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Stereoselective synthesis of (-)-α-kainic acid and (+)-α-allokainic acid via trimethylstannyl-mediated radical carbocyclization and oxidative destannylation
(-)-α-Kainic acid (1) and its C4 epimer (+)-α-allokainic acid (2) have been prepared from L-serine. The requisite stereochemical array in (-)-α-kainic acid (1) was introduced using a trimethylstannyl radical carbocyclization of a diene, which gave the 2,3-trans/3,4-cis and 2,3-trans/3,4-trans componnds in a 2.8:1 ratio and in high yield. The destannylation of the trisubstituted pyrrolidine nucleus was achieved via an oxidative cleavage of the C-Sn bond with ceric ammonium nitrate. This provided a dimethyl acetal that was further transformed into the intended α-kainic acid. When the same radical carbocyclization was attempted on a triene, the 2,3-trans/3,4-trans and the 2,3-trans/3,4-cis adducts were obtained in a 2.5:1 ratio, respectively. This approach was used to synthesize (+)-α-allokainic acid.
Hanessian, Stephen,Ninkovic, Sacha
p. 5418 - 5424
(1996)
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Synthesis and biochemical evaluation of Aminopropanolyl-Thymine tri-Phosphate (ap-TTP)
Deoxyribonucleoside triphosphates (dNTPs) are building blocks for the biosynthesis of DNA. Various modified dNTPs’ analogs have synthesized by structural changes of nucleoside’s susgar and nucleobases and employed for synthesis of modified DNA. A very few modified dNTPs have prepared from non-sugar nucleoside analogs. This report describes the synthesis of acyclic nucleoside triphosphate (NTP) analog from amino acid L-Serine as aminopropanolyl-thymine triphosphate (ap-TTP) and demonstrate its biochemical evaluation as enzymatic incorporation of ap-TTP into DNA with DNA polymerases with primer extension methods. Alanyl peptide nucleicacids (Ala-PNA) are the analogs of DNA which contains alanyl backbone. Aminopropanolyl–analogs are derivatives of alanyl back bone. Ap-TTP analog is nucleoside triphosphate analog derived from Ala-PNA. Importantly, this report also sheds light on the crystal packing arrangement of alaninyl thymine ester derivative in solid-state and reveals the formation of self-duplex assembly in anti-parallel fashion via reverse Watson-Crick hydrogen bonding and π–π interactions. Hence, ap-TTP is a useful analog which also generates the free amine functional group at the terminal of DNA oligonucleotide after incorporation.
Gade, Chandrasekhar Reddy,Sharma, Nagendra K.
p. 730 - 743
(2020)
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Simple and efficient procedure for a multigram synthesis of both trans - And cis -1-Amino-2-(trifluoromethyl)cyclopropane-1-carboxylic Acid
A simple and efficient procedure for the multigram synthesis of both (±)-trans- and (±)-cis-1-amino-2-(trifluoromethyl)cyclopropane-1- carboxylic acid was developed. The key step of the synthesis is the addition of 1-diazo-2,2,2-trifluoroethane to methyl 2-[(tert-butoxycarbonyl)amino]acrylate, followed by thermal decomposition of the resulting pyrazoline. Gram quantities of trans- and cis-1-amino-2-(trifluoromethyl)cyclopropane-1-carboxylic acid were easily prepared from l-serine in one synthetic run. Georg Thieme Verlag Stuttgart - New York.
Artamonov, Olexiy S.,Mykhailiuk, Pavel K.,Voievoda, Nataliia M.,Volochnyuk, Dmitry M.,Komarov, Igor V.
p. 443 - 446
(2010)
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Efficient Hydro- and Organogelation by Minimalistic Diketopiperazines Containing a Highly Insoluble Aggregation-Induced, Blue-Shifted Emission Luminophore**
We report the synthesis, gelation abilities and aggregation-induced, blue-shifted emission (AIBSE) properties of two minimalistic diketopiperazine-based gelators. Despite containing a highly insoluble luminophore that makes up more than half of their respective molecular masses, efficient hydrogelation by multiple stimuli for one and efficient organogelation for the other compound are reported. Insights into the aggregation and gelation properties were gained through examination of the photophysical and material properties of selected gels, which are representative of the different modes of gelation. The synthesis of the gelators is highly modular and based on readily available amino acid building blocks, allowing the efficient and rapid diversification of these core structures and fine-tuning of gel properties.
Molkenthin, Martin,Nachtsheim, Boris J.,Nau, Werner M.
supporting information
p. 16488 - 16497
(2021/10/25)

Biocompatible Photoinduced Alkylation of Dehydroalanine for the Synthesis of Unnatural α-Amino Acids
A site-selective alkylation of dehydroalanine to access protected unnatural amino acids is described. The protocol is characterized by the wide nature of alkyl radicals employed, mild conditions, and functional group compatibility. This protocol is further extended to access peptides, late-stage functionalization of pharmaceuticals, and enantioenriched amino acids.
Delgado, José A. C.,Correia, José T. M.,Pissinati, Emanuele F.,Paix?o, Márcio W.
supporting information
p. 5251 - 5255
(2021/07/20)

Late-Stage Intermolecular Allylic C-H Amination
Allylic amination enables late-stage functionalization of natural products where allylic C-H bonds are abundant and introduction of nitrogen may alter biological profiles. Despite advances, intermolecular allylic amination remains a challenging problem due to reactivity and selectivity issues that often mandate excess substrate, furnish product mixtures, and render important classes of olefins (for example, functionalized cyclic) not viable substrates. Here we report that a sustainable manganese perchlorophthalocyanine catalyst, [MnIII(ClPc)], achieves selective, preparative intermolecular allylic C-H amination of 32 cyclic and linear compounds, including ones housing basic amines and competing sites for allylic, ethereal, and benzylic amination. Mechanistic studies support that the high selectivity of [MnIII(ClPc)] may be attributed to its electrophilic, bulky nature and stepwise amination mechanism. Late-stage amination is demonstrated on five distinct classes of natural products, generally with >20:1 site-, regio-, and diastereoselectivity.
Clark, Joseph R.,Dixon, Charlie F.,Feng, Kaibo,Han, Wei,Ide, Takafumi,Koch, Vanessa,Teng, Dawei,Wendell, Chloe I.,White, M. Christina
supporting information
p. 14969 - 14975
(2021/10/01)

Alcohol functionality in the fatty acid backbone of sphingomyelin guides the inhibition of blood coagulation
Cell-surface sphingomyelin (SM) inhibits binary and ternary complex activity of blood coagulation by an unknown mechanism. Here we show the OH functionality of SM contributes in forming the close assembly through intermolecular H-bond and through Ca2+ chelation, which restricts the protein-lipid/protein-protein interactions and thus inhibits the coagulation procedure.
Mallik,Prasad,Das,Sen
p. 3390 - 3398
(2021/02/03)

Me3SI-promoted chemoselective deacetylation: a general and mild protocol
A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.
Gurawa, Aakanksha,Kashyap, Sudhir,Kumar, Manoj
p. 19310 - 19315
(2021/06/03)

Synthesis and Biological Evaluation of CF3Se-Substituted α-Amino Acid Derivatives
Several CF3Se-substituted α-amino acid derivatives, such as (R)-2-amino-3-((trifluoromethyl)selanyl)propanoates (5 a/6 a), (S)-2-amino-4-((trifluoromethyl)selanyl)butanoates (5 b/6 b), (2R,3R)-2-amino-3-((trifluoromethyl)selanyl)butanoates (5 c/6 c), (R)-2-((S)-2-amino-3-phenylpropanamido)-3-((trifluoromethyl)selanyl)propanoates (11 a/12 a), and (R)-2-(2-aminoacetamido)-3-((trifluoromethyl)selanyl)propanoates (11 b/12 b), were readily synthesized from natural amino acids and [Me4N][SeCF3]. The primary in vitro cytotoxicity assays revealed that compounds 6 a, 11 a and 12 a were more effective cell growth inhibitors than the other tested CF3Se-substituted derivatives towards MCF-7, HCT116, and SK-OV-3 cells, with their IC50 values being less than 10 μM for MCF-7 and HCT116 cells. This study indicated the potentials of CF3Se moiety as a pharmaceutically relevant group in the design and synthesis of novel biologically active molecules.
Han, Zhou-Zhou,Dong, Tao,Ming, Xiao-Xia,Kuang, Fu,Zhang, Cheng-Pan
p. 3177 - 3180
(2021/07/28)

New Spisulosine Derivative promotes robust autophagic response to cancer cells
Therapy resistance by evasion of apoptosis is one of the hallmarks of human cancer. Therefore, restoration of cell death by non-apoptotic mechanisms is critical to successfully overcome therapy resistance in cancer. By rational drug design approach, here we try to provide evidence that subtle changes in the chemical structure of spisulosine completely switched its cytotoxic function from apoptosis to autophagy. Our most potent molecule (26b) in a series of 16 synthesized derivatives showed robust autophagic cell death in diverse cancer cells sparing normal counterpart. Compound 26b mediated lethal autophagy induction was confirmed by formation of characteristic autophagic vacuoles, LC3 puncta formation, upregulation of signature autophagy markers like Beclin and Atg family proteins. Altogether, we have detected novel autophagy inducer small molecule which can be tested further for drug discovery research.
Chaturvedi, Priyank,Datta, Dipak,Ganesher, Asha,Meena, Sanjeev,Mitra, Kalyan,Panda, Gautam,Sahai, Rohit
(2020/01/13)

N-AS-triggered SPMs are direct regulators of microglia in a model of Alzheimer’s disease
Sphingosine kinase1 (SphK1) is an acetyl-CoA dependent acetyltransferase which acts on cyclooxygenase2 (COX2) in neurons in a model of Alzheimer’s disease (AD). However, the mechanism underlying this activity was unexplored. Here we show that N-acetyl sphingosine (N-AS) is first generated by acetyl-CoA and sphingosine through SphK1. N-AS then acetylates serine 565 (S565) of COX2, and the N-AS-acetylated COX2 induces the production of specialized pro-resolving mediators (SPMs). In a mouse model of AD, microglia show a reduction in N-AS generation, leading to decreased acetyl-S565 COX2 and SPM production. Treatment with N-AS increases acetylated COX2 and N-AS-triggered SPMs in microglia of AD mice, leading to resolution of neuroinflammation, an increase in microglial phagocytosis, and improved memory. Taken together, these results identify a role of N-AS in the dysfunction of microglia in AD.
Bae, Jae-sung,Choi, Min-Koo,Han, Seung Hoon,Jin, Hee Kyung,Kim, Hee-Jin,Kim, Seung Hyun,Lee, Ju Youn,Park, Cheol-Min,Park, Min Hee,Schuchman, Edward H.,Song, Im-Sook,Yu, Eunsoo
(2020/05/16)

Catalytic Enantioselective Direct Aldol Addition of Aryl Ketones to α-Fluorinated Ketones
The catalytic enantioselective synthesis of α-fluorinated chiral tertiary alcohols from (hetero)aryl methyl ketones is described. The use of a bifunctional iminophosphorane (BIMP) superbase was found to facilitate direct aldol addition by providing the strong Br?nsted basicity required for rapid aryl enolate formation. The new synthetic protocol is easy to perform and tolerates a broad range of functionalities and heterocycles with high enantioselectivity (up to >99:1 e.r.). Multi-gram scalability has been demonstrated along with catalyst recovery and recycling. 1H NMR studies identified a 1400-fold rate enhancement under BIMP catalysis, compared to the prior state-of-the-art catalytic system. The utility of the aldol products has been highlighted with the synthesis of various enantioenriched building blocks and heterocycles, including 1,3-aminoalcohol, 1,3-diol, oxetane, and isoxazoline derivatives.
Barber, David M.,Dixon, Darren J.,Thomson, Connor J.
supporting information
p. 5359 - 5364
(2020/02/28)

Liposomal FRET Assay Identifies Potent Drug-Like Inhibitors of the Ceramide Transport Protein (CERT)
Ceramide transfer protein (CERT) mediates non-vesicular transfer of ceramide from endoplasmic reticulum to Golgi apparatus and thus catalyzes the rate-limiting step of sphingomyelin biosynthesis. Usually, CERT ligands are evaluated in tedious binding assays or non-homogenous transfer assays using radiolabeled ceramides. Herein, a facile and sensitive assay for CERT, based on F?rster resonance energy transfer (FRET), is presented. To this end, we mixed donor and acceptor vesicles, each containing a different fluorescent ceramide species. By CERT-mediated transfer of fluorescent ceramide, a FRET system was established, which allows readout in 96-well plate format, despite the high hydrophobicity of the components. Screening of a 2 000 compound library resulted in two new potent CERT inhibitors. One is approved for use in humans and one is approved for use in animals. Evaluation of cellular activity by quantitative mass spectrometry and confocal microscopy showed inhibition of ceramide trafficking and sphingomyelin biosynthesis.
Aglar, ?znur,Arenz, Christoph,Banhart, Sebastian,Cong, Xiaojing,Hamdo, Housam H.,Heuer, Dagmar,Kleuser, Burkhard,M?ller, Heiko M.,Saied, Essa M.,Samaha, Doaa,Schumacher, Fabian
supporting information
p. 16616 - 16621
(2020/11/30)

Synthesis method and application of 1-aza -5-germanium-5-alkyl bicyclic [3.3.3] undecane compound.
The invention provides a 1-aza-5-germanium hetero-5-alkyl bicyclic [3.3.3] hendecane compound having a structure shown in the formula I, and the types of the 1-aza-5-germanium hetero-5-alkyl bicyclic[3.3.3] hendecane compound are expanded. The provided compound can serve as a nucleophilic reagent, the air and humidity conditions of the nucleophilic reagent are stable, and the efficiency of the Ge-Stille coupling reaction of aryl halogen and the 1-aza-5-germanium hetero-5-alkyl bicyclic [3.3.3] hendecane compound is high.
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Paragraph 0189; 0194

(2020/05/11)

Cyclic Sulfamidite as Simultaneous Protecting Group for Amino Alcohols: Development of a Mild Deprotection Protocol Using Thiophenol
This study describes the novel utility of cyclic sulfamidite as a simultaneous protecting group for 1,2- or 1,3-amino alcohols. An exceptionally mild and neutral condition for the removal of the cyclic sulfamidite was developed. The deprotection condition demonstrated a broad range of functional-group compatibility, including a substrate bearing a Z-enyne structure without any loss of double-bond stereochemistry.
Sakata, Juri,Akita, Kazunari,Sato, Manabu,Shimomura, Masashi,Tokuyama, Hidetoshi
p. 996 - 1000
(2020/11/03)

Exploration of the Fluoride Reactivity of Aryltrifluoroborate on Selective Cleavage of Diphenylmethylsilyl Groups
The first known report on the fluoride catalytic reactivity of potassium aryltrifluoroborate is described. The fluoride reactivity of phenyltrifluoroborate was controlled by substituents on the trifluoroborate-attached benzene, such as the methoxy group a
Fujiki, Katsumasa,Tanaka, Katsunori
supporting information
p. 4616 - 4620
(2020/07/06)

Synthesis and Biological Evaluation of a Library of AGE-Related Amino Acid Triazole Crosslinkers
Three N-Boc-protected amino acids, l-serine, l-aspartic, and l-glutamic acid, were either converted into their methyl azidoalkanoates or various alkynes via Bestmann-Ohira strategy or via reaction with propargylamine and propargyl bromide, respectively. The Cu-catalyzed click reaction provided a library of amino acid based triazoles, which were further N-methylated to triazolium iodides or deprotected and precipitated as free amino acid triazole dihydrochlorides. The biological properties of all derivatives were investigated by cytotoxicity assay (against L929 mouse fibroblasts) and broth microdilution method (E. coli ΔTolC and S. aureus). First results reveal complete inactivity for triazolium iodides with cell viabilities and microbial growths nearly 100 %, indicating them as possible analogs of advanced glycation endproducts (AGEs).
Agelidis, Nektarios,Altevogt, Luca,Baro, Angelika,Bilitewski, Ursula,Bugdayci, Bakiye,Icik, Esra,Jolly, Anthony,L?ffler, Paul,Laschat, Sabine
supporting information

(2020/09/01)

Chiral combinatorial preparation and biological evaluation of unique ceramides for inhibition of sphingomyelin synthase
Enantiomers or diastereomers of chiral bioactive compounds often exhibit different biological and toxicological properties. Here, we report the efficient synthesis of four stereoisomers of sphingosine and derivatization of unique chiral ceramides through a combinatorial chemistry by solid-phase activated resin ester. In addition, to test the effectivity of stereochemistry of ceramide, we demonstrated a cell-based assay of sphingomyelin synthase inhibition in the presence ofchiral unique ceramides, which suggested that libraries of this sort will be a rich source of biologically active synthetic molecules.
Koolath, Sajeer,Monde, Kenji,Murai, Yuta,Suga, Yoshiko
supporting information

(2020/02/04)

Synthesis of C3-symmetric star-shaped molecules containing α-amino acids and dipeptides via Negishi coupling as a key step
We demonstrate a new synthetic strategy toward star-shaped C3-symmetric molecules containing α-amino acid (AAA) derivatives and dipeptides. In this regard, trimerization and Negishi cross-coupling reactions are used as the key steps starting fr
Kotha, Sambasivarao,Todeti, Saidulu
p. 371 - 377
(2019/02/20)

Photocatalytic Reductive Formation of α-Tertiary Ethers from Ketals
A general photocatalytic reductive strategy for the construction of unsymmetrical α-tertiary dialkyl ethers is reported. By merging Lewis acid-mediated ketal activation and visible-light photocatalytic reduction, in situ-generated α-alkoxy radicals were found to engage in addition reactions with a variety of olefinic partners. Good reaction efficiency is demonstrated with a range of ketals of aromatic and aliphatic ketones. Extension to acetal substrates is also described, demonstrating the overall synthetic utility of this methodology for complex ether synthesis.
Rossolini, Thomas,Ferko, Branislav,Dixon, Darren J.
supporting information
p. 6668 - 6673
(2019/09/03)

Trifluoromethyl selenoamino acid derivative and preparation method thereof
The invention discloses a trifluoromethyl selenoamino acid derivative and a preparation method thereof. The preparation method comprises the following steps: by taking amino acid as an initial raw material, performing an N-Boc protection reaction with an N-Boc protection reagent so as to obtain amino N-Boc protected amino acid; performing an esterification reaction on the amino N-Boc protected amino acid with an esterification reagent so as to obtain an esterification product; performing a sulfonylation reaction on the esterification product with a sulfonylation reagent so as to obtain a sulfonylation product; and performing a trifluoromethyl selenium formation reaction on the sulfonylation product with a trifluoromethyl selenium salt, so as to obtain the amino N-Boc protected trifluoromethyl selenoamino acid derivative. The reaction is not only simple and convenient in operation, mild in condition, high in yield and good in functional group resistance, but also cheap in raw material,easy in raw material obtaining, and a very practical method is provided for synthesizing the trifluoromethyl selenoamino acid derivative.
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(2019/11/28)

Pseudoenantiomeric glycoclusters: Synthesis and testing of heterobivalency in carbohydrate-protein interactions
Multivalent carbohydrate-protein interactions are key events in cell recognition processes and have been extensively studied by means of synthetic glycomimetics. To date, frequently the valency, i.e. the multiplicity of the ligand attached to a polyvalent
Brekalo, Jasna,Despras, Guillaume,Lindhorst, Thisbe K.
supporting information
p. 5929 - 5942
(2019/06/24)

Preparation method of cis-3-hydroxyl-L-proline
The invention provides a preparation method of cis-3-hydroxyl-L-proline. The preparation method comprises the following steps of using the industrially produced L-serine as the starting raw material,introducing a second chiral center into the nucleophilic addition reaction of aldehyde via an ortho chiral induction format, and separating the product and an isomer by a column separating method; constructing an intermediate of which the carbon number is the same with the carbon number of a target product through the hydroxyl protection and the hydroboration-oxidizing reaction, constructing a five-elemental ring of the proline via the cyclization reaction in molecules, and removing the protective radicals, so as to obtain the cis-3-hydroxyl-L-proline. The cis-3-hydroxyl-L-proline prepared bythe preparation method has the advantages that the chemical purity and optical purity are high; the whole technology is simple and is easy to implement, the cost is low, the expensive or hypertoxic raw material or reagent is not used, and the cis-3-hydroxyl-L-proline is suitable for kilogram-level production; the higher implementing value and social and economic benefits are realized.
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Paragraph 0014; 0038; 0039; 0047-0048

(2019/02/04)

Development of Macrocyclic Peptides Containing Epoxyketone with Oral Availability as Proteasome Inhibitors
Macrocyclization has been frequently utilized for optimizing peptide or peptidomimetic-based compounds. In an attempt to obtain potent, metabolically stable, and orally available proteasome inhibitors, 30 oprozomib-derived macrocyclic peptides with structural diversity in their N-terminus and linker were successively designed and synthesized for structure-activity relationship (SAR) studies. As a consequence, the macrocyclic peptides with N-methyl-pyrazole (24p, 24x), imidazole (24t), and pyrazole (24v) as their respective N-termini exhibited favorable in vitro activity and metabolic stability, which translated into their potent in vivo proteasome inhibitory activity after oral administration. In particular, compound 24v, as the most distinguished one among this series, displayed excellent chymotrypsin-like (ChT-L, β5) inhibitory potency (IC50 = 16 nM), low nanomolar antiproliferative activity against all three of the tested cell lines, and superior metabolic stability in mouse liver microsome (MLM), as well as favorable inhibition against ChT-L compared to that of oprozomib in BABL/c mice following po administration at a comparatively low dose, thereby representing a promising candidate for further development.
Li, Daqiang,Zhang, Xiaotuan,Ma, Xiaodong,Xu, Lei,Yu, Jianjun,Gao, Lixin,Hu, Xiaobei,Zhang, Jiankang,Dong, Xiaowu,Li, Jia,Liu, Tao,Zhou, Yubo,Hu, Yongzhou
p. 9177 - 9204
(2018/10/24)

Painting argyrins blue: Negishi cross-coupling for synthesis of deep-blue tryptophan analogue β-(1-azulenyl)-L alanine and its incorporation into argyrin C
The argyrins are a family of non-ribosomal peptides that exhibits different biological activities through only small structural changes. Ideally, a biologically active molecule can be tracked and observed in a variety of biological and clinical settings in a non-invasive manner. As a step towards this goal, we report here a chemical synthesis of unnatural deep blue amino acid β-(1-azulenyl)-L alanine with different fluorescence and photophysical properties, which allows a spectral separation from the native tryptophan signal. This might be especially useful for cell localization studies and visualizing the targeted proteins. In particular, the synthesis of β-(1-azulenyl)-L alanine was achieved through a Negishi coupling which proved to be a powerful tool for the synthesis of unnatural tryptophan analogs. Upon β-(1-azulenyl)-L alanine incorporation into argyrin C, deep blue octapeptide variant was spectrally and structurally characterized.
Stempel, Erik,Kaml, Robert Franz-Xaver,Budisa, Nediljko,Kalesse, Markus
p. 5259 - 5269
(2018/05/16)

Total Synthesis and Biological Evaluation of Siladenoserinol A and its Analogues
The total synthesis of siladenoserinol A, an inhibitor of the p53–Hdm2 interaction, has been achieved. AuCl3-catalyzed hydroalkoxylation of an alkynoate derivative smoothly and regioselectively proceeded to afford a bicycloketal in excellent yield. A glycerophosphocholine moiety was successfully introduced through the Horner–Wadsworth–Emmons reaction using an originally developed phosphonoacetate derivative. Finally, removal of the acid-labile protecting groups, followed by regioselective sulfamate formation of the serinol moiety afforded the desired siladenoserinol A, and benzoyl and desulfamated analogues were also successfully synthesized. Biological evaluation showed that the sulfamate is essential for biological activity, and modification of the acyl group on the bicycloketal can improve the inhibitory activity against the p53–Hdm2 interaction.
Yoshida, Masahito,Saito, Koya,Kato, Hikaru,Tsukamoto, Sachiko,Doi, Takayuki
supporting information
p. 5147 - 5150
(2018/03/26)

Generating Stereodiversity: Diastereoselective Fluorination and Highly Diastereoselective Epimerization of α-Amino Acid Building Blocks
Diastereoselective fluorination of N-Boc (R)- and (S)-2,2-dimethyl-4-((arylsulfonyl)methyl)oxazolidines and a previously unknown diastereoselective epimerization at the fluorine-bearing carbon atom α to the sulfone was realized. Diastereoselectivities of both reactions were excellent for benzothiazolyl sulfones, allowing access to two enantiomerically pure diastereomers from one chiral precursor. To demonstrate synthetic utility, the benzothiazolyl sulfones were converted to diastereomerically pure (S,S)- and (R,S)-benzyl sulfones via sulfinate salts and to amino acids. To understand the diastereoselectivities, DFT analysis was performed.
Wei, Wei,Khangarot, Rama Kanwar,Stahl, Lothar,Veresmortean, Cristina,Pradhan, Padmanava,Yang, Lijia,Zajc, Barbara
supporting information
p. 3574 - 3578
(2018/06/26)

Photocatalytic Three-Component Umpolung Synthesis of 1,3-Diamines
A visible-light-mediated photocatalytic umpolung synthesis of 1,3-diamines from in situ-generated imines and dehydroalanine derivatives is described. Pivoting on a key nucleophilic addition of photocatalytically generated α-amino radicals to electron-deficient alkenes, this three-component coupling reaction affords 1,3-diamines efficiently and diastereoselectively. The mild protocol tolerates a wide variety of functionalities including heterocycles, pinacol boronates, and aliphatic chains. Application to biologically relevant α-amino-γ-lactam synthesis and extension to 1,3-aminoalcohols is also demonstrated.
Rossolini, Thomas,Leitch, Jamie A.,Grainger, Rachel,Dixon, Darren J.
supporting information
p. 6794 - 6798
(2018/10/24)

Serine- and threonine-derived diamine equivalents for site-specific incorporation of platinum centers in peptides, and the anticancer potential of these conjugates
A modular strategy that allows introduction of one or more reactive platinum units at chosen locations along a peptide sequence is presented. This makes use of diazides generated from serine and threonine as diamine equivalents which can be conjugated to the peptide under standard coupling conditions. Reduction of these diazides using Pd/C and H2 followed by platination affords the final products in good yields. Following this, we prepared a new class of peptide-platinum conjugates and carried out preliminary cytotoxicity evaluation and DNA interaction studies. Inclusion of lysine residues in the sequence was found to improve DNA interaction and anticancer activities compared to analogous conjugates with hydrophobic side chains.
Kumbhakonam, Sateeshkumar,Vellaisamy, Kasipandi,Saroj, Soumya,Venkatesan, Nalini,Karunagaran,Manheri, Muraleedharan Kannoth
p. 2450 - 2458
(2018/02/19)

Unlocking the potential of phenacyl protecting groups: CO2-based formation and photocatalytic release of caged amines
Orthogonal protection and deprotection of amines remain important tools in synthetic design as well as in chemical biology and material research applications. A robust, highly efficient, and sustainable method for the formation of phenacyl-based carbamate esters was developed using CO2 for the in situ preparation of the intermediate carbamates. Our mild and broadly applicable protocol allows for the formation of phenacyl urethanes of anilines, primary amines, including amino acids, and secondary amines in high to excellent yields. Moreover, we demonstrate the utility by a mild and convenient photocatalytic deprotection protocol using visible light. A key feature of the [Ru(bpy)3](PF6)2-catalyzed method is the use of ascorbic acid as reductive quencher in a neutral, buffered, two-phase acetonitrile/water mixture, granting fast and highly selective deprotection for all presented examples.
Speckmeier, Elisabeth,Klimkait, Michael,Zeitler, Kirsten
p. 3738 - 3745
(2018/04/14)

Synthesis of a cisplatin derivative from lithocholic acid
A new steroidal-platinum(II) hybrid compound was synthesized using a simple and efficient methodology. The synthesis was performed by a convergent approach with cross metathesis (CM) as a key step. An olefin derived from lithocholic acid and a vinyl substituted ethylenediamine derived from L-serine were used as chiral building blocks, which were combined in the CM step. The most important advantage of this method was the utilization of L-serine as a cheap, stereoisomerically pure substrate. A steroid with a diamino system in the side chain was subjected to reaction with potassium tetrachloroplatinate to obtain the target platinum(II) complex. Attempts to synthesize similar diamine systems using the asymmetric Strecker reaction were unsuccessful.
Hryniewicka, Agnieszka,?otowski, Zenon,Seroka, Barbara,Witkowski, Stanis?aw,Morzycki, Jacek W.
p. 5392 - 5398
(2018/02/12)

Synthesis and characterization of selenium(I/II) and tellurium(IV) derivatives of amino acids
The direct reaction between Te metal and methyl 2-(2-bromoacetamido)propanoate (27) at room temperature, yields the first example of organotellurium(IV) derivative (MeOC(O)CH(Me)NHCOCH2)2TeBr2 (31). Similarly, reaction of Te with methyl 2-(2-bromoacetamido)acetate (26) and methyl 2-(2-bromoacetamido)-3-phenylpropanoate (28) in presence of NaI in acetone gives MeOC(O)CH2NHCOCH2I (29), MeOC(O)CH(R)NHCOCH2)2TeI2 (R = H (30) and CH2Ph (32). Treatment of 26/27/28 with Li2Te2/Li2Se2 readily provides the [MeOC(O)CH(CH3)NHCOCH2]2Te2, (33); [MeOC(O)CH2NHCOCH2]2Se2, (34); [MeOC(O)CH(CH2Ph)NHCOCH2]2Se2, (35) and [Figure presented] (36). Similarly the reaction of (2,6-dimethyl-4-tert-butylC6H2)SeNa with 28 readily provide the [MeOC(O)CH(CH2Ph)NHCOCH2]SeC6H2-2,6-dimethyl-4-tert-butyl), (37) in good yield. Molecule [MeOC(O)CHNH(Boc)CH2]2Se2, (38) and [NaOC(O)CHNH(Boc)CH2Te(2,4,6-Me3C6H2] (39) were prepared by the treatment of Li2Se2/2,4,6-Me3C6H2TeNa with methyl 3-bromo-2-((tert-butoxycarbonyl)amino)propanoate and N-(t-Boc)-L-serine β-lactone respectively. These compounds are purified by chromatography and characterized by a number of analytical techniques such as (1H, 13C, 77Se and 125Te NMR) spectroscopy, mass spectrometry and elemental analysis. The single crystal X-ray studies of 29, 30, 31, 36 and 38 revealed the presence of characteristic O?Se/Te, secondary bonding interactions. A detailed analysis of the crystal structures of the compound reveals interesting supramolecular assembly.
Singh, Puspendra,Singh, Harkesh B.,Butcher, Ray J.
supporting information
p. 1 - 9
(2018/09/21)

Solution-phase automated synthesis of an α-amino aldehyde as a versatile intermediate
A solution-phase automated synthesis of the versatile synthetic intermediate, Garner's aldehyde, was demonstrated. tert-Butoxycarbonyl (Boc) protection, acetal formation, and reduction of the ester to the corresponding aldehyde were performed utilizing our originally developed automated synthesizer, ChemKonzert. The developed procedure was also useful for the synthesis of Garner's aldehyde analogues possessing fluorenylmethyloxycarbonyl (Fmoc) or benzyloxycarbonyl (Cbz) protection.
Masui, Hisashi,Yosugi, Sae,Fuse, Shinichiro,Takahashi, Takashi
supporting information
p. 106 - 110
(2017/02/15)

Enantioselective Anion Recognition by Chiral Halogen-Bonding [2]Rotaxanes
The application of chiral interlocked host molecules for discrimination of guest enantiomers has been largely overlooked, which is surprising given their unique three-dimensional binding cavities capable of guest encapsulation. Herein, we combined the stringent linear geometric interaction constraints of halogen bonding (XB), the noncovalent interaction between an electrophilic halogen atom and a Lewis base, with highly preorganized and conformationally restricted chiral cavities of [2]rotaxanes to achieve enantioselective anion recognition. Representing the first detailed investigation of the use of chiral XB rotaxanes for this purpose, extensive 1H NMR binding studies and molecular dynamics (MD) simulation experiments revealed that the chiral rotaxane cavity significantly enhances enantiodiscrimination compared to the non-interlocked free axle and macrocycle components. Furthermore, by examining the enantioselectivities of a family of structurally similar XB [2]rotaxanes containing different combinations of chiral and achiral macrocycle and axle components, the dominant influence of the chiral macrocycle in our rotaxane design for determining the effectiveness of chiral discrimination is demonstrated. MD simulations reveal the crucial geometric roles played by the XB interactions in orientating the bound enantiomeric anion guests for chiral selectivity, as well as the critical importance of the anions' hydration shells in governing binding affinity and enantiodiscrimination.
Lim, Jason Y. C.,Marques, Igor,Félix, Vítor,Beer, Paul D.
supporting information
p. 12228 - 12239
(2017/09/12)

Synthesis of Nontoxic Fluorous Sphingolipids as Molecular Probes of Exogenous Metabolic Studies for Rapid Enrichment by Fluorous Solid Phase Extraction
Fluorous solid-phase extraction (FSPE) is a useful technique for efficient selective enrichment of fluorous compounds from nonfluorous molecules. Sphingolipids and their metabolites, which are ubiquitous building blocks of eukaryotic and prokaryotic cell membranes, play crucial roles, for example, as signaling molecules. However, details of the functions and metabolic mechanisms of exogenous sphingolipids have remained unknown compared with those of their endogenous analogs. To better understand these unknown roles, chemical probes with appropriate biological and physicochemical properties are needed. In this study, we designed and synthesized new fluorous sphingolipids to reveal these roles. Furthermore, we confirmed that they could be efficiently and rapidly separated from normal sphingolipids by FSPE, and that they hardly showed any cytotoxic activity, similarly to normal sphingolipids at the same dose. We also showed that these fluorinated ceramides could act as metabolic substrates for sphingomyelin synthase 2 (SMS2). This demonstrates their potential for further biological studies.
Saito, Shota,Murai, Yuta,Usuki, Seigo,Yoshida, Masafumi,Hammam, Mostafa A. S.,Mitsutake, Susumu,Yuyama, Kohei,Igarashi, Yasuyuki,Monde, Kenji
supporting information
p. 1045 - 1051
(2017/02/23)

New reagent for the introduction of Boc protecting group to amines: Boc-OASUD
A new reagent, tert-butyl (2,4-dioxo-3-azaspiro [5,5] undecan-3-yl) carbonate (Boc-OASUD) for the preparation of N-Boc-amino acids is described. The Boc-OASUD reacts with amino acids and their esters at room temperature in the presence of a base and gives N-Boc-amino acids and their esters in good yields and purity. Introduction of the Boc group takes place without racemization. The Boc-OASUD, being a solid and more stable, is a better alternative to di-tert-butyl dicarbonate which is low melting and has to be dispensed in plastic containers than glass because of its poor stability.
Maheswara Rao, B. Leela,Nowshuddin, Shaik,Jha, Anjali,Divi, Murali K.,Rao
supporting information
p. 2127 - 2132
(2017/10/31)

Tetranuclear zinc cluster: A dual purpose catalyst for per-: O -acetylation and de- O -acetylation of carbohydrates
The trifluoroacetic acid adduct of tetranuclear zinc cluster Zn4(OCOCF3)6O catalysis in per-O-acetylation and de-O-acetylation of carbohydrates at 70 °C can be tuned by adjusting the reaction medium. Per-O-acetylation of hexopyranoses with a near stoichiometric amount of acetic anhydride in toluene resulted in the exclusive formation of pyranosyl products as an anomeric mixture, whereas de-O-acetylation of acetates occurred in methanol in high yields. In the latter, methanol acts as both nucleophile and solvent, and the reaction conditions were compatible to acid- and base-sensitive groups and amino acid derivatives.
Lin, Ting-Wei,Adak, Avijit K.,Lin, Hong-Jyune,Das, Anindya,Hsiao, Wei-Chen,Kuan, Ting-Chun,Lin, Chun-Cheng
p. 58749 - 58754
(2016/07/07)

Hydroxy-Directed Amidation of Carboxylic Acid Esters Using a Tantalum Alkoxide Catalyst
We describe herein a new strategy for the chemoselective synthesis of amides by using a metal-catalyzed hydroxy-directed reaction. A hydroxy group located at the β-position of an ester group promoted the activation of a carbonyl group with a tantalum alkoxide catalyst followed by amidation reactions, leading to a wide variety of β-hydroxyamides with excellent chemeselectivity. The chemoselective amidation strategy can be extended to the catalytic synthesis of dipeptide derivatives, which remains challenging research subjects in modern organic synthesis.
Tsuji, Hiroaki,Yamamoto, Hisashi
supporting information
p. 14218 - 14221
(2016/11/13)

Asymmetric Synthesis of N-Boc-(R)-Silaproline via Rh-Catalyzed Intramolecular Hydrosilylation of Dehydroalanine and Continuous Flow N-Alkylation
An asymmetric synthesis of a silicon-containing proline surrogate, N-Boc-(R)-silaproline (1), is described. Starting from N-Boc-dehydroalanine ester, deprotonation, followed by N-alkylation with chloromethyldimethylsilane under flow conditions, afforded the N-alkylated product 8 in 91% yield. An unprecedented enantioselective (NBD)2RhBF4/Josiphos 404-1 catalyzed 5-endo-trig hydrosilylation afforded the silaproline ester in 85-90% yield and >95% ee. Subsequent saponification and salt formation upgraded 1 to >99% ee.
Chung, John Y. L.,Shevlin, Michael,Klapars, Artis,Journet, Michel
supporting information
p. 1812 - 1815
(2016/05/19)

Improved synthetic routes to the selenocysteine derivatives useful for Boc-based peptide synthesis with benzylic protection on the selenium atom
Selenocysteine (Sec) derivatives, i.e., Boc-Sec(MBn)-OH (1) and Boc-Sec(MPM)-OH (2), which are useful for chemical synthesis of selenopeptides, were obtained from L-serine in five steps with total yields of 73% and 74%, respectively. The enantiomeric excesses were confirmed to be >99% e.e. by optical resolution using a chiral column on HPLC. On the other hand, for the case of a Fmoc-protected Sec derivative, i.e., Fmoc-Sec(MPM)-OH, similar reactions resulted in low yields and partial racemization taking place. [PRESENTED EQUATION]
Shimodaira, Shingo,Iwaoka, Michio
p. 260 - 271
(2017/03/09)

Synthesis of 2-oxazolines by in situ desilylation and cyclodehydration of β-hydroxyamides
A powerful method for the synthesis of 2-oxazolines from silyl-protected β-hydroxyamides is reported. Using diethylaminosulfur trifluoride (DAST) or its tetrafluoroborate salt (XtalFluor-E), silyl-protected β-amidoalcohols can be in situ deprotected and d
Brandst?tter, Marco,Roth, Fabian,Luedtke, Nathan W.
p. 40 - 51
(2016/09/09)

Structure-activity relationships of lysophosphatidylserine analogs as agonists of G-protein-coupled receptors GPR34, P2Y10, and GPR174
Lysophosphatidylserine (LysoPS) is an endogenous lipid mediator generated by hydrolysis of membrane phospholipid phosphatidylserine. Recent ligand screening of orphan G-protein-coupled receptors (GPCRs) identified two LysoPS-specific human GPCRs, namely, P2Y10 (LPS2) and GPR174 (LPS3), which, together with previously reported GPR34 (LPS1), comprise a LysoPS receptor family. Herein, we examined the structure-activity relationships of a series of synthetic LysoPS analogues toward these recently deorphanized LysoPS receptors, based on the idea that LysoPS can be regarded as consisting of distinct modules (fatty acid, glycerol, and l-serine) connected by phosphodiester and ester linkages. Starting from the endogenous ligand (1-oleoyl-LysoPS, 1), we optimized the structure of each module and the ester linkage. Accordingly, we identified some structural requirements of each module for potency and for receptor subtype selectivity. Further assembly of individually structure-optimized modules yielded a series of potent and LysoPS receptor subtype-selective agonists, particularly for P2Y10 and GPR174.
Ikubo, Masaya,Inoue, Asuka,Nakamura, Sho,Jung, Sejin,Sayama, Misa,Otani, Yuko,Uwamizu, Akiharu,Suzuki, Keisuke,Kishi, Takayuki,Shuto, Akira,Ishiguro, Jun,Okudaira, Michiyo,Kano, Kuniyuki,Makide, Kumiko,Aoki, Junken,Ohwada, Tomohiko
supporting information
p. 4204 - 4219
(2015/06/08)

Methodology for Synthesis of Enantiopure 3,5-Disubstituted Pyrrol-2-ones
A new synthetic route towards chiral 3,5-disubstituted pyrrol-2-ones by starting from amino acids has been developed. The sequence features the conversion of amino acids into their corresponding alkynoic acid derivative followed by a Pd-catalyzed hydrosta
Krenk, Ondej,Kratochvl, Ji,pulk, Marcel,Buchta, Vladimr,Kune, Ji,Novkov, Lucie,Ghavre, Mukund,Pour, Milan
p. 5414 - 5423
(2015/08/24)

BROMODOMAIN-INHIBITING COMPOUNDS AND PHARMACEUTICAL COMPOSITION COMPRISING SAME FOR PREVENTING OR TREATING A CANCER
Provided is a novel compound having bromodomain and extra terminal domain (BET) protein inhibiting activities, and a pharmaceutical composition comprising the same which can be useful for prevention or treatment of precancerous transformation or cancer.
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Page/Page column 23; 24

(2015/11/27)

Mild deprotection of PMB ethers using tert-butyl bromide
A convenient and high yielding method for the cleavage and scavenging of p-methoxybenzyl protecting group of several alcohols using tert-butyl bromide in refluxing acetonitrile is described. Under these mild conditions other protecting groups such as acid sensitive allyl, benzyl, and Me3CPh2Si ethers, or isopropylidene acetals were unchanged. Interestingly, a selective alkoxy-PMB cleavage was observed in the presence of a PMB phenoxy ether.
Rival, Nicolas,Albornoz Grados, Arantxa,Schiavo, Lucie,Colobert, Fran?oise,Hanquet, Gilles
p. 6823 - 6826
(2015/11/27)

Docking model of the nicotinic acetylcholine receptor and nitromethylene neonicotinoid derivatives with a longer chiral substituent and their biological activities
In the present study, nitromethylene neonicotinoid derivatives possessing substituents that contain a sulfur atom, oxygen atom or aromatic ring at position 5 on the imidazolidine ring were synthesized to evaluate their affinity for the nicotinic acetylcholine receptor (nAChR) and their insecticidal activity against adult female houseflies. Comparing the receptor affinity of the alkylated derivative with the receptor affinity of compounds possessing either ether or thioether groups revealed that conversion of the carbon atom to a sulfur atom did not influence the receptor affinity, whereas conversion to an oxygen atom was disadvantageous for the receptor affinity. The receptor affinity of compounds possessing a benzyl or phenyl group was lower than that of the unsubstituted compound. Analysis of the three-dimensional quantitative structure-activity relationship using comparative molecular field analysis demonstrated that steric hindrance of the receptor should exist around the C3 of an n-butyl group attached at position 5 on the imidazolidine ring. A docking study of the nAChR-ligand model suggested that the ligand-binding region expands as the length of the substituent increases by brushing against the amino acids that form the binding region. The insecticidal activity of the compounds was positively correlated with the receptor affinity by considering log P and the number of heteroatoms, including sulfur and oxygen atoms, in the substituents, suggesting that the insecticidal activity is influenced by the receptor affinity, hydrophobicity, and metabolic stability of the compounds.
Nagaoka, Hikaru,Nishiwaki, Hisashi,Kubo, Takuya,Akamatsu, Miki,Yamauchi, Satoshi,Shuto, Yoshihiro
p. 759 - 769
(2015/02/19)

CONFORMATIONALLY CONSTRAINED, FULLY SYNTHETIC MACROCYCLIC COMPOUNDS
The conformationally restricted, spatially defined macrocyclic ring system of formula (I) is constituted by three distinct molecular parts: Template A, conformation Modulator B and Bridge C. Macrocycles described by this ring system I are readily manufactured by parallel synthesis or combinatorial chemistry in solution or on solid phase. They are designed to interact with a variety of specific biological target classes, examples being agonistic or antagonistic activity on G-protein coupled receptors (GPCRs), inhibitory activity on enzymes or antimicrobial activity. In particular, these macrocycles show inhibitory activity on endothelin converting enzyme of subtype 1 (ECE-1) and/or the cysteine protease cathepsin S (CatS), and/or act as antagonists of the oxytocin (OT) receptor, thyrotropin-releasing hormone (TRH) receptor and/or leukotriene B4 (LTB4) receptor, and/or as agonists of the bombesin 3 (BB3) receptor, and/or show antimicrobial activity against at least one bacterial strain. Thus they are showing great potential as medicaments for a variety of diseases.
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Paragraph 0460

(2015/02/25)

DIPEPTIDE AND TRIPEPTIDE EPOXY KETONE PROTEASE INHIBITORS
Provided herein are dipeptide and tripeptide epoxy ketone protease inhibitors, methods of their preparation, related pharmaceutical compositions, and methods of using the same. For example, provided herein are compounds of Formula (X): and pharmaceutically acceptable salts and compositions including the same. The compounds and compositions provided herein may be used, for example, in the treatment of proliferative diseases including cancer and autoimmune diseases.
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Paragraph 00319; 00321

(2014/10/04)

A 3,4-trans-fused cyclic protecting group facilitates α-selective catalytic synthesis of 2-deoxyglycosides
A practical approach has been developed to convert glucals and rhamnals into disaccharides or glycoconjugates with high α-selectivity and yields (77-97 %) using a trans-fused cyclic 3,4-O-disiloxane protecting group and TsOH·H2O (1 mol %) as a catalyst. Control of the anomeric selectivity arises from conformational locking of the intermediate oxacarbenium cation. Glucals outperform rhamnals because the C6 side-chain conformation augments the selectivity.
Balmond, Edward I.,Benito-Alifonso, David,Coe, Diane M.,Alder, Roger W.,McGarrigle, Eoghan M.,Galan, M. Carmen
supporting information
p. 8190 - 8194
(2014/08/18)

METHODS FOR THE SYNTHESIS OF SPHINGOMYELINS AND DIHYDROSPHINGOMYELINS
The present invention includes methods for the synthesis of sphingomyelins and dihydrosphingomyelins. The present invention also includes methods for the synthesis of sphingosines and dihydrosphingosines. The present invention further includes methods for the synthesis of ceramides and dihydroceramides.
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Paragraph 0309

(2014/09/30)

METHODS FOR THE SYNTHESIS OF SPHINGOMYELINS AND DIHYDROSPHINGOMYELINS
The present invention includes methods for the synthesis of sphingomyelins and dihydrosphingomyelins. The present invention also includes methods for the synthesis of sphingosines and dihydrosphingosines. The present invention further includes methods for the synthesis of ceramides and dihydroceramides.
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Paragraph 00256

(2014/09/29)

Stereoselective synthesis of lanthionine derivatives in aqueous solution and their incorporation into the peptidoglycan of Escherichia coli
The three diastereoisomers - (R,R), (S,S) and meso - of lanthionine were synthesized in aqueous solution with high diastereoselectivity (>99%). The (S) and (R) enantiomers of two differently protected sulfamidates were opened by nucleophilic attack of (R) or (S)-cysteine. Acidification and controlled heating liberated the free lanthionines. Using the same chemistry, an α-benzyl lanthionine was also prepared. The proposed method, which avoids the need of enrichment by recrystallization, opens the way to the labelling of these compounds with 35S. Furthermore, in vivo bioincorporation into Escherichia coli W7 was studied. No incorporation of α-benzyl lanthionine was observed. In contrast, meso-lanthionine can effectively replace meso-diaminopimelic acid in vivo, while in the presence of (R,R)-lanthionine the initial increase of bacterial growth was followed by cell lysis. In the future, meso-[35S]lanthionine could be used to study the biosynthesis of peptidoglycan and its turnover in relation to cell growth and division.
Denoel, Thibaut,Zervosen, Astrid,Gerards, Thomas,Lemaire, Christian,Joris, Bernard,Blanot, Didier,Luxen, Andre
p. 4621 - 4628
(2014/10/16)