- A "clickable" styryl dye for fluorescent DNA labeling by excitonic and energy transfer interactions
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In conclusion, we have shown that the CyIQ dye represents a promising covalently attached fluorescent label for DNA, since it shows good brightness and excellent photostability. In particular, the photochemical stability of CyIQ is significantly enhanced compared to the routinely applied fluoresceine. The dye is "clickable", that means it can be incorporated postsynthetically and therefore easily into oligonucleotides by using the cycloaddition between azides and acetylenes. In this study, the "click" reaction was performed representatively to 2'-propargylated uridines in DNA. This structural approach has the advantage that the preference for pairing between the modified uridine and adenine in the counterstrand is potentially maintained and thereby the DNA duplex conformation stays stable.[9a] One could envision that this experimentally simple labeling method can be extended to other acetylene-containing building blocks in RNA and DNA, which are either commercially or synthetically available. Beside the application as single internal DNA marker, the CyIQ label can be combined with itself and TR, all chromophors adjacent to each other as intra-strand fluorophore pairs. Excitonic interactions between the CyIQ dyes and energy transfer interactions between CyIQ and thiazole red provide interesting alternatives for fluorescence readouts for DNA hybridization, which are either fluorescence enhancement or fluorescence color change, respectively.
- Rubner, Moritz M.,Holzhauser, Carolin,Bohlaender, Peggy R.,Wagenknecht, Hans-Achim
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Read Online
- CO2 triggering and controlling orthogonally multiresponsive photochromic systems
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We report a new generic method of reversibly controlling the photochromism of spiropyrans. It was found that the photochromic effect of spiropyrans can be reversibly switched on and off by addition and removal of carbon dioxide (CO2) to spiropyran in alcohol solutions containing an amidine (i.e., DBU) that acts as a CO2 sensitizer. Spiropyrans are not photochromic in the presence of DBU but photochromic when CO2 is subsequently added to the solution. The CO2 is readily removed by inert gas bubbling, thus allowing facile activation and deactivation of the photochromic effect. Carbon dioxide, without the presence of the sensitizing amidine, had no effect on photochromism of the spiropyrans. Other photochromic dyes classes such as spirooxazines and chromenes are not affected by this CO2/DBU stimulus. As a result, orthogonal activation of mixtures of spirooxazines and spiropyrans was achieved to provide four color states (clear, yellow, green, and blue) by varying the combinations of the stimuli of UV, visible light, CO 2, and CO2 depleted. This finding now permits the many applications using spiropyrans to be CO2 responsive.
- Darwish, Tamim A.,Evans, Richard A.,James, Michael,Malic, Nino,Triani, Gerry,Hanley, Tracey L.
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Read Online
- Strand displacement and duplex invasion into double-stranded DNA by pyrrolidinyl peptide nucleic acids
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The so-called acpcPNA system bears a peptide backbone consisting of 4′-substituted proline units with (2′R,4′R) configuration in an alternating combination with (2S)-amino-cyclopentane-(1S)-carboxylic acids. acpcPNA forms exceptionally stable hybrids with complementary DNA. We demonstrate herein (i) strand displacements by single-stranded DNA from acpcPNA-DNA hybrids, and by acpcPNA strands from DNA duplexes, and (ii) strand invasions by acpcPNA into double-stranded DNA. These processes were studied in vitro using synthetic oligonucleotides and by means of our concept of wavelength-shifting fluorescent nucleic acid probes, including fluorescence lifetime measurements that allow quantifying energy transfer efficiencies. The strand displacements of preannealed 14mer acpcPNA-7mer DNA hybrids consecutively by 10mer and 14mer DNA strands occur with rather slow kinetics but yield high fluorescence color ratios (blue:yellow or blue:red), fluorescence intensity enhancements, and energy transfer efficiencies. Furthermore, 14mer acpcPNA strands are able to invade into 30mer double-stranded DNA, remarkably with quantitative efficiency in all studied cases. These processes can also be quantified by means of fluorescence. This remarkable behavior corroborates the extraordinary versatile properties of acpcPNA. In contrast to conventional PNA systems which require 3 or more equivalents PNA, only 1.5 equivalents acpcPNA are sufficient to get efficient double duplex invasion. Invasions also take place even in the presence of 250 mM NaCl which represents an ionic strength nearly twice as high as the physiological ion concentration. These remarkable results corroborate the extraordinary properties of acpcPNA, and thus acpcPNA represents an eligible tool for biological analytics and antigene applications.
- Bohl?nder, Peggy R.,Vilaivan, Tirayut,Wagenknecht, Hans-Achim
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Read Online
- Total Synthesis of Phenanthropiperidine Alkaloids by Sequential Alkylation of N,N-Dibenzylaminoacetonitrile
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Two representative members of the phenanthropiperidine alkaloid family, tylophorine (1) and cryptopleurine (2), were synthesized by a bidirectional alkylation strategy employing dibenzylaminoacetonitrile as a substrate. This approach relies on the unprecedented condensation of metallated α-aminonitriles with bromomethylphenanthrenes to provide fully substituted α-aminonitriles, which are subjected to a NaBH4-mediated reductive decyanation process to form homobenzylic amines. From these intermediates, a terminal leaving group was introduced by simple chemical manipulation, and its displacement by a free primary amine under two favorable cyclization processes led to the formation of the future E-ring of both alkaloids in high yields. Finally, a late Pictet-Spengler cyclization ensured the formation of a D-ring for the alkaloids 1 and 2.
- Bouvry, Christelle,Cupif, Jean-Fran?ois,Franzetti, Milène,Hurvois, Jean-Pierre
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p. 6037 - 6051
(2021/12/10)
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- Method for efficiently preparing iodo alcohol
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The invention discloses a method for efficiently preparing iodohydrin. The preparation method is characterized in that a cyclic ether compound, iodine and hydrogen are used as the reaction raw materials and rhodium and phosphine ligand are used as the catalyst to perform reaction in an organic inert solvent under a positive pressure condition to obtain the target iodohydrin, and the reaction formula of the reaction is as shown in the specification, wherein Z is alkane or aromatic hydrocarbon. The method has the advantages that the iodination of the method can be easily achieved, reaction condition requirements are low, large-scale industrial production can be achieved, and the yield of the iodohydrin can mostly reach 90% or above; the method is cheap in substrate, easy in substrate obtaining, simple to operate, environmentally friendly, high in yield and the like; the low-cost, high-efficiency, clean and environment-friendly method is easy to achieve industrial production and promisingin application prospect.
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Paragraph 0013; 0029-0030
(2021/04/17)
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- Rhodium-Catalyzed Generation of Anhydrous Hydrogen Iodide: An Effective Method for the Preparation of Iodoalkanes
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The preparation of anhydrous hydrogen iodide directly from molecular hydrogen and iodine using a rhodium catalyst is reported for the first time. The anhydrous hydrogen iodide generated was proven to be highly active in the transformations of alkenes, phenyl aldehydes, alcohols, and cyclic ethers to the corresponding iodoalkanes. Therefore, the present methodology not only has provided convenient access to anhydrous hydrogen iodide but also offers a practical preparation method for various iodoalkanes in excellent atom economy.
- Zeng, Chaoyuan,Shen, Guoli,Yang, Fan,Chen, Jingchao,Zhang, Xuexin,Gu, Cuiping,Zhou, Yongyun,Fan, Baomin
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p. 6859 - 6862
(2018/10/25)
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- Preparation of useful building blocks, α-iodo- and bromoalkanols from cyclic ethers using the Dowex H+/NaX (X = I, Br) approach
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Our recently reported novel green chemistry tool was effectively used for opening cyclic ethers to produce α-iodo- and bromoalkanols. The synthesis of 4-iodobutanoic acid from γ-butyrolactone has also been described. The method is based on the use of a dried Dowex H+/NaX (X = Br, I)-system, which is effective at producing α-iodoalkanols and some α-bromoalkanols from commercially available cyclic ethers. Additionally, opening of three different crown ethers to form α-iodo(polyethylene)glycols with various chain lengths is demonstrated. Haloalkanols are important building blocks in synthetic chemistry e.g. for medicinal chemistry purposes.
- Turhanen, Petri A.,Veps?l?inen, Jouko J.
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p. 15937 - 15940
(2016/02/19)
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- Development of indazolylpyrimidine derivatives as high-affine EphB4 receptor ligands and potential PET radiotracers
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Due to their essential role in the pathogenesis of cancer, members of the Eph (erythropoietin-producing hepatoma cell line-A2) receptor tyrosine kinase family represent promising candidates for molecular imaging. Thus, the development and preparation of novel radiotracers for the noninvasive imaging of the EphB4 receptor via positron emission tomography (PET) is described. First in silico investigations with the indazolylpyrimidine lead compound which is known to be highly affine to EphB4 were executed to identify favorable labeling positions for an introduction of fluorine-18 to retain the affinity. Based on this, reference compounds as well as precursors were developed and labeled with carbon-11 and fluorine-18, respectively. For this purpose, a protecting group strategy essentially had to be generated to prevent unwanted methylation and to enable the introduction of fluorine-18. Further, a convenient radiolabeling strategy using [11C]methyl iodide was established which afforded the isotopically labeled radiotracer in 30-35% RCY (d.c.) which is identical with the original inhibitor molecule. A spiro ammonium precursor was prepared for radiolabeling with fluorine-18. Unfortunately, the labeling did not lead to the desired 18F-radiotracer under the chosen conditions.
- Ebert, Kristin,Wiemer, Jens,Caballero, Julio,K?ckerling, Martin,Steinbach, J?rg,Pietzsch, Jens,Mamat, Constantin
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p. 6025 - 6035
(2015/11/10)
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- HIV INTEGRASE INHIBITORS
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The present invention features compounds that are HIV integrase inhibitors and therefore are useful in the inhibition of HIV replication, the prevention and/or treatment of infection by HIV, and in the treatment of AIDS and/or ARC.
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- Ni-catalyzed cascade cyclization-kumada alkyl-alkyl cross-coupling
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Suggesting novel disconnections: A powerful Ni-catalyzed cascade reaction involving cyclization followed by cross-coupling allows the formation of up to three alkyl-alkyl bonds in a single operation by using alkene-containing alkyl iodides and Grignard reagents (see scheme; acac=acetylacetonate; TMEDA=N,N′,N′-tetramethyl ethylenediamine). Mechanistic experimental and computational studies suggest a NiI-NiII-Ni III catalytic cycle and the intermediacy of radicals. Copyright
- Guisan-Ceinos, Manuel,Soler-Yanes, Rita,Collado-Sanz, Daniel,Phapale, Vilas B.,Bunuel, Elena,Cardenas, Diego J.
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supporting information
p. 8405 - 8410
(2013/07/25)
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- Visible-light degradable polymer coated hollow mesoporous silica nanoparticles for controlled drug release and cell imaging
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A core-shell nanocomposite based on photo-degradable polymer coated hollow mesoporous silica nanoparticles (HMS) was successfully prepared for targeted drug delivery and visible-light triggered release, as well as fluorescence cell imaging. The HMS nanoparticles were first modified by the long-chain hydrocarbon octadecyltrimethoxysilane (C18) and fluorescent agent Rhodamine B isothiocyanate (RITC), and then encapsulated by a photodegradable amphiphilic copolymer via a self-assembly process. The obtained nanocarrier showed a high drug loading content due to the hollow core and mesopores of the HMS and could target folic acid receptor over-expressed tumor cells efficiently for conjugating folic acid (FA) in the amphiphilic polymer. The drug release could be triggered by the irradiation of green light (500-540 nm) due to the photodegradation of amphiphilic copolymer coated on the HMS. Furthermore, the targeted drug delivery and controlled release processes could be tracked by fluorescence imaging for the doping of RITC on the HMS. The In vitro results suggested that a smart visible light responsive drug delivery system was successfully prepared for the potential applications of cancer diagnosis and therapy.
- Yang, Shun,Li, Najun,Chen, Dongyun,Qi, Xiuxiu,Xu, Yujie,Xu, Ying,Xu, Qingfeng,Li, Hua,Lu, Jianmei
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p. 4628 - 4636
(2013/09/12)
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- Synthesis and evaluation of cyanine-styryl dyes with enhanced photostability for fluorescent DNA staining
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The photostability of cyanine-styryl dyes of the indole-quinolinium type can be significantly improved by structural variations while the excellent optical properties including the bright fluorescence in the presence of DNA can be maintained or even improved, too.
- Bohlaender, Peggy R.,Wagenknecht, Hans-Achim
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supporting information
p. 7458 - 7462
(2013/11/06)
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- Visible light-responsive micelles formed from dialkoxyanthracene-containing block copolymers
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A class of dialkoxyanthracene-containing diblock copolymers is synthesized which possesses visible light-responsivity. These copolymers can self-assemble into a micellar structure in water. Green visible light (540 nm) is able to scissor these anthracene species and cleave the diblock copolymer into two fragments, inducing disassembly of the self-assembled micelles.
- Yan, Qiang,Hu, Jun,Zhou, Rong,Ju, Yong,Yin, Yingwu,Yuan, Jinying
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supporting information; experimental part
p. 1913 - 1915
(2012/03/13)
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- Synthesis and physical properties of ferrocene derivatives (XXV) liquid crystallinity of 1,3-disubstituted ferrocene derivatives
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Liquid crystallinity of 1,3-disubstituted ferrocene derivatives was studied by DSC and polarizing microscope. The name of the derivatives is 1,3-bis[-[4-(4-methoxyphenoxycarbonyl)phenoxy]alkyloxycarbonyl]ferrocene. Nine members from n = 2 to 10 were synthesized (n is carbon number of alkyl chain in the sample). All samples except n = 2 and 4 exhibited monotropic nematic liquid crystalline phase. In addition, smectic X (not yet completely identified) was also observed in n = 8 and 10. Liquid crystalline phase transition phenomena were discussed from a viewpoint of molecular shape. Copyright Taylor & Francis Group, LLC.
- Nakamura, Naotake,Kagawa, Shinya
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experimental part
p. 150 - 159
(2012/01/03)
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- Synthesis and physical properties of ferrocene derivatives (XXIII): Phase transition and unique molecular structure of monosubstituted ferrocene derivatives
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The monosubstituted ferrocene derivatives, -[4-(4-methoxyphenoxycarbonyl) phenoxy]alkoxycarbonyl ferrocene, were synthesized in order to compare the liquid crystallinity to that of disubstituted ferrocene derivatives, 1,1'-bis[-[4-(4-methoxy-phenoxycarbonyl)phenoxy]alkoxycarbonyl]ferrocene. Some of the monosubstituted ferrocene derivatives containing relatively longer flexible spacer showed the liquid crystalline phase, nematic and/or smectic phases. The crystal structure of 2-[4-(4-methoxyphenoxycarbonyl)phenoxy] ethoxycarbonyl ferrocene was determined by X-ray diffraction method using a single crystal. The molecular structure revealed a bent structure that is almost a half of "Z" shaped molecular structure of 1,1'-bis[2-[4-(4- methoxyphenoxycarbonyl)phenoxy]ethoxycarbonyl]ferrocene.
- Nakamura, Naotake,Hiro, Kazuya,Nishikawa, Masako,Okabe, Takashi,Uno, Kenjiro
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scheme or table
p. 122 - 131
(2010/08/05)
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- Cationic surfactants
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A surfactant comprising a polyether segment including at least one pendant alkoxyfluoroalkyl group, and a cationic substituent defined by one of the formulae: or the substituted derivatives thereof.
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Page/Page column 3
(2008/06/13)
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- METHOD AND APPARATUS FOR THE USE OF [11C] CARBON MONIXIDE IN LABELING SYNTHESIS BY PHOTO-INITIATED CARBONYLATION
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Methods and reagents for photo-initiated carbonylation with carbon-isotope labeled carbon monoxide using amines and alkyl/aryl iodides are provided. The resultant carbon-isotope labeled amides are useful as radiopharmaceuticals, especially for use in Positron Emission Tomography (PET). Associated kits for PET studies are also provided.
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Page/Page column 28-29
(2008/06/13)
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- A new strategy for synthesis of polymeric supports with triazene linkers
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A new strategy based on the use of diethylamine triazenes for stabilization and generation of polymer supported diazonium ions was described. New economical syntheses of four new polymeric supports with 3- and 6-carbon atom spacers and triazene linkers derived from meta- and para-aminophenol were described and compared to the traditional methods. The possible application of the polymer bound triazene masked diazonium salts as supports for immobilization of secondary amines (nortropine and 4-piperidinole and their esterification and oxidation), and as amine scavengers was shown. The new supports with meta-C3-T2 and para-C3-T2 linkers showed higher loadings and typically gave products with good yields and purities.
- Lazny, Ryszard,Nodzewska, Aneta,Klosowski, Piotr
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p. 121 - 130
(2007/10/03)
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- The asymmetric synthesis of α-substituted α-methyl and α-phenyl phosphonic acids: Design, carbanion geometry, reactivity and preparative aspects of chiral alkyl bicyclic phosphonamides
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The design, preparation, structural and spectroscopic analyses of topologically unique and enantiomerically pure alkyl phosphonamides are described. In the case of α-ethyl and α-benzyl phosphonamides, the geometry of both the secondary and tertiary carbanions was determined to be planar through deprotonation/deuteration/alkylation experiments. Stereoselective alkylations of such systems proceeded in good yields and with high diastereoselectivities. The resulting α,α-alkylated phosphonamides were hydrolyzed to give the corresponding α,α-alkyl phosphonic acids with high degrees of enantiomeric purity.
- Bennani, Youssef L.,Hanessian, Stephen
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p. 13837 - 13866
(2007/10/03)
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- Intramolecular Nucleophilic Acyl Substitution Reactions Mediated by Samarium(II) Iodide: A Convergent Approach to the Preparation of Enantiomerically Enriched 4-Hydroxy Ketones from 3-Iodopropyl Carboxylates
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Intramolecular nucleophilic acyl substitution (I NAS) reactions of substituted δ-iodopropylcarboxylates have been achieved using samarium(II) iodide (SmI2) in the presence of an iron(III) catalyst.Diverse ester starting materials containing stereogenic centers placed in varying postions on the substrates have been converted to acyclic 4-hydroxy ketone derivatives in good yields using this method.No racemization of stereogenic centers α to the carbonyl was observed in any of the reactions examined.Consequently, the method serves as a convenient, high-yield synthesis of functionalized, enantiomerically enriched acyclic ketones possesing stereogenic centers far removed from one another.
- Molander, Gary A.,Shakya, Sagar R.
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p. 3445 - 3452
(2007/10/02)
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- Syntheses and Physical Properties of Ferrocene Derivatives(III) Liquid Crystallinity of Disubstituted Ferrocene Derivatives
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A new series of 1,1'-disubstituted ferrocene derivatives, 1,1'-bisalkoxycarbonyl>ferrocene, incorporating a variable carbon number of methylene chain units has been prepared.The thermal behavior of these compounds has been examined by polarizing microscopy observations and differential scanning calorimetry measurements.Four of five kinds of samples synthesized here showed liquid crystallinity near the ambient temperature.Furthermore, these compounds have a fairly wide temperature range of liquid crystalline states. - Keywords: Ferrocene, liquid crystal, 1,1'-disubstituted derivatives, transition metal complex, phase transition
- Hanasaki, T.,Ueda, M.,Nakamura, N.
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p. 257 - 268
(2007/10/02)
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- Formation of 14-membered carbocycles by intramolecular Michael addition on ynones and enones
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The base-catalyzed intramolecular Michael addition of substituted malonates on ynones or enones proceeds efficiently to give the 14-membered carbocycles.
- Girard, Suzanne,Deslongchamps, Pierre
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p. 1265 - 1273
(2007/10/02)
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- N-(3-[18F]fluoropropyl)-N-nordiprenorphine: synthesis and characterization of a new agent for imaging opioid receptors with positron emission tomography.
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A series of N-fluoroalkyl (1-5) and N-alkyl (6-8) analogues of the high-affinity opioid receptor antagonist diprenorphine (9) has been synthesized and evaluated with in vitro binding assays. Three of the N-fluoroalkyl compounds were prepared with the positron-emitting radionuclide 18F (1a, 2a, 5a), and their biodistribution was determined in rats. Compounds 2a and 5a were made by using a two-step labeling procedure, [18F]fluoride displacement of an iodoalkyl triflate followed by N-alkylation, that required 2 h and proceeded in 4-6% overall radiochemical yield at the end of synthesis. The effective specific activity of compounds 2a and 5a, determined by competitive receptor binding assay, was 840-1820 Ci/mmol. Compound 1a was made by the same two-step procedure, with the bromoalkyl triflate, in 0.3-0.6% radiochemical yield at an effective specific activity of 106-264 Ci/mmol. Specificity of binding in vivo was measured as the percent injected dose/gram of striatal tissue divided by the percent injected dose/gram of cerebellar tissue. The best striatum to cerebellum ratio (3.32 +/- 0.74 at 30 min) was achieved with N-(3-[18F]-fluoropropyl)-N-nordiprenorphine (2a, [18F]FPND). The high specific binding demonstrated by this compound indicates that it may be useful for in vivo imaging of opioid receptors with positron emission tomography.
- Chesis,Hwang,Welch
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p. 1482 - 1490
(2007/10/02)
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- A Rapid and Efficient Method for the Fluoroalkylation of Amines and Amides. Development of a Method Suitable for Incorporation of the Short-Lived Positron Emitting Radionuclide Fluorine-18
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We have described a two-step method for the preparation of fluoroalkyl-substituted amines and amides.The sequence involves fluoride ion displacement of a haloalkyl trifluoromethanesulfonate (triflate), followed by fluoroalkylation of the heteroatom system (amine or amide) by the fluoroalkyl halide.Alternatively, the fluoroalkyl halide can be prepared by halofluorination of a terminal olefin.These reactions have been used to prepare various fluoroalkyl derivatives of N-phenylpiperazine and N-fluoroalkyl derivatives of the neuroleptic agent spiperone (7).The sequence is rapid, convenient, and efficient, even when fluoride ion is the limiting reagent.Therefore, it is readily adaptable to the preparation of a variety of compounds labeled with the short half-life (t1/2 = 110 min) positron-emitting radionuclide fluorine-18.
- Chi, Dae Yoon,Kilbourn, Michael R.,Katzenellenbogen, John A.,Welch, Michael J.
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p. 658 - 664
(2007/10/02)
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- NEW GENERAL SYNTHESIS OF MEDIUM RING-LACTONES VIA A REGIOSELECTIVE β-SCISSION OF ALKOXYL RADICALS GENERATED FROM CATACONDENSED LACTOLS
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We describe a new general method for the synthesis of medium-sized lactones based on ring-enlargement via a regioselective β-scission of alkoxyl radicals generated by photolysis from the hypoiodites of several catacondensed lactols.The syntheses of 9-membered lactones from 6/5 fused lactols, 10-menbered lactones including a naturally occuring lactone, phoracantholide I, from 6/6 or 7/5 fused lactols, and 11-membered lactones from 7/6 or 8/5 fused lactols are shown to be achieved by the present method.This new method may have a potential for application to the synthesis of either smaller or larger-sized lactones.
- Suginome, Hiroshi,Yamada, Shinji
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p. 3371 - 3386
(2007/10/02)
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