- Solid-state synthesis of cyclo LD-diphenylalanine: A chiral phase built from achiral subunits
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The solid-state structure of LL/DD or LD/DL diphenylalanine diluted in KBr pellets is studied by infrared (IR) absorption and vibrational circular dichroism (VCD) spectroscopy. The structure depends on the absolute configuration of the residues. The natural LL diphenylalanine exists as a mixture of neutral and zwitterionic structures, depending on the humidity of the sample, while mostly the zwitterion is observed for LD diphenylalanine whatever the experimental conditions. The system undergoes spontaneous cyclization upon heating at 125°C, resulting to the formation of a diketopiperazine (DKP) dipeptide as the only product. The reaction is faster for LD than for LL diphenylalanine. As expected, LL and DD diphenylalanine react to form the LL and DD enantiomers of cyclo diphenylalanine. Interestingly, the DKP dipeptides formed from the LD or DL diphenylalanine show unexpected optical activity, with opposite VCD spectra for the products formed from the LD and DL reagents. This is explained in terms of chirality synchronization between the monomers within the crystal, which retain the symmetry of the reagent, resulting to the formation of a new chiral phase made from transiently chiral molecules.
- Pérez-Mellor, Ariel,Le Barbu-Debus, Katia,Zehnacker, Anne
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- Insight into structural description of novel 1,4-Diacetyl-3,6-bis(phenylmethyl)-2,5-piperazinedione: synthesis, NMR, IR, Raman, X-ray, Hirshfeld surface, DFT and docking on breast cancer resistance protein
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In this work, novel 1,4-diacetyl-3,6-bis(phenylmethyl)-2,5-piperazinedione (2) is prepared exclusively as the (R,S)-stereoisomer evidenced and confirmed by X-ray diffraction analysis. In addition, spectroscopic (NMR, IR, Raman) analyses were used to characterize the new compound. 2 crystallizes in the Pbca orthorhombic space group, with a symmetry center located at the centroid of the diketopiperazine ring. The structure of 2 is compact with the two phenyl rings folded over and under the diketopiperazine ring, conferring thereby a unique S shape to the molecule. The crystal structure is stabilized by intramolecular interactions, whereas the crystal packing is stabilized by intermolecular H-bond and C?H···π interactions. The different intermolecular interactions were confirmed using Hirshfeld surface analysis and molecular fingerprint. Molecular 2D fingerprint that quantify the different interactions highlights that H···H (58.2%), H···O/O···H (24.8%) and C···H/H···C (14.2%) account for 97.2% of all contacts. The topology of the interaction energy in the crystal structure is obtained and described. The Cremer and Pople puckering parameters indicate that the diketopiperazine ring adopts a flattened chair conformation with Θ = 0.00 ° and Q = 0.2233 (11) ?. Moreover, a computational investigation revealed that the optimized structure of 2 using DFT calculation shows excellent agreement with the experimental data. As potential pharmacological active molecule, the molecular docking on breast cancer resistance protein (BCRP) reveals that 2 could interacts with the binding domain residues Phe728, Tyr949, Ser975 and Val978 and could be consider as promising BCRP inhibitor.
- Etsè, Koffi Sénam,Zaragoza, Guillermo
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- Preventing Candida albicans biofilm formation using aromatic-rich piperazines
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The global increase in microbial resistance is an imminent threat to public health. Effective treatment of infectious diseases now requires new antimicrobial therapies. We report herein the discovery of aromatic-rich piperazines that inhibit biofilm forma
- Simon, Ga?lle,Bérubé, Christopher,Paquet-C?té, Pierre-Alexandre,Grenier, Daniel,Voyer, Normand
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- Anti-biofilm and anti-adherence properties of novel cyclic dipeptides against oral pathogens
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Microorganisms embedded in a biofilm are significantly more resistant to antimicrobial agents and the defences of the human immune system, than their planktonic counterpart. Consequently, compounds that can inhibit biofilm formation are of great interest for novel therapeutics. In this study, a screening approach was used to identify novel cyclic dipeptides that have anti-biofilm activity against oral pathogens. Five new active compounds were identified that prevent biofilm formation by the cariogenic bacterium Streptococcus mutans and the pathogenic fungus Candida albicans. These compounds also inhibit the adherence of microorganisms to a hydroxylapatite surface. Further investigations were conducted on these compounds to establish the structure–activity relationship, and it was deduced that the common cleft pattern is required for these molecules to act effectively against biofilms.
- Simon, Ga?lle,Bérubé, Christopher,Voyer, Normand,Grenier, Daniel
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p. 2323 - 2331
(2018/12/11)
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- Heterogeneous Catalytic Hydrogenation of Chiral Amino Acid Methyl Esters to Amino Alcohols with Retention of Configuration Over Mg-Modified Cu/ZnO/Al2O3 Catalyst
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Selective hydrogenation of amino acid methyl esters to chiral amino alcohols is an important and fascinating process. The CuZn0.3Mg0.1AlOx catalyst for the synthesis of chiral amino alcohols was prepared by the fractional
- Zhan, Bing,Zhang, Shuangshuang,Yu, Jun,Xiao, Xiuzheng,Guo, Xiaoming,Mao, Dongsen,Lu, Guanzhong
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p. 2160 - 2166
(2017/07/25)
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- Interfacial supramolecular biomimetic epoxidation catalysed by cyclic dipeptides
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We synthesised a library of cis- and trans-cyclic dipeptides and evaluated their efficacy as catalysts in the asymmetric Weitz-Scheffer epoxidation of trans-chalcone. A thorough investigation relying on structure-activity studies and computational studies provided insights into the mechanism of the process. Our results revealed some structural features required for efficient conversion and for introduction of chirality into the product. The cyclic dipeptide acts as a catalyst by templating a supramolecular arrangement at the aqueous-organic interface required for efficient transformations to occur. Among all cyclic dipeptides investigated, cyclo(Leu-Leu) was the most efficient supramolecular catalyst.
- Bérubé, Christopher,Barbeau, Xavier,Cardinal, Sébastien,Boudreault, Pierre-Luc,Bouchard, Corinne,Delcey, Nicolas,Lagüe, Patrick,Voyer, Normand
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p. 330 - 349
(2017/03/15)
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- Novel chiral N,N′-dimethyl-1,4-piperazines with metal binding abilities
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With the objective of developing novel chiral ligands, we report an efficient strategy to prepare chiral N,N-dimethyl-1,4-piperazines, six-member heterocyclic molecules that possess metal binding features. We prepared and characterized 18 piperazines, and evaluated their ability to complex different mono- and divalent metals, using a rapid picrate extraction technique. Some newly prepared diamine ligands were used in diethylzinc alkylation of aryl aldehydes. Yields increased significantly in the presence of the diamine ligands, though enantioselectivity was low. The results demonstrate the validity of the approach for preparing and identifying useful chiral diamine ligands.
- Bérubé, Christopher,Cardinal, Sébastien,Boudreault, Pierre-Luc,Barbeau, Xavier,Delcey, Nicolas,Giguère, Martin,Gleeton, Dave,Voyer, Normand
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p. 8077 - 8084
(2015/12/30)
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- A SYNTHETIC CYCLIC DIPEPTIDE AND A PROCESS THEREOF
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The disclosure relates to preparation and self-assembly of aromatic cyclic dipeptide into one and two dimensional nano, meso and micro structures. The said structures of cyclic dipeptide can be electrospinned into threads, fabrics, suture, bandage materials. They are also useful in cell culturing, tissue culturing, drug delivery system, as composite materials, as inhibitors of fibrillization and in Biomedical research such as neurological regeneration and organ replacement studies.
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Page/Page column 16
(2011/06/11)
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- Biomimetic protecting-group-free 2′, 3′-selective aminoacylation of nucleosides and nucleotides
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Aminoacyl phosphate monoesters can be prepared free of an amino-protecting group and used directly in lanthanum-promoted selective monoacylation of either the 2′ or 3′-hydroxyl of nucleosides and nucleotides. For example, phenylalanyl ethyl phosphate rapi
- Her, Sohyoung,Kluger, Ronald
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supporting information; experimental part
p. 676 - 678
(2011/03/22)
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- Investigation of reaction mechanism of amino acids and phosphorus trichloride by 31P NMR and ESI-MS/MS
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The reaction of amino acids and phosphorus trichloride in THF was studied by 31P NMR tracing and ESI-MS/MS. A series of hydridophoranes and cyclic dipeptides were obtained. The reaction presented interesting diversity and the reaction mechanism was proposed. The mechanism suggests that phosphorus plays an important role in the synthesis of amino acid hydridophorane and cyclic dipeptides. The results also show that 31P NMR and ESI-MS/MS are useful tools for the investigation of reaction mechanism. Copyright
- Cao, Yanchun,Cao, Shuxia,Xie, Yali,Zong, Xiangkun,Zhao, Yufen
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experimental part
p. 1173 - 1179
(2012/04/23)
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- Engineered transaminopeptidase, aminolysin-S for catalysis of peptide bond formation to give linear and cyclic dipeptides by one-pot reaction
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Aminopeptidase from Streptomyces thermocyaneoviolaceus NBRC14271 was engineered into transaminopeptidase and used to catalyze an aminolysis reaction to give linear and cyclic dipeptides from cost-effective substrates such as the ester derivatives of amino
- Usuki, Hirokazu,Uesugi, Yoshiko,Arima, Jiro,Yamamoto, Yukihiro,Iwabuchi, Masaki,Hatanaka, Tadashi
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supporting information; experimental part
p. 580 - 582
(2010/05/01)
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- Synthesis of a reported calpain inhibitor isolated from Streptomyces griseus
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The reported diketopiperazine calpain inhibitor, cis-L-L-3,6-bis-(4-hydroxybenzyl)-1,4-dimethylpiperazine-2,5-dione 1, and its analogues 3 and 4 were synthesized from the corresponding amino acids. The previously assigned structure of 1 is confirmed but n
- Donkor,Sanders, M. Lee
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p. 2647 - 2649
(2007/10/03)
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- EMEHETERONE: SYNTHESIS AND STRUCTURAL REVISION
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Emeheterone, a fungal metabolite, was synthesized from DL-phenylalanine.Based on the results of this synthesis, the structure of emeheterone was redetermined as 3,6-dibenzyl-2-hydroxy-5-methoxypyrazine 4-oxide.
- Ohta, Akihiro,Kojima, Akihiko,Aoyagi, Yutaka
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p. 1655 - 1662
(2007/10/02)
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- Pyrazine Chemistry. II. Reduction of 3,6-Dibenzylidenepiperazine-2,5-diones
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A reinvestigation of the reduction of 3,6-dibenzylidenepiperazine-2,5-dione (1) with zinc and acetic acid established that this reaction gave (Z)-6-benzyl-3-benzylidenepiperazine-2,5-dione (10).When a mixture of acetic acid and hydrochloric acid was used
- Marcuccio, Sebastian M.,Elix, John A.
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p. 1791 - 1794
(2007/10/02)
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- Pyrazine Chemistry. III. Synthesis and Stereochemistry of 1,4-Dimethyl and 1,4-Diacetyl Derivatives of 3,6-Dibenzylpiperazine-2,5-dione
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The trans- and (+/-)cis-isomers of 1,4-dimethyl-and 1,4-diacetyl-3,6-dibenzylpiperazine-2,5-dione were synthesized.The hydriodic acid reduction of 3,6-dibenzylidene-1,4-dimethylpiperazine-2,5-dione gave (+/-)-cis-3,6-dibenzyl-1,4-dimethylpiperazine-2,5-dione although this product has previously been assigned the trans-geometry.The unknown isolated from the permanganate oxidation of (+)-cis-1,4-diacetyl-3,6-dibenzylpiperazine-2,5-dione has been identified as the corresponding trans-isomer.
- Marcuccio, Sebastian M.,Elix, John A.
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p. 2397 - 2402
(2007/10/02)
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