- Stereoselective reduction of N-hydroxy-α-iminocarbonyl-oligopeptide methyl esters with Zn-MsOH
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The reduction of N-hydroxy-α-imino esters with Zn-MsOH in THF afforded α-amino esters in high yields. The reduction of N-hydroxy-α-iminocarbonyl-oligopeptide methyl esters prepared from L-phenylalanine and L-leucine di-, tri-, tetrapeptides gave the corre
- Kise, Naoki,Takaoka, Shuji,Yamauchi, Masahiro,Ueda, Nasuo
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- A new class of α-ketoamide derivatives with potent anticancer and anti-SARS-CoV-2 activities
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Inhibitors of the proteasome have been extensively studied for their applications in the treatment of human diseases such as hematologic malignancies, autoimmune disorders, and viral infections. Many of the proteasome inhibitors reported in the literature target the non-primed site of proteasome's substrate binding pocket. In this study, we designed, synthesized and characterized a series of novel α-keto phenylamide derivatives aimed at both the primed and non-primed sites of the proteasome. In these derivatives, different substituted phenyl groups at the head group targeting the primed site were incorporated in order to investigate their structure-activity relationship and optimize the potency of α-keto phenylamides. In addition, the biological effects of modifications at the cap moiety, P1, P2 and P3 side chain positions were explored. Many derivatives displayed highly potent biological activities in proteasome inhibition and anticancer activity against a panel of six cancer cell lines, which were further rationalized by molecular modeling analyses. Furthermore, a representative α-ketoamide derivative was tested and found to be active in inhibiting the cellular infection of SARS-CoV-2 which causes the COVID-19 pandemic. These results demonstrate that this new class of α-ketoamide derivatives are potent anticancer agents and provide experimental evidence of the anti-SARS-CoV-2 effect by one of them, thus suggesting a possible new lead to develop antiviral therapeutics for COVID-19.
- An, Jing,Chen, Yiling,Ciechanover, Aaron,Fuk-Woo Chan, Jasper,Huang, Lina S.,Huang, Ziwei,Liang, Boqiang,Nie, Linlin,Wang, Juan,Warshel, Arieh,Wu, Meixian,Wu, Yi,Xu, Yan,Ye, Hui,Yuan, Shuofeng,Yuen, Kwok-Yung,Zhou, Jiao
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- Structure-Based Design of Inhibitors Selective for Human Proteasome β2c or β2i Subunits
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Subunit-selective proteasome inhibitors are valuable tools to assess the biological and medicinal relevance of individual proteasome active sites. Whereas the inhibitors for the β1c, β1i, β5c, and β5i subunits exploit the differences in the substrate-binding channels identified by X-ray crystallography, compounds selectively targeting β2c or β2i could not yet be rationally designed because of the high structural similarity of these two subunits. Here, we report the development, chemical synthesis, and biological screening of a compound library that led to the identification of the β2c- and β2i-selective compounds LU-002c (4; IC50 β2c: 8 nM, IC50 β2i/β2c: 40-fold) and LU-002i (5; IC50 β2i: 220 nM, IC50 β2c/β2i: 45-fold), respectively. Co-crystal structures with β2 humanized yeast proteasomes visualize protein-ligand interactions crucial for subunit specificity. Altogether, organic syntheses, activity-based protein profiling, yeast mutagenesis, and structural biology allowed us to decipher significant differences of β2 substrate-binding channels and to complete the set of subunit-selective proteasome inhibitors.
- Xin, Bo-Tao,Huber, Eva M.,De Bruin, Gerjan,Heinemeyer, Wolfgang,Maurits, Elmer,Espinal, Christofer,Du, Yimeng,Janssens, Marissa,Weyburne, Emily S.,Kisselev, Alexei F.,Florea, Bogdan I.,Driessen, Christoph,Van Der Marel, Gijsbert A.,Groll, Michael,Overkleeft, Herman S.
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supporting information
p. 1626 - 1642
(2019/02/19)
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- Potent and Highly Selective Inhibitors of the Proteasome Trypsin-like Site by Incorporation of Basic Side Chain Containing Amino Acid Derived Sulfonyl Fluorides
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A unique category of basic side chain containing amino acid derived sulfonyl fluorides (SFs) has been synthesized for incorporation into new proteasome inhibitors targeting the trypsin-like site of the 20S proteasome. Masking the former α-amino functionality of the amino acid starting derivatives as an azido functionality allowed an elegant conversion to the corresponding amino acid derived sulfonyl fluorides. The inclusion of different SFs at the P1 site of a proteasome inhibitor resulted in 14 different peptidosulfonyl fluorides (PSFs) having a high potency and an excellent selectivity for the proteolytic activity of the β2 subunit over that of the β5 subunit. The results of this study strongly indicate that a free N-terminus of PSFs inhibitors is crucial for high selectivity toward the trypsin-like site of the 20S proteasome. Nevertheless, all compounds are slightly more selective for inhibition of the constitutive over the immunoproteasome.
- Artschwager, Raik,Ward, David J.,Gannon, Susan,Brouwer, Arwin J.,Van De Langemheen, Helmus,Kowalski, Hubert,Liskamp, Rob M. J.
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supporting information
p. 5395 - 5411
(2018/05/30)
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- Divergent Stereoselectivity in Phosphothreonine (pThr)-Catalyzed Reductive Aminations of 3-Amidocyclohexanones
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Phosphothreonine (pThr)-embedded peptide catalysts are found to mediate the reductive amination of 3-amidocyclohexanones with divergent selectivity. The choice of peptide sequence can be used to alter the diastereoselectivity to favor either the cis-product or trans-product, which are obtained in up to 93:7 er. NMR studies and DFT calculations are reported and indicate that both pathways rely on secondary interactions between substrate and catalyst to achieve selectivity. Furthermore, catalysts appear to accomplish a parallel kinetic resolution of the substrates. The facility for phosphopeptides to tune reactivity and access multiple products in reductive aminations may translate to the diversification of complex substrates, such as natural products, at numerous reactive sites.
- Shugrue, Christopher R.,Featherston, Aaron L.,Lackner, Rachel M.,Lin, Angela,Miller, Scott J.
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supporting information
p. 4491 - 4504
(2018/04/26)
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- Synthesis and biological evaluation of curcumin derivatives with water-soluble groups as potential antitumor agents: An in vitro investigation using tumor cell lines
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Three series of curcumin derivatives including phosphorylated, etherified, and esterified products of curcumin were synthesized, and their anti-tumor activities were assessed against human breast cancer MCF-7, hepatocellular carcinoma Hep-G2, and human cervical carcinoma HeLa cells. Compared with curcumin, compounds 3, 8, and 9 exhibited stronger antitumor cell line growth activities against HeLa cells. Compound 12 also showed higher antitumor cell line growth activities on MCF-7 cells than curcumin. Among them, 4-((1E,6E)-7-(4-Hydroxy-3-methoxyphenyl)-3,5-dioxohepta-1,6-dienyl)-2-methoxyphenyl dihydrogen phosphate(3) showed the strongest activity with an half maximal inhibitory concentration (IC50) of 6.78 μM against HeLa cells compared with curcumin with an IC50 of 17.67 μM. Stabilities of representatives of the three series were tested in rabbit plasma in vitro, and compounds 3 and 4 slowly released curcumin inplasma. The effect of compound 3 on HeLa cell apoptosis was determined by examining morphological changes by DAPI (4′,6-diamidino-2-phenylindole) staining as well as Annexin V-FITC/Propidium Iodide (PI) double staining and flow cytometry. The results showed that 3 induced cellular apoptosis in a dose-dependent manner. Together our findings show that 3 merits further investigation as a new potential antitumor drug candidate.
- Ding, Luyang,Ma, Shuli,Lou, Hongxiang,Sun, Longru,Ji, Mei
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p. 21501 - 21514
(2016/01/25)
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- Additivity or cooperativity: Which model can predict the influence of simultaneous incorporation of two or more functionalities in a ligand molecule?
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Predicting how binding affinity responds to ligand structural modifications in structure-activity relationship studies (SAR) is a major challenge in medicinal chemistry. This is particularly true when two or more of these modifications are carried out simultaneously. In this study, we present binding affinity data from several series of thermolysin inhibitors in which simultaneous structural modifications were investigated to determine whether they are cooperative or additive. Data revealed that, while additivity is at work in some cases, cooperativity is more commonly demonstrated. Cooperativity and additivity were then correlated with ligand descriptors, such as the spacing and the topological features of the modified groups, in a manner that may provide guidance as to when each model should be utilized. Cooperativity was particularly associated with contiguous groups and small unbranched hydrophobic side chain. Additivity, on the other hand, was associated with moderately distant hydrophobic group combinations and side chain branching. Such correlations can improve the predictability of SAR studies and can provide a starting point for additional investigations that may lead to further significant enhancements in the current scoring functions.
- Nasief, Nader N.,Hangauer, David
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p. 897 - 915
(2015/05/27)
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- Influence of neighboring groups on the thermodynamics of hydrophobic binding: An added complex facet to the hydrophobic effect
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The thermodynamic consequences of systematic modifications in a ligand side chain that binds in a shallow hydrophobic pocket, in the presence and absence of a neighboring ligand carboxylate group, were evaluated using isothermal titration calorimetry (ITC
- Nasief, Nader N.,Hangauer, David
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supporting information
p. 2315 - 2333
(2014/04/17)
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- Dissecting the hydrophobic effect on the molecular level: The role of water, enthalpy, and entropy in ligand binding to thermolysin
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The hydrophobic effect is associated with the successive replacement of water molecules in the binding site of a protein by hydrophobic groups of the ligand. Although the hydrophobic effect is assumed to be entropy-driven, large changes in enthalpy and entropy are observed with the model system thermolysin. Structural changes in the binding features of the water molecules ultimately determine the thermodynamics of the hydrophobic effect. Copyright
- Biela, Adam,Nasief, Nader N.,Betz, Michael,Heine, Andreas,Hangauer, David,Klebe, Gerhard
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supporting information
p. 1822 - 1828
(2013/04/23)
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- Cyclic dipeptides exhibit potency for scavenging radicals
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Twenty kinds of cyclic dipeptides containing l-leucine were synthesized, and their antioxidant activity against .OH and O2·- was investigated. Compounds possessing polar amino acid residues, such as Asp, Cys, Glu, Lys, Pro, Ser, and Trp, exhibited higher antioxidant activity against .OH than vitamin E. However, only cyclo(l-Cys-l-Leu) scavenged O2·-.
- Furukawa, Tadashi,Akutagawa, Takashi,Funatani, Hitomi,Uchida, Toshikazu,Hotta, Yoshihiro,Niwa, Masatake,Takaya, Yoshiaki
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experimental part
p. 2002 - 2009
(2012/05/04)
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- Isolation, structure elucidation and total synthesis of lajollamide a from the marine fungus Asteromyces cruciatus
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The marine-derived filamentous fungus Asteromyces cruciatus 763, obtained off the coast of La Jolla, San Diego, USA, yielded the new pentapeptide lajollamide A (1), along with the known compounds regiolone (2), hyalodendrin (3), gliovictin (4), 1N-norgliovicitin (5), and bis-N-norgliovictin (6). The planar structure of lajollamide A (1) was determined by Nuclear Magnetic Resonance (NMR) spectroscopy in combination with mass spectrometry. The absolute configuration of lajollamide A (1) was unambiguously solved by total synthesis which provided three additional diastereomers of 1 and also revealed that an unexpected acid-mediated partial racemization (2:1) of the L-leucine and L-N-Me-leucine residues occurred during the chemical degradation process. The biological activities of the isolated metabolites, in particular their antimicrobial properties, were investigated in a series of assay systems.
- Gulder, Tobias A. M.,Hong, Hanna,Correa, Jhonny,Egereva, Ekaterina,Wiese, Jutta,Imhoff, Johannes F.,Gross, Harald
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p. 2912 - 2935
(2013/02/23)
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- Design and synthesis of Hsp90 inhibitors: Exploring the SAR of Sansalvamide A derivatives
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Utilizing the structure-activity relationship we have developed during the synthesis of the first two generations and mechanism of action studies that point to the interaction of these molecules with the key oncogenic protein Hsp90, we report here the design of 32 new Sansalvamide A derivatives and their synthesis. Our new structures, designed from previously reported potent compounds, were tested for cytotoxicity on the HCT116 colon cancer cell line, and their binding to the biological target was analyzed using computational studies involving blind docking of derivatives using Autodock. Further, we show new evidence that our molecules bind directly to Hsp90 and modulate Hsp90's binding with client proteins. Finally, we demonstrate that we have integrated good ADME properties into a new derivative.
- Sellers, Robert P.,Alexander, Leslie D.,Johnson, Victoria A.,Lin, Chun-Chieh,Savage, Jeremiah,Corral, Ricardo,Moss, Jason,Slugocki, Tim S.,Singh, Erinprit K.,Davis, Melinda R.,Ravula, Suchitra,Spicer, Jamie E.,Oelrich, Jenna L.,Thornquist, Andrea,Pan, Chung-Mao,McAlpine, Shelli R.
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experimental part
p. 6822 - 6856
(2010/10/18)
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- Synthesis of substituted imidazolidin-2-ones as aminoacyl-tRNA synthase inhibitors
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Substituted imidazolidin-2-ones deduced as potential inhibitors of IleRS by docking simulations were synthesized from an aziridine-2-carboxaldehyde. Reductive amination of an aziridine-2-carboxaldehyde with dipeptides for the substituents at N1 and followed by aziridine-ring expansion with triphosgene afforded 4-chloromethylimidazolidin-2-ones whose chloride were further manipulated towards phenylurea, pyrimidin-2-yl-urea or benzenesulfonamide at C4.
- Eum, Heesung,Lee, Yuno,Kim, Songmi,Baek, Ayoung,Son, Minky,Lee, Keun Woo,Ko, Seung Whan,Kim, Sunghoon,Yun, Sae Young,Lee, Won Koo,Ha, Hyun-Joon
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experimental part
p. 611 - 614
(2010/08/06)
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- A comprehensive study of Sansalvamide A derivatives: The structure-activity relationships of 78 derivatives in two pancreatic cancer cell lines
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We report an extensive structure-activity relationship (SAR) of 78 compounds active against two pancreatic cancer cell lines. Our comprehensive evaluation of these compounds utilizes SAR that allow us to evaluate which features of potent compounds play a
- Pan, Po-Shen,Vasko, Robert C.,Lapera, Stephanie A.,Johnson, Victoria A.,Sellers, Robert P.,Lin, Chun-Chieh,Pan, Chung-Mao,Davis, Melinda R.,Ardi, Veronica C.,McAlpine, Shelli R.
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experimental part
p. 5806 - 5825
(2009/12/24)
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- Comprehensive study of sansalvamide A derivatives and their structure-activity relationships against drug-resistant colon cancer cell lines
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We report an extensive structure-activity relationship (SAR) of 62 compounds active against two drug-resistant colon cancer cell lines. Our comprehensive evaluation of two generations of compounds utilizes SAR, NMR, and molecular modeling to evaluate the
- Otrubova, Katerina,Lushington, Gerald,Vander Velde, David,McGuire, Kathleen L.,McAlpine, Shelli R.
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p. 530 - 544
(2008/09/18)
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- Isomeric control of protein recognition with amino acid- And dipeptide-functionalized gold nanoparticles
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Amino acid and dipeptide-functionalized gold nanoparticles (NPs) possessing L/D-leucine and/or L/D-phenylalanine residues have been constructed in order to target the surfaces of α-chymotrypsin (ChT) and cytochrome c (CytC). Isothermal titration calorimet
- You, Chang-Cheng,Agasti, Sarit S.,Rotello, Vincent M.
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p. 143 - 150
(2008/09/18)
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- Synthesis and cytotoxicity of a new class of potent decapeptide macrocycles
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(Chemical Equation Presented) Described are the syntheses of five decapeptides that are C-2-symmetrical derivatives of the natural product pentapeptide sansalvamide A. Derivatives were made using a succinct convergent synthesis. These analogues share no s
- Davis, Melinda R.,Styers, Thomas J.,Rodriguez, Rodrigo A.,Pan, Po-Shen,Vasko, Robert C.,McAlpine, Shelli R.
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p. 177 - 180
(2008/09/19)
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- MACROCYCLIC PEPTIDES AND METHODS FOR MAKING AND USING THEM
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The invention provides novel macrocyclic peptides and methods for their preparation. The invention also provides pharmaceutical compositions and methods to treat, prevent or ameliorate a cell proliferative disease or conditions, e.g., a cancer, in a subje
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Page/Page column 43
(2008/06/13)
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- Synthesis of second-generation Sansalvamide A derivatives: Novel templates as potential antitumor agents
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We report the synthesis of 34 second-generation Sansalvamide A derivatives. San A derivatives have unique anticancer properties and target multiple cancers, including colon, pancreatic, breast, prostate, and melanoma. As novel templates, the derivatives d
- Rodriguez, Rodrigo A.,Pan, Po-Shen,Pan, Chung-Mao,Ravula, Suchitra,Lapera, Stephanie,Singh, Erinprit K.,Styers, Thomas J.,Brown, Joseph D.,Cajica, Julia,Parry, Emily,Otrubova, Katerina,McAlpine, Shelli R.
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p. 1980 - 2002
(2007/10/03)
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- High-yielding macrocyclization conditions used in the synthesis of novel Sansalvamide A derivatives
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Described are the syntheses of nine Sansalvamide A derivatives using new, high-yielding, in situ deprotection-cyclization conditions that are general for this series of macrocycles, 55% average for both steps. This is 10-fold greater than previously repor
- Styers, Thomas J.,Rodriguez, Rodrigo,Pan, Po-Shen,McAlpine, Shelli R.
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p. 515 - 517
(2007/10/03)
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- Synthesis of Sansalvamide A derivatives and their cytotoxicity in the MSS colon cancer cell line HT-29
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We report the synthesis of thirty-six Sansalvamide A derivatives, and their biological activity against colon cancer HT-29 cell line, a microsatellite stable (MSS) colon cancer cell-line. The thirty-six compounds can be divided into three subsets, where t
- Styers, Thomas J.,Kekec, Ahmet,Rodriguez, Rodrigo,Brown, Joseph D.,Cajica, Julia,Pan, Po-Shen,Parry, Emily,Carroll, Chris L.,Medina, Irene,Corral, Ricardo,Lapera, Stephanie,Otrubova, Katerina,Pan, Chung-Mao,McGuire, Kathleen L.,McAlpine, Shelli R.
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p. 5625 - 5631
(2007/10/03)
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- Synthesis and cytotoxicity of novel Sansalvamide A derivatives
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(Chemical Equation Presented) Described are the syntheses of 14 derivatives of the natural product Sansalvamide A, where two are more active against HCT 116 colon cancer cell lines than the natural product. These derivatives were synthesized using a combi
- Carroll, Chris L.,Johnston, Jennifer V. C.,Kekec, Ahmet,Brown, Joseph D.,Parry, Emily,Cajica, Julia,Medina, Irene,Cook, Kristina M.,Corral, Ricardo,Pan, Po-Shen,McAlpine, Shelli R.
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p. 3481 - 3484
(2007/10/03)
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- A rapid and efficient synthesis of β-casomorphin employing Boc-amino acids and 9-fluorenylmethyl chloroformate as a coupling agent
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The synthesis of β-casomorphin H-Tyr-Pro-Phe-Pro-Gly-OH employing Boc group for Nα-protection and 9-fluorenylmethyl chloroformate (Fmoc-Cl) for the formation of peptide bond is described. The protocol employing Fmoc-Cl as coupling reagent is found to be simple, efficient and rapid. All the intermediate peptides as well as the final protected peptide Boc-Tyr( iBu)-Pro-Phe-Pro-Gly-OMe have been isolated and fully characterized. They have been obtained in good yield and with high purity.
- Babu, V.V. Suresh,Tantry
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p. 2708 - 2712
(2007/10/03)
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- N, N′-Carbonyldisaccharin: A new condensing agent for the synthesis of amides, esters and peptides
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A new, easy to handle and efficient condensing agent N,-N′ -carbonyldisaccharin 2 has been readily synthesised by the reaction of saccharin 1 and trichloromethyl chloroformate in toluene. The condensing agent 2 is demonstrated to be useful for the synthesis of amides, esters and dipeptides under mild conditions in a one-pot procedure.
- Yadav,Dubey, Suman,Singh, Amrish
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p. 2601 - 2603
(2007/10/03)
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- A New and Efficient Synthesis of Unnatural Amino Acids and Peptides by Selective 3,3-Dimethyldioxirane Side-Chain Oxidation
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N-Boc derivatives of Leu, Met, Thr, Trp, and Pro, the properties of which resemble those of the respective α-amino acid residues present in proteins, rapidly oxidize in the presence of 3,3-dimethyldioxirane to give different products depending on the stru
- Saladino, Raffaele,Mezzetti, Maurizio,Mincione, Enrico,Torrini, Ines,Paradisi, Mario Paglialunga,Mastropietro, Gaia
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p. 8468 - 8474
(2007/10/03)
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- Synthesis of a new saccharin derivative (BID-SPy) and its utilization as a condensing reagent in the preparation of dipeptides
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A new saccharin derivative, thiopyridyl-benzisothiazole 1,1-dioxide (BID-SPy, 2), has been prepared by the reaction of BID-Cl (1) and 2-mercaptopyridine, and utilized as a coupling reagent in the synthesis of amides and N-protected dipeptides.
- Ahmed, A,Akhter, H
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p. 564 - 565
(2007/10/02)
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- 4-Acetamidophenyl esters and 4-acetamidoanilides of L-arginine,p-guanidino-L-phenylalanine, L-lysine, N2-[D-fructos-3-O-yl and D-glucos-3-O-yl]acetyl-L-lysine as potential acrosin inhibitors
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Syntheses of4-acetamidophenyl esters and 4-acetamidoanilides of L-lysine,p-guanidino-L-phenylalanine,L-leucyl-L-lysine, L-leucyl-L-leucyl-L-lysine, N 2-[(1-2-O-isopropylidene-α-D-glucofuranos-3-O-yl)acetyl]-L- rysine, N 2-[(1,2-O-iso
- Chrusciel, R. Alan,Bauer, Ludwig,Kaminski, JoAnne M.,Zaneveld, Lourens J. D.
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p. 8831 - 8854
(2007/10/02)
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- Synthesis of hpGRF (Somatocrinin) in liquid phase and intermediate peptides
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The invention relates to synthesis of hpGRF (Somatocrinin) in liquid phase and to intermediate peptides, comprising:--coupling, one after the other and in the order of the sequence of the GRF, the fragments in which: (a) the side acid functions of the aspartic and glutamic acids and the side amine function of the lysine are protected by protector groups stable in the conditions of deprotection of the group Boc, (b) the guanidine function of the arginine is protected by protonation, and (c) the N-terminal amino acid is protected on the amine by the Boc group;--selectively eliminating the group Boc from the N-terminal amine of the peptide in phase of elongation by hydrolysis with trifluoroacetic acid, said coupling being effected in an aprotic polar solvent and--eliminating, at the end of sequence, all the protector groups by hydrolysis with the aid of a 0.1 to 1M solution of methanesulfonic or trifluoromethanesulfonic acid in trifluoroacetic acid.
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- 3,3'-(Phenylphosphinylidene)bis and 3,3'-(Phenylphosphinylidene)bis. New Activating Agents
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New activating agents, 3,3'-(phenylphophinylidene)bis (4) and 3,3'-(phenylphosphinylidene)bis (5), were readily prepared by the reaction of phenylphosphonic dichloride (3) with 2(3H)-benzoxazolone (1) and 2(3H)-benzothiazolone (2) respectively in the presence of triethylamine at room temperature.The new activating agents 4 and 5 were found to be useful for the preparation of amides, esters, and dipeptides under mild conditions.Furthemore, the direct polycondensation of isophthalic acid with aromatic diamines using the activating agent 4 in the presence of pyridine proceeded fast at room temperature to produce polyamides with inherent viscosities up to 0.80 dL/g.
- Ueda, Mitsuru,Mochizuki, Amane,Hiratsuka, Ichiro,Oikawa, Hideaki
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p. 3291 - 3297
(2007/10/02)
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- 1,2-Benzisoxazol-3-yl Diphenyl Phosphate: A New, Reactive Activating Agent for the Synthesis of Amides, Esters, and Peptides via Condensation
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A new activating agent for condensations, 1,2-benzisoxazol-3-yl diphenyl phosphate (1), was readily prepared in high yield by the reaction of 1,2-benzisoxazol-3-ol (2) with diphenyl phosphorochloridate (3) in the presence of triethylamine in benzene.The reaction of the carboxylic acids with the amines in the presence of 1 was investigated by two procedures, a two-step method and a one-step procedure.Both methods gave the corresponding amides and esters in high yields under mild conditions, but the one-step procedure was found to be superior to the two-step procedure because of its simplicity and speed.Furthermore, the activating agent 1 was shown to be a useful peptide forming reagent.
- Ueda, Mitsuru,Oikawa, Hideaki
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p. 760 - 763
(2007/10/02)
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- THE SYNTHESIS OF AMIDES, ESTERS, AND THIOESTERS
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Diethyl 2-(3-oxo-2,3-dihydro-1,2-benzisosulfonazolyl)phosphonate is a highly reactive condensing agent, which provides good yield route to amides, esters, and thioesters from a variety of amines, active hydroxylamines, and thiols and acids.
- Miyake, Muneharu,Kirisawa, Makoto,Tokutake, Norio
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p. 123 - 126
(2007/10/02)
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- 2(3H)-BENZOXAZOLETHIONE.
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A new condensing agent, N,N prime -carbonyldi left bracket 2(3H)-benzoxazolethione right bracket , was readily prepared by the reaction of 2-benzoxazolethiol and trichloromethyl chloroformate in benzene. The condensing agent is shown to be useful for the preparation of amides, esters, and dipeptides under mild conditions. A successful polyamide synthesis by the polycondensation of isophthalic acid with diamines using the condensing agent is also described.
- Ueda,Kawaharasaki,Imai
-
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- A New and Effective Synthetic Method for the Preparation of the Esters, Peptides, and Lactones Using 3-(5-Nitro-2-oxo-1,2-dihydro-1-pyridyl)-1,2-benzisothiazole 1,1-Dioxide. Synthesis of (+/-)-E-Dodecen-11-olide, Recifeiolide
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3-(5-nitro-2-oxo-1,2-dihydro-1-pyridyl)-1,2-benzisothiazole 1,1-dioxide (BID-NPy), readily prepared from 3-chloro-1,2-benzisothiazole 1,1-dioxide and 5-nitro-2-pyridone, proved to be a very useful condensing reagent.A variety of esters, dipeptides, and lactones were obtained in excellent yields.Furthemore, BID-NPy was successfully employed for the lactonization step in a new synthesis of a naturally occuring (+/-)-(E)-8-dodecen-11-olide, recifeiolide.
- Ahmed, Alauddin,Taniguchi, Nagahiro,Fukuda, Hirohiko,Kinoshita, Hideki,Inomata, Katsuhiko,Kotake, Hiroshi
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p. 781 - 786
(2007/10/02)
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- Facile Synthesis of Cyclic Dipeptides and Detection of Racemization
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Several cyclic dipeptides were synthesized by refluxing methanolic solution of dipeptide methyl esters in high yield and purity.Cyclic dipeptides prepared by the Fischer method, the Nitecki method, and the present methanol-reflux method were compared with
- Ueda, Toshihisa,Saito, Morinobu,Kato, Tetsuo,Izumiya, Nobuo
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p. 568 - 572
(2007/10/02)
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- 1,2-BENZISOXAZOL-3(2H)-ONE.
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A new condensing agent, N,N prime -carbonyldi left bracket 1,2-benzisoxazol-3(2H)-one right bracket (6), was readily prepared by the reaction of 1,2-benzisoxazol-3-ol and trichloromethyl chloroformate in toluene. The condensing agent 6 was shown to be very useful for the preparation of amides, esters, and dipeptides under mild conditions. A successful polyamide synthesis by one-pot polycondensation of isophthalic acid with diamines using 6 is also described.
- Ueda,Oikawa,Kawaharasaki,Imai
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p. 2485 - 2489
(2007/10/02)
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- Synthesis of N-Pyridoylamino Acid and Peptide Derivatives with Antitubercular Activity: Part II - Optically Active N-Nicotinoyl Dipeptide Derivatives
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A series of optically active N-nicotinoyl dipeptide derivatives including methyl and ethyl esters, hydrazides, hydrazones and free acids have been synthesized and screened for their in-vitro activity against the virulent strain Mycobacterium tuberculosis
- Abou Ghalia, M. H.,Salem, Ezzeldin M.
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p. 135 - 138
(2007/10/02)
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- 3-(5-NITRO-2-PYRIDON-1-YL)-1,2-BENZOISOTHIAZOLE 1,1-DIOXIDE (BID-NPy) AS A NEW EFFECTIVE CONDENSING REAGENT
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3-(5-Nitro-2-pyridon-1-yl)-1,2-benzoisothiazole 1,1-dioxide (BID-NPy) was found to be a useful condensing reagent.Various dipeptides and esters were prepared in good yields using this reagent.
- Ahmed, Alauddin,Fukuda, Hirohiko,Inomata, Katsuhiko,Kotake, Hiroshi
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p. 1161 - 1164
(2007/10/02)
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