- Far-red photoactivatable BODIPYs for the super-resolution imaging of live cells
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The identification of viable designs to construct switchable fluorescent probes and operate them in the interior of live cells is essential to allow the acquisition of SMLM images and permit the visualization of cellular components with sub-diffraction resolution. Our laboratories developed a mechanism to switch the fluorescence of BODIPY chromophores with the photoinduced cleavage of oxazine heterocycles under mild 405-nm illumination. With appropriate structural modifications, these switchable molecules can be engineered to immobilize covalently on large biomolecules within lysosomal compartments of live COS-7 cells and produce bright far-red fluorescence with optimal contrast upon activation. Such a combination of properties permits the acquisition of PALM images of the labeled organelles with localization precision of ca. 15 nm. This article reports the experimental protocols for the synthesis of and live-cell labeling with these compounds as well as for the reconstruction of super-resolution images of the resulting biological preparations.
- Zhang, Yang,Tang, Sicheng,Ravelo, Laura,Cusido, Janet,Raymo, Fran?isco M.
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- An activated O --> N acyl transfer auxiliary: efficient amide-backbone substitution of hindered difficult peptides.
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Overcoming the phenomenon known as difficult synthetic sequences has been a major goal in solid-phase peptide synthesis for over 30 years. In this work the advantages of amide backbone-substitution in the solid-phase synthesis of difficult peptides are augmented by developing an activated N(alpha)()-acyl transfer auxiliary. Apart from disrupting troublesome intermolecular hydrogen-bonding networks, the primary function of the activated N(alpha)()-auxiliary was to facilitate clean and efficient acyl capture of large or beta-branched amino acids and improve acyl transfer yields to the secondary N(alpha)()-amine. We found o-hydroxyl-substituted nitrobenzyl (Hnb) groups were suitable N(alpha)()-auxiliaries for this purpose. The relative acyl transfer efficiency of the Hnb auxiliary was superior to the 2-hydroxy-4-methoxybenzyl (Hmb) auxiliary with protected amino acids of varying size. Significantly, this difference in efficiency was more pronounced between more sterically demanding amino acids. The Hnb auxiliary is readily incorporated at the N(alpha)()-amine during SPPS by reductive alkylation of its corresponding benzaldehyde derivative and conveniently removed by mild photolysis at 366 nm. The usefulness of the Hnb auxiliary for the improvement of coupling efficiencies in the chain-assembly of difficult peptides was demonstrated by the efficient Hnb-assisted Fmoc solid-phase synthesis of a known hindered difficult peptide sequence, STAT-91. This work suggests the Hnb auxiliary will significantly enhance our ability to synthesize difficult polypeptides and increases the applicability of amide-backbone substitution.
- Miranda,Meutermans,Smythe,Alewood
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- A convenient approach to an advanced intermediate toward the naturally occurring, bioactive 6-substituted 5-hydroxy-4-aryl-1H-quinolin-2-ones
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5-Hydroxy-4-aryl-3,4-dihydro-1H-quinolin-2-ones are a small family of natural products isolated from fungal strains of Penicillium and Aspergillus. Most of its members, which are insecticides and anthelmintics, carry an isoprenoid C-6 side chain. The synthesis of a 6-propenyl-substituted advanced intermediate for the total synthesis of these natural products is presented in this paper. This was achieved through the stereoselective construction of a β,β-diarylacrylate derivative from 6-nitrosalicylaldehyde, using a Wittig olefination and a Heck-Matsuda arylation, followed by a selective Fe0-mediated reductive cyclization. Installation of the 6-propenyl side chain was performed by 5-O-allylation of the heterocycle, followed by Claisen rearrangement and conjugative migration of the allyl double bond, as the key steps. The Grubbs II-catalyzed olefin cross metathesis of the 6-allyl moiety with 2-methylbut-2-ene to afford a precursor of peniprequinolone is also reported.
- Simonetti, Sebastián O.,Larghi, Enrique L.,Kaufman, Teodoro S.
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- Far-Red Photoactivatable BODIPYs for the Super-Resolution Imaging of Live Cells
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The photoinduced disconnection of an oxazine heterocycle from a borondipyrromethene (BODIPY) chromophore activates bright far-red fluorescence. The high brightness of the product and the lack of autofluorescence in this spectral region allow its detection at the single-molecule level within the organelles of live cells. Indeed, these photoactivatable fluorophores localize in lysosomal compartments and remain covalently immobilized within these organelles. The suppression of diffusion allows the reiterative reconstruction of subdiffraction images and the visualization of the labeled organelles with excellent localization precision. Thus, the combination of photochemical, photophysical and structural properties designed into our fluorophores enable the visualization of live cells with a spatial resolution that is inaccessible to conventional fluorescence imaging.
- Zhang, Yang,Song, Ki-Hee,Tang, Sicheng,Ravelo, Laura,Cusido, Janet,Sun, Cheng,Zhang, Hao F.,Raymo, Fran?isco M.
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- Compound with dual inhibitory activity TDO, IDOO1 and application of compound for treating neurodegenerative disease (by machine translation)
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The present invention provides a compound of formula I, or a pharmaceutically acceptable salt thereof, or a solvate thereof, which can selectively inhibit TDO, IDOO1, which has a significant inhibitory effect on TDO and/or IDOO1. In addition, the prepared compound has a remarkable anti-tumor effect, has a certain treatment effect on's disease and's disease, and has a good application prospect in the field of medicine preparation. (by machine translation)
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Paragraph 0172-0175
(2020/10/06)
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- Synthesis of five libraries of 6,5-fused heterocycles to establish the importance of the heterocyclic core for antiplasmodial activity
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Research has indicated that N-myristoyl transferase, an enzyme that catalyzes the addition of a myristate group to the N-terminal glycine residues of proteins, is involved in the myristoylation of more than 100 proteins. Genetic knockdown of the enzyme proved detrimental for the viability of the parasite P. knowlesi. A crystal structure of P. vivax N-myristoyl transferase (pvNMT), containing a 3-methyl benzofuran ligand has made it possible to assess key amino acid residue-ligand interactions. We synthesized five libraries of 6,5-fused heterocycles to establish the importance of the heterocycles as core scaffolds, as well as introduced various aromatic amides and esters to determine which carbonylic group affects the potency of each heterocyclic antiplasmodial agent.
- Jacobs, Leon,de Kock, Carmen,Taylor, Dale,Pelly, Stephen C.,Blackie, Margaret A.L.
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p. 5730 - 5741
(2018/11/06)
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- Co-immobilization of Laccase and TEMPO in the Compartments of Mesoporous Silica for a Green and One-Pot Cascade Synthesis of Coumarins by Knoevenagel Condensation
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Co-immobilization of bio- and chemocatalysts produces sustainable, recyclable hybrid systems that open new horizons for green cascade approaches in organic synthesis. Here, the co-immobilization of laccase and 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) in mesoporous silica was used for the one-pot aqueous synthesis of 30 coumarin-3-carboxylate derivatives under mild conditions through the condensation of in situ oxidized 2-hydroxybenzyl alcohols and malonate derivatives. A maximum yield was obtained after incubating at pH 6.0 and 45 °C for 24 h. An efficient organic synthesis was catalyzed by the hybrid catalyst in 10 % organic solvent. More than 95 % of the initial activity of the enzyme was preserved after 10 cycles, and no significant catalyst deactivation occurred after 10 runs. This new system efficiently catalyzed the in situ aerobic oxidation of salicyl alcohols, followed by Knoevenagel condensation, which confirmed the possibility of producing efficient hybrid catalysts by co-immobilization of catalytic species in mesoporous materials.
- Mogharabi-Manzari, Mehdi,Amini, Mohsen,Abdollahi, Mohammad,Khoobi, Mehdi,Bagherzadeh, Ghodsieh,Faramarzi, Mohammad Ali
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p. 1542 - 1546
(2018/02/28)
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- Pd-Catalyzed Ortho C-H Hydroxylation of Benzaldehydes Using a Transient Directing Group
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The direct Pd-catalyzed ortho C-H hydroxylation of benzaldehydes was achieved using 4-chloroanthranilic acid as the transient directing group, 1-fluoro-2,4,6-trimethylpyridnium triflate as the bystanding oxidant, and p-toluenesulfonic acid as the putative oxygen nucleophile. The unusual C-H chlorination and polyfluoroalkoxylation reactions signaled the importance of external nucleophiles to the outcome of Pd(IV) reductive eliminations.
- Chen, Xiao-Yang,Ozturk, Seyma,Sorensen, Erik J.
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supporting information
p. 6280 - 6283
(2017/12/08)
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- Cyclic tetrapeptides via the ring contraction strategy: Chemical techniques useful for their identification
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Cyclic tetrapeptides are a class of natural products that have been shown to have broad ranging biological activities and good pharmacokinetic properties. In order to synthesise these highly strained compounds a ring contraction strategy had previously been reported. This strategy was further optimised and a suite of techniques, including the Edman degradation and mass spectrometry/mass spectrometry, were developed to enable characterisation of cyclic tetrapeptide isomers. An NMR solution structure of a cyclic tetrapeptide was also generated. To illustrate the success of this strategy a library of cyclic tetrapeptides was synthesised. The Royal Society of Chemistry.
- Horton, Douglas A.,Bourne, Gregory T.,Coughlan, Justin,Kaiser, Sonya M.,Jacobs, Carolyn M.,Jones, Alun,Ruehmann, Andreas,Turner, Jill Y.,Smythe, Mark L.
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experimental part
p. 1386 - 1395
(2008/10/09)
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- Effect of aldehyde and methoxy substituents on nucleophilic aromatic substitution by [18F]fluoride
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For a series of benzaldehydes only with a leaving group or with both a leaving group and a single methoxy substituent 18F-fluorination via nucleophilic aromatic substitution (SNAr) was studied in DMF and Me2SO. In general, the radiochemical yields were clearly higher in DMF than in Me2SO. In the fluorodehalogenation reaction (leaving group: halogen = Br, Cl), extremely low radiochemical yields were observed in Me2SO (2SO (within 3 min reaction time, 90% of the precursor was consumed; radiochemical yield = 1.0 ± 0.5%); however, in DMF oxidation was always kept at a low level during the entire reaction (13C-NMR ppm values of the aromatic carbon atom bearing the leaving group.
- Shen, Bin,L?ffler, Dirk,Zeller, Klaus-Peter,übele, Michael,Reischl, Gerald,Machulla, Hans-Jürgen
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p. 1461 - 1468
(2008/09/18)
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- Pyridine derivatives
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Pyridine compounds of general formula: wherein —R1represents in which R11is hydrogen, C1-6alkyl, halogen, hydroxy, C1-12alkoxy, nitro, amino, C1-6alkylsulfonylamino, C1-6alkoxycarbonyl, C1-6alkylamino, di(C1-6alkyl)amino, C1-6alkanoylamino, phenyl C1-6alkylamino, phenylsulfonylamino, or —O—(CH2)n—R111; R2represents hydrogen or halogen; R3represents hydrogen, —CR31R32R33, or —NR34R35; R4is hydrogen, carbamoyl, CN, carboxyl, etc.; R5is amino, C1-6alkylamino, di C1-6alkylamino, etc. or salt thereof. The compound has an excellent anti-inflammatory activity, and other biological activity.
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- Vicarious nucleophilic substitution of hydrogen in nitrophenyl toluenesulfonates
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Toluenesulfonates of nitrophenols react with carbanions possessing leaving groups giving products of the vicarious nucleophilic substitution of hydrogen. The yields and orientation depend on the reaction conditions and the structure of the reagents. The products obtained can be easily hydrolyxed to the corresponding phenols or - in certain cases - to hydroxynitrobenzaldehydes.
- Makosza, Mieczyslaw,Ziobrowski, Tadeusz,Serebriakov, Mikhail,Kwast, Andrzej
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p. 4739 - 4750
(2007/10/03)
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- CONVENIENT SYNTHESIS OF A SIMPLE COUMARIN FROM SALICYLALDEHYDE AND WITTIG REAGENT (III): SYNTHESIS OF NITROCOUMARINS
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Reaction of nitrosalicylaldehydes (1) with carbethoxymethylenetriphenylphosphorane in Et2NPh, in Ph2O, and in the absence of solvent (neat) at 210-215 deg C was investigated.Reaction of 3-nitrosalicylaldehyde (1d) in Et2NPh afforded the benzoxazole (6) and the aminocoumarin (3e) along with the expected coumarin (3d).It was clarified that the origin of carbon-unit introduced for the formation of the benzoxazole ring came from the alkyl group of solvent.
- Harayama, Takashi,Nakatsuka, Kazumitsu,Nishioka, Hiromi,Maurakami, Kyoko,Ohmori, Yukiko,et al.
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p. 2729 - 2738
(2007/10/02)
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