- Urea based foldamers
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N,N′-linked oligoureas are a class of enantiopure, sequence-defined peptidomimetic oligomers without amino acids that form well-defined and predictable helical structures akin to the peptide α-helix. Oligourea-based foldamers combine a number of features—such as synthetic accessibility, sequence modularity, and folding fidelity—that bode well for their use in a range of applications from medicinal chemistry to catalysis. Moreover, it was recently recognized that this synthetic helical backbone can be combined with regular peptides to generate helically folded peptide-oligourea hybrids that display additional features in terms of helix mimicry and protein-surface recognition properties. Here we provide detailed protocols for the preparation of requested monomers and for the synthesis and purification of homo-oligoureas and peptide-oligourea hybrids.
- Yoo, Sung Hyun,Li, Bo,Dolain, Christel,Pasco, Morgane,Guichard, Gilles
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- Design, synthesis, and structure-activity relationship studies of L-amino alcohol derivatives as broad-spectrum antifungal agents
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To discover broad spectrum antifungal agents, two strategies were applied, and a novel class of L-amino alcohol derivatives were designed and synthesized. 3-F substituted compounds 14i, 14n, 14s and 14v exhibited excellent antifungal activities with broad antifungal spectra against C. albicans and C. tropicalis, with MIC values in the range of 0.03–0.06 μg/mL, and against A. fumigatus and C. neoformans, with MIC values in the range of 1–2 μg/mL. Notably, Compounds 14i, 14n, 14s and 14v also displayed moderate activities against fluconazole-resistance strains 17# and CaR that were isolated from AIDS patients. Moreover, only compounds in the S-configuration showed antifungal activity. Preliminary mechanistic studies showed that the potent antifungal activity of compound 14v stemmed from inhibition of C. albicans CYP51. Compounds 14n and 14v were almost nontoxic to mammalian A549 cells, and their stability in human plasma was excellent.
- Zhao, Liyu,Tian, Linfeng,Sun, Nannan,Sun, Yin,Chen, Yixuan,Wang, Xinran,Zhao, Shizhen,Su, Xin,Zhao, Dongmei,Cheng, Maosheng
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p. 374 - 385
(2019/06/05)
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- Synthesis, biological evaluation, and molecular modeling studies of chiral chloroquine analogues as antimalarial agents
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In a focused exploration, we designed, synthesized, and biologically evaluated chiral conjugated new chloroquine (CQ) analogues with substituted piperazines as antimalarial agents. In vitro as well as in vivo studies revealed that compound 7c showed potent activity (in vitro 50% inhibitory concentration, 56.98 nM for strain 3D7 and 97.76 nM for strain K1; selectivity index in vivo [up to at a dose of 12.5 mg/kg of body weight], 3,510) as a new lead antimalarial agent. Other compounds (compounds 6b, 6d, 7d, 7h, 8c, 8d, 9a, and 9c) also showed moderate activity against a CQ-sensitive strain (3D7) and superior activity against a CQ-resistant strain (K1) of Plasmodium falciparum. Furthermore, we carried out docking and three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of all in-house data sets (168 molecules) of chiral CQ analogues to explain the structure-activity relationships (SAR). Our new findings specify the significance of the H-bond interaction with the side chain of heme for biological activity. In addition, the 3D-QSAR study against the 3D7 strain indicated the favorable and unfavorable sites of CQ analogues for incorporating steric, hydrophobic, and electropositive groups to improve the antimalarial activity.
- Kondaparla, Srinivasarao,Debnath, Utsab,Dola, Vasantha Rao,Sinha, Manish,Katti, Seturam B.,Soni, Awakash,Srivastava, Kumkum,Puri, Sunil K.
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- Synthesis, SAR and biological studies of sugar amino acid-based almiramide analogues: N-methylation leads the way
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Leishmaniasis, caused by the protozoan parasites of the genus Leishmania, is one of the most neglected diseases endemic in many continents posing enormous global health threats and therefore the discovery of new antileishmanial compounds is of utmost urgency. The antileishmanial activities of a library of sugar amino acid-based linear lipopeptide analogues were examined with the aim to identify potential drug candidates to treat visceral leishmaniasis. It was found that among the synthesized analogues, most of the permethylated compounds exhibited more activity in in vitro studies against intra-macrophagic amastigotes than the non-methylated analogues. SAR and NMR studies revealed that introduction of the N-methyl groups inhibited the formation of any turn structure in these molecules, which led to their improved activities.
- Das, Dipendu,Khan, Hina P. A.,Shivahare, Rahul,Gupta, Suman,Sarkar, Jayanta,Siddiqui, Mohd. Imran,Ampapathi, Ravi Sankar,Chakraborty, Tushar Kanti
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p. 3337 - 3352
(2017/04/21)
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- Synthesis and biological activity evaluation of dolastatin 10 analogues with N-terminal modifications
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We have described the synthesis of the two complex units (2R,3R,4S)-dolaproine (Dap) and (3R,4S,5S)-dolaisoleuine (Dil) of dolastatin 10 from natural amino acids. The stereoselective syntheses of N-Boc-Dap (4a) and N-Boc-(2S)-iso-Dap (4b) were performed by employing crotylation of N-Boc-L-prolinal as a key step. Barbier-type allylation of N-Boc-L-isoleucinal provided a mild and convenient approach for the synthesis of N-Boc-Dil (5a) and N-Boc-(3S)-iso-Dil (5b). Ten dolastatin 10 analogues have been designed and synthesized with N-terminal modifications based on the known compound monomethylauristatin F (MMAF, 3). In comparison with MMAF (3), four of the compounds showed enhanced potency against HCT 116 human colon cancer cells in?vitro.
- Wang, Xin,Dong, Suzhen,Feng, Dengke,Chen, Yazhou,Ma, Mingliang,Hu, Wenhao
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p. 2255 - 2266
(2017/03/24)
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- Chemo- and Diastereoselective N-Heterocyclic Carbene-Catalyzed Cross-Benzoin Reactions Using N-Boc-α-amino Aldehydes
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N-Boc-α-amino aldehydes are shown to be excellent partners in cross-benzoin reactions with aliphatic or heteroaromatic aldehydes. The chemoselectivity of the reaction and the facial selectivity on the amino aldehyde allow cross-benzoin products to be obtained in good yields and good diastereomeric ratios. The developed method is utilized as the key step in a concise total synthesis of d-arabino-phytosphingosine.
- Haghshenas, Pouyan,Gravel, Michel
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supporting information
p. 4518 - 4521
(2016/09/28)
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- Design, synthesis and evaluation of novel indole derivatives as AKT inhibitors
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Herein, we describe the discovery and synthesis of a new series of 1,2,4,7-tetra-substituted indole derivatives as novel AKT inhibitors by optimization of a weak hit methyl 4-(2-aminoethoxy)-1H-indole-2-carboxylate (1). Both representative compounds 6a and 6o exhibited the most potent inhibitory activities against AKT1, with inhibition rates of 72.5% and 78.6%, respectively, at concentrations of 10 nM. In addition, compounds 6a and 6o also potently inhibited the phosphorylation of the downstream GSK3 protein and displayed slightly better anti-proliferative activities in a prostate cancer cell line.
- Yang, Dezhi,Wang, Peng,Liu, Jianzhen,Xing, Hualu,Liu, Yang,Xie, Wencheng,Zhao, Guisen
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p. 366 - 373
(2014/01/17)
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- Tetrahydroquinoline-derived macrocyclic toolbox: The discovery of antiangiogenesis agents in zebrafish assay
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A novel approach to incorporate the macrocyclic rings onto the privileged substructure, i.e., tetrahydroquinoline scaffold, is developed. The presence of an amino acid-derived moiety in the macrocyclic skeleton provides an opportunity to modulate the nature of the chiral side chain. Further, evaluation in a zebrafish screen identified three active small molecules (2.5b, 3.2d, and 4.2) as antiangiogenesis agents at 2.5 μM.
- Reddy Guduru, Shiva Krishna,Chamakuri, Srinivas,Chandrasekar, Gayathri,Kitambi, Satish Srinivas,Arya, Prabhat
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supporting information
p. 666 - 670
(2013/07/26)
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- Samarium iodide-mediated Reformatsky reactions for the stereoselective preparation of β-hydroxy-γ-amino acids: Synthesis of isostatine and dolaisoleucine
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The synthesis of β-hydroxy-γ-amino acids via SmI 2-mediated Reformatsky reactions of α- chloroacetyloxazolidinones with aminoaldehydes is reported. Diastereoselective coupling is demonstrated to depend on the absolute configuration of the Evans chiral auxiliary employed in the reaction, allowing erythro or threo products to be obtained selectively. The potential utility of the methodology is exemplified by the facile synthesis of biologically relevant N-Boc-isostatine (2b) and N-Boc-dolaisoleucine (3c). This article not subject to U.S. Copyright. Published 2011 by the American Chemical Society.
- Nelson, Christopher G.,Burke, Terrence R.
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p. 733 - 738
(2012/03/26)
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- RTD-1 mimic containing γPNA scaffold exhibits broad-spectrum antibacterial activities
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Macrocyclic peptides with multiple disulfide cross-linkages, such as those produced by plants and those found in nonhuman primates, as components of the innate immunity, hold great promise for molecular therapy because of their broad biological activities
- Rapireddy, Srinivas,Nhon, Linda,Meehan, Robert E.,Franks, Jonathan,Stolz, Donna Beer,Tran, Dat,Selsted, Michael E.,Ly, Danith H.
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supporting information; experimental part
p. 4041 - 4044
(2012/04/10)
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- Reduction of carboxylic acids using esters of benzotriazole as high-reactivity intermediates
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Herein, we describe a simple and practical protocol for the reduction of carboxylic acids via the in situ formation of hydroxybenzotriazole esters followed by reaction with sodium borohydride to give the corresponding alcohols. The reaction proceeds with excellent yields in the presence of water. Georg Thieme Verlag Stuttgart - New York.
- Morales-Serna, Jose Antonio,Garcia-Rios, Erendira,Bernal, Jorge,Paleo, Ehecatl,Gavino, Ruben,Cardenas, Jorge
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scheme or table
p. 1375 - 1382
(2011/06/19)
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- Synthesis of novel N-protected β3-amino nitriles: study of their hydrolysis involving a nitrilase-catalyzed step
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Several commercially available nitrilases were investigated with regard to their potential to hydrolyze N-protected β3-amino nitriles into their corresponding N-protected β3-amino acids. The biotransformations were obtained in different proportions depending on the nitrilase involved. The best hydrolysis results were achieved for the N-Cbz-β3-amino nitrile from l-alanine using the NIT-107, in a phosphate buffer at 0.05 M. However, no biotransformation into the corresponding acids was observed for the N-sulfonylamide β3-amino nitriles. Two simple and efficient procedures to prepare the β3-amino nitriles from their analogous α-amino acids are described. Thirty four new substances were synthesized and characterized over the course of this work.
- Veitia, Maite Sylla-Iyarreta,Brun, Pierre Louis,Jorda, Pierre,Falguieres, Annie,Ferroud, Clotilde
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scheme or table
p. 2077 - 2089
(2010/03/04)
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- Syntheis of new chiral 5,6,7,8-tetrahydrotetrazolo[1,5-a]pyrazines from α-amino acid derivatives following "click" chemistry
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An efficient and practical synthesis of new chiral fused tetrazoles have been synthesized following [3+2] cycloaddition reaction starting from α-amino acid derivatives.
- Mohapatra, Debendra K.,Maity, Pradip K.,Ghorpade, Ravindra V.,Gurjar, Mukund K.
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body text
p. 865 - 872
(2010/09/16)
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- Discovery of novel P3 sulfonamide-capped inhibitors of HCV NS3 protease. Inhibitors with improved cellular potencies
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Hepatitis C Virus (HCV) infection is the major cause of chronic liver disease, leading to cirrhosis and hepatocellular carcinoma, which affects more than 200 million people worldwide. Currently the only therapeutic regimens are subcutaneous interferon-α or PEG-interferon alone or in combination with oral ribavirin. Although combination therapy is reasonably successful with the majority of genotypes, its efficacy against the predominant genotype (genotype 1) is moderate at best, with only ~50% of the patients showing sustained virological response. We recently disclosed the discovery of Boceprevir, SCH 503034 (1), which is a novel, potent, selective, orally bioavailable NS3 protease inhibitor that has been shown to be efficacious in humans and is currently undergoing clinical trials. As second generation compounds, we have further explored various novel structures with the aim of improving enzyme and cellular binding activities of 1. Herein, we disclose our efforts toward the identification of a novel P3 sulfonamide-capped inhibitor that demonstrated improved binding and cellular activity compared to 1. X-ray structure of one of these inhibitors bound to the enzyme revealed a hydrogen bond of the P3 sulfonamide group to Cys-159 which resulted in improved binding and cellular potency.
- Venkatraman, Srikanth,Blackman, Mellissa,Wu, Wanli,Nair, Latha,Arasappan, Ashok,Padilla, Angela,Bogen, Stéphane,Bennett, Frank,Chen, Kevin,Pichardo, John,Tong, Xiao,Prongay, Andrew,Cheng, Kuo-Chi,Girijavallabhan, Viyyoor,George Njoroge
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experimental part
p. 4486 - 4495
(2009/10/10)
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- A new method for the synthesis of chiral β-branched α-amino acids
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A new method for the synthesis of chiral β-branched α-amino acids based on a copper-mediated directed allylic substitution reaction with Grignard reagents is reported. This is the first case in which a δ-stereogenic center is controlling the diastereosele
- Spangenberg, Thomas,Schoenfelder, Angele,Breit, Bernhard,Mann, Andre
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p. 3881 - 3884
(2008/02/11)
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- Antimicrobial metabolites produced by an intertidal Acremonium furcatum
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In a screening for antimicrobial metabolites, amides of d-allo- and l-isoleucine derivatives were isolated from the culture of a marine strain of Acremonium furcatum. Structural elucidation of these compounds was performed by analysis of spectroscopic data and confirmed by synthesis. All of the compounds, natural and synthetic intermediates, were bioassayed against bacteria and phytopathogenic fungi, with many showing remarkable antifungal activities.
- Gallardo, Gabriela L.,Butler, Matias,Gallo, Mariana L.,Rodriguez, M. Alejandra,Eberlin, Marcos N.,Cabrera, Gabriela M.
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p. 2403 - 2410
(2007/10/03)
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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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- Stereoselective synthesis, solution structure and metal complexes of (1S,2S)-2-amino-1-hydroxyalkylphosphonic acids
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The highly stereoselective synthesis of (1S,2S)-2-amino-1-hydroxyalkylphosphonic acids was achieved by addition of dimethyl phosphite to N-protected aminoaldehydes. Relative configuration and solution conformations of (1S,2S)-2-amino-1-hydroxy-alkylphosphonic acids (in D2O) and their dimethyl esters (in CDCl3 and CD3OD) were established by means of NMR basing on the dependence between observed values of coupling constants (3JHH, 3JPC, 3JHP) and corresponding dihedral angles. Potentiometric and spectroscopic methods were used for the evaluation of the structure of the complexes of (1S,2S)-2-amino-1-hydroxy-alkylphosphonic acids with Zn(II) and Cu(II) ions in aqueous solutions.
- Drag, Marcin,Latajka, Rafal,Gumienna-Kontecka, Elzbieta,Kozlowski, Henryk,Kafarski, Pawel
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p. 1837 - 1845
(2007/10/03)
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- A facile and simple method for the reduction of N-protected amino acids and peptides to the corresponding alcohols
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A practical and chemoselective method for the reduction of N-protected amino acids and peptides including carboxylic acids to their corresponding alcohols is outlined.
- Srivastava, Tumul,Srivastava, Tushar K.,Haq,Katti, Seturam B.
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p. 516 - 517
(2007/10/03)
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- Assignment of the absolute configuration of β-chiral primary alcohols by NMR: Scope and limitations
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The prediction of the absolute configuration of β-chiral primary alcohols from the 1H NMR spectra of their esters with (R)- and (S)- 9-anthrylmethoxyacetic acids (9-AMA, 3) is discussed. Low-temperature NM experiments, MM, semiempirical, ab initio, and aromatic shielding effect calculations allowed the identification of the main conformers and showed that, in all alcohols for which the calculated ΔE(ag) (CVff) is in the range of 0.7-1.5 kcal/mol, conformer a/a is the most stable. A simple model for the assignment of the absolute configuration from NMR data is presented and its reliability corroborated with alcohols (8-20) of known configuration. Nevertheless, cyclic alcohols 21-23 have much higher ΔE(ag) values (2.2-3.1 kcal/mol) due to their different conformational composition, and their absolute configuration cannot be reliably predicted by this method.
- Latypov, Shamil K.,Ferreiro, María J.,Qui?oá, Emilio,Riguera, Ricardo
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p. 4741 - 4751
(2007/10/03)
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- Reaction of diisopropoxytitanium (III) tetrahydroborate with selected organic compounds containing representative functional groups
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Diisopropoxytitanium(III) tetrahydroborate, (1PrO)2TiBH4), generated in situ in dichloromethane from diisopropoxytitanium dichloride and benzyltriethylammonium borohydride in a 1:2 ratio selectively reduces aldehydes, ketones, acid chlorides, carboxylic acids, and N-Boc-protected amino acids to the corresponding alcohols in excellent yield under very mild reaction conditions (-78 to 25°C).
- Ravikumar,Chandrasekaran, Srinivasan
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p. 826 - 830
(2007/10/03)
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- HIGHLY DIASTEREOSELECTIVE SYNTHESIS OF N-BOC DOLAISOLEUINE, UNUSUAL AMINO ACID IN DOLASTATIN 10
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Photolysis of 5-phenylthiooxazolidin-2-one (4) in the presence of (n-Bu3Sn)2 and n-Bu3SnCH2CH=CH2 afforded 5-allyl derivative (5) which was led to N-Boc dolaisoleuine (11), one component of dolastatine 10 (2), via 6-10.
- Kano, Shinzo,Yuasa, Yoko,Shibuya, Shiroshi
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p. 1597 - 1600
(2007/10/02)
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- PREPARATION OF N-PROTECTED α-AMINO ALCOHOLS BY ACETOXYBOROHYDRIDE REDUCTION OF N-PROTECTED α-AMINO ACID ESTERS
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N-Protected α-amino alcohols were prepared by reduction of N-protected α-amino acid esters by sodium acetoxyborohydride in dioxane at elevated temperature.The reductions proceed with excellent yields and without racemisation.Reduction of the carbamate protecting groups was not observed.
- Soucek, Milan,Urban, Jan,Saman, David
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p. 761 - 765
(2007/10/02)
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- The role of hydroxymethyl function on the biological activity of the antitumor antibiotic sparsomycin
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The synthesis is described of the sparsomycin analogues 11-14 from the L-amino acids valine, isoleucine, phenylalanine and proline, respectively. The sparsomycin derivative 21 was not prepared in a similar way from glycine, but from cystamine following a different reaction route. These analogues, as well as the O-methylated and O-acetylated derivatives 15 and 16, respectively, were tested in vitro for their protein synthesis inhibitory activity and for their inhibition of colony formation of murine leukemia L1210 cells. The results of these assays indicate that the hydroxymethyl function of 1 is not essential for its biological activity, and that increase of lipophilicity in this 'northern' region of 1 does not noticeably affect the activity of the drug.
- Van den Broek,Fennis,Arevalo,Lazaro,Ballesta,Lelieveld,Ottenheijm
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p. 503 - 510
(2007/10/02)
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- New Methods and Reagents in Organic Synthesis. 67. A General Synthesis of Derivatives of Optically Pure 2-(1-Aminoalkyl)thiazole-4-carboxylic Acids
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Preparations of 2-(1-aminoalkyl)thiazole-4-carboxylic acids (thiazole amino acids), important constituents of a series of cytotoxic cyclic peptides from marine organisms, have been conveniently and efficiently achieved as their N- and C-protected derivatives 6 from N-Boc or N-Z α-amino acids 1 in five steps.Esterification of 1 with methyl iodide followed by reduction with lithium chloride-sodium borohydride afforded N-protected amino alcohols 3.Selective reduction of the α-ester functions of the glutamic acid derivatives (Z-D- and Z-L-Glu(O-t-Bu)-OMe and O-t-Bu) was also achieved under the above reduction conditions.Dimethyl sulfoxide oxidation, followed by condensation with cysteine methyl ester afforded the thiazolidine derivatives 5, which were conveniently dehydrogenated with manganese dioxide, called chemical manganese dioxide (CMD) and produced for batteries, to give the desired thiazole amino acid derivetives 6.The glutamine derivatives (Z-D- and Z-L-(gln)Thz-OMe) were prepared from the corresponding glutamic acid derivatives (Z-D- and Z-L-6f).No appreciable racemization was observed in the above conversion, which was proven by HPLC of the 3,5-dinitrobenzoyl derivatives of thiazole amino acids 6 using a chiral column.
- Hamada, Yasumasa,Shibata, Makoto,Sugiura, Tsuneyuki,Kato, Shinji,Shioiri, Takayuki
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p. 1252 - 1255
(2007/10/02)
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