design, synthesis and catalytic property of L-proline derivatives as organocatalysts for direct aldol reaction
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A series of chiral prolinamide compounds with pyridine-2, 6-dicarboxylic acid moieties derived from L-proline have been designed and synthesized, their catalytic properties for direct asymmetric aldol reactions were also studied in this article. These catalysts gave the aldol product in high yield (87%) and high enantioselectivity, up to 85%, of the anti-structure at room temperature but gave disappointing results at a lower temperature or when additive was added. Conditions, including solvents, temperature and additives were screened for the reactions. Moreover, the influence of presence of water on yield and stereoselectivity was also discussed. Copyright
- Wang, Lei,Tang, Ruiren,Yang, Hua
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p. 591 - 598
(2013/11/06)
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- Henry-Nef reaction: A practical and versatile chiral pool route to 2-substituted pyrrolidine and piperidine alkaloids
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The paper describes the synergistic protocol developed by combinatorial Henry and Nef reaction for the synthesis of 2-substituted pyrrolidine and piperidine alkaloids containing 1,3-aminoketone and 1,3-amino alcohol units. The utility of the protocol is demonstrated by asymmetric synthesis of 12 natural products of which asymmetric synthesis of (-)-N-methylpelletierine is presented for the first time. The one-carbon homologation described also provides an alternate route for the synthesis of key intermediates homoprolinol and homopipecolinol used as synthetic precursors for several alkaloids and construction of β-amino acids from α-amino acids.
- Bhat, Chinmay,Tilve, Santosh G.
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p. 6129 - 6143
(2013/07/27)
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- NOVEL ARYLALKENE DERIVATIVES AND USE THEREOF AS SELECTIVE ESTROGEN RECEPTOR MODULATORS
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The invention provides novel ethylene derivatives represented by Formula I, which may be used as selective estrogen receptor modulators (SERMs) and useful in the prophylaxis and/or treatment of estrogen-dependent conditions or conditions.
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Paragraph 0144
(2013/07/19)
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- Synthesis of (R)-norbgugaine and its potential as quorum sensing inhibitor against Pseudomonas aeruginosa
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(R)-Bgugaine is a natural pyrrolidine alkaloid from Arisarum vulgare, which shows antifungal and antibacterial activity. In this Letter, we have accomplished the simple synthesis of norbgugaine (demethylated form of natural bgugaine) employing Wittig olefination and cat. hydrogenation as the key steps and its biological studies are reported for the first time. The synthesized norbgugaine was evaluated for inhibition of quorum sensing mediated virulence factors (motility, biofilm formation, pyocyanin pigmentation, rhamnolipid production and LasA protease) in Pseudomonas aeruginosa wherein swarming motility is reduced by 95%, and biofilm formation by 83%.
- Majik, Mahesh S.,Naik, Deepak,Bhat, Chinmay,Tilve, Santosh,Tilvi, Supriya,D'Souza, Lisette
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supporting information
p. 2353 - 2356
(2013/05/09)
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- Coordinating chiral ionic liquids
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A practical synthesis of novel coordinating chiral ionic liquids with an amino alcohol structural motif was developed starting from commercially available amino alcohols. These basic chiral ionic liquids could be successfully applied as catalysts in the asymmetric alkylation of aldehydes and gave high enantioselectivities of up to 91% ee.
- Vasiloiu, Maria,Leder, Sonja,Gaertner, Peter,Mereiter, Kurt,Bica, Katharina
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p. 8092 - 8102
(2013/12/04)
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- Chiral aminophosphines as catalysts for enantioselective double-michael indoline syntheses
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The bisphosphine-catalyzed double-Michael addition of dinucleophiles to electron-deficient acetylenes is an efficient process for the synthesis of many nitrogencontaining heterocycles. Because the resulting heterocycles contain at least one stereogenic center, this double-Michael reaction would be even more useful if an asymmetric variant of the reaction were to be developed. Aminophosphines can also facilitate the double-Michael reaction and chiral amines are more readily available in Nature and synthetically; therefore, in this study we prepared several new chiral aminophosphines. When employed in the asymmetric double-Michael reaction between ortho-tosylamidophenyl malonate and 3-butyn-2-one, the chiral aminophosphines produced indolines in excellent yields with moderate asymmetric induction.
- Khong, San N.,Kwon, Ohyun
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scheme or table
p. 5626 - 5650
(2012/07/03)
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- Modular bifunctional chiral thioureas as versatile organocatalysts for highly enantioselective aza-Henry reaction and michael addition
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A series of new modular bifunctional chiral thiourea organocatalysts were synthesized from natural Cinchona alkaloids and amino acids, and their performance in the aza-Henry reaction of nitroalkanes to imines, the Michael addition of acetylacetone to nitroolefins and the Michael addition of acetone to nitroolefins was investigated. Under the mild conditions, the important building blocks β-nitro amines and γ-nitro carbonyl compounds could be obtained in good yields (up to 95%) with excellent enantioselectivities (up to 99% ee) and diastereoselectivity (up to 17:1). Copyright
- Li, Hua,Zhang, Xu,Shi, Xin,Ji, Nan,He, Wei,Zhang, Shengyong,Zhang, Bangle
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p. 2264 - 2274
(2012/11/06)
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- Asymmetric syntheses of pyrrolidine and piperidine derivatives Via regio-and stereo-selective ring-opening reactions of chiral aziridine
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Asymmetric synthesis of cyclic β-amino alcohols (pyrrolidine and piperidine derivatives) has been achieved using a chiral aziridine as the starting material. The key step of this synthetic methodology is regio- and stereo-controlled ring-opening of the chiral aziridine with acetic acid or acetyl chloride.
- Higashiyama, Kimio,Matsumura, Masataka,Kurita, Emiko,Yamauchi, Takayasu
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p. 371 - 380
(2013/08/15)
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- Synthesis of (-)-hygrine, (-)-norhygrine, (-)-pseudohygroline and (-)-hygroline via Nef reaction
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Synthesis of tropane alkaloids (-)-hygrine, (-)-norhygrine and sedum alkaloids (-)-pseudohygroline and (-)-hygroline is described from l-proline via Henry and Nef reactions.
- Bhat, Chinmay,Tilve, Santosh G.
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scheme or table
p. 6566 - 6568
(2012/01/02)
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- Proline-derived aminotriazole ligands: Preparation and use in the ruthenium-catalyzed asymmetric transfer hydrogenation
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The preparation of 2-triazolyl- and 2-triazolylmethylpyrrolidines from L-proline and L-trans-4-hydroxyproline is described, along with their evaluation as chiral ligands in ruthenium-catalyzed asymmetric transfer hydrogenation. Modular evolution of the ligands by introduction of remote substituents is also presented, showing a surprisingly important effect on the performance of the ligands.
- Cambeiro, Xacobe C.,Pericas, Miquel A.
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supporting information; experimental part
p. 113 - 124
(2011/04/12)
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- Novel cyclic β-aminophosphonate derivatives as efficient organocatalysts for the asymmetric Michael addition reactions of ketones to nitrostyrenes
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Three novel catalysts based upon cyclic β-aminophosphonate derivatives 13 were designed to catalyze the asymmetric Michael addition reactions of ketones to β-nitrostyrenes. Among the catalysts that have been prepared in this study, cyclic β-aminophosphonic acid monoethylester 3 showed the highest catalytic ability, giving the corresponding Michael adduct in good yields, high enantioselectivities (up to 92%ee), and high diastereoselectivities (syn:anti up to 95:5).
- Widianti, Triana,Hiraga, Yoshikazu,Kojima, Satoshi,Abe, Manabu
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experimental part
p. 1861 - 1868
(2010/11/18)
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- Synthesis of new [(2S)-N-(p-Tolylsulfonyl)-2-Pyrrolidinyl]Propyl 2,3,4-Tri-O-Acetyl- and 2,3,4-Tri-O-Benzyl-β-L-Fucopyranosides
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Synthesis of two new glycoheterocyclic compounds, [(2S)-N-(p-tolylsulfonyl) -2-pyrrolidinyl]propyl 2,3,4-tri-O-acetyl- and 2,3,4-tri-O-benzyl-β-L- fucopyranosides la and lb, starting from δ-amino alcohol (-)-[(2S)-N-(ptolylsulfonyl)-2-pyrrolidinyl]propan-l-ol 2 and O-α-L-fucosyltrichloroacetimidates 3a or 3b as glycosyl donor is described. Hitherto δ-aminoalcohol 2 was synthesized from L-proline without any racemization during its preparation.
- E Silva, Maria Joselice,Srivastava, Rajendra M.,Doboszewski, Bogdan,Cottier, Louis,Sinou, Denis
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scheme or table
p. 105 - 111
(2011/06/26)
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- Chiral lithium amide mediated asymmetric synthesis of 3-aryl-3,4- dihydroisocoumarins
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An asymmetric synthesis of 3-aryl-3,4-dihydroisocoumarins using the reaction of laterally lithiated 4,4-dimethyl-2-(o-tolyl)oxazoline with aromatic aldehydes, in the presence of an external chiral ligand, gave products with enantiomeric excess (ee) in the range of 60-70%. ARKAT USA, Inc.
- Sharma, Arvind Kumar,Maheshwary, Yogita,Singh, Paramjit,Singh, Kamal Nain
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scheme or table
p. 54 - 62
(2010/10/19)
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- Enantioselective nucleophilic addition of trimethylsilylacetylene to N-phosphinoylimines promoted by C2-symmetric proline-derived β-amino alcohol
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(Chemical Equation Presented) Both C2- and C3- symmetric proline-derived β-amine alcohol ligands were designed, synthesized, and successfully applied to the enantioselective direct addition of trimethylsilylacetylene to N-phosphinoylimines. Aromatic, heteroaromatic, and aliphatic N-(diphenylphosphinoyl) imines and several N-(diethoxyphosphoryl) imines were tested, and optically active propargylic amides in good yields (up to 92%) and excellent enantioselectivities (up to 95%) were obtained by the simple experimental procedure. The convenience, mild conditions, and easy deprotection of the phosphonamide products made the present method very attractive. Furthermore, the Michael-type addition process of C=N alkynylation was studied and proposed on the basis of React 31P NMR investigation.
- Zhu, Shaoqun,Yan, Wenjin,Mao, Bin,Jiang, Xianxing,Wang, Rui
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supporting information; experimental part
p. 6980 - 6985
(2009/12/07)
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- SUBSTITUTED SULFONAMIDE DERIVATIVES
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The invention relates to substituted sulfonamide derivatives, processes for the preparation thereof, medicaments containing these compounds and the use of substituted sulfonamide derivatives for the preparation of medicaments.
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Page/Page column 102
(2009/11/29)
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- Asymmetric epoxidation of styrenes catalyzed by molybdenum complexes with amino alcohol ligands
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Two common amino alcohols, prolinol and isolucinol, and their derivatives have been screened to coordinate with MoO2(acac)2 to form in situ catalysts for asymmetric epoxidation of styrenes with the highest enantioselectivity of 84% for 4-fluoro-styrene under the optimized reaction conditions.
- Wang, Yi,Wu, Zhiqing,Li, Zhengkai,Zhou, Xiang-Ge
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body text
p. 2509 - 2511
(2009/09/05)
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- Syntheis of new chiral 5,6,7,8-tetrahydrotetrazolo[1,5-a]pyrazines from α-amino acid derivatives following "click" chemistry
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An efficient and practical synthesis of new chiral fused tetrazoles have been synthesized following [3+2] cycloaddition reaction starting from α-amino acid derivatives.
- Mohapatra, Debendra K.,Maity, Pradip K.,Ghorpade, Ravindra V.,Gurjar, Mukund K.
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body text
p. 865 - 872
(2010/09/16)
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- Asperelines A-F, peptaibols from the marine-derived fungus Trichoderma asperellum
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Fermentation of the marine-derived fungus Trichoderma asperellum, collected from the sediment of the Antarctic Penguin Island, resulted in the isolation of six new peptaibols named asperelines A-F (1-6), which are characterized by an acetylated N-terminus and a C-terminus containing an uncommon prolinol residue. Structures were determined by extensive 1D and 2D NMR (1H- 1H COSY, HMQC, HMBC, NOESY) spectroscopic data analysis combined with ESIMS/MS fragmentation. The absolute configurations of the amino acid residues possessing a chiral R-carbon and of the prolinol residue were determined to be L and S, respectively, using a new method of 1H NMR spectroscopic comparison of complexes formed between the chiral reagent Ru(D 4-Por*)CO and amino acids derived from the peptaibols with those formed with reference standards.
- Ren, Jinwei,Xue, Chunmei,Tian, Li,Xu, Minjuan,Chen, Jian,Deng, Zhiwei,Proksch, Peter,Lin, Wenhan
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experimental part
p. 1036 - 1044
(2011/02/28)
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- REVERSIBLE ROOM-TEMPERATURE IONIC LIQUIDS
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One aspect of the present invention relates to salts that are room-temperature ionic liquids (RTILs), methods of making them, and methods of using them in connection with temporary or permanent gas sequestration. Another aspect of the present invention relates to a class of solvents which can be transformed into RTILs by exposure to a gas, and methods of using them in connection with temporary or permanent gas sequestration.
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Page/Page column 95
(2008/12/07)
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- 2-[(Imidazolylthio)methyl]pyrrolidine as a trifunctional organocatalyst for the highly asymmetric Michael addition of ketones to nitroolefins
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The direct asymmetric Michael addition of ketones to nitroolefins catalyzed by 2-[(imidazol-2-ylthio)methyl]pyrrolidine, constructed from natural L-proline and imidazolylthio platforms, with salicylic acid as a co-catalyst has been developed to give the products in high yields (up to 95%) and with excellent enantioselectivities (up to 99% ee). The highly efficient catalytic performance may be attributed to the dual activation of the Michael substrates by the trifunctional organocatalysts and the co-catalyst salicylic acid, leading to the formation of a stable transition state complex through the synergic effect of hydrogen-bonding and electrostatic interactions. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Xu, Dan-Qian,Wang, Li-Ping,Luo, Shu-Ping,Wang, Yi-Feng,Zhang, Shuai,Xu, Zhen-Yuan
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scheme or table
p. 1049 - 1053
(2009/04/05)
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- Exploiting π shielding interactions of η6 arene chromium (0) complexes: New auxiliaries derived from the biogenic chiral pool
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A family of highly selective chiral auxiliaries containing arene chromium (0) complexes has been prepared using biogenic precursors from the chiral pool. The systems, derived from isomannide, prolinol, and xylofuranose were applied to the asymmetric Diels-Alder reaction of derived acrylate esters. Factors influencing stereoselectivity with the auxiliaries have been investigated and delineated including the impact of mixed ligands on the chromium (0) complex. Under optimal conditions, the auxiliaries give >95% e.e. and 98:2 exo:endo ratio in cycloaddition with cyclopentadiene.
- Li, Jane,Xie, Longfei,Guzel, Mustafa,Heaton, Steven B.,Ma, Dong,Kallmerten, Amy E.,Jones, Graham B.
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p. 5459 - 5473
(2008/03/12)
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- Highly enantioselective Michael additions in water catalyzed by a PS-supported pyrrolidine
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The development of a highly efficient, polymer-supported organocatalyst for the Michael addition of ketones to nitroolefins is described. A 1,2,3-triazole ring, constructed through a click 1,3-cycloaddition, plays the double role of grafting the chiral pyrrolidine monomer onto the polystyrene backbone and of providing a structural element, complementary to pyrrolidine, key to high catalytic activity and enantioselectivity. Optimal operation in water and full recyclability make the triazole linker attractive for the immobilization of organocatalysts.
- Alza, Esther,Cambeiro, Xacobe C.,Jimenez, Ciril,Pericas, Miquel A.
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p. 3717 - 3720
(2008/02/12)
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- MODULATORS OF CENTRAL NERVOUS SYSTEM NEUROTRANSMITTERS
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Disclosed are agents having pharmacological activity against cellular receptors and intracellular singaling, particularly receptors and sigaling pathways of central nervous system (CNS) neurotransmitters. Also disclosed are related methods and compositions for the treatment or prevention of diseases or disorders using the agents.
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Page/Page column 56-57
(2010/10/20)
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- Ion-supported chiral pyrrolidines as enantioselective catalysts for direct Michael addition of nitroalkenes in [BMIm]PF6
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Imidazolium-supported-pyrrolidine-catalyzed asymmetric Michael addition reactions of unmodified ketones and aldehydes to nitroalkenes were performed in [BMIm]PF6 to give products in up to 98% yield and 99% enantioselectivity. The catalytic system presented a synergistic effect in the improvement of reaction performance and could be recycled. Georg Thieme Verlag Stuttgart.
- Xu, Danqian,Luo, Shuping,Yue, Huadong,Wang, Liping,Liu, Yunkui,Xu, Zhenyuan
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p. 2569 - 2572
(2008/09/16)
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- Functionalized chiral ionic liquids as highly efficient asymmetric organocatalysts for michael addition to nitroolefins
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(Chemical Equation Presented) Catalytic combination: By combining the advantages of organocatalysts and ionic liquids, a functionalized chiral ionic liquid such as 1 can act as a highly efficient and reusable organocatalyst for the asymmetric Michael addition reaction of ketones and aldehydes with nitroalkenes.
- Luo, Sanzhong,Mi, Xueling,Zhang, Long,Liu, Song,Xu, Hui,Cheng, Jin-Pei
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p. 3093 - 3097
(2007/10/03)
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- Asymmetric synthesis of highly substituted azapolycyclic compounds via 2-alkenyl sulfoximines: Potential scaffolds for peptide mimetics
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The application of metalated, enantiomerically pure acyclic and cyclic 2-alkenyl sulfoximines for the synthesis of highly substituted aza(poly)cyclic ring systems is described. The method relies on a one-pot combination of a reagent-controlled allyl transfer reaction to α- or β-amino aldehydes, followed by a Michael-type cyclization of the intermediate vinyl sulfoximines generated in the first step. The sulfur-free target compounds are preferentially obtained by samarium iodide treatment of the sulfonimidoyl substituted heterocycles. In addition to this methodological work, initial results on the biological activity of selected examples are reported. Furthermore, a concept for the transformation of peptidic lead structures into non-peptide mimetics is described, and the relevance of the new approach to highly substituted azaheterocycles in this context is discussed.
- Reggelin, Michael,Junker, Bernd,Heinrich, Timo,Slavik, Stefan,Buehle, Philipp
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p. 4023 - 4034
(2007/10/03)
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- Synthesis and properties of novel chiral-amine-functionalized ionic liquids
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A novel class of chiral-amine-functionalized ionic liquids (CAFILs) has been synthesized efficiently from natural amino acids, and their structures have been determined by spectroscopic analysis and low temperature X-ray diffraction analysis. The CAFILs have been characterized by physical properties such as melting point, glass transition temperature, thermal degradation and specific rotation. NMR measurements indicate that the CAFILs may be promising alternatives in the field of chiral discrimination.
- Luo, Shu-Ping,Xu, Dan-Qian,Yue, Hua-Dong,Wang, Li-Ping,Yang, Wen-Long,Xu, Zhen-Yuan
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p. 2028 - 2033
(2007/10/03)
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- Total synthesis and identification of two diastereoisomers of 1-methyl-2-[N-(p-tolylsulfonyl)-2-pyrrolidinyl]ethyl β-L-fucopyranoside
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The reaction of a racemic mixture of (2R,2′S)- and (2S,2′R)-N-(p-tolylsulfonyl)-2-pyrrolidinyl-2-propanol, prepared from (S)-proline, with 2,3,4-tri-O-acetyl-α-l-fucopyranosyl trichloroacetimidate led to both diastereoisomers of the title compound after O-deacetylation.
- E Silva, Maria Joselice,Cottier, Louis,Srivastava, Rajendra M.,Sinou, Denis,Thozet, Alain
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p. 309 - 314
(2007/10/03)
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- Exploiting π-shielding interactions: A highly selective chiral auxiliary derived from a biogenic building block
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A chiral auxiliary template, designed on the basis of π-shielding capability has been prepared from readily available L-proline. Cycloaddition to an acrylate derivative gave high endo preference, and diastereoselectivity as high as 99% was attainable. The electronic factors contributing to selectivity were probed, and the technology successfully applied to a polymer supported variant.
- Xie, Longfei,Jones, Graham B.
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p. 3579 - 3582
(2007/10/03)
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