- The Cyclopentyl Group, As a Small but Bulky Terminal Group, Allows Rapid and Efficient Active Transport
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Secondary ammonium salts bearing a cyclopentyl terminal group rapidly formed pseudorotaxane with 1.5 equiv of DB24C8. Acylation of the pseudorotaxane with 50 equiv of benzoyl chloride in the presence of 50 equiv of triethylamine in toluene afforded rotaxane, the product of active transport, in 95% yield. The cyclopentyl group is small enough to allow rapid formation of pseudorotaxane, and bulky enough to facilitate the quantitative active transport by steric repulsion. (Chemical Equation Presented).
- Nishiyama, Junya,Makita, Yoshimasa,Kihara, Nobuhiro
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Read Online
- A convenient asymmetric synthesis of a β-amino ester with additional functionalization as a precursor for peptide nucleic acid (PNA) monomers
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We report the asymmetric synthesis of di-3-pentyl (3S,αS,7E)-3-N- benzyl-N-α-methylbenzylamino-dec-7-enedioate (9), which contains the correct functionalization to produce δ-amino acid derivatives to be used as monomers for Peptide Nucleic Acid (PNA) formation With this aim, thymine-pentanoic acid 15 and some of its ester derivatives were obtained, their reactivity was studied and the noteworthy ethyl ester 12 was quantitatively produced by transesterification of methyl ester 11, thus paving the way for the synthesis of the thymine-containing amino ester IV, which has been designed as a building block for a Nucleic-Acid analog with a chiral, flexible peptide backbone
- Garrido, Narciso M.,Diez, David,Dominguez, Sara H.,Rosa Sanchez,Garcia, Mercedes,Urones, Julio G.
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Read Online
- Synthesis and spectral properties of 6′-triazolyl-dihydroxanthene-hemicyanine fused near-infrared dyes
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We describe the synthesis of a range of 6′-triazolyl-dihydroxanthene-hemicyanine (DHX-hemicyanine) fused dyes through an effective copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click"reaction, with the aim of providing molecular diversity and evaluating the spectral properties of these near-infrared (NIR)-active materials. This was implemented by reacting 15 different aliphatic and aromatic azides with a terminal alkynyl-based DHX-hemicyanine hybrid scaffold prepared in four steps and 35% overall yield from 4-bromosalicylaldehyde. The resulting triazole derivatives have been fully characterized and their optical properties determined both in organic solvents and under simulated physiological conditions (phosphate buffered saline containing 5% of bovine serum albumin protein). This systematic study is a first important step towards the development of NIR-I fluorogenic "click-on"dyes or related photoactive agents for light-based diagnostic and/or therapeutic applications.
- Gu, Lingyue,Renault, Kévin,Romieu, Anthony,Richard, Jean-Alexandre,Srinivasan, Rajavel
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supporting information
p. 12208 - 12215
(2020/07/30)
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- Design, synthesis, and biological evaluation of dual targeting inhibitors of histone deacetylase 6/8 and bromodomain BRPF1
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Histone modifying proteins, specifically histone deacetylases (HDACs) and bromodomains, have emerged as novel promising targets for anticancer therapy. In the current work, based on available crystal structures and docking studies, we designed dual inhibitors of both HDAC6/8 and the bromodomain and PHD finger containing protein 1 (BRPF1). Biochemical and biophysical tests showed that compounds 23a,b and 37 are nanomolar inhibitors of both target proteins. Detailed structure-activity relationships were deduced for the synthesized inhibitors which were supported by extensive docking and molecular dynamics studies. Cellular testing in acute myeloid leukemia (AML) cells showed only a weak effect, most probably because of the poor permeability of the inhibitors. We also aimed to analyse the target engagement and the cellular activity of the novel inhibitors by determining the protein acetylation levels in cells by western blotting (tubulin vs histone acetylation), and by assessing their effects on various cancer cell lines.
- Erdmann, Frank,Günther, Stefan,Ghazy, Ehab,Hügle, Martin,Herp, Daniel,Jung, Manfred,Morales, Elizabeth R.,Robaa, Dina,Romier, Christophe,Schmidt, Matthias,Schmidtkunz, Karin,Sippl, Wolfgang,Zeyen, Patrik
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supporting information
(2020/06/03)
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- Nanostructured Micelle Nanotubes Self-Assembled from Dinucleobase Monomers in Water
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Despite the central importance of aqueous amphiphile assemblies in science and industry, the size and shape of these nano-objects is often difficult to control with accuracy owing to the non-directional nature of the hydrophobic interactions that sustain them. Here, using a bioinspired strategy that consists of programming an amphiphile with shielded directional Watson–Crick hydrogen-bonding functions, its self-assembly in water was guided toward a novel family of chiral micelle nanotubes with partially filled lipophilic pores of about 2 nm in diameter. Moreover, these tailored nanotubes are successfully demonstrated to extract and host molecules that are complementary in size and chemical affinity.
- Aparicio, Fátima,Casado, Santiago,Chamorro, Paula B.,Chamorro, Raquel,González-Rodríguez, David
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supporting information
p. 17091 - 17096
(2020/07/30)
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- Efficient flow fischer esterification of carboxylic acids with alcohols using sulfonic acid-functionalized silica as supported catalyst
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Flow Fischer esterification of carboxylic acids using hydroxy-substituted sulfonic acid-functionalized silica (HOSAS) packed into a stainless steel column reactor was investigated. HO-SAS well catalyzed flow esterification of long chain carboxylic acids with methanol within 3min of residence time at 110°C, and the methyl esters were quantitatively obtained. The flow esterification protocol was applied to the synthesis of a variety of esters (19 examples) and scalable synthesis was also successful.
- Furuta, Akihiro,Fukuyama, Takahide,Ryu, Ilhyong
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p. 607 - 612
(2017/06/19)
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- Synthesis of long-wavelength absorbing porphyrin m-benzoic acids as molecular tectons for surface studies
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Porphyrins are becoming increasingly important building blocks in material science. This is due in part to several favorable characteristics; such as strong absorption into the infrared region, tunable electronic properties and the possibility to modify and define the porphyrin core in multiple ways. Herein we report synthetic methodologies for porphyrin-based molecular tectons for surface studies. The study aims to generate porphyrins with directional anchoring groups of different length and we report a library of long-wavelength absorbing porphyrins with a special focus on organometallic coupling reactions for the introduction of benzoic acid moieties as anchor groups.
- Meindl, Alina,Ryan, Aoife A.,Flanagan, Keith J.,Senge, Mathias O.
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p. 1518 - 1541
(2017/08/02)
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- Dual stimuli-responsive self-assembled supramolecular nanoparticles
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Supramolecular nanoparticles (SNPs) encompass multiple copies of different building blocks brought together by specific noncovalent interactions. The inherently multivalent nature of these systems allows control of their size as well as their assembly and disassembly, thus promising potential as biomedical delivery vehicles. Here, dual responsive SNPs have been based on the ternary host-guest complexation between cucurbit[8]uril (CB[8]), a methyl viologen (MV) polymer, and mono- and multivalent azobenzene (Azo) functionalized molecules. UV switching of the Azo groups led to fast disruption of the ternary complexes, but to a relatively slow disintegration of the SNPs. Alternating UV and Vis photoisomerization of the Azo groups led to fully reversible SNP disassembly and reassembly. SNPs were only formed with the Azo moieties in the trans and the MV units in the oxidized states, respectively, thus constituting a supramolecular AND logic gate. A guiding light: UV/Vis irradiation and chemical reduction have been used for the reversible disassembly/reassembly and irreversible disintegration, respectively, of responsive supramolecular nanoparticles stabilized by ternary host-guest complexes (see picture). The disassembly proceeds through an initial aggregation phase that is attributed to different response times of the multivalent core and the monovalent shell upon photoswitching.
- Stoffelen, Carmen,Voskuhl, Jens,Jonkheijm, Pascal,Huskens, Jurriaan
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supporting information
p. 3400 - 3404
(2014/04/03)
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- Synthesis of new calix[4]arene amide derivatives and investigation of their DNA cleavage activity
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This study comprises the synthesis of new p-tert-butylcalix[4]arene with different amide functional groups and summarises an investigation of their DNA cleavage activities. The structural investigations of the synthesised compounds were examined by FTIR, 1H NMR, 13C NMR, elemental analysis and FAB-MS techniques. The interaction between these compounds and pBR322 plasmid DNA has been investigated via agarose gel electrophoresis and, according to the results, compounds 5, 7, 8 and 13 exhibit efficient DNA cleavage activity. In the electrophoresis images of 5, 7 and 8, Form IV which is small DNA fragment was observed in addition to supercoiled Form I, open circular Form II and linear Form III. 2013
- Oezkan, Seyda Cigdem,Yilmaz, Aydan,Oezmen, Ismail
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- Cancer phototherapy in living cells by multiphoton release of doxorubicin from gold nanospheres
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Doxorubicin is a widely used but toxic cancer chemotherapeutic agent. In order to localize its therapeutic action and minimize side effects, it was covalently conjugated to peptide-encapsulated gold nanospheres by click-chemistry and then photo-released in a controlled fashion by a multiphoton process. Selective treatment of a chosen region in a 2D layer of U2Os cancer cells is shown by driving photorelease with 561 nm irradiation at μW power. These results show promising directions for the development of practical applications based on nanocarriers that can ensure drug delivery with high spatial and temporal control. The Royal Society of Chemistry 2013.
- Voliani, Valerio,Signore, Giovanni,Vittorio, Orazio,Faraci, Paolo,Luin, Stefano,Perez-Prieto, Julia,Beltram, Fabio
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p. 4225 - 4230
(2013/09/02)
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- The discovery and optimization of novel dual inhibitors of topoisomerase ii and histone deacetylase
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A novel class of podophyllotoxin derivatives have been designed and synthesized based on the synergistic antitumor effects of topoisomerase II and histone deacetylase inhibitors. Their inhibitory activities towards histone deacetylases and Topo II and their cytotoxicities in cancer cell lines were evaluated. The aromatic capping group connection, linker length and zinc-binding group were systematically varied and preliminary conclusions regarding structure-activity relationships are discussed. Among all of the synthesized hybrid compounds, compound 24d showed the most potent HDAC inhibitory activity at a low nanomolar level and exhibited powerful antiproliferative activity towards HCT116 colon carcinoma cells at a low micromolar level. Further exploration of this series led to the discovery of potent dual inhibitor 32, which exhibited the strongest in vitro cytotoxic activity.
- Zhang, Xuan,Bao, Bin,Yu, Xiuhua,Tong, Linjiang,Luo, Yu,Huang, Qingqing,Su, Mingbo,Sheng, Li,Li, Jia,Zhu, Hong,Yang, Bo,Zhang, Xiongwen,Chen, Yi,Lu, Wei
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p. 6981 - 6995
(2013/11/06)
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- High-throughput synthesis of azide libraries suitable for direct "click" chemistry and in situ screening
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A key challenge in current drug discovery is the development of high-throughput (HT) amenable chemical reactions that allow rapid synthesis of diverse chemical libraries of enzyme inhibitors. The Cu(I)-catalyzed, 1,3-dipolar cycloaddition between an azide and an alkyne, better known as "click chemistry", is one such method that has received the most attention in recent years. Despite its popularity, there is still a lack of robust and efficient chemical strategies that give access to diverse libraries of azide-containing building blocks (key components in click chemistry). We report herein a highly robust and efficient strategy for high-throughput synthesis of a 325-member azide library. The method is highlighted by its simplicity and product purity. The utility of the library is demonstrated with the subsequent "click" synthesis of the corresponding bidentate inhibitors against PTP1B.
- Srinivasan, Rajavel,Tan, Lay Pheng,Wu, Hao,Yang, Peng-Yu,Kalesh, Karunakaran A.,Yao, Shao Q.
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supporting information; experimental part
p. 1821 - 1828
(2009/06/28)
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- Scandium triflate catalyzed transesterification of carboxylic esters
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The direct transesterification of carboxylic esters is efficiently catalyzed with Sc(OTf)3 (10 mol%) in boiling alcoholic solvent. Methyl, ethyl, isopropyl, and allyl esters were prepared from a broad range of different substrates in high yields. The application of microwave irradiation led to significantly reduced reaction times. Georg Thieme Verlag Stuttgart.
- Remme, Nicole,Koschek, Katharina,Schneider, Christoph
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p. 491 - 493
(2007/12/27)
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- Synthesis of phosphonic acids with the semicarbazide group for the functionalization of metal oxide mid zeolite nanoparticles
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The syntheses of two phosphonic acids possessing the Fmoc-protected semicarbazide group are described. The key step was the Curtius rearrangement, performed in the presence of dibenzyl phosphonate esters. Preliminary experiments showed that the phosphonic acid can be grafted at the surface of oxide nanoparticles and colloidal zeolite nanocrystals, without deprotection of the Fmoc group.
- Doussineau, Tristan,Durand, Jean-Olivier,Granier, Michel,Sma?hi, Monique,Valtchev, Valentin
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p. 1735 - 1738
(2007/10/03)
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- Cyclic hydroxamates, especially multiply substituted [1,2]oxazinan-3-ones
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Routes to putative N-acyl-D-ala-D-ala surrogates, beginning with the conversion of 4-, 5-, and 6-membered lactones into 5-, 6-, and 7-membered cyclic hydroxamates, are reported. The key step of the synthesis is trimethylaluminium-promoted cyclization of an ω-aminooxyester. The 7-membered cyclic hydroxamate crystallizes in a chair conformation. Extension of the reaction sequence to homoserine or homoserine lactone leads to cyclocanaline and N-acylated cyclocanalines. The 4-phenylacetamido derivative of cyclocanaline crystallizes in a boat conformation. The attachment of a 2-carboxypropyl substituent to the ring nitrogen of a 4-acylaminocyclocanaline has been effected, prior to cyclization, by coupling of the acyclic aminooxyester precursor to the triflate of benzyl lactate or, after cyclization, by coupling to tert-butyl α-bromopropionate in the presence of potassium fluoride - alumina, followed by removal of the protecting group in each case. A six-membered homolog of the antibiotic lactivicin has been synthesized by the reaction of 4-phenylacetamidocyclocanaline with benzyl 2-oxoglutarate in the presence of carbodiimide, followed by hydrogenolysis. Starting with methyl 2,4-dibromo-2,4-dideoxy-L-erythronate, which is available in two steps from L-ascorbic acid, these reaction sequences have been applied to the stereospecific synthesis of a D-alanine derivative whose nitrogen atom is enclosed within a 3,4-disubstituted [1,2]oxazinan-3-one.
- Wolfe, Saul,Wilson, Marie-Claire,Cheng, Ming-Huei,Shustov, Gennady V.,Akuche, Christiana I.
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p. 937 - 960
(2007/10/03)
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- New ω-phthalimidoperoxyalkanoic acids in decontamination. Destruction of some toxic organophosphorus and organosulfur pollutants
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Chemical decontamination of toxic compounds (chemical warfare agents and/or insecticides) is of increasing importance. In this study, we report the use of ω-phthalimidoperoxyalkanoic acids 2 in the destruction of paraoxon (O,O-diethyl-O-para-nitrophenylphosphate), a well-known insecticide, and 2-chloro-2′-phenyldiethyl sulfide (a half mustard). We show that while all the peroxyacids used in this series allow the destruction of toxic compounds, the length n of the alkanoic side chain is important to the choice of the optimal industrial compound, which is 2d (n = 5).
- Lion,Da Conceicao,Delmas,Magnaud
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p. 1182 - 1184
(2007/10/03)
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- Acetophenone-based linker for solid phase synthesis of secondary amides and sulfonamides on the multipin(TM) support
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A new and simple linker has been developed for synthesis of secondary amides and sulfonamides. This application is based on the reductive amination reaction between the acetophenone subunit of the linker and a wide range of primary amines including aliphatic and aromatic amines. Cleavage is effected under mild acidic conditions (20% TFA/DCM) to release the products in good yield and purity.
- Bui, Chinh T.,Bray, Andrew M.,Ercole, Francesca,Pham, Yen,Rasoul, Firas A.,Maeji, N. Joe
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p. 3471 - 3474
(2007/10/03)
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- Porphyrin receptors for amines, amino acids, and oligopeptides in water
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A series of water-soluble porphyrin receptors having a hydrophobic binding pocket, a Lewis acidic site (Zn), and an electrostatic recognition site (COO- groups) were prepared. All the porphyrin receptors have a [meso- tetrakis(p-carboxyphenyl)porphyrinato]zinc (Zn·TCPP) as a common structural unit, and eight ω-carboxyalkyloxy groups (alkyloxy = methoxy (1), butoxy (2), decyloxy (3)) at the ortho positions of the phenyl groups. These receptors bind amines, α-amino acid esters, and oligopeptides in water with significant selectivity. For binding of hydrophilic guests, 1, 2, and 3 bind histamine in pH 8 buffer at 25 °C with binding constants of 157000, 31000, and 18200 M-1, respectively, where the coordination (Imd-Zn) and the salt bridge (NH3+--OOC) stabilized the complex. The large dependence of the binding constants on the ionic strength indicated that the electrostatic interaction between the ammonium group of histamine and the carboxylate groups of receptor contributes significantly to tight binding in water. Receptors 1-3 also bind a cationic guest, Arg-OMe, with a binding constant of 440-11000 M-1. The effective charge of the receptors for electrostatic recognition of Arg-OMe in pH 9 Borax (1 = 0.1 M) at 25 °C was evaluated by the Debye-Huckel limiting law as 4.2, 4.3, and 3.0 for 1, 2, and 3, respectively. These observations indicate that a salt bridge, which is exposed to water and involves hydrogen bonding, as seen in the 1-histamine and 1-Arg-OMe complexes, can be used as a significant recognition force. Binding of Arg-OMe by 2 and 3 was entropically driven, and binding of Arg-OMe by 1 was enthalpically driven. Therefore, the driving force of binding is desolvation from the ionic groups in the former case and the electrostatic attraction in the latter case. For binding of hydrophobic guests, 3 binds Trp-OMe or pyridine in water with binding constants of 7000-8000 M-1, while 1 and Zn·TCPP bind these guests less tightly with binding constants of 20- 500 M-1, indicating the importance of the long alkyl chains to provide a hydrophobic binding pocket above the porphyrin plane.
- Mizutani, Tadashi,Wada, Kenji,Kitagawa, Susumu
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p. 11425 - 11431
(2007/10/03)
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- ALKYL TELLURAALKANOATES CnH2n+1Te(CH2)mCOOR (R = CH3, C2H5 OR H)
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Methyl telluraalkanoates, CnH2n + 1Te(CH2)mCOOR (n, m: 4, 7; 6, 4; 6, 7; 6, 9; 7, 4; 8, 7; 11, 2; 11, 5; 18, 11) were synthesized in yields ranging from 33 to 82 percent based on the quantities of the methyl ω-bromoalkanoates substrates.Disodium ditelluride was obtained from tellurium and sodium in ethylenediamine and was treated with alkyl bromides to give dialkyl ditellurides.The crude ditellurides were reduced with NaBH4 to the alkane tellurolates which were coupled with methyl ω-bromoalkanoates to give the methyl telluraalkanoates.Ethyl 4-tellurapentadecanoatewas prepared similarly from ethyl 3-bromopropanoate.The telluraalkanoates were characterized by elemental analyses, mass spectrometry, NMR spectrometry, and UV and IR spectrophotometry.Telluraalkanoates radiolabeled with 123mTe or other radioisotopes have been reported elsewhere to be preferentially taken up by the heart and promise to be useful as myocardial imaging agents.
- Grigsby, Robert A.,Irgolic, Kurt J.,Knapp, Furn F.
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- Synthesis of 7,8,9,10,11,12,20,21,22,23,24,25-Dodecahydrodibenzotetraoxacyclodocosin, a Crown Ether
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A number of symmetrical diesters and an unsymmetrical type have been synthesised from pyrocatechol.Under conditions in which intramolecular acyloin formation was anticipated the product from one symmetrical compound, ethyl 4-(o-ethoxycarbonylpropoxyphenoxy)butyrate, was a cyclic bis-β-keto-ester resulting in reasonable yield from intermolecular Dieckmann cyclisation.Hydrolysis to the 9,22 diketone, and its reduction to 7,8,9,10,11,12,20,21,22,23,24,25-dodecahydrodibenzotetraoxacyclodocosin 'dibenzo-22-crown-4', proceeded smoothly.An unsymmetrical intermediate, methyl 4-(o-ethoxycarbonylmethoxypropylphenoxy)butyrate, was prepared for similar cyclisation and in preliminary experiments appeared to give acyloin and β-keto-ester products.The method represents a different approach to crown ether systems of certain types.
- Tyman, John H. P.,Grundy, Jesse,Brown, George R.
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p. 336 - 343
(2007/10/02)
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