- Application of triazenes for protection of secondary amines
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Use of the phenyldiazenyl group, which serves as a protecting group for secondary amines is described in detail. The triazene protected amine is compatible with oxidative and reductive conditions as well as with strong bases (LDA, tert-butyllithium) and alkylating reagents. The amine is regenerated by action of trifluoroacetic acid and a suitable reducing agent (EtOH or NaH2PO2).
- Lazny, Ryszard,Sienkiewicz, Michal,Br?se, Stefan
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Read Online
- Discovery of Novel Apigenin-Piperazine Hybrids as Potent and Selective Poly (ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors for the Treatment of Cancer
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Poly (ADP-ribose) polymerase-1 (PARP-1) is a potential target for the discovery of chemosensitizers and anticancer drugs. Amentoflavone (AMF) is reported to be a selective PARP-1 inhibitor. Here, structural modifications and trimming of AMF have led to a series of AMF derivatives (9a-h) and apigenin-piperazine/piperidine hybrids (14a-p, 15a-p, 17a-h, and 19a-f), respectively. Among these compounds, 15l exhibited a potent PARP-1 inhibitory effect (IC50 = 14.7 nM) and possessed high selectivity to PARP-1 over PARP-2 (61.2-fold). Molecular dynamics simulation and the cellular thermal shift assay revealed that 15l directly bound to the PARP-1 structure. In in vitro and in vivo studies, 15l showed a potent chemotherapy sensitizing effect against A549 cells and a selective cytotoxic effect toward SK-OV-3 cells through PARP-1 inhibition. 15l·2HCl also displayed good ADME characteristics, pharmacokinetic parameters, and a desirable safety margin. These findings demonstrated that 15l·2HCl may serve as a lead compound for chemosensitizers and the (BRCA-1)-deficient cancer therapy.
- Long, Huan,Hu, Xiaolong,Wang, Baolin,Wang, Quan,Wang, Rong,Liu, Shumeng,Xiong, Fei,Jiang, Zhenzhou,Zhang, Xiao-Qi,Ye, Wen-Cai,Wang, Hao
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p. 12089 - 12108
(2021/09/06)
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- Design, synthesis and SAR of antitubercular benzylpiperazine ureas
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Abstract: N-furfuryl piperazine ureas disclosed by scientists at GSK Tres Cantos were chosen as antimycobacterial hits from a phenotypic whole-cell screen. Bioisosteric replacement of the furan ring in the GSK Tres Cantos molecules with a phenyl ring led to molecule (I) with an MIC of 1?μM against Mtb H37Rv, low cellular toxicity (HepG2 IC50 ~ 80?μM), good DMPK properties and specificity for Mtb. With the aim of delineating the SAR associated with (I), fifty-five analogs were synthesized and screened against Mtb. The SAR suggests that the piperazine ring, benzyl urea and piperonyl moieties are essential signatures of this series. Active compounds in this series are metabolically stable, have low cellular toxicity and are valuable leads for optimization. Molecular docking suggests these molecules occupy the Q0 site of QcrB like Q203. Graphic Abstract: Bioisosteric replacement of N-furfuryl piperazine-1-carboxamides yielded molecule (I) a novel lead with satisfactory PD, metabolism, and toxicity profiles.[Figure not available: see fulltext.]
- Satish, Sohal,Chitral, Rohan,Kori, Amitkumar,Sharma, Basantkumar,Puttur, Jayashree,Khan, Afreen A.,Desle, Deepali,Raikuvar, Kavita,Korkegian, Aaron,Martis, Elvis A. F.,Iyer, Krishna R.,Coutinho, Evans C.,Parish, Tanya,Nandan, Santosh
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- Synthesis and Evaluation of Bifunctional Aminothiazoles as Antiretrovirals Targeting the HIV-1 Nucleocapsid Protein
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Small molecule inhibitors of the HIV-1 nucleocapsid protein (NC) are considered as promising agents in the treatment of HIV/AIDS. In an effort to exploit the privileged 2-amino-4-phenylthiazole moiety in NC inhibition, here we conceived, synthesized, and tested in vitro 18 NC inhibitors (NCIs) bearing a double functionalization. In these NCIs, one part of the molecule is deputed to interact noncovalently with the NC hydrophobic pocket, while the second portion is designed to interact with the N-terminal domain of NC. This binding hypothesis was verified by molecular dynamics simulations, while the linkage between these two pharmacophores was found to enhance antiretroviral activity both on the wild-type virus and on HIV-1 strains with resistance to currently licensed drugs. The two most interesting compounds 6 and 13 showed no cytotoxicity, thus becoming valuable leads for further investigations.
- Mori, Mattia,Dasso Lang, Maria Chiara,Saladini, Francesco,Palombi, Nastasja,Kovalenko, Lesia,De Forni, Davide,Poddesu, Barbara,Friggeri, Laura,Giannini, Alessia,Malancona, Savina,Summa, Vincenzo,Zazzi, Maurizio,Mely, Yves,Botta, Maurizio
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supporting information
p. 463 - 468
(2019/04/25)
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- 2,2,6,6-Tetramethylpiperidin-1-yloxycarbonyl: A Protecting Group for Primary, Secondary, and Heterocyclic Amines
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The 2,2,6,6-tetramethylpiperidin-1-yloxycarbonyl (Tempoc) protecting group is readily introduced by the reaction of amines with a new acyl transfer reagent, 4-nitrophenyl (2,2,6,6-tetramethylpiperidin-1-yl) carbonate (NPTC). Tempoc has a reactivity profile that complements the commonly used t-butyloxycarbonyl (Boc) and benzyloxycarbonyl (Cbz) protecting groups. Deprotection can be achieved under mild reductive conditions with in situ generated Cu(I) species or by thermolytic cleavage at 135 °C. Mechanistic studies on the deprotection of Tempoc-indole suggest a combination of ionic and radical fragmentation pathways under thermal conditions.
- Lizza, Joseph R.,Bremerich, Maximilian,McCabe, Stephanie R.,Wipf, Peter
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supporting information
p. 6760 - 6764
(2018/10/25)
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- BENZIMIDAZOL DERIVATIVES FOR TREATING FILOVIRUS INFECTION
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The present invention relates to compounds comprising a benzimidazole scaffold, and the use of such compounds for the treatment of viral diseases. The invention also relates to pharmaceutical compositions comprising said compounds as an active ingredient. In particular the compounds of the invention comprising a benzimidazole scaffold are used for the treatment of filoviruses or retroviruses, and preferably for the treatment of Ebola virus or HIV virus.
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Page/Page column 21; 22
(2018/04/13)
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- Unlocking the potential of phenacyl protecting groups: CO2-based formation and photocatalytic release of caged amines
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Orthogonal protection and deprotection of amines remain important tools in synthetic design as well as in chemical biology and material research applications. A robust, highly efficient, and sustainable method for the formation of phenacyl-based carbamate esters was developed using CO2 for the in situ preparation of the intermediate carbamates. Our mild and broadly applicable protocol allows for the formation of phenacyl urethanes of anilines, primary amines, including amino acids, and secondary amines in high to excellent yields. Moreover, we demonstrate the utility by a mild and convenient photocatalytic deprotection protocol using visible light. A key feature of the [Ru(bpy)3](PF6)2-catalyzed method is the use of ascorbic acid as reductive quencher in a neutral, buffered, two-phase acetonitrile/water mixture, granting fast and highly selective deprotection for all presented examples.
- Speckmeier, Elisabeth,Klimkait, Michael,Zeitler, Kirsten
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p. 3738 - 3745
(2018/04/14)
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- VICINAL PRIMARY DIAMINES ASSOCIATED WITH METAL AND/OR FREE RADICAL CHELATION MOTIFS, AND ACTIVE AGAINST CARBONYL AND OXIDATIVE STRESS, AND USE THEREOF
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The invention relates to compounds of Formula I: or the salts thereof, as well as the use thereof in the pharmaceutical, cosmetic or agrofood industry.
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- Discovery of 2-substituted 1H-benzo[d]immidazole-4-carboxamide derivatives as novel poly(ADP-ribose)polymerase-1 inhibitors with in?vivo anti-tumor activity
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Novel 1H-benzo[d]immidazole-4-carboxamide derivatives bearing five-membered or six-membered N-heterocyclic moieties at the 2-position were designed and synthesized as PARP-1 inhibitors. Structure-activity relationships were conducted and led to a number of potent PARP-1 inhibitors having IC50 values in the single or double digit nanomolar level. Some potent PARP-1 inhibitors also had similar inhibitory activities against PARP-2. Among all the synthesized compounds, compound 10a and 11e displayed strong potentiation effects on temozolomide (TMZ) in MX-1?cells (PF50?=?7.10, PF50?=?4.17). In?vivo tumor growth inhibition was investigated using compound 10a in combination with TMZ, and it was demonstrated that compound 10a could strongly potentiate the cytotoxicity of TMZ in MX-1 xenograft tumor model. Two co-crystal structures of compounds 11b and 15e complexed with PARP-1 were achieved and demonstrated a unique binding mode of these benzo-imidazole derivatives.
- Zhou, Jie,Ji, Ming,Zhu, Zhixiang,Cao, Ran,Chen, Xiaoguang,Xu, Bailing
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supporting information
p. 26 - 41
(2017/03/23)
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- Development of potent and selective tissue transglutaminase inhibitors: Their effect on TG2 function and application in pathological conditions
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Potent-selective peptidomimetic inhibitors of tissue transglutaminase (TG2) were developed through a combination of protein-ligand docking and molecular dynamic techniques. Derivatives of these inhibitors were made with the aim of specific TG2 targeting to the intra- and extracellular space. A cell-permeable fluorescently labeled derivative enabled detection of in situ cellular TG2 activity in human umbilical cord endothelial cells and TG2-transduced NIH3T3 cells, which could be enhanced by treatment of cells with ionomycin. Reaction of TG2 with this fluorescent inhibitor in NIH3T3 cells resulted in loss of binding of TG2 to cell surface syndecan-4 and inhibition of translocation of the enzyme into the extracellular matrix, with a parallel reduction in fibronectin deposition. In human umbilical cord endothelial cells, this same fluorescent inhibitor also demonstrated a reduction in fibronectin deposition, cell motility, and cord formation in Matrigel. Use of the same inhibitor in a mouse model of hypertensive nephrosclerosis showed over a 40% reduction in collagen deposition.
- Badarau, Eduard,Wang, Zhuo,Rathbone, Dan L.,Costanzi, Andrea,Thibault, Thomas,Murdoch, Colin E.,El Alaoui, Said,Bartkeviciute, Milda,Griffin, Martin
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p. 1347 - 1361
(2015/12/26)
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- Practical and cost-effective manufacturing route for the synthesis of a β-lactamase inhibitor
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Compound 1, a potent and irreversible inhibitor of β-lactamases, is in clinical trials with β-lactam antibiotics for the treatment of serious and antibiotic-resistant bacterial infections. A short, scalable, and cost-effective route for the production of this densely functionalized polycyclic molecule is described.
- Miller, Steven P.,Zhong, Yong-Li,Liu, Zhijian,Simeone, Michael,Yasuda, Nobuyoshi,Limanto, John,Chen, Zheng,Lynch, Joseph,Capodanno, Vincent
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supporting information
p. 174 - 177
(2014/01/23)
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- Selective cleavage of 3,5-bis-(trifluoromethyl)benzylcarbamate by SmI 2-Et3N-H2O
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A novel electron poor protection group for amines has been developed. It undergoes rapid cleavage by SmI2-Et3N-H2O and its orthogonality towards the regular benzyl carbamate group (CBz) under reductive or transfer hydrogenolytic conditions is reported.
- Ankner, Tobias,Said Stalsmeden, Anna,Hilmersson, Goeran
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p. 6867 - 6869
(2013/07/26)
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- Aminolysis of benzyl 2-pyridyl thionocarbonate and t-butyl 2-pyridyl thionocarbonate: Effects of nonleaving groups on reactivity and reaction mechanism
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A kinetic study is reported for nucleophilic substitution reactions of benzyl 2-pyridyl thionocarbonate (5b) and t-butyl 2-pyridyl thionocarbonate (6b) with a series of alicyclic secondary amines in H2O at 25.0 °C. Generalbase catalysis, which has often been reported to occur for aminolysis of esters possessing a C=S electrophilic center, is absent for the reactions of 5b and 6b. The Bronsted-type plots for the reactions of 5b and 6b are linear with ssnuc = 0.29 and 0.43, respectively, indicating that the reactions of 5b proceed through a stepwise mechanism with formation of a zwitterionic tetrahedral intermediate (T±) being the rate-determining step while those of 6b proceed through a concerted mechanism. The reactivity of 5b and 6b is similar to that of their oxygen analogues (i.e., benzyl 2-pyridyl carbonate 5a and t-butyl 2-pyridyl carbonate 6a, respectively), indicating that the effect of modification of the electrophilic center from C=O to C=S (i.e., from 5a to 5b and from 6a to 6b) on reactivity is insignificant. In contrast, 6b is much less reactive than 5b, indicating that the replacement of the PhCH2 in 5b by the t-Bu in 6b results in a significant decrease in reactivity as well as a change in the reaction mechanism (i.e., from a stepwise mechanism to a concerted pathway). It has been concluded that the contrasting reactivity and reaction mechanism for the reactions of 5b and 6b are not due to the electronic effects of PhCH2 and t-Bu but are caused by the large steric hindrance exerted by the bulky t-Bu in 6b.
- Kim, Min-Young,Lee, Jae-In,Um, Ik-Hwan
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p. 1115 - 1119
(2013/07/28)
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- Unsymmetrical tetrasubstituted ureas from tertiary carbamoylimidazole: Activation by AlMe3
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An efficient and general method for the synthesis of unsymmetrical tetrasubstituted ureas from carbamoylimidazole is described. The conversion is achieved by the concurrent quarternization of the imidazole nitrogen and activation of amines with AlMe3. The Royal Society of Chemistry 2012.
- Velavan,Sumathi,Balasubramanian
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supporting information; experimental part
p. 6420 - 6431
(2012/09/05)
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- Aminolysis of benzyl 4-pyridyl carbonate in acetonitrile: Effect of modification of leaving group from 2-pyridyloxide to 4-pyridyloxide on reactivity and reaction mechanism
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A kinetic study is reported for nucleophilic substitution reactions of benzyl 4-pyridyl carbonate 6 with a series of alicyclic secondary amines in MeCN. The plot of pseudo-first-order rate constant (kobsd) vs. [amine] curves upward, which is typical for reactions reported previously to proceed through a stepwise mechanism with two intermediates (i.e., a zwitterionic tetrahedral intermediate T± and its deprotonated form T-). Dissection of kobsd into the second-and third-order rate constants (i.e., Kk2 and Kk3, respectively) reveals that Kk3 is significantly larger than Kk2, indicating that the reactions proceed mainly through the deprotonation pathway (i.e., the k3 process) in a high [amine] region. This contrasts to the recent report that the corresponding aminolysis of benzyl 2-pyridyl carbonate 5 proceeds through a forced concerted mechanism. An intramolecular H-bonding interaction was suggested to force the reactions of 5 to proceed through a concerted mechanism, since it could accelerate the rate of leaving-group expulsion (i.e., an increase in k2). However, such H-bonding interaction, which could increase k2, is structurally impossible for the reactions of 6. Thus, presence or absence of an intramolecular H-bonding interaction has been suggested to be responsible for the contrasting reaction mechanisms (i.e., a forced concerted mechanism for the reaction of 5 vs. a stepwise mechanism with T± and T-as intermediates for that of 6).
- Bae, Ae Ri,Um, Ik-Hwan
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p. 2719 - 2723
(2012/11/07)
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- Kinetics and reaction mechanism of aminolyses of benzyl 2-pyridyl carbonate and t-butyl 2-pyridyl carbonate in acetonitrile
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Second-order rate constants (kN) have been measured spectrophotometrically for the reactions of benzyl 2- pyridyl carbonate 3 and t-butyl 2-pyridyl carbonate 4 with a series of alicyclic secondary amines in MeCN at 25.0 ± 0.1 ° C. Substrate 4 is much less reactive than 3 and the steric hindrance exerted by the bulky t-Bu group in 4 has been attributed to its decreased reactivity. The Bronsted-type plots for the reactions of 3 and 4 are linear with ssnuc = 0.57 and 0.45, respectively. Thus, the reactions have been concluded to proceed through a concerted mechanism, although the current reactions were expected to proceed through a stepwise mechanism with a zwitterionic tetrahedral intermediate T±. It has been proposed that the rate of leaving-group expulsion is accelerated by the intramolecular H-bonding interaction in T± and the "push" provided by the RO group through the resonance interaction. Thus, the enhanced nucleofugality forces the reactions to proceed through a concerted mechanism. The reactivity-selectivity principle (RSP) is not applicable to the current reaction systems, since the reaction of the less reactive 4 results in a smaller ssnuc than that of the more reactive 3. Steric hindrance exerted by the bulky t-Bu group in 4 has been suggested to be responsible for the failure of the RSP. Copyright
- Bae, Ae Ri,Um, Ik-Hwan
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scheme or table
p. 1547 - 1550
(2012/07/28)
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- Aza-peptidyl michael acceptor and epoxide inhibitors - Potent and selective inhibitors of Schistosoma mansoni and Ixodes ricinus legumains (asparaginyl endopeptidases)
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Aza-peptide Michael acceptors and epoxides with the general structure of YCO-Ala-Ala-AAsn-trans-CH=CHCOR and YCO-Ala-Ala-AAsn-EP-COR, respectively, are shown to be potent inhibitors of asparaginyl endopeptidases (legumains) from the bloodfluke, Schistosoma mansoni (SmAE), and the hard tick, Ixodes ricinus (IrAE). Structure-activity relationships (SARs) were determined for a set of 41 aza-peptide Michael acceptors and eight aza-peptide epoxides. Both enzymes prefer disubstituted amides to monosubstituted amides in the P10 position, and potency increased as we increased the hydrophobicity of the inhibitor in this position. Extending the inhibitor to P5 resulted in increased potency, especially against IrAE, and both enzymes prefer small over large hydrophobic residues at P2. Aza-peptide Michael acceptor inhibitors are more potent than aza-peptide epoxide inhibitors, and for some of these compounds, second-order inhibiton rate constants are the fastest yet discovered. Given the central functions of these enzymes in both parasites, the data presented here may facilitate the eventual design of selective antiparasitic drugs.
- Ovat, Asli,Muindi, Fanuel,Fagan, Crystal,Brouner, Michelle,Hansell, Elizabeth,Dvo?ák, Jan,Sojka, Daniel,Kopá?ek, Petr,McKerrow, James H.,Caffrey, Conor R.,Powers, James C.
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experimental part
p. 7192 - 7210
(2010/07/05)
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- Molecular features of the prazosin molecule required for activation of Transport-P
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Closely related structural analogues of prazosin have been synthesised and tested for inhibition and activation of Transport-P in order to identify the structural features of the prazosin molecule that appear to be necessary for activation of Transport-P. So far, all the compounds tested are less active than prazosin. It is shown that the structure of prazosin appears to be very specific for the activation. Only quinazolines have been found to activate, and the presence of the 6,7-dimethoxy and 4-amino groups appears to be critically important.
- da Silva, Joaquim Fernando Mendes,Walters, Marcus,Al-Damluji, Saad,Ganellin, C. Robin
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p. 7254 - 7263
(2008/12/23)
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- Solid-Phase Assisted N-1 Functionalization of Azamacrocycles
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A simple solid-phase assisted strategy for the N-1 functionalization of azamacrocycles is described. Compounds such as cyclen, cyclam and piperazine can be selectively modified by temporary attachment to solid-phase resins providing an efficient and clean method to prepare biomedically interesting moieteies.
- Oliver, Morag,Jorgensen, Michael R.,Miller, Andrew D.
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p. 453 - 456
(2007/10/03)
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- Macrocyclic compounds and their use
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The subject invention pertains to macrocyclic compounds, and their use, the compounds having the formula (I) wherein X is a ring bearing an optionally-protected functional group or solid phase group R1, Y is a linker optionally bearing an optionally-protected functional group or solid phase group R2, m is at least 3, and each instance of X, Y, R1 and R2 may be the same or different.
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- Inhibitors of hepatitis C virus NS3 protease
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The present invention relates generally to a novel class of pyrimidinones of Formula (I): that are useful as serine protease inhibitors, and more particularly as Hepatitis C virus NS3 protease inhibitors. This invention also relates to pharmaceutical compositions comprising these compounds and methods of using the same.
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- Synthesis of Macrocyclic, Triazine-Based Receptor Molecules
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The synthesis of triazine-based macrocyclic scaffolds is presented. The strategy employed allows for the facile functionalization of the macrocyclic molecules and combinatorial construction of putative receptor molecules. It is shown that the functional groups on the macrocyclic molecules, the size of the rings and the nature of the diamines linking the triazines can all be varied. In addition to the description of the stepwise synthesis of these compounds, it is shown that macrocycles based on triazine and xylenediamine are able to bind pyranosides and cyanuric acid.
- Loewik, Dennis W. P. M.,Lowe, Christopher R.
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p. 2825 - 2840
(2007/10/03)
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- A stepwise synthesis of triazine-based macrocyclic scaffolds
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The synthesis of a non-peptidic triazine-based macrocyclic scaffold is presented. The strategy employed allows for the facile functionalisation of the macrocyclic molecules and combinatorial construction of putative receptor molecules. (C) 2000 Elsevier Science Ltd.
- L?wik, Dennis W. P. M.,Lowe, Christopher R.
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p. 1837 - 1840
(2007/10/03)
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- Selective hydrogenolysis of novel benzyl carbamate protecting groups
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Highly efficient and selective hydrogenolysis of the 2-naphthylmethyl carbamate group (CNAP) in the presence of the 4-trifluoromethylbenzyl carbamate group (CTFB) has been observed for a wide range of substrates.
- Papageorgiou, Edward A.,Gaunt, Matthew J.,Yu, Jin-Quan,Spencer, Jonathan B.
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p. 1049 - 1051
(2007/10/03)
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- Secondary amides of (R)-3,3,3-trifluoro-2-hydroxy-2-methylpropionic acid as inhibitors of pyruvate dehydrogenase kinase
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N'-Methyl-N-(4-tert-butyl-1,2,5,6-tetrahydropyridine)thiourea, SDZ048- 619 (1), is a modest inhibitor (IC50 = 180 μM) of pyruvate dehydrogenase kinase (PDHK). In an optimization of the N-methylcarbothioamide moiety of 1, it was discovered that amides with a small acyl group, in particular appropriately substituted amides of (R)-3,3,3-trifluoro-2-hydroxy-2- methylpropionic acid, are inhibitors of PDHK. Utilizing this acyl moiety, herein is reported the rationale leading to the optimization of a series of acylated piperazine derivatives. Methyl substitution of the piperazine at the 2- and 5-positions (with S and R absolute stereochemistry) markedly increased the potency of the lead compound (> 1000-fold). Oral bioavailability of the compounds in this series is good and is optimal (as measured by AUC) when the 4-position of the piperazine is substituted with an electron-poor benzoyl moiety. (+)-1-N-[2,5-(S,R)-Dimethyl-4-N-(4-cyanobenzoyl)piperazine]-(R)- 3,3,3-trifluoro-2-hydroxy-2-methylpropanamide (14e) inhibits PDHK in the primary enzymatic assay with an IC50 of 16 ± 2 nM, enhances the oxidation of [14C]lactate into 14CO2 in human fibroblasts with an EC50 of 57 ± 13 nM, diminishes lactate significantly 2.5 h post-oral-dose at doses as low as 1 μmol/kg, and increases the ex vivo activity of PDH in muscle, liver, and fat tissues in normal Sprague-Dawley rats. These PDHK inhibitors, however, do not lower glucose in diabetic animal models.
- Aicher, Thomas D.,Anderson, Robert C.,Gao, Jiaping,Shetty, Suraj S.,Coppola, Gary M.,Stanton, James L.,Knorr, Douglas C.,Sperbeck, Donald M.,Brand, Leonard J.,Vinluan, Christine C.,Kaplan, Emma L.,Dragland, Carol J.,Tomaselli, Hollis C.,Islam, Amin,Lozito, Robert J.,Liu, Xilin,Maniara, Wieslawa M.,Fillers, William S.,Dominick Delgrande,Walter, Eric,Mann, William R.
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p. 236 - 249
(2007/10/03)
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- Use of xanthine derivatives for the treatment of nerve damage following an interruption in blood circulation
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Use of xanthine derivatives for the treatment of nerve damage following an interruption in blood circulation. The invention relates to the use of xanthine derivatives of the formula I STR1 in which R2 is a (C1 -C4)-alkyl group and at least one of the symbols R1 and R3 is a radical of the formula II or III STR2 in which A is CHOH, CO or dioxolane, R4 is a hydrogen atom or a (C1 -C4)-alkyl group and n is 0 to 5, and in which R5 and R6 are hydrogen atoms or (C1 -C4)-alkyl groups or, together with the nitrogen atom to which they are bonded, form a 5- to 7-membered ring, it being possible for one carbon atom to be replaced by an oxygen or nitrogen atom, m is 1 or 2 and the other radical R1 or R3, if appropriate, is a hydrogen atom, a (C1 -C6)-alkyl group or a (C3 -C6)-alkenyl group, for the preparation of medicaments for the prophylaxis and treatment of nerve damage following an interruption in blood circulation, and novel xanthine derivatives, and to processes for their preparation.
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- Triazenes: A useful protecting strategy for sensitive secondary amines
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The application of aryl triazene as a protecting group for sensitive secondary amines such as 4-piperidone (2) is described. The triazene protected amine is compatible with oxidative and reductive conditions as well as with lithiating and alkylating reagents. The free amine is regenerated by treatment with trifluoroacetic acid.
- Lazny, Ryszard,Poplawski, Janusz,K?bberling, Johannes,Enders, Dieter,Br?se, Stefan
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p. 1304 - 1306
(2007/10/03)
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- L-selectride as a convenient reagent for the selective cleavage of carbamates
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L-Selectride(R) was shown to selectively cleave methyl carbamates in the presence of more sterically demanding carbamates, including the selective cleavage of a methyl carbamate in the presence of an N-Boc group.
- Coop, Andrew,Rice, Kenner C.
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p. 8933 - 8934
(2007/10/03)
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- pH-Controlled selective protection of polyaza macrocycles
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Piperazine (1), tetraazacyclododecane 3 and pentaazacyclopentadecane 4 react with chloroformates in acid solution to give the selectively protected carbamate derivatives 1a,3a-d, and 4a. The benzyloxycarbonyl derivatives 3d and 4a were alkylated with tertbutyl bromoacetate and removal of the benzyloxycarbonyl protection by catalytic hydrogenation afforded tert-butyl esters 5b and 6b in good yields.
- Kovacs, Zoltan,Sherry, A. Dean
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p. 759 - 763
(2007/10/03)
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- New piperazinylalkylpiperazinedione compounds
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The invention relates to the compounds selected from those of formula I STR1 in which, R1 and R2 form together and with the piperazine-2,6-dione radical to which they are attached a hexahydropyrazinoisoquinolinedione radical, a primidinyl radical or a phenyl radical optionally substituted by an alkyl radical of 1 to 4 carbon atoms or a trifluoromethyl radical, n is an integer from 2 to 4.
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- Anti-leishmanial lepidine derivatives
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The subject 8-[6-(N-heterocyclic-substituted)hexylamino]-6-methoxy lepidineerivatives have the formula: STR1 wherein Z represents methyl or, together with the two contiguous carbon atoms, the benzo moiety of a benzopiperazinyl derivative when Y is --N(R')--, n is an integer from 0 to 2; Y represents --O--, --S--, --S(O)--, --S(O)2 --, and --N(R')--; R' represents hydrogen, alkyl, lower alkyl, R" substituted lower alkyl, cycloalkyl, aryl, sulfonyl, saturated 1,4-diazepinyl, lower alkyl N-cyanocarboximidothioate, or --C(O)R'"; R" represents at least one of hydroxy, alkoxy, aralkoxy, amino, lower alkyl substituted amino, phenyl, halogenated phenyl, or sufonyl; and R'" represents lower alkyl, alkoxy, aralkoxy, amino, lower alkyl substituted amino or aryl substituted amino; and pharmaceutically acceptable salts thereof. These derivatives afford improvement in means for the chemotherapy of leishmaniasis when administered parenterally or orally to infected animals.
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- CYCLOPIPERAZINES: A NEW APPROACH TO CHIRAL MACROCYCLIC RECEPTORS
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The synthesis and preliminary substrate binding properties of a series of piperazine-containing macrocycles are described.
- Larkins, Helen L.,Hamilton, Andrew D.
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p. 2721 - 2724
(2007/10/02)
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