2488-15-5Relevant articles and documents
Catalytic hydrolysis of α-amino esters in the presence of chiral palladacycles
Ageeva,Kurzeev,Kazankov
, p. 548 - 552 (2007)
The rate of hydrolysis of esters derived from optically active α-amino acids, catalyzed by chiral cyclopalladated benzylamines, depends on the configuration of chiral centers in the substrate and catalyst. The catalytic hydrolysis of sulfur-containing amino esters follows an intramolecular mechanism, and the difference in the reaction rates for the stereoisomers increases in going from ortho-palladated primary benzylamines (k S/k R = 1.1) to tertiary amines (k S/k R = 1.5); the strongest catalytic effect is observed for an ester and a complex with the same absolute configuration of the chiral centers. The efficiency of intermolecular catalysis is greater for a complex and ester with opposite absolute configurations of the chiral centers, and the rate constants of catalytic hydrolysis for two pairs of stereoisomers coincide within experimental error. The maximal difference in the reaction rates is observed for cyclopalladated secondary benzylamines; it reaches 2.3 for the phenylalanine ester. Nauka/Interperiodica 2007.
Dehydropeptide-based plasmonic magnetogels: A supramolecular composite nanosystem for multimodal cancer therapy
Almeida, B. G.,Amaral, V. S.,Castanheira, Elisabete M. S.,Coutinho, Paulo J. G.,Ferreira, Paula M. T.,Hilliou, Loic,Jervis, Peter J.,Martins, J. A.,Moreira, Rute,O. Amorim, C.,Pereira, David M.,Veloso, Sérgio R. S.
, p. 45 - 64 (2019)
Supramolecular hydrogels are highly promising candidates as biomedical materials owing to their wide array of properties, which can be tailored and modulated. Additionally, their combination with plasmonic/magnetic nanoparticles to form plasmonic magnetogels further improves their potential in biomedical applications through the combination of complementary strategies, such as photothermia, magnetic hyperthermia, photodynamic therapy and magnetic-guided drug delivery. Here, a new dehydropeptide hydrogelator, Npx-l-Met-Z-ΔPhe-OH, was developed and combined with two different plasmonic/magnetic nanoparticle architectures, i.e., core/shell manganese ferrite/gold nanoparticles and gold-decorated manganese ferrite nanoparticles with ca. 55 nm and 45 nm sizes, respectively. The magnetogels were characterized via HR-TEM, FTIR spectroscopy, circular dichroism and rheological assays. The gels were tested as nanocarriers for a model antitumor drug, the natural compound curcumin. The incorporation of the drug in the magnetogel matrices was confirmed through fluorescence-based techniques (FRET, fluorescence anisotropy and quenching). The curcumin release profiles were studied with and without the excitation of the gold plasmon band. The transport of curcumin from the magnetogels towards biomembrane models (small unilamellar vesicles) was assessed via FRET between the fluorescent drug and the lipid probe Nile Red. The developed magnetogels showed promising results for photothermia and photo-Triggered drug release. The magnetogels bearing gold-decorated nanoparticles showed the best photothermia properties, while the ones containing core/shell nanoparticles had the best photoinduced curcumin release.
Synthesis, in vitro and in vivo biological evaluation of dihydroartemisinin derivatives with potential anti-Toxoplasma gondii agents
Deng, Hao,Huang, Xing,Jin, Chun-Mei,Jin, Chunmei,Quan, Zhe-Shan
, (2019/12/26)
In this study, four series of dihydroartemisinin derivatives were designed, synthesized, and evaluated for anti-toxoplasma gondii activity, and calculated the selectivity index (SI). It was the higher the SI, the better the effect of this compound against Toxoplasma gondii. Our goal was to filter out compounds that were bigger SI than the lead compound. The compound with the highest SI was selected for the anti-toxoplasmosis test in mice in vivo. Among the synthesized compounds, the (3R,5aS,6R,8aS,9R,12R,12aR)-3,6,9-trimethyl-decahydro-12H-3,12-epoxy[1,2]di-oxepino[4,3 -i]isochromen-10-yl-(te-rt-butoxycarbonyl)-L-alaninate (A2) exhibited the most potent anti-T. gondii activity and low cytotoxicity (SI: 6.44), yielding better results than the lead compound DHA (SI: 1.00) and the clinically used positive-control drug spiramycin (SI: 0.72) in vitro. Furthermore, compound A2 had better growth inhibitory effects on T. gondii in vivo than spiramycin did and significantly reduced the number of tachyzoites in the peritoneal cavity of mice (P 0.01). The evaluation of the data generated in the T. gondii mouse infection model indicates that compound A2 treatment was a good inhibitor of T. gondii in vivo and that it was effective in relieving the liver damage induced by T. gondii. In addition, the results of a docking study revealed that A2 could become a better T. gondii calcium-dependent protein kinase1 (TgCDPK1) inhibitor. For this reason, compound A2 has potential as an anti-parasitic drug. Further studies are required to elucidate the mechanism of the action of compound A2, as well as to develop drug delivery systems for patients.
Synthesis, characterization and antimicrobial activity of some novel 1-substituted benzimidazole derivatives
Astley, Demet,Isik, Erkut,Yasa, Ihsan,Yuksekdanaci, Seda
, p. 1372 - 1379 (2020/10/06)
Background: Benzimidazole derivatives are an important class of heterocyclic compounds in organic chemistry as they are related to a wide range of biological properties, including antimicrobial activity. Methods: A series of 1-naphthoyl and benzoyl benzimidazole derivatives were synthesised, identified and screened for their antimicrobial activities against a number of different test organisms such as Escherichia coli, Pseudomonas aureginosa, Klebsiella pneumoniae, Staphylococcus aureus, En-terococcus faecalis, Bacillus cereus, Salmonella typhimurium, Candida albicans (yeast). Results and Discussion: Benzimidazole derivatives (3a-d) were synthesised by using 4 different aminoacids. L-methionine, L-isoleucine, D-Phenylysine and L-Phenylamine as starting materials in the study. Experimental studies involve the use of benzimidazole derivatives (3a-d) of the selected amino acids to synthesize the benzoyl and naphthoyl derivatives of benzimidazole (4a-d, 5a-c). The structures of the synthesized compounds were confirmed by spectroscopic analyses (FTIR,1H-NMR,13C-NMR) and elemental analysis. Conclusion: In this study, only one compound (5a) showed a low MIC value against the eukaryotic microorganism C. albicans. The other six compounds showed higher antimicrobial activities against the prokaryotes C. albicans which is a normal flora in the mouth but is one of the organisms that cause infections leading to the weakening of the human immune system. Compound 5a is a can-didate for future alternative antimicrobial drugs against C. albicans infections. In addition, compound 5a has a potential to be used as an inhibitor against P. aureginosa for the treatment of cyst-ic fibrosis.
Synthesis of pyrimidine nucleoside and amino acid conjugates
Koplūnait?, Martyna,Butkut?, Kamil?,Me?kys, Rolandas,Taurait?, Daiva
supporting information, (2020/11/13)
The synthesis of novel pyrimidine nucleoside bioconjugates with amino acids is presented. The N4-amino acid-acylated 2′-deoxycytidine analogues, modified with various amino acids, were synthesized using a three-step synthesis and obtained in moderate overall yields. Novel amino acid-alkylated 2′-deoxycytidine derivatives were obtained during the rearrangement of amino acid-acylated derivatives that occurred during Boc deprotection.
DIPEPTIDE MIMETICS OF NGF AND BDNF NEUROTROPHINS
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Paragraph 0187, (2019/04/16)
The invention relates to compounds having either agonist or antagonist activities for the neurotrophins NGF and BDNF and represented by monomeric or dimeric substituted dipeptides that are analogs of the exposed portions of loop 1 or loop 4 regions of these neurotrophins near or at a beta-turn of the respective loop. N-acylated substituents of these dipeptides are biostereoisomers of the amino acid residues preceding these dipeptide sequences in the neurotrophin primary structure. The dimeric structure is produced advantageously by using hexatnethylenediaanine to which dipeptides are attached via their carboxyl groups. The claimed compounds displayed neuroprotective and differentiation-inducing activities in cellular models and enhanced the amount of phosphorylated tyrosine kinase A and the heat shock proteins Hsp32 and Hsp70 in the concentration range of 10 -9 to 10 -5 M. They also displayed neuroprotective, anti-parkinsonian, anti-stroke, anti-ischemic, anti-depressant and anti-amnestic activities in animal models and were active in experimental models of Alzheimer's disease. These in vivo effects of the claimed compounds are displayed in the dose range of 0.01 to 10 mg/kg when administered intraperitoneally.
Rhamnolipid inspired lipopeptides effective in preventing adhesion and biofilm formation of Candida albicans
Jovanovic, Milos,Radivojevic, Jelena,O'Connor, Kevin,Blagojevic, Stevan,Begovic, Biljana,Lukic, Vera,Nikodinovic-Runic, Jasmina,Savic, Vladimir
supporting information, p. 209 - 217 (2019/03/23)
Rhamnolipids are biodegradable low toxic biosurfactants which exert antimicrobial and anti-biofilm properties. They have attracted much attention recently due to potential applications in areas of bioremediation, therapeutics, cosmetics and agriculture, however, the full potential of these versatile molecules is yet to be explored. Based on the facts that many naturally occurring lipopeptides are potent antimicrobials, our study aimed to explore the potential of replacing rhamnose in rhamnolipids with amino acids thus creating lipopeptides that would mimic or enhance properties of the parent molecule. This would allow not only for more economical and greener production but also, due to the availability of structurally different amino acids, facile manipulation of physico-chemical and biological properties. Our synthetic efforts produced a library of 43 lipopeptides revealing biologically more potent molecules. The structural changes significantly increased, in particular, anti-biofilm properties against Candida albicans, although surface activity of the parent molecule was almost completely abolished. Our findings show that the most active compounds are leucine derivatives of 3-hydroxy acids containing benzylic ester functionality. The SAR study demonstrated a further increase in activity with aliphatic chain elongation. The most promising lipopeptides 15, 23 and 36 at 12.5 μg/mL concentration allowed only 14.3%, 5.1% and 11.2% of biofilm formation, respectively after 24 h. These compounds inhibit biofilm formation by preventing adhesion of C. albicans to abiotic and biotic surfaces.
Tertiary-butoxycarbonyl (Boc) – A strategic group for N-protection/deprotection in the synthesis of various natural/unnatural N-unprotected aminoacid cyanomethyl esters
Karmakar, Ananta,Basha, Mushkin,Venkatesh Babu,Botlagunta, Murali,Malik, Noormohamed Abdul,Rampulla, Richard,Mathur, Arvind,Gupta, Arun Kumar
supporting information, p. 4267 - 4271 (2018/11/03)
A number of cyanomethyl esters of natural/unnatural aminoacids with un-protected amino functionality were synthesized because of their synthetic and medicinal importance. Critical N-Boc deprotection methods in the presence of labile (hydrolytic sensitivity) cyanomethyl functionality were screened thoroughly and it was found that readily available 4M HCl in 1,4-dioxane solution (2–4 equiv); acetonitrile, 0 °C, 2–4 h was a suitable condition. This condition was generalized and successfully applied to a variety of alkyl, alkynyl, aryl, heteroaryl, benzyl, azido, spiro amino acid cyanomethylesters irrespective of the nature of the amine (primary or secondary) and the distance between the amine and ester group to achieve final deprotected amino esters with high yield, and purity compared to other commonly known N-protecting groups (Cbz, Fmoc, Ac, Bn, Bz etc.). It was also demonstrated that N-Boc protected aminoacid cyanomethylesters are stable enough to carry out further functionalization compared to N-unprotected counterparts.
Synthesis of Histidine-Containing Oligopeptides via Histidine-Promoted Peptide Ligation
Huang, Kai-Jin,Huang, Yi-Chen,Lin, Yuya A.
supporting information, p. 400 - 403 (2018/02/21)
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.
Synthesis and evaluation of chirally defined side chain variants of 7-chloro-4-aminoquinoline to overcome drug resistance in malaria chemotherapy
Dola, Vasantha Rao,Soni, Awakash,Agarwal, Pooja,Ahmad, Hafsa,Raju, Kanumuri Siva Rama,Rashid, Mamunur,Wahajuddin, Muhammad,Srivastava, Kumkum,Haq,Dwivedi,Puri,Katti
, (2017/03/09)
A novel 4-aminoquinoline derivative [(S)-7-chloro-N-(4-methyl-1-(4-methyl-piperazin-1-yl)pentan-2-yl)-quinolin-4-amine triphosphate] exhibiting curative activity against chloroquine-resistant malaria parasites has been identified for preclinical development as a blood schizonticidal agent. The lead molecule selected after detailed structure-activity relationship (SAR) studies has good solid-state properties and promising activity against in vitro and in vivo experimental malaria models. The in vitro absorption, distribution, metabolism, and excretion (ADME) parameters indicate a favorable drug-like profile.
