- Catalytic hydrolysis of α-amino esters in the presence of chiral palladacycles
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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.
- Ageeva,Kurzeev,Kazankov
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Read Online
- Dehydropeptide-based plasmonic magnetogels: A supramolecular composite nanosystem for multimodal cancer therapy
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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.
- 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.
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Read Online
- Synthesis, in vitro and in vivo biological evaluation of dihydroartemisinin derivatives with potential anti-Toxoplasma gondii agents
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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.
- Deng, Hao,Huang, Xing,Jin, Chun-Mei,Jin, Chunmei,Quan, Zhe-Shan
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- Synthesis, characterization and antimicrobial activity of some novel 1-substituted benzimidazole derivatives
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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.
- Astley, Demet,Isik, Erkut,Yasa, Ihsan,Yuksekdanaci, Seda
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p. 1372 - 1379
(2020/10/06)
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- Synthesis of pyrimidine nucleoside and amino acid conjugates
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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.
- Koplūnait?, Martyna,Butkut?, Kamil?,Me?kys, Rolandas,Taurait?, Daiva
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supporting information
(2020/11/13)
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- DIPEPTIDE MIMETICS OF NGF AND BDNF NEUROTROPHINS
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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.
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Paragraph 0187
(2019/04/16)
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- Rhamnolipid inspired lipopeptides effective in preventing adhesion and biofilm formation of Candida albicans
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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.
- Jovanovic, Milos,Radivojevic, Jelena,O'Connor, Kevin,Blagojevic, Stevan,Begovic, Biljana,Lukic, Vera,Nikodinovic-Runic, Jasmina,Savic, Vladimir
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supporting information
p. 209 - 217
(2019/03/23)
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- Tertiary-butoxycarbonyl (Boc) – A strategic group for N-protection/deprotection in the synthesis of various natural/unnatural N-unprotected aminoacid cyanomethyl esters
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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.
- Karmakar, Ananta,Basha, Mushkin,Venkatesh Babu,Botlagunta, Murali,Malik, Noormohamed Abdul,Rampulla, Richard,Mathur, Arvind,Gupta, Arun Kumar
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supporting information
p. 4267 - 4271
(2018/11/03)
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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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- Synthesis and evaluation of chirally defined side chain variants of 7-chloro-4-aminoquinoline to overcome drug resistance in malaria chemotherapy
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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.
- Dola, Vasantha Rao,Soni, Awakash,Agarwal, Pooja,Ahmad, Hafsa,Raju, Kanumuri Siva Rama,Rashid, Mamunur,Wahajuddin, Muhammad,Srivastava, Kumkum,Haq,Dwivedi,Puri,Katti
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- Copper promoted: N -alkylation of sulfoximines with alkylboronic acid under mild conditions
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The copper meditated N-methylation of sulfoximines using methylboronic acid is reported. The reactions provide excellent yields in a short span of time under mild conditions. The optimized conditions were also found to be suitable for the N-alkylation of sulfoximine with different alkylboronic acids. In addition, N-methylation and cyclopropylation of the bioactive l-methionine sulfoximine derivative was demonstrated under standard reaction conditions.
- Gupta, Surabhi,Chaudhary, Priyanka,Muniyappan, Nalluchamy,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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supporting information
p. 8493 - 8498
(2017/10/27)
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- Synthesis and anticancer activities of glycyrrhetinic acid derivatives
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A total of forty novel glycyrrhetinic acid (GA) derivatives were designed and synthesized. The cytotoxic activity of the novel compounds was tested against two human breast cancer cell lines (MCF-7, MDA-MB-231) in vitro by the MTT method. The evaluation results revealed that, in comparison with GA, compound 42 shows the most promising anticancer activity (IC50 1.88 ± 0.20 and 1.37 ± 0.18 μM for MCF-7 and MDA-MB-231, respectively) and merits further exploration as a new anticancer agent.
- Li, Yang,Feng, Ling,Song, Zhi-Fang,Li, Hai-Bei,Huai, Qi-Yong
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- Dual Catalytic Decarboxylative Allylations of α-Amino Acids and Their Divergent Mechanisms
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The room temperature radical decarboxylative allylation of N-protected α-amino acids and esters has been accomplished via a combination of palladium and photoredox catalysis to provide homoallylic amines. Mechanistic investigations revealed that the stability of the α-amino radical, which is formed by decarboxylation, dictates the predominant reaction pathway between competing mechanisms.
- Lang, Simon B.,O'Nele, Kathryn M.,Douglas, Justin T.,Tunge, Jon A.
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supporting information
p. 18589 - 18593
(2016/01/25)
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- Synthesis and biological evaluation of novel curcuminoid derivatives
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Curcuminoids have been reported to possess multiple bioactivities, such as antioxidant, anticancer and anti-inflammatory properties. Three novel series of curcuminoid derivatives (11a-h, 15a-h and 19a-d) with enhanced bioactivity have been synthesized. Among the synthesized compounds, 11b exhibited the most significant activity with an MIC of 0.5 μ M /mL against selected medically important Gram-positive cocci (S aureus and S viridans) and Gram-negative bacilli (E. coli and E. cloacae). The derivatives exhibited remarkable results in an antioxidant test with an IC50 2.4- to 9.3-folder smaller than curcuminoids. With respect to antiproliferative activity against Hep-G2, LX-2, SMMC7221 and MDA-MB-231, the derivatives exhibited an effect stronger than curcuminoids with an IC50 ranging from 0.18 to 4.25 μ M.
- Cao, Ya-Kun,Li, Hui-Jing,Song, Zhi-Fang,Li, Yang,Huai, Qi-Yong
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p. 16349 - 16372
(2015/01/08)
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- INTERMEDIATES OF SITAGLIPTIN AND PREPARATION PROCESS THEREOF
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Disclosed are intermediates of Sitagliptin, a preparation process thereof, and a process for synthesizing Sitagliptin using these intermediates. Sitagliptin is synthesized by using chiral amino compounds as a raw material, without having to build a chiral center with a chiral asymmetric catalytic hydrogenation, and high-pressure hydrogenation is avoided.
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Paragraph 0040; 0041
(2013/10/22)
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- INTERMEDIATES OF SITAGLIPTIN AND PREPARATION PROCESS THEREOF
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Disclosed are intermediates of Sitagliptin, a preparation process thereof, and a process for synthesizing Sitagliptin using these intermediates. Sitagliptin is synthesized by using chiral amino compounds as a raw material, without having to build a chiral center with a chiral asymmetric catalytic hydrogenation, and high-pressure hydrogenation is avoided.
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Paragraph 0082-0084
(2013/11/05)
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- Synthesis and cytotoxic activity of methyl glycyrrhetinate esterified with amino acids
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Methyl glycyrrhetinate was esterified at position C3 of ring A using different amino acids. A short, unbranched chain of four carbon atoms with two amino groups in positions 2 and 4 was shown to be the most active compound of this series (IC50 = 0:8 M on liposarcoma Lipo cells). These compounds trigger apoptosis as shown by an acridine orange/ethidium bromide assay, trypan blue tests and DNAladdering experiments.
- Csuk, Rene,Schwarz, Stefan,Siewert, Bianka,Kluge, Ralph,Stroehl, Dieter
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p. 731 - 746
(2012/11/13)
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- Design, synthesis, and biological activity of thiazole derivatives as novel influenza neuraminidase inhibitors
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A series of novel influenza neuraminidase (NA) inhibitors based on thiazole core were synthesized and evaluated for their ability to inhibit NA of influenza A virus (H3N2). All compounds were synthesized in good yields starting from commercially available 2-amino-4-thiazole-acetic ester using a suitable synthetic strategy. These compounds showed moderate inhibitory activity against influenza A NA. The most potent compound of this series is compound 4d (IC50=3.43 μM), which is about 20-fold less potent than oseltamivir, and could be used to design novel influenza NA inhibitors that exhibit increased activity based on thiazole ring.
- Liu,Zhang, Lei,Gong, Jianzhi,Fang, Hao,Liu, Ailin,Du, Guanhua,Xu, Wenfang
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scheme or table
p. 506 - 513
(2012/06/01)
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- Benzotriazole reagents for the syntheses of Fmoc-, Boc-, and Alloc-protected amino acids
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Stable Fmoc-, Boc-, and Alloc-benzotriazoles react with various amino acids including unprotected serine and glutamic acid, in the presence of triethylamine at 20° as reagents to introduce -amino protecting groups to afford Fmoc-, Boc-, and Alloc-protected amino acids (77-94%) free of dipeptide and tripeptide impurities. Fmoc-, and Alloc-Gly-Gly-OH dipeptides were prepared in 90% yields by N-acylation of glycylglycine with Fmoc- and Alloc-benzotriazoles in the presence of triethylamine. Synthesized N-protected amino acids were greater than 99% pure, analyzed by HPLC. Georg Thieme Verlag Stuttgart - New York.
- Ibrahim, Tarek S.,Tala, Srinivasa R.,El-Feky, Said A.,Abdel-Samii, Zakaria K.,Katritzky, Alan R.
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p. 2013 - 2016
(2011/10/08)
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- Design, synthesis and primary activity assay of bi- or tri-peptide analogues with the scaffold l-arginine as amino-peptidase N/CD13 inhibitors
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A series of bi- or tri-peptide analogues with the scaffold l-arginine were designed, synthesized and evaluated for their inhibitory activities against amino-peptidase N (APN) and metalloproteinase-2 (MMP-2). The primary activity assay showed that all the compounds exhibited higher inhibitory activities against APN than MMP-2. Within this series, compounds C6 and C7 (IC50 = 4.2 and 4.3 μM) showed comparable APN inhibitory activities with the positive control bestatin (IC50 = 3.8 μM).
- Mou, Jiajia,Fang, Hao,Liu, Yingzi,Shang, Luqing,Wang, Qiang,Zhang, Lei,Xu, Wenfang
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scheme or table
p. 887 - 895
(2010/05/02)
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- Novel 3-phenylpropane-1,2-diamine derivates as inhibitors of aminopeptidase N (APN)
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Aminopeptidase N (APN) is an essential peptidase involved in the process of tumor invasion and metastasis. Here we describe a novel class of inhibitor with 3-phenylpropane-1,2-diamine as scaffold to APN. Preliminary activity evaluation with enzyme inhibition studies showed that compound 12i exhibited potent and selective inhibitory activity towards APN with the IC50 value 15.5 ± 1.2 μM.
- Shang, Luqing,Wang, Qiang,Fang, Hao,Mu, Jiajia,Wang, Xuejian,Yuan, Yumei,Wang, Binghe,Xu, Wenfang
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scheme or table
p. 9984 - 9990
(2009/04/06)
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- Exploration of the P1 SAR of aldehyde cathepsin K inhibitors.
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The synthesis and biological activity of a series of aldehyde inhibitors of cathepsin K are reported. Exploration of the properties of the S(1) subsite with a series of alpha-amino aldehyde derivatives substituted at the P(1) position afforded compounds with cathepsin K IC(50)s between 52 microM and 15 nM.
- Catalano, John G,Deaton, David N,Furfine, Eric S,Hassell, Annie M,McFadyen, Robert B,Miller, Aaron B,Miller, Larry R,Shewchuk, Lisa M,Willard Jr., Derril H,Wright, Lois L
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p. 275 - 278
(2007/10/03)
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- Monofunctional platinum complexes showing potent cytotoxicity against human liver carcinoma cell line BEL-7402
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Three novel Pt(II) complexes [PtL1′Cl] I (L1′ = glycine-N′-8-quinolylamide), [PtL2′Cl] II (L2′= L-alanine-N′-8-quinolylamide), and [PtL3Cl] III [L3 = N-(tert-butoxycarbonyl)-L-methionine-N′-8-quinolylamide] have been synthesized and characterized. The crystal structure of complexes II and III showed that the ligands are three-coordinated with only one Cl- as the leaving group. Complex II crystallized in the monoclinic system with space group P2(1), a = 9.502(2) ?, b = 4.724(1) ?, c = 14.800(3) ?, while complex III crystallized in the orthorhombic system with space group P2(1)2(1)2(1), a = 5.441(1) ?, b = 12.978(3) ?, c = 29.438(6) ?. These complexes have been tested against a wide range of tumor cell lines including BEL-7402, HCT-116, SPC-A4, MOLT-4, P388, HL-60, A-549, SGC-7901, MKN-28, and HO-8910. Complex III is highly cytotoxic against the HCT-116 (IC50 = 0.38 μM), SPC-A4 (IC50 = 0.43 μM), BEL-7402 (IC50 = 0.43 μM), and MOLT-4 (IC50 = 0.61 μM) cell lines. The cell line most sensitive to III is human liver carcinoma cell line BEL-7402, which has a response rate of 75.1% at 6.6 × 10-7 M, nearly 6 times higher than that of cisplatin.
- Zhang, Junyong,Wang, Xiaoyong,Tu, Chao,Lin, Jun,Ding, Jian,Lin, Liping,Wang, Zheming,He, Cheng,Yan, Chunhua,You, Xiaozeng,Guo, Zijian
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p. 3502 - 3507
(2007/10/03)
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- Soluble alpha-amino acid salts in acetonitrile: practical technology for the production of some dipeptides.
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Alpha-amino acids are soluble in acetonitrile when treated with phosphazene bases. As a result, the protection/deprotection events that are usually required for peptide coupling reactions can be minimized. This is illustrated in the synthesis of the important angiotensin-converting enzyme (ACE) inhibitor enalapril. [reaction: see text]
- Palomo, Claudio,Palomo, Antonio L,Palomo, Francisco,Mielgo, Antonia
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p. 4005 - 4008
(2007/10/03)
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- Selective detachment of Boc-protected amino acids and peptides from Merrifield, PAM and Wang resins by trimethyltin hydroxide
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We describe the development of a new non-acidolytic and non- nucleophilic method for the selective cleavage by trimethyltin hydroxide of amino acids and dipeptides at benzyl ester links attached to resins commonly used in peptide synthesis.
- Furlan, Ricardo L. E.,Mata, Ernesto G.,Mascaretti, Oreste A.,Pena, Clara,Coba, Marcelo P.
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p. 13023 - 13034
(2007/10/03)
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- Hybridomas and monoclonal antibodies which specifically bind human basic fibroblast growth factor
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A monoclonal antibody is produced from a cloned hybridoma, and the monoclonal antibody combines specifically with basic fibroblast growth factor (bFGF). Therefore, the monoclonal antibody can be advantageously used for assay reagents on bFGF or for purification of bFGF.
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- APPROACHES TOWARD THE TOTAL SYNTHESES OF ASTIN A, B, AND C
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Two nonessential amino acids, (+)-(S)-2-aminobutanoic acid and the methyl ester of L-β-phenylalanine , were synthesized to provide a tripeptide which will be used in the total syntheses of astins A, B, and C.
- Jiang, Jianjun,Schumacher, Kelly K.,Joullie, Madeleine M.,Davis, Franklin A.,Reddy, Rajarathnam E.
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p. 2121 - 2124
(2007/10/02)
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- One-Pot Conversion of Fluorenylmethyl Carbamates into tert-Butyl Carbamates
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N-Fluorenylmethoxycarbonyl groups may be efficiently converted into N-tert-butoxycarbonyl groups by potassium fluoride/Et3N in the presence of Boc2O.
- Li, Wen-Ren,Jiang, Jianjun,Joullie, Madelaine M.
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p. 1413 - 1414
(2007/10/02)
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- Synthesis of a putative subtype specific antigenic heptapeptide from Escherichia coli K88 ad protein fimbriae.
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The heptapeptide methyl ester Phe-Asn-Glu-Asn-Met-Ala-Tyr-OMe covering the amino acid sequence of the region 213-219 of Escherichia Coli K88 ad protein fimbriae is synthesized using N alpha-t-butyloxycarbonyl-protection and benzyl groups for side-chain-protection. All condensation reactions are performed in 84-97% yield by preactivation of the protected amino acids by dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotriazole (HOBt), and reaction of the resulting active ester with amine in the presence of 4-methylmorpholine (NMM). A mechanism is proposed for the nitrile formation in the side-chain of activated asparagine, and the suppression of this side-reaction is investigated. The repetitive deprotection is performed in a mixture of trifluoroacetic acid (TFA), phenol and p-cresol to give the TFA salts in virtually quantitatively yields. The final deprotection of the heptapeptide is carried out in a mixture of 25% hydrogen fluoride (HF) and dimethyl sulfide (DMS) in an overall yield of 48%. The serological and conformational properties of the synthetic peptide are under investigation.
- Meldal
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p. 242 - 249
(2007/10/02)
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- Synthesis of a putative antigenic heptapeptide from Escherichia coli K88 ab protein fimbriae.
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The heptapeptide Tyr-Arg-Glu-Asp-Met-Glu-Tyr-OMe, spanning region 213-219 of Escherichia coli K88 ab protein fimbriae, was synthesized with an overall yield of 37% using dicyclohexylcarbodiimide (DCC) and 1-hydroxybenzotriazole (HOBt) preactivation in all condensation reactions. The C-terminal was protected as the methyl ester. The protection scheme of N alpha-tert-butyloxycarbonyl-(Boc) and benzyl-(Bzl) or benzyloxycarbonyl (Z) groups for side chain protection was found to be orthogonal when a mixture of trifluoroacetic acid (TFA), phenol (PhOH) and p-cresol (CrOH) was used for repetitive deprotection. The final deprotection of Boc-Tyr(Bzl)-Arg(Z2)-Glu(Bzl)-Asp(Bzl)-Met-Glu(Bzl+ ++)-Tyr(Bzl)-OMe (17) was accomplished in 80% yield by prolonged treatment with hydrogen fluoride, dimethyl sulfide, p-cresol and p-thiocresol. The BSA-linked synthetic peptide was used in immunisation experiments on rabbits.
- Meldal
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p. 250 - 256
(2007/10/02)
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- Alkyl 1-Chloroalkyl Carbonates: Reagents for the Synthesis of Carbamates and Protection of Amino Groups
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The synthesis of 1-chloroalkyl carbonates and their reaction with various type of amines are described.This reaction is useful for the synthesis of carbamate pesticides and for the protection of various amino groups, including amino acids.
- Barcelo, Gerard,Senet, Jean-Pierre,Sennyey, Gerard,Bensoam, Jean,Loffet, Albert
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p. 627 - 632
(2007/10/02)
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- New Amino-protective Reagents for t-Butoxycarbonylation and Benzyloxycarbonylation of Amines and Amino Acids
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New amino-protective reagents for t-butoxycarbonylation and benzyloxycarbonylation of amines and amino acids have been developed. t-Butyl 2-pyridyl carbonate and t-butyl S-(2-pyridyl) thiocarbonate react cleanly with various amines and amino acids to afford N-Boc amines and N-Boc amino acids in high yields.Benzyl 2-pyridyl carbonate and O-benzyl S-(2-pyridyl) thiocarbonate are also found to be very effective in the benzyloxycarbonylation of amino acids.
- Kim, Sunggak,Lee, Jae In,Yi, Kyu Yang
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p. 3570 - 3575
(2007/10/02)
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- 2(1H)-Pyridone as Leaving Group in Acylation Reactions - Applications in Peptide Synthesis
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Alkyl 2-pyridyl carbonates 3 or mixtures of 3 and the isomeric N-(alkoxycarbonyl)-2-pyridones 3' are useful for the introduction of urethane protective groups into amino acids.The N-protected amino acids 7 - 10 react with 2(1H)-pyridone (1a) using the carbodiimide method to yield 2-pyridyl active esters 11, which easily undergo coupling reactions with amino acid esters 12 with elimination of 1a to give peptides 13 in good yields as well as high optical purities.
- Effenberger, Franz,Brodt, Werner
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p. 468 - 482
(2007/10/02)
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- t-BUTYL 2-PYRIDYL CARBONATE. A USEFUL REAGENT FOR t-BUTOXYLATION OF AMINO ACIDS
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t-Butyl 2-pyridyl carbonate, a stable crystalline compound, is found to be very efficient in the t-butoxycarbonylation of amino acids.
- Kim, Sunggak,Lee, Jae In
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p. 237 - 238
(2007/10/02)
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- FORMATION CONSTANTS OF SILVER(I) COMPLEXES OF SOME SULPHUR-CONTAINING DIPEPTIDES AND VALYLVALINE
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Formation constants at 25 deg C and l = 0.10 mol dm-3 (KNO3) have been determined for the complexes of AgI with a range of nine dipeptides which incorporate side-chains containing one (glycylmethionine and methionylglycine) or two sulphur donor atoms.In the latter case dipeptides formed from amino acids of the same and of different chiralities were studied (e.g.L-methionyl-L-methionine and L-methionyl-D-methionine).The results are compared with those for valylvaline.Values for the formation constants are interpreted in terms of the preferred conformations of the dipeptides, and the tendency for AgI to bond to S-donor atoms or to adopt linear co-ordination through the formation of dimeric complexes.
- Lyons, Anthony Q.,Pettit, Leslie D.
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p. 2305 - 2308
(2007/10/02)
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- 3-Alkoxycarbonyl-2-oxazolones and Their Homopolymers as Highly Preservable Amino-Protecting Reagents. tert-Butoxy-carbonylation and Benzyloxycarbonylation of Amino Groups
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Highly preservable amino protecting reagents derived from the 2-oxazolone moiety as a common activating mediator have been developed. 3-Alkoxycarbonyl-2-oxazolones serve as easily handled reagents for amino protection, including tert-butoxycarbonylation, benzyloxycarbonylation, p-methoxybenzyloxycarbonylation, methoxycarbonylation and ethoxycarbonylation.For example, high yield N-protection of α-amino acids has been smoothly performed by the use of 3-tert-butoxycarbonyl and 3-benzyloxycarbonyl-2-oxazolones in aqueous solution at room temperature.A series of homopolymers, poly(3-alkoxycarbonyl-2-oxazolone), is readily obtainable by radical-initiated chain reaction of the corresponding 4,5-unsubstituted oxazolone monomers (except for the tert-butoxy derivate, which failed to give polymeric compounds), and these were successfully used for amino protection as well.Use of the polymer reagents greatly simplifies the purification procedure, though a longer reaction time is required.Keywords - 3-alkoxycarbonyl-2-oxazolone; poly(2-alkoxycarbonyl-2-oxazolone); 3-tert-butoxycarbonyl-2-oxazolone; 3-benzyloxycarbonyl-2-oxazolone; amino protection
- Kunieda, Takehisa,Higuchi, Tsunehiko,Abe, Yoshihiro,Hirobe, Masaaki
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p. 2174 - 2181
(2007/10/02)
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- SYNTHESIS OF MESOIONIC TRIAZOLOPYRIDINE. III. APPLICATIONS OF N-ACYL MESOIONIC TRIAZOLOPYRIDINES AS ACYLATING REAGENTS.
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Utility of N-acyl mesoionic triazolopyridines as acylating reagents was investigated concerning with peptide synthesis. Several dipeptides and N-alkoxycarbonyl amino acids were prepared by use of these reagents.
- Saito,Shimizu
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p. 2974 - 2980
(2007/10/02)
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- CLEAVAGE OF PEPTIDE TO SPARROW-RESIN BOND BY CATALYTIC TRANSFER HYDROGENOLYSIS WITH 1,4-CYCLOHEXADIENE
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Cleavage of benzyl ester-type linkage to the Sparrow modified polystyrene support was attempted with the aid of catalytic transfer hydrogenation using 1,4-cyclohexadiene and palladium black, and satisfactory yields were obtained.This will provide an alternatively efficient and mild method for the final deblocking step during improved solid phase peptide synthesis.
- Colombo, Roberto
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p. 1119 - 1122
(2007/10/02)
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- Synthetic pentapeptide having opiate agonist activity
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A synthetic pentapeptide of opiate agonist activity having the formula H-Tyr-Gly-Gly-Phe-Met-NH2 formed in a solid-state method.
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- Untriakontapeptide with opiate activity
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An untriakontapeptide having significant opiate agonist activity has been isolated from camel pituitary glands. The structure of this peptide has been determined and this peptide was then synthesized utilizing solid phase peptide synthesis. Both natural and synthetic material show identical physical and biological properties.
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