- Development of a prodrug of salicylic acid, salicylic Acid-L-alanine conjugate, utilizing hydrolysis by rabbit intestinal microorganisms
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The hydrolysis of salicylic acid-L-alanine conjugate (salicyl-L-alanine) following oral, intravenous, intracaecal and rectal administration (60, 10, 5 and 5 mg kg-1 respectively: salicylic acid equivalent) was examined in rabbits. Salicylic acid was detected in the blood 2 h after oral administration of salicyl-L-alanine and reached a maximum concentration at 10 h, whereas salicyl-L-alanine was rapidly eliminated. In contrast, unchanged salicyl-L-alanine only was found following intravenous administration of salicyl-L-alanine, suggesting that presystemic de-conjugation of salicyl-L-alanine was involved. The intestinal mucosal de-conjugation of salicyl-L-alanine was not recognized in the in-situ intestinal sac preparation with complete mesenteric venous blood collection. Immediate and very extensive salicylic acid formation in the caecum was found following intracaecal administration of salicyl-L-alanine. After oral pretreatment of rabbits with kanamycin sulphate, a significant inhibition of salicylic acid formation following intracaecal administration of salicyl-L-alanine was observed, indicating that the intestinal microorganisms were responsible for the biotransformation of salicyl-L-alanine. In-vitro incubation of salicyl-L-alanine with gut contents showed that the major source of its hydrolysis was the hind gut. Consequently, the blood concentration of salicylic acid was prolonged extensively following rectal administration of salicyl-L-alanine, suggesting the usefulness of salicyl-L-alanine as a prodrug of salicylic acid.
- Nakamura,Tagami,Nishida,Sasaki
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- Synthesis and structure of α/δ-hybrid peptides - Access to novel helix patterns in foldamers
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Stimulated by an overview on all periodic folding patterns of α/δhybrid peptides with 1:1 alternating backbone provided by ab initio molecular orbital theory, the first representatives of this foldamer class were synthesized connecting novel C-linked carb
- Sharma, Gangavaram V. M.,Babu, Bommagani Shoban,Ramakrishna, Kallaganti V. S.,Nagendar, Pendem,Kunwar, Ajit C.,Schramm, Peter,Baldauf, Carsten,Hofmann, Hans-Joerg
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- Three new metabolites from the endophytic fungus Climacocystis montana isolated from the root bark of Paeonia ostia
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Two new pyridine derivatives climacomontaninates A–B (1–2), and a new sesquiterpenoid derivative climacomontanetate (3), together with twelve known compounds (4–15) were isolated from the culture extract of the fungal strain Climacocystis montana from the root bark of Paeonia ostii. The structures of these compounds were determined through spectroscopic methods such as NMR and HRMS. Moreover, we expound the absolute configuration of 1 using the organic synthesis method. The cytotoxicity against five human cancer cell lines of new compounds were evaluated by SRB assay.
- Zhang, Pei-liang,Wang, Gang,Liu, Jin-song,Xu, Feng-qing,Zhao, Zhen-zhu,Wang, Wen-xiang,Wang, Ju-tao,Wang, Guo-kai,Wu, Pei-yun
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- ENANTIOSELECTIVE ALKYLATION OF ENOLATE DERIVED FROM GLYCINE INFLUENCE OF THE IMINE MOIETY
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Optically active alanine was obtained by asymmetric one carbon transfer reaction.Variation of the nature of the imine moiety in the enantioselective alkylation of Schiff bases derived from glycine caused the enantiomeric excess to shift from 0 to 70 percent.
- Duhamel, Pierre,Jamal Eddine, Jamal,Valnot, Jean-Yves
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- Triazolyl-donor-acceptor chromophore-decorated unnatural amino acids and peptides: FRET events in a β-turn conformation
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The β-turn conformation and FRET process were established in the designed tripeptide containing fluorescent triazolyl donor and acceptor-decorated unnatural amino acids separated by a natural alanine.
- Bag, Subhendu Sekhar,Jana, Subhashis,Yashmeen, Afsana,Senthilkumar,Bag, Raghunath
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- 2-Methyltetrahydro-3-benzazepin-1-ols – The missing link in SAR of GluN2B selective NMDA receptor antagonists
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The NMDA receptor containing GluN2B subunits represents a promising target for the development of drugs for the treatment of various neurological disorders including neurodegenerative diseases. In order to study the role of CH3 and OH moieties trisubstituted tetrahydro-3-benzazepines 4 were designed as missing link between tetra- and disubstituted 3-benzazepines 2 and 5. The synthesis of 4 comprises eight reaction steps starting from alanine. The intramolecular Friedel-Crafts acylation to obtain the ketone 12 and the base-catalyzed elimination of trifluoromethanesulfinate (CF3SO2?) followed by NaBH4 reduction represent the key steps. The GluN2B affinity of the cis-configured 3-benzazepin-1-ol cis-4a with a 4-phenylbutyl side chain (Ki = 252 nM) is considerably lower than the GluN2B affinity of (R,R)-2 (Ki = 17 nM) indicating the importance of the phenolic OH moiety for the interaction with the receptor protein. Introduction of an additional CH3 moiety in 2-position led to a slight decrease of GluN2B affinity as can be seen by comparing the affinity data of cis-4a and 5. The homologous phenylpentyl derivative cis-4b shows the highest GluN2B affinity (Ki = 56 nM) of this series of compounds. According to docking studies cis-4a adopts the same binding mode as the cocrystallized ligand ifenprodil-keto 1A and 5 at the interface of the GluN2B and GluN1a subunits. The same crucial H-bonds are formed between the C([dbnd]O)NH2 moiety of Gln110 within the GluN2B subunit and the protonated amino moiety and the OH moiety of (R,R)-cis-4a.
- Dey, Sougata,Schepmann, Dirk,Wünsch, Bernhard
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- Novel emissive bio-inspired non-proteinogenic coumarin-Alanine amino acid: Fluorescent probe for polyfunctional systems
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Two new bio-inspired non-proteinogenic compounds L1 and L2, containing coumarin and/or acridine chromophores and bearing as spacer an alanine amino acid were successfully synthesized and fully characterized by elemental analysis, 1H and 13
- Oliveira, Elisabete,Capelo, José Luis,Lima, Jo?o Carlos,Lodeiro, Carlos
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- Synthesis of β 3-amino acid and peptides from D-ribose
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Synthesis of new β 3-amino acid, peptides and conformational analysis are reported from d-ribose, using Wittig olefination and Aza-Michael addition.
- Reddy, Karnekanti Rajender,Sridhar, Gattu,Sharma, Gangavaram V. M.
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- Design and synthesis of hydrophobic and chiral anions from amino acids as precursor for functional ionic liquids
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Hydrophobic ionic liquids composed of tetrabutylphosphonium cation and chiral anions derived from amino acids modified with trifluoromethane sulfonyl groups have been synthesized using a simple method. The Royal Society of Chemistry 2006.
- Fukumoto, Kenta,Ohno, Hiroyuki
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- New generation ionic liquids: Cations derived from amino acids
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Two families of a new generation of ionic liquids, in which the chiral cations are directly derived from naturally occurring α-amino acids and α-amino acid ester salts, have been obtained via very simple preparations. The Royal Society of Chemistry 2005.
- Tao, Guo-Hong,He, Ling,Sun, Ning,Kou, Yuan
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- Multiple alkylation and mapping of the active site of α-chymotrypsin by carbonium ions generated with active-site-directed enzyme-activated nitrosoamide substrates
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The inhibition of α-chymotrypsin with 13C-enriched alanine- and phenylalanine-based N-nitrosoamides, as active-site-directed and enzyme-activated inhibitors, results in the alkylation (benzylation) of side chains and also of the amide linkages of the protein backbone (both at O and N). 13C NMR spectra of the denatured inhibited enzyme (in Gdn.HCl) indicate that alkylation has occurred at O, N, S, and C sites. 13C NMR spectra of the amino acid mixtures from fully hydrolyzed inhibited enzymes show that the pattern of alkylation is strikingly different for inhibitions by the alanine- and phenylalanine-based inhibitors. In the case of the phenylalanine-based inhibitor, approximately equally intense signals are observed at 52.32, 51.31, 36.78, and 32.91 ppm, while with the alanine-based inhibitor, a major signal appears at 52.35 ppm, with minor signals appearing at 36.83 and 32.9 ppm. Chromatographic and NMR evidence is presented to indicate that the 52.32-52.35-ppm signal stems from N-benzylglycine. The chemical shift data suggest that the 51.31-ppm signal stems from N-benzylserine and the 36.78-36.83-ppm signal from S-benzylcysteine. Mechanisms are presented to account for the formation of those products.
- White,Li,Cousins,Roswell
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- Straightforward Synthesis of Fluorinated Enals via Photocatalytic α-Perfluoroalkenylation of Aldehydes
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(Per)fluorinated substances represent an important compound class with regard to drug design and material chemistry. We found a mild, operationally simple, and inexpensive photocatalytic perfluoroalkenylation reaction giving tetrasubstituted, highly electron-deficient enals straight from aldehydes. This one-step reaction tolerates various functional groups and can be applied to a wide range of substrates giving the products in yields of 52-84%.
- Wulkesch, Christian,Czekelius, Constantin
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p. 7425 - 7438
(2021/06/21)
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- Hydrogen-Borrowing Alkylation of 1,2-Amino Alcohols in the Synthesis of Enantioenriched γ-Aminobutyric Acids
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For the first time we have been able to employ enantiopure 1,2-amino alcohols derived from abundant amino acids in C?C bond-forming hydrogen-borrowing alkylation reactions. These reactions are facilitated by the use of the aryl ketone Ph*COMe. Racemisation of the amine stereocentre during alkylation can be prevented by the use of sub-stoichiometric base and protection of the nitrogen with a sterically hindered triphenylmethane (trityl) or benzyl group. The Ph* and trityl groups are readily cleaved in one pot to give γ-aminobutyric acid (GABA) products as their HCl salts without further purification. Both steps may be performed in sequence without isolation of the hydrogen-borrowing intermediate, removing the need for column chromatography.
- Hall, Christopher J. J.,Goundry, William R. F.,Donohoe, Timothy J.
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supporting information
p. 6981 - 6985
(2021/03/01)
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- N-Alkenylation of hydroxamic acid derivatives with ethynyl benziodoxolone to synthesizecis-enamides through vinyl benziodoxolones
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The stereoselective synthesis ofcis-β-N-alkoxyamidevinyl benziodoxolones (cis-β-N-RO-amide-VBXs) fromO-alkyl hydroxamic acids in the presence of an ethynyl benziodoxolone-acetonitrile complex (EBX-MeCN) is reported herein. The reaction was performed under mild conditions including an aqueous solvent, a mild base, and room temperature. The reaction tolerated variousO-alkyl hydroxamic acids derived from carboxylic acids, such as amino acids, pharmaceuticals, and natural products. Vinyl dideuteratedcis-β-N-MeO-amide-VBXs were also synthesized using deuterium oxide as the deuterium source. Valine-derivedcis-β-N-MeO-amide-VBX was stereospecifically derivatized to hydroxamic acid-derivedcis-enamides without the loss of stereoselectivity or reduction in the deuterium/hydrogen ratio.
- Shimbo, Daisuke,Maruyama, Toshifumi,Tada, Norihiro,Itoh, Akichika
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supporting information
p. 2442 - 2447
(2021/04/02)
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- Two-Dimensional Barriers for Probing Conformational Shifts in Macrocycles
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We describe the development and use of composite two-dimensional barriers in macrocyclic backbones. These tunable constructs derive their mode of action from heterocyclic rearrangements. The Boulton-Katritzky reaction has been identified as a particularly versatile means to effect a composite barrier, allowing the examination of the influence of heterocycle translocation on conformation. Kinetic studies using 1H NMR have revealed that the in-plane atom movement is fast in 17, 18, 19-membered rings but slows down in 16-membered rings. The analysis by NMR and MD simulation experiments is consistent with the maintenance of rare cis-amide motifs during conformational interconversion. Taken together, our investigation demonstrates that heterocyclic rearrangement reactions can be used to control macrocyclic backbones and provides fundamental insights that may be applicable to the development of a wide range of other conformational control elements.
- Kobori, Shinya,Huh, Sungjoon,Appavoo, Solomon D.,Yudin, Andrei K.
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supporting information
p. 5166 - 5171
(2021/05/04)
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- Post-synthetic functionalization of tryptophan protected peptide sequences through indole (C-2) photocatalytic alkylation
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We report a selective, mild, and efficient C-H functionalization of tryptophan and tryptophan-containing peptides with activated α-bromo-carbonyl compounds under visible-light irradiation. The protocol efficiency is outlined by the wide substrate scope and excellent tolerance of sensitive functional groups present in the amino acid side chains. The method can be successfully extended to access pharmaco-peptide conjugate scaffolds.
- Ackermann, Lutz,Berlinck, Roberto G. S.,Bernardi, Darlon I.,Delgado, José A. C.,Kaplaneris, Nikolaos,Lima, Rafaely N.,Paix?o, Márcio W.
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supporting information
p. 5758 - 5761
(2021/06/16)
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- One-pot synthesis of 1,2,4-oxadiazoles from chalcogen amino acid derivatives under microwave irradiation
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A series of sulfur- and selenium-bearing, amino acid-derived 1,2,4-oxadiazoles were obtained by a simple procedure. The method consists of EDC-promoted coupling of chalcogen amino acid derivatives with arylamidoximes in acetone, followed by solvent removal and microwave irradiation in water medium. Influence of amidoxime substituents, of the chalcogen atom and of the amino acid side chain is discussed. The results showed this to be a fast, easy and effective method to obtain these compounds, with good functional-group tolerance, potentially favouring future applications in organic synthesis.
- Wolf, Lucas,Mayer, Jo?o C.P.,Quoos, Natália,Sauer, André C.,Schwab, Ricardo S.,Rodrigues, Oscar E.D.,Dornelles, Luciano
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supporting information
(2021/06/06)
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- Eco-friendly synthesis of peptides using fmoc-amino acid chlorides as coupling agent under biphasic condition
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Background: Agro-waste derived solvent media act as a greener process for the peptide bond formation using Nα-Fmoc-amino acid chloride and amino acid ester salt with in situ neutralization and coupling under biphasic condition. The Fmoc-amino acid chlorides are prepared by the reported procedure of freshly distilled SOCl2 with dry CH2Cl2. The protocol found many added ad-vantages such as neutralization of amino acid ester salt and not required additional base for the neu-tralization, and directly coupling take place with Fmoc-amino acid chloride gave final product dipeptide ester in good to excellent yields. The protocol occurs with complete stereo chemical integrity of the configuration of substrates. Here, we revisited Schotten-Baumann condition, instead of using inorganic base. Objective: To develop green protocol for the synthesis of peptide bond using Fmoc-amino acid chloride with amino acid esters salt. Methods: The final product isolated is analyzed in several spectroscopic and analytical techniques such as FT-IR,1H-,13C-NMR, Mass spectrometry and RP-HPLC to check stereo integrity and puri-ty of the product. Conclusion: The present method developed greener using natural agro-waste (lemon fruit shell ash) derived solvent medium for the reaction and not required chemical entity.
- Kantharaju, Kamanna,Khatavi, Santosh Y.
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p. 699 - 707
(2021/08/23)
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- Ribose conversion with amino acids into pyrraline platform chemicals-expeditious synthesis of diverse pyrrole-fused alkaloid compounds
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One-pot conversion of sustainable d-ribose with l-amino acid, methyl esters produced pyrrole-2-carbaldehydes 5 in reasonable yields (32-63%) under pressurized conditions of 2.5 atm at 80 °C. The value-added pyrraline compounds 5 as platform chemicals were utilized for quick installation of poly-heterocyclic cores for the development of pyrrole-motif natural and artificial therapeutic agents. A pyrrole-fused piperazin-2-one scaffold 6 was prepared by reductive amination of pyrralines 5 with benzylamine. While further cyclization of pyrralines 5 with ethane-1,2-diamine produced pyrrolo-piperazin-2-ones 7 with an extra imidazolidine ring, the reaction with 2-amino alcohols derived from natural l-amino acids, alanine, valine, and phenylalanine, respectively provided pyrrolo-piperazin-2-ones 8, 9, and 10 with oxazolidine as the third structural core. Cell viability and an anti-inflammatory effect of the synthesized compounds were briefly tested by the MTT method and the Griess assay, among which 8h and 10g exhibited significant anti-inflammatory effects with negligible cell toxicity.
- Cho, Soohyeon,Gu, Lina,In, Ik Joon,Kim, Hakwon,Koo, Sangho,Lee, Taehoon,Wu, Bo
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p. 31511 - 31525
(2021/11/30)
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- Convenient method for the synthesis of some novel chiral methyl 2-(2-oxo-2H-benzo[e][1,3]oxazin-3(4H)-yl)propanoate derivatives and biological evaluation of their antioxidant, cytotoxic, and molecular docking properties
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Ten chiral methyl 2-(2-oxo-2H-benzo[e][1,3]oxazin-3(4H)-yl)propanoate derivatives 6a-6j have been synthesized from optically pure amino methyl phenol 5 and 4-nitrophenyl chloroformate. These derivatives 6a-6j are characterized by 1H NMR, 13C NMR, FT-IR, and HRMS spectral techniques. Optical purity of these derivatives was confirmed by chiral HPLC method. Ten synthesized ester derivatives 6a-6j were screened for their in vitro antioxidant activity. Among the compounds 6b-d and 6h-j have exhibited comparable antioxidant activity with ascorbic acid as a standard. Compounds 6a and 6e-g have shown moderate antioxidant activity. Further, the in vitro cytotoxicity of these compounds were studied through MTT cell proliferation assay in addition the effect on LDH leakage and NO release. Among the derivatives, 6j showed extremely best activity and the IC50 value (12.54 ± 0.71 μM) is very close to doxorubicin (7.2 ± 0.58 μM) as a standard. Compounds 6b, 6h, and 6i showed better inhibition next to compound 6j on the viability of HepG2 cells with an IC50 value (μM) of 56.02 ± 1.4, 41.76 ± 0.58, and 38.17 ± 0.34, respectively. Also, molecular docking studies have been carried out with STAT-3 (PDB ID: 1BG1) and BCL-2 (PDB ID: 4AQ3) proteins against the four active compounds 6b, 6h, 6i, and 6j. The binding energies of the tested compounds were in the range of ?7.76 to ?8.41 kcal/mol, which is very close to doxorubicin (?8.53 kcal/mol) as a standard. These molecular docking results are in good agreement with the in vitro studies.
- Matam, Sivakumar,Kaliyan, Prabakaran,Selvaraj, Loganathan,Muthu, Seenivasa Perumal,Lohanathan, Bharathi Priya,Viswanadhan, Vijaya Padma,Makala, Himesh,Venkatasubramanian, Ulaganathan
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supporting information
p. 569 - 579
(2020/12/11)
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- Amino acid conjugates of 2-mercaptobenzimidazole provide better anti-inflammatory pharmacology and improved toxicity profile
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Benzimidazole is an important pharmacophore for clinically active drugs against inflammation and treatment of pain, however, it is associated with gastrointestinal side effects. Here we synthesized benzimidazole based agents with significant analgesic/anti-inflammatory potential but with less gastrointestinal adverse effects. In this study, we synthesized novel, orally bioavailable 2-mercaptobenzimidazole amino acid conjugates (4a–4o) and screened them for analgesic, anti-inflammatory and gastro-protective effects. The synthesized 2-mercaptbenzimidazole derivatives were characterized for their structure using FTIR, 1H NMR and 13C NMR spectroscopic techniques. The 2-mercaptobenzimidazole amino acid conjugates have found to possess potent analgesic, anti-inflammatory and gastroprotective activities, particularly with compound 4j and 4k. Most of the compounds exhibited remarkable anti-ulcer and antisecretory effects. Molecular docking studies were carried out to study the binding affinities and interactions of the synthesized compounds with target proteins COX-2 (PDB ID: 3LN1) and H+/K+-ATPase (PDB ID: 5Y0B). Our results support the clinical promise of these newly synthesized 2-mercaptobezimidazol conjugates as a component of therapeutic strategies for inflammation and analgesia, for which the gastric side effects are always a major limitation.
- Khan, Muhammad T.,Nadeem, Humaira,Khan, Arif-ullah,Abbas, Muzaffar,Arif, Muazzam,Malik, Nadia Shamshad,Malik, Zulkifal,Javed, Ibrahim
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p. 1057 - 1072
(2020/08/13)
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- Re-Engineering Organocatalysts for Asymmetric Friedel-Crafts Alkylation of Indoles through Computational Studies
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The discovery of efficient organocatalysts is generally carried out by thorough experimental screening of different candidates. We recently reported an efficient organocatalyst for iminium-ion-based asymmetric Diels-Alder reactions following a rational design approach. This result encouraged us to test this optimal catalyst in the mechanistically related Friedel-Crafts alkylation of indoles, but to our surprise, almost null enantioselectivity was observed. The results did not significantly improve with structurally related catalysts, and a totally unexpected facial selectivity inversion was also noticed. Using DFT calculations by modeling the competing transition structures with ONIOM, we could unravel the origins of those findings, further employed to predict the most efficient catalyst for this new transformation. The computational results were validated experimentally (up to 92:8 er), providing another successful example of a general strategy to accelerate catalyst development which still remains underexplored.
- Gerosa, Gabriela G.,Marcarino, Maribel O.,Spanevello, Rolando A.,Suárez, Alejandra G.,Sarotti, Ariel M.
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p. 9969 - 9978
(2020/09/03)
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- Synthesis and antimalarial activity of (S)-methyl-(7-chloroquinolin-4-ylthio)acetamidoalquilate derivatives
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The synthesis of five new (S)-methyl-(7-chloroquinolin-4-ylthio)acetamidoalquilate derivatives is carried out under a modified version of the Steglich esterification reaction between different l-amino acid methyl esters and 2-(7-chloroquinolin-4-ylthio)acetic acid. Two of the compounds showed significant inhibition (>50%) of β-hematin formation. The two active structures were tested in vivo as potential antimalarials in mice infected with Plasmodium berghei ANKA, a chloroquine susceptible strain. Compounds 6b and 6e exhibited antimalarial activity comparable to that of chloroquine.
- Colmenarez, Custodiana,Acosta, María,Rodríguez, Miguel,Charris, Jaime
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p. 161 - 166
(2020/01/09)
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- Deregulation of hepatic mek1/2–erk1/2 signaling module in iron overload conditions
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The liver, through the production of iron hormone hepcidin, controls body iron levels. High liver iron levels and deregulated hepcidin expression are commonly observed in many liver diseases including highly prevalent genetic iron overload disorders. In spite of a number of breakthrough investigations into the signals that control hepcidin expression, little progress has been made towards investigations into intracellular signaling in the liver under excess of iron. This study examined hepatic signaling pathways underlying acquired and genetic iron overload conditions. Our data? demonstrate that hepatic iron overload associates with a decline in the activation of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (Erk) kinase (Mek1/2) pathway by selectively affecting the phosphorylation of Erk1/2. We propose that Mek1/2-Erk1/2 signaling is uncoupled from iron-Bmp-Smad-mediated hepcidin induction and that it may contribute to a number of liver pathologies in addition to toxic effects of iron. We believe that our findings will advance the understanding of cellular signaling events in the liver during iron overload of different etiologies.
- Tangudu, Naveen Kumar,Buth, Nils,Strnad, Pavel,Cirstea, Ion C,Spasi?, Maja Vuji?
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- Hydroxyphosphinylacetic acid as a chiral auxiliary compound
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The aim of the presented research was to check whether 2-hydroxy-2-(ethoxyphenylphosphinyl)acetic acid is a versatile chiral phosphonic auxiliary (readily seen in 31P NMR). The preliminary studies indicate that this compound may be used as chiral derivatizing agents for amines and alcohols, since the separation of selected examples of diastereomeric alcohols and amines in 31P NMR spectra was found to be satisfactory. The preliminary research about using this compound as a CSA are also promising.
- Majewska, Paulina
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p. 585 - 590
(2019/01/04)
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- Administration of ferrocene-modified amino acids induces changes in synaptic transmission in the CA1 area of the hippocampus
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A series of ferrocene-modified amino acid methyl esters with pyrazole linker was prepared in good to quantitative yields starting from easy accessible ferrocene pyrazole carbaldehyde and amino acids in racemic and enantio enriched forms under reductive amination conditions (NaBH (OAc)3, reflux, 3 hr). The resulting enantiomers were resolved using analytical HPLC on modified cellulose or amylose as chiral selectors. In vivo electrophysiological experiments were performed in the CA1 field of the hippocampus on 3a Fc-Gly, (L)-3b Fc-Ala, and (D)-3b Fc-Ala compounds. An increasing in the amplitudes of responses of local potentials (up to 25%) of the CA1 region in the studied groups was found after intraperitoneal administration of ferrocene compounds 3a and (D)-3b compared with control rats treated with saline.
- Dobryakova, Yulia V.,Ilyin, Mikhail M.,Markevich, Vladimir A.,Rodionov, Alexey N.,Simenel, Alexander A.,Snegur, Lubov V.
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- Synthesis, CYP 450 evaluation, and docking simulation of novel 4-aminopyridine and coumarin derivatives
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Four series of novel compounds based on 4-aminopyridine, glatiramer acetate, pyrone, and coumarin backbones were sufficiently synthesized and identified by spectroscopic methods. CYP enzyme inhibition assays of five predominate human P450 isozymes indicate that all compounds, except for 4-hydrazide pyridine 1c, seem to be less toxic than 4-aminopyridine. Further investigation of the compounds using molecular docking experiments revealed different, the same, or stronger binding modes for most of the synthesized compounds, with both polar and hydrophobic interactions with the 1WDA and 1J95 receptors compared to benzoyl l-arginine amide and 4-aminopyridine, respectively. These results introduce the synthesized compounds as K+ channel blockers that could be considered for in vivo CNS disease studies.
- Ghalehshahi, Hajar G.,Balalaie, Saeed,Sohbati, Hamid R.,Azizian, Homa,Alavijeh, Mohammad S.
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- Rhodium-Catalyzed Enantioselective Synthesis of Oxazinones via an Asymmetric Ring Opening-Lactonization Cascade of Oxabicyclic Alkenes
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The rhodium-catalyzed asymmetric ring opening reaction of oxabicyclic alkenes is shown to be an efficient method for synthesizing chiral heterocycles. We demonstrate that the pairwise combination of chiral catalyst with chiral amino-acid-derived pronucleophiles results in a stereodivergent synthesis of diastereomeric hydroxyesters. A favorable conformational preference induces the subsequent lactonization of one diastereomer leading to the highly enantioselective synthesis of oxazinones.
- Yen, Andy,Pham, Anh Hoang,Larin, Egor M.,Lautens, Mark
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supporting information
p. 7549 - 7553
(2019/10/02)
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- Mechanistic Studies on the Organocatalytic α-Chlorination of Aldehydes: The Role and Nature of Off-Cycle Intermediates
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Herein we report the isolation and characterization of aminal intermediates in the organocatalytic α-chlorination of aldehydes. These species are stable covalent ternary adducts of the substrate, the catalyst and the chlorinating reagent. NMR-assisted kinetic studies and isotopic labeling experiments with the isolated intermediate did not support its involvement in downstream stereoselective processes as proposed by Blackmond. By tuning the reactivity of the chlorinating reagent, we were able to suppress the accumulation of rate-limiting off-cycle intermediates. As a result, an efficient and highly enantioselective catalytic system with a broad functional group tolerance was developed.
- Ponath, Sebastian,Menger, Martina,Grothues, Lydia,Weber, Manuela,Lentz, Dieter,Strohmann, Carsten,Christmann, Mathias
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supporting information
p. 11683 - 11687
(2018/09/10)
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- Synthesis of Histidine-Containing Oligopeptides via Histidine-Promoted Peptide Ligation
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Histidine-containing peptides are valuable therapeutic agents for a treatment of neurodegenerative diseases. However, the synthesis of histidine-containing peptides is not trivial due to the potential of imidazole sidechain of histidine to act as a nucleophile if unprotected. A peptide ligation method utilizing the imidazole sidechain of histidine has been developed. The key imidazolate intermediate that acts as an internal acyl transfer catalyst during ligation is generated by deprotonation. Transesterification with amino acids or peptides tethered with C-terminal thioester followed by N→N acyl shifts led to the final ligated products. A range of histidine-containing dipeptides could be synthesized in moderate to good yields via this method without protecting the imidazole sidechain. The protocol was further extended to tripeptide synthesis via a long-range N→N acyl transfer, and tetrapeptide synthesis.
- Huang, Kai-Jin,Huang, Yi-Chen,Lin, Yuya A.
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supporting information
p. 400 - 403
(2018/02/21)
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- Fluoroquinolone such amino derivative and use thereof (by machine translation)
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The invention belongs to the field of pharmaceutical chemistry, and in particular relates to a fluoroquinolone derivatives and use thereof. The invention through structural modification of the fluoroquinolone drugs such as shown in formula I, the compounds of the invention not only can the Mycobacterium tuberculosis and the normal bacterial caused by the treatment of infection, bacteria also holds keeps the fungus, citrus pathogens, nicotinamide N - methyltransferase (NNMT) and interleukin IL - 17 PPI has inhibitory activity. The compounds of the invention preparation process operation is convenient, mild condition, to obtain the antibacterial activity is enhanced, water-soluble improve, many compounds toxic side effects, it is expected to reduce the amount of medicine used, shorten the treatment cycle, improve patient's compliance, for tuberculosis drug and other disease research provide new molecular type with the study. (by machine translation)
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Paragraph 0104; 0105; 0106
(2018/04/26)
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- Method for preparing L-alaninamide hydrochloride
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The invention relates to a method for preparing L-alaninamide hydrochloride. The method comprises the following specific steps: A. dissolving L-alanine in methanol and adding an appropriate amount ofchloride catalyst to undergo an esterification reaction; B. introducing an ammonia gas into the esterified product to undergo an aminolysis reaction; C. heating a reaction solution after aminolysis invacuum to remove ammonia, and then filtering out ammonium chloride; D. acidifying the filtered reaction solution to adjust the pH, and then adding an appropriate amount of ketone to precipitate a crystal, namely, L-alaninamide hydrochloride. The method for preparing the L-alaninamide hydrochloride provided by the invention has a simple route and relatively low cost, and is suitable for mass production.
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Paragraph 0015-0017
(2018/06/04)
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- Fluoroquinolone amino derivatives and use thereof in prevention and control of citrus diseases
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Citrus canker and brown spot are common diseases of citrus. At present, few drugs are available to prevent and control the two diseases and have certain defects. Amino groups at the 7th positions of fluoroquinolone drugs are linked with an active fragment by means of a connecting structure so as to obtain compounds shown in a formula I or a formula II. Experiments prove that the compounds providedby the invention have effects of preventing and controlling the citrus canker and the brown spot and have very good application prospect.
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Paragraph 0108; 0109; 0128; 0129; 0148; 0149
(2018/07/30)
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- Synthesis and characterization of selenium(I/II) and tellurium(IV) derivatives of amino acids
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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.
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supporting information
p. 1 - 9
(2018/09/21)
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- Synthesis of 4-N-α-coumaryl amino acids and investigation of their antioxidant, antimicrobial activities and fluorescence spectra
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An efficient metal-free approach for the synthesis of N-coumaryl amino acids and the first one-step synthesis of 4-hydrazinocoumarin from 4-hydroxycoumarin was developed. The nucleophilic addition of amino acid methyl esters to 4-tosylcoumarins produced a series of 4-N-α-coumaryl amino acids in good to excellent yields without racemization. The antioxidant activities of the synthesized compounds were investigated using DPPH and FRAP methods. 4-Hydrazinocoumarin and N-coumaryl tyrosine had the best antioxidant activity. The antimicrobial activities of the compounds against Gram-positive was stronger than Gram-negative. 4-Hydrazinocoumarin showed the best antibacterial effect.
- Ghalehshahi, Hajar Golshadi,Balalaie, Saeed,Aliahmadi, Atousa,Moghimi, Roya
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p. 1461 - 1470
(2018/08/03)
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- Synthesis method for nitro group-containing natural product chrysamides B and diastereoisomer-compound thereof
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The invention belongs to the technical fields of medicinal chemistry and organic synthesis, and relates to a synthesis method for a nitro group-containing natural product chrysamides B, a chrysamidesB diastereoisomer-compound and a synthesis method and application thereof. According to the invention, a convergent synthesis method is adopted to condense chiral epoxy carboxylic acid and chiral dimethylpiperazine ring, and thereby the nitro group-containing natural product chrysamides B with a symmetrical structure and the chrysamides B diastereoisomer-compound are easily and efficiently synthesized. By three-step continuous oxidation, chiral epoxy carboxylic acid is prepared from p-nitrobenzaldehyde which is easy to obtain commercially, and dimethylpiperazine ring is prepared by reduction after alanine dimerization. The compound shows inhibitory activity on pasteurella multocida. Such a convergent synthesis route can be applied to the chemical synthesis of compounds with the similar structure and related derivatives, opening up a broad development space for novel antibiotic drugs.
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Paragraph 0036; 0037
(2018/11/22)
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- Synthesis and Biological Evaluation of a Series of Novel Celastrol Derivatives with Amino Acid Chain
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The synthesis of celastrol analogues containing amino acid ester at the C(29) position and their evaluation for cytotoxic activities in?vitro were reported. The MTT test showed that a set of derivatives with lower IC50 values than that of the positive control group cisplatin and the parent compound celastrol, which exhibited greater antiproliferative activities. The most potent title compounds 2a and 2e exhibited cytotoxic activities in?vitro against HeLa and A549 cell lines with IC50 values of 0.371 and 0.237?μm, 0.235 and 0.109?μm, respectively. The apoptosis assay demonstrated that 2a and 2e can induces of A549 cell apoptosis in low concentrations. These results showed that 2a and 2e may be promising for further research as antitumor agents.
- Pang, Chaohai,Luo, Jinhui,Liu, Chunhua,Wu, Xuejin,Wang, Dingyong
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- Synthesis and Deployment of an Elusive Fluorovinyl Cation Equivalent: Access to Quaternary α-(1′-Fluoro)vinyl Amino Acids as Potential PLP Enzyme Inactivators
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Developing specific chemical functionalities to deploy in biological environments for targeted enzyme inactivation lies at the heart of mechanism-based inhibitor development but also is central to other protein-tagging methods in modern chemical biology including activity-based protein profiling and proteolysis-targeting chimeras. We describe here a previously unknown class of potential PLP enzyme inactivators; namely, a family of quaternary, α-(1′-fluoro)vinyl amino acids, bearing the side chains of the cognate amino acids. These are obtained by the capture of suitably protected amino acid enolates with β,β-difluorovinyl phenyl sulfone, a new (1′-fluoro)vinyl cation equivalent, and an electrophile that previously eluded synthesis, capture and characterization. A significant variety of biologically relevant AA side chains are tolerated including those for alanine, valine, leucine, methionine, lysine, phenylalanine, tyrosine, and tryptophan. Following addition/elimination, the resulting transoid α-(1′-fluoro)-β-(phenylsulfonyl)vinyl AA-esters undergo smooth sulfone-stannane interchange to stereoselectively give the corresponding transoid α-(1′-fluoro)-β-(tributylstannyl)vinyl AA-esters. Protodestannylation and global deprotection then yield these sterically encumbered and densely functionalized quaternary amino acids. The α-(1′-fluoro)vinyl trigger, a potential allene-generating functionality originally proposed by Abeles, is now available in a quaternary AA context for the first time. In an initial test of this new inhibitor class, α-(1′-fluoro)vinyllysine is seen to act as a time-dependent, irreversible inactivator of lysine decarboxylase from Hafnia alvei. The enantiomers of the inhibitor could be resolved, and each is seen to give time-dependent inactivation with this enzyme. Kitz-Wilson analysis reveals similar inactivation parameters for the two antipodes, L-α-(1′-fluoro)vinyllysine (Ki = 630 ± 20 μM; t1/2 = 2.8 min) and D-α-(1′-fluoro)vinyllysine (Ki = 470 ± 30 μM; t1/2 = 3.6 min). The stage is now set for exploration of the efficacy of this trigger in other PLP-enzyme active sites.
- McCune, Christopher D.,Beio, Matthew L.,Sturdivant, Jill M.,De La Salud-Bea, Roberto,Darnell, Brendan M.,Berkowitz, David B.
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supporting information
p. 14077 - 14089
(2017/10/17)
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- Chiral-pool synthesis of 1,2,4-trisubstituted 1,4-diazepanes as novel σ1 receptor ligands
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Starting from enantiomerically pure amino acids, 1,4-diazepanes with various substituents in 1, 2, and 4-position were synthesized following the late stage diversification strategy. The key step in the formation of the seven-membered ring was the intramolecular EDC coupling of amino acids 15, 26, and 39. The configuration in 2-position does not influence the σ1 affinity and selectivity over related receptors. A cyclohexylmethyl or a butyl group are the preferred substituents in 4-position, whereas a methyl moiety in 2-position and a (substituted) benzyl moiety in 1-position result in the highest σ1 affinity. These results fit nicely to the reported σ1 pharmacophore models. The compounds did not inhibit the structurally related fungal enzyme sterol Δ8,7-isomerase, but showed inhibition of diverse enzymes in late cholesterol biosynthesis at high concentrations. In a screening against more than 50 target proteins, (2S)-1-benzyl-4-(4-methoxybenzyl)-2-methyl-1,4-diazepane ((S)-28b, Ki(σ1) = 0.86 nM) showed a clean receptor profile. The dose dependent potentiation of electrically stimulated contractions of guinea pig vas deferens indicates σ1 agonistic activity of (S)-28b. Even at a dose of 100 mg/kg (S)-28b did not induce severe toxic or behavioral effects in the Irwin screen. Clear cognition enhancing effects were observed for (S)-28b after inducing amnesia by scopolamine.
- Fanter, Lena,Müller, Christoph,Schepmann, Dirk,Bracher, Franz,Wünsch, Bernhard
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p. 4778 - 4799
(2017/10/05)
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- Amino acid ester derivatives cationic chiral ionic liquid and its preparation method
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The invention provides an amino-acid ester derivative cation type chiral ionic liquid and a preparation method thereof. A general formula of the amino-acid ester derivative cation type chiral ionic liquid is AX, wherein A represents an amino-acid ester cation derivative, and X represents one of BF4, PF6 and HSO4. The preparation method comprises steps as follows: amino acid, methyl alcohol and thionyl chloride react at the low temperature, and amino acid ester hydrochloride is obtained; amino acid ester hydrochloride has a Mannich reaction with paraformaldehyde and acetone, and amino acid ester derivative Mannich base is obtained; amino acid ester derivative Mannich base reacts with bromo-hydrocarbon, and a bromate type chiral ionic liquid of the amino-acid ester derivative is obtained; bromide ions of the bromate type chiral ionic liquid of the amino-acid ester derivative are exchanged, and the amino-acid ester derivative cation type chiral ionic liquid is obtained. The amino-acid ester derivative cation type chiral ionic liquid has the multiple advantages of high selectivity of a chiral substance as well as non-volatility, non-toxicity and pollution prevention of an ionic liquid, and is suitable for large-scale production of the fine chemical industry.
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Paragraph 0045; 0046; 0055; 0056; 0065; 0066
(2017/08/25)
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- NR2B SELECTIVE NMDA-RECEPTOR ANTAGONISTS FOR TREATMENT OF IMMUNE-MEDIATED INFLAMMATORY DISEASES
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The present invention provides novel means and methods for treatment auf immunemediated inflammatory diseases.
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Paragraph 200
(2017/03/21)
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- Benzoxaborole Antimalarial Agents. Part 5. Lead Optimization of Novel Amide Pyrazinyloxy Benzoxaboroles and Identification of a Preclinical Candidate
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Carboxamide pyrazinyloxy benzoxaboroles were investigated with the goal to identify a molecule with satisfactory antimalarial activity, physicochemical properties, pharmacokinetic profile, in vivo efficacy, and safety profile. This optimization effort discovered 46, which met our target candidate profile. Compound 46 had excellent activity against cultured Plasmodium falciparum, and in vivo against P. falciparum and P. berghei in infected mice. It exhibited good PK properties in mice, rats, and dogs. It was highly active against the other 11 P. falciparum strains, which are mostly resistant to chloroquine and pyrimethamine. The rapid parasite in vitro reduction and in vivo parasite clearance profile of 46 were similar to those of artemisinin and chloroquine, two rapid-acting antimalarials. It was nongenotoxic in an Ames assay, an in vitro micronucleus assay, and an in vivo rat micronucleus assay when dosed orally up to 2000 mg/kg. The combined properties of this novel benzoxaborole support its progression to preclinical development.
- Zhang, Yong-Kang,Plattner, Jacob J.,Easom, Eric E.,Jacobs, Robert T.,Guo, Denghui,Freund, Yvonne R.,Berry, Pamela,Ciaravino, Vic,Erve, John C. L.,Rosenthal, Philip J.,Campo, Brice,Gamo, Francisco-Javier,Sanz, Laura M.,Cao, Jianxin
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p. 5889 - 5908
(2017/07/22)
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- THERAPEUTIC COMPOUNDS
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The present invention relates to compounds that are antagonists of the orexin-1 receptor. The compounds have the structural formula (I) defined herein. The present invention also relates to processes for the preparation of these compounds, to pharmaceutical compositions comprising them, and to their use in the treatment of diseases or disorders associated with orexin-1 receptor activity.
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Page/Page column 31; 32
(2017/08/22)
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- Ferrocene-modified amino acids: synthesis and in vivo bioeffects on hippocampus
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A method for the ferrocene modification of amino acids of natural and synthetic origin has been developed. In the in vivo studies, the hippocampal electrical activity under the action of ferrocenyl(phenylpyrazolyl)glycine (1) was assessed. A meaningful rise (up to 25% compared to the control) in the response amplitudes of the focal potentials of the hippocampal region СА1 after intraperitoneal administration of compound 1 at the dose of 2.0 mg kg–1 was established.
- Rodionov,Snegur,Simenel,Dobryakova, Yu. V.,Markevich
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p. 136 - 142
(2017/07/05)
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- Phosphoramidate protides of five flavones and their antiproliferative activity against HepG2 and L-O2 cell lines
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A series of flavone-7-phosphoramidate derivatives were synthesized and tested for their antiproliferative activity in vitro against human hepatoma cell line HepG2 and human normal hepatic cell line L-O2. Compound 8d, 16d and 17d, incorporating the amino acid alanine, exhibited high inhibitory activity on HepG2 cell line with IC50 values of 9.0 μmol/L, 5.5 μmol/L and 6.6 μmol/L. The introduction of acyl groups played a pivotal role in the selective inhibition toward human hepatoma HepG2 cells, except for compound 8a, 9a and 16b. Compound 8d, 16d and 17d could significantly induce G2/M arrest in HepG2 cells. Specially, Compound 16d could lead early apoptosis in HepG2 cells.
- Li, Yue-Qing,Yang, Fei,Wang, Liu,Cao, Zhi,Han, Tian-Jiao,Duan, Zhe-Ang,Li, Zhen,Zhao, Wei-Jie
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p. 196 - 208
(2016/05/02)
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- Discovery of 2'-α-C-Methyl-2'-β-C-fluorouridine Phosphoramidate Prodrugs as Inhibitors of Hepatitis C Virus
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2′-α-C-Methyl-2′-β-C-fluorouridine and its phosphoramidate prodrugs were synthesized and evaluated for their inhibitory activity against HCV. The structure?activity relationship analysis of the phosphoramidate moiety found that 17m, 17q, and 17r exhibit potent activities against HCV, with EC50 values of 1.82 ± 0.19, 0.88 ± 0.12, and 2.24 ± 0.22 μM, respectively. The docking study revealed that the recognition of the 2′-β-F by Arg158, 3′-OH by N291, and the Watson?Crick pairing with the template allowed 23 to form the in-line conformation necessary for its incorporation into the viral RNA chain.
- Zeng, Debin,Zhang, Rui,Nie, Quandeng,Cao, Lin,Shang, Luqing,Yin, Zheng
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supporting information
p. 1197 - 1201
(2016/12/18)
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- Synthesis and biological evaluation of novel phosphoramidate derivatives of coumarin as chitin synthase inhibitors and antifungal agents
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A series of novel phosphoramidate derivatives of coumarin have been designed and synthesized as chitin synthase (CHS) inhibitors. All the synthesized compounds have been screened for their chitin synthase inhibition activity and antimicrobial activity in vitro. The bioactive assay manifested that most of the target compounds exhibited good efficacy against CHS and a variety of clinically important fungal pathogens. In particular, compound 7t with IC50 of 0.08 mM against CHS displayed stronger efficiency than the reference Polyoxin B with IC50 of 0.16 mM. In addition, the apparent Ki values of compound 7t was 0.096 mM while the Km of Chitin synthase prepared from Candida tropicalis was 3.86 mM for UDP-Nacetylglucosamine, and the result of the Ki showed that the compounds was a non-competitive inhibitor of the CHS. As far as the antifungal activity is concerned, compounds 7o, 7r and 7t were highly active against Aspergillus flavus with MIC values in the range of 1 μg/mL to 2 μg/Ml while the results of antibacterial screening showed that these compounds have negligible actions to the tested bacteria. These results indicated that the design of these compounds as antifungal agents was rational.
- Ji, Qinggang,Ge, Zhiqiang,Ge, Zhixing,Chen, Kaizhi,Wu, Hualong,Liu, Xiaofei,Huang, Yanrong,Yuan, Lvjiang,Yang, Xiaolan,Liao, Fei
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p. 166 - 176
(2015/12/04)
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- Catalysts and temperature driven melt polycondensation reaction for helical poly(ester-urethane)s based on natural L-amino acids
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Catalyst and temperature driven melt polycondensation reaction was developed for natural L-amino acid monomers to produce new classes of poly(ester-urethane)s. Wide ranges of catalysts from alkali, alkali earth metal, transition metal and lanthanides were developed for the condensation of amino acid monomers with diols to yield poly(ester-urethane)s. A-B Diblock and A-B-A triblock species were obtained by carefully choosing mono- or diols in model reactions. More than two dozens of transition metal and lanthanide catalysts were identified for the polycondensation to yield high molecular weight poly(ester-urethane)s. Theoretical studies revealed that the carbonyl carbon in ester possessed low electron density compared to the carbonyl carbon in urethane which driven the thermo-selective polymerization process. Optical purity of the L-amino acid residues in the melt polycondensation process was investigated using D- and L-isomers and the resultant products were analyzed by chiral-HPLC and CD spectroscopy. CD analysis revealed that the amino acid based polymers were self-assembled as β-sheet and polyproline type II secondary structures. Electron and atomic force microscopic analysis confirmed the formation of helical nano-fibrous morphology in poly(ester-urethane)s. The newly developed melt polycondensation process is very efficient and optimized for wide range of catalysts to produce diverse polymer structures from natural L-amino acids.
- Anantharaj, Santhanaraj,Jayakannan, Manickam
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p. 1065 - 1077
(2016/03/12)
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- Synthesis and evaluation of xanthine oxidase inhibitory and antioxidant activities of 2-arylbenzo[b]furan derivatives based on salvianolic acid C
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Xanthine oxidase (XO) is the key enzyme in humans which is related to a variety of diseases such as gout, hyperuricemia and cardiovascular diseases. In this work, a series of 2-arylbenzo[b]furan derivatives were synthesized based on salvianolic acid C, and they were evaluated for xanthine oxidase inhibitory and antioxidant activities. Compounds 5b, 6a, 6e and 6f showed potent xanthine oxidase inhibitory activities with IC50values ranging from 3.99 to 6.36?μM, which were comparable with that of allopurinol. Lineweaver-Burk plots analysis revealed that the representative derivative 6e could bind to either xanthine oxidase or the xanthine oxidase-xanthine complex, which exhibited a mixed-type competitive mechanism. A DPPH radical scavenging assay showed most of the hydroxyl-functionalized 2-arylbenzo[b]furan derivatives possessed the potent antioxidant activity, which was further validated on LPS-stimulated RAW 264.7 macrophages model. The structure-activity relationships were preliminary analyzed and indicated that the structural skeleton of 2-arylbenzo[b]furan and phenolic hydroxyl groups played an important role in maintaining xanthine oxidase inhibitory effect and antioxidant property for the series of derivatives. Meanwhile, molecular docking studies were performed to further confirm the structure-activity relationships and investigate the proposed binding mechanisms of compounds 5d, 6d and 10d binding to the protein.
- Tang, Hong-Jin,Zhang, Xiao-Wei,Yang, Lin,Li, Wei,Li, Jia-Huang,Wang, Jin-Xin,Chen, Jun
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p. 637 - 648
(2016/09/14)
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- Synthesis of chiral (indol-2-yl)methanamines and insight into the stereochemistry protecting effects of the 9-phenyl-9-fluorenyl protecting group
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Tetrahydro-β-carbolines, a privileged structural feature in natural products and pharmaceutically active compounds, has been the cause for considerable research interest, spanning many decades. Herein is reported the synthesis of the structurally closely related compounds denoted as (indol-2-yl)methanamines, in 99% ee using amino acid starting materials, coupled with a 9-phenyl-9-fluorenyl (Pf) protecting group strategy. Furthermore a conformational study of Pf-protected α-amino carbonyl compounds were undertaken by means of DFT refined molecular mechanics calculation, X-ray crystallography measurements and NMR experiments in order to elucidate the stereochemical protecting properties induced by the Pf group. Herein is presented a highly efficient stereospecific synthesis of (indol-2-yl)methanamines from amino acids together with a mechanistic study on the stereochemistry protecting effects of the 9-phenyl-9-fluorenyl protecting group with the aid of DFT calculations, NMR and X-ray crystallography.
- Lood, Christopher S.,Laine, Aino E.,H?gn?sbacka, Antonia,Nieger, Martin,Koskinen, Ari M. P.
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p. 3793 - 3805
(2015/06/16)
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- Enantiomerically Pure 2-Methyltetrahydro-3-benzazepin-1-ols Selectively Blocking GluN2B Subunit Containing N-Methyl-d-aspartate Receptors
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A chiral pool synthesis was developed to obtain all four stereoisomeric 2-methyl-3-(4-phenylbutyl)tetrahydro-3-benzazepin-1-ols 21, 31, and 32 in a seven- to eight-step sequence. The phenols 32 reveal slightly higher GluN2B affinity than the methyl ethers 21. The GluN2B affinity increases in the order (1R,2S) (1S,2S) (1S,2R) (1R,2R). The stereoisomeric phenols (R,R)-32 and (S,R)-32 show the highest GluN2B affinity and the highest cytoprotective activity. Both compounds represent GluN2B selective allosteric NMDA receptor antagonists. Docking of the 3-benzazepin-1-ols into the ifenprodil binding site of the crystallized GluN1b/GluN2B N-terminal domains led to free binding energies, which correlate nicely with the experimentally determined GluN2B affinities. The similar GluN2B affinity of the stereoisomeric phenols (S,S)-32, (R,R)-32, and (S,R)-32 is explained by different binding modes of the 3-benzazepine scaffold. The benzyl ethers 31 reveal unexpectedly high GluN2B affinity but do not show cytoprotective effects. The additional benzyl moiety of 31 binds into a previously unrecognized lipophilic subpocket.
- Tewes, Bastian,Frehland, Bastian,Schepmann, Dirk,Robaa, Dina,Uengwetwanit, Tanaporn,Gaube, Friedemann,Winckler, Thomas,Sippl, Wolfgang,Wünsch, Bernhard
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supporting information
p. 6293 - 6305
(2015/08/24)
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- Synthesis, toxicity and chemo-sensitization of HeLa cells to etoposide, of some 2-methyl amino acid ester-substituted-1,3-benzoxazines
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A number of new L- or LD-2-amino acid ester-(substituted)-benz[1,3]oxazines 12-17 were synthesized from the reaction of free L- or LD-amino acid ester 9a-d with 2-methylthio-1,3-benzoxazines 11a-g. The structures of the new products 12-17 were confirmed from their 1H, 13CNMR and IR spectra and CHN microanalysis. Some of these compounds weakly inhibited DNA-PK and platelet aggregation. Studies of the toxicity for some of the new compounds showed mostly no inhibitory effects on HeLa cell growth at 1 and 10 μM and some up to 40 μM. The chemo-sensitization to etoposide by some of the compounds revealed that the most effective chemo-sensitizers at 10 μM were 14c (1.83 fold), 12e (1.42 fold), 15a (0.8 fold), 16d (0.76 fold) and 1c (0.74). However, at 1 μM in the presence of etoposide, some compounds were shown to be more effective. No direct link was observed between the type of the L-amino acid methyl ester as well as the 7-, 8-, or 7, 8-substitution on the aromatic ring on the effectiveness of the chemo-sensitizers; however, the 7-hydroxy group did lower the effective chemo-sensitizers values.
- Ihmaid, Saleh K.,Fitzgibbon, Cheree,Al-Rawi, Jasim M. A.
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p. 2825 - 2837
(2015/02/19)
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- Efficient asymmetric addition of diethylzinc to aldehydes using C 2-novel chiral pyridine β-amino alcohols as chiral ligands
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A series of novel C2-symmetric chiral pyridine β-amino alcohol ligands have been synthesized from 2,6-pyridine dicarboxaldehyde, m-phthalaldehyde and chiral β-amino alcohols through a two-step reaction. All their structures were characterized by 1H NMR, 13C NMR and IR. Their enantioselective induction behaviors were examined under different conditions such as the structure of the ligands, reaction temperature, solvent, reaction time and catalytic amount. The results show that the corresponding chiral secondary alcohols can be obtained with high yields and moderate to good enantiomeric excess. The best result, up to 89% ee, was obtained when the ligand 3c (2S,2R)-2,2-((pyridine-2,6-diylbis(methylene)) bisazanediyl))bis(4-methyl-1,1-diphenylpentan-1-ol) was used in toluene at room temperature. The ligand 3g (2S,2R)-2,2-((1,3-phenylenebis(methylene)) bis(azanediyl))bis(4-methyl-1,1-diphenylpentan-1-ol) was prepared in which the pyridine ring was replaced by the benzene ring compared to 3c in order to illustrate the unique role of the N atom in the pyridine ring in the inductive reaction. The results indicate that the coordination of the N atom of the pyridine ring is essential in the asymmetric induction reaction. Copyright
- Zhang, Weijie,Tang, Ruiren,Yu, Huirong,Gao, Shu
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p. 545 - 551
(2014/07/07)
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- Synthesis of enantiomerically enriched indolines and tetrahydroisoquinolines from (S)-amino acid-derived chiral carbocations: An easy access to (3S,4R)-demethoxy-3-isopropyl diclofensine
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Enantiomerically enriched indolines and tetrahydroisoquinolines were synthesized within 5 min to 2 h in high yields from easily accessible (S)-amino acid derived chiral carbocations. The diastereoselective Friedel-Crafts reaction is promoted by a Lewis acid (AlCl3) offering trans-diastereoselectivity. The rate of the reaction and diastereoselectivity of the product are significantly influenced by steric hindrance of the amino acids substituents and aryl groups. The methodology can be applied for the synthesis of the enantiomerically enriched bioactive scaffold (3S,4R)-demethoxy-3-isopropyl diclofensine. This journal is
- Manna, Sudipta Kumar,Panda, Gautam
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p. 8318 - 8324
(2015/01/09)
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- New helical folds in α-peptides with alternating chirality
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In α-peptides, the 8/10 helix is theoretically predicted to be energetically unstable and has not been experimentally observed so far. Based on our earlier studies on 'helical induction' and 'hybrid helices', we have adopted the 'end-capping' strategy to induce the 8/10 helix in α-peptides by using short α/β-peptides. Thus, α-peptides containing a regular string of α-amino acids with alternating chirality were end capped by α/β-peptides with 11/9-helical motifs at the termini. Extensive NMR spectroscopy studies of these peptides revealed the presence of a hitherto unknown 8/10-helical pattern; the H-bonds in the shorter pseudorings were rather weak. The approach of using short helical motifs to induce new mixed helices in α-peptides could provide avenues for more versatile design strategies. A new twist: α-Peptides containing a regular string of α-amino acids with alternating chirality were end capped by α/β-peptides with 11/9-helical motifs at the termini. Extensive NMR spectroscopy studies of these peptides revealed the presence of a hitherto unknown 8/10-helical pattern in this hybrid helix (see figure); the H-bonds in the shorter pseudorings were rather weak. The addition of helix-stabilizing influences may enhance the propensity and stability of these uncommon folding patterns in oligomers of α-amino acids.
- Sharma, Gangavaram V. M.,Venkateshwarlu, Gajulapati,Reddy, Pothula Purushotham,Kunwar, Ajit C.
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p. 11428 - 11438
(2015/02/02)
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- Synthesis and characterization of captopril derivatives
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To develop more potential angiotensin converting enzyme (ACE) inhibitors, a series of captopril (Cap) derivatives were synthesized, including Cap-glycine methyl ester, Cap-l-alanine methyl ester, Cap-l-aspartic acid dimethyl ester, Cap-l-lysine methyl ester, Cap-O-acylisourea, acetyl captopril, and benzoyl captopril. The resulting products were characterized by IR and UV-visible spectroscopy and MS, which showed the desired products were successfully synthesized. This could serve as a guide for rational design of highly potent ACE inhibitors.
- Li, He-Ping,Zhang, Juan-Juan,Qin, Long,Zhao, Ming-Dong
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p. 621 - 629
(2013/07/27)
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- Effects of alanine methyl ester hydrochlorides on thermal behaviour of biodegradable poly(L-lactic acid)
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Alanine methyl ester hydrochlorides (AMEH) was synthesized to improve the crystallization of poly(L-lactic acid) (PLLA) and PLLA/AMEH was prepared by melt blending and hot-press forming process. The thermal behaviour of PLLA/AMEH was investigated by DSC. Non-isothermal crystallization showed that alanine methyl ester hydrochloride made the melt crystallization peak become much sharper in the cooling process and the crystallization enthalpy increases from 1.379 to 9.941 J g-1 with the addition of 2 % alanine methyl ester hydrochloride at a cooling rate of 1 °C/min from melt. The melting behaviour of PLLA/2 % AMEH after at different crystallization temperature for 1 h confirmed that double-melting peak of PLLA/2 % AMEH resulted from melting-recrystallization, However, the hightemperature melting peak becomes smaller with increasing of crystallization temperature. Copyright
- Cai, Yan-Hua,Xu, Qiang,Tang, Ying,Luo, Wen,Zhang, Shen-Wei,Hao, Hai-Tao
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p. 1749 - 1750
(2013/05/21)
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