- Molecular and supramolecular helicity induction in trityl group-containing compounds: The case of chiral 3,3,3-triphenylpropionic acid derivatives
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The process of dynamic chirality transmission from permanent chirality element to stereodynamic triphenylmethyl group placed in the distance of 4 bonds, has been studied for series of optically active 3,3,3-triphenylpropionic acid derivatives. Structural
- Skowronek, Pawe?,Czapik, Agnieszka,Rajska, Zuzanna,Kwit, Marcin
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- Synthesis and photophysical properties of 2-azolyl-6-piperidinylpurines
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[Figure not available: see fulltext.] A synthesis of novel fluorescent 2-azolyl-6-piperidinylpurine derivatives was designed. Azolyl substituent at purine C-2 atom was introduced via nucleophilic aromatic substitution or in the case of tetrazolyl and 1,2,3-triazolyl substituents via a ring formation on a preinstalled amine or azide moiety, respectively. The obtained purine intermediates were functionalized at N-9 position using Mitsunobu reaction conditions to achieve amorphous compounds, which form thin-layer films of good quality. The synthesized push-pull systems exhibited fluorescence with emission in range of 360–400 nm and quantum yields up to 66% in CH2Cl2 solution and up to 45% in the thin-layer film.
- Novosjolova, Irina,Sebris, Armands,Traskovskis, Kaspars,Turks, Māris
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p. 560 - 567
(2021/06/14)
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- Development of a fluorescent cardiomyocyte specific binding probe
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Cardiomyocytes are the major component of the heart. Their dysfunction or damage could lead to serious cardiovascular diseases, which have claimed numerous lives around the world. A molecule able to recognize cardiomyocytes would have significant value in diagnosis and treatment. Recently a novel peptide termed myocyte targeting peptide (MTP), with three residues of a non-natural amino acid biphenylalanine (Bip), showed good affinity to cardiomyocytes. Its selectivity towards cardiac tissues was concluded to be due to the ability of Bip to bind cardiac troponin I. With the aim of optimizing the affinity and the specificity towards cardiac myocytes and to better understand structure-activity relationship, a library of MTP derivatives was designed. Exploiting a fluorescent tag, the selectivity of the MTP analogs to myocardium over skeletal and stomach muscle tissues was assayed by fluorescence imaging. Among the tested sequences, the peptide probe Bip2, H-Lys(FITC)-Arg-Arg-Arg-Arg-Arg-Arg-Arg-Gly-Ser-Gly-Ser-Bip-Bip-NH2, displayed the best selectivity for cardiomyocytes.
- Pes, Lara,Kim, Young,Tung, Ching-Hsuan
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p. 1706 - 1717
(2016/04/05)
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- Hexameric resorcinarene capsule is a bronsted acid: Investigation and application to synthesis and catalysis
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Molecular capsules have attracted interest as simple enzyme mimetics and several examples of catalytic transformations in water-soluble metal-ligand based systems have been reported. This is not the case for hydrogen-bond based molecular capsules, which in contrast can be employed in organic solvents. We describe herein our investigations of such a system: The resorcin[4]arene hexamer is one of the largest hydrogen bond-based self-assembled capsules and has been studied intensively due to its ready availability. We present evidence that the capsule acts as a reasonably strong Bronsted acid (pK a approximately 5.5-6). This finding explains the capsule's high affinity toward tertiary amines that are protonated and therefore encounter cation-π interactions inside the cavity. We were able to translate this finding into a first synthetic application: A highly substrate-selective Wittig reaction. We also report that this property renders the capsule an efficient enzyme-like catalyst for substrate selective diethyl acetal hydrolysis.
- Zhang, Qi,Tiefenbacher, Konrad
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supporting information
p. 16213 - 16219
(2013/11/19)
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- Dual polyrotaxane: One-pot synthesis of topological polymer by using metathesis reaction
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The topological polyrotaxane was built from an ammonium salt as an axle component bearing one olefin and one bulky unit at the end of chain and the derivative of dibenzo-24-crown-8 (DB24C8) as a wheel component having one terminal olefin. In this system, two kinds of reactions work at the same time as a driving force of the polymer construction. One is the inclusion reaction between the ammonium salt part of axle and the wheel, another is metathesis reaction between olefins of the axle and olefins of the wheel. Copyright
- Yamabuki, Kazuhiro,Isobe, Yukio,Onimura, Kenjiro,Oishi, Tsutomu
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p. 1196 - 1197
(2008/03/13)
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- Synthesis and identification of small molecules that potently induce apoptosis in melanoma cells through G1 cell cycle arrest
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Late-stage malignant melanoma is a cancer that is refractory to current chemotherapeutic treatments. The average survival time for patients with such a diagnosis is 6 months. In general, the vast majority of anticancer drugs operate through induction of cell cycle arrest and cell death in either the DNA synthesis (S) or mitosis (M) phase of the cell cycle. Unfortunately, the same mechanisms that melanocytes possess to protect cells from DNA damage often confer resistance to drugs that derive their toxicity from S or M phase arrest. Described herein is the synthesis of a combinatorial library of potential proapoptotic agents and the subsequent identification of a class of small molecules (triphenylmethylamides, TPMAs) that arrest the growth of melanoma cells in the G1 phase of the cell cycle. Several of these TPMAs are quite potent inducers of apoptotic death in melanoma cell lines (IC50 ~ 0.5 μM), and importantly, some TPMAs are comparatively nontoxic to normal cells isolated from the bone marrow of healthy donors. Furthermore, the TPMAs were found to dramatically reduce the level of active nuclear factor κ-B (NFκB) in the cell; NFκB is known to be constitutively active in melanoma, and this activity is critical for the proliferation of melanoma cells and their evasion of apoptosis. Compounds that reduce the level of NFκB and arrest cells in the G1 phase of the cell cycle can provide insights into the biology of melanoma and may be effective antimelanoma agents.
- Dothager, Robin S.,Putt, Karson S.,Allen, Brittany J.,Leslie, Benjamin J.,Nesterenko, Vitaliy,Hergenrother, Paul J.
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p. 8686 - 8696
(2007/10/03)
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- Synthesis and preliminary characterization of some polyester rotaxanes
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A series of polyester rotaxanes containing polysebacate backbones [decamethylene, tri(ethyleneoxy), and 1,4-butylene] and ethylene oxide-based crown ethers [30-crown-10,42-crown-14, 60-crown-20, and bis(p-phenylene)-34-crown-10] was synthesized via step growth polymerizations using diacid chloride-diol and transesterification reactions. The polyrotaxanes were purified by multiple reprecipitations in good solvents for the crown ethers, and the physical linkage of the crown ether to the polymeric backbone was confirmed by a variety of experiments, including hydrolysis, NMR, GPC, and VPO. Up to 55 wt % macrocycle was incorporated, depending on the size and shape of the macrocycle and the feed ratios employed. In all cases, the solubilities of the polyrotaxanes were strongly influenced by the cyclic component; enhanced solubilities in polar solvents were observed relative to the simple parent polysebacates. Mark-Houwink K and a values were also strongly affected by rotaxane formation; in the case most thoroughly investigated, K decreased by almost 2 orders of magnitude and a doubled. Interpretation of this observation is complicated by the changes in solubility. Thermal behavior was also affected. In the tri-(ethyleneoxy) system, Tg is lowered in the rotaxanes; in the 60-crown-20 system, the macrocycle crystallized! The poly(butylene sebacate) 60-crown-20 and 42-crown-14 systems also possessed two crystalline phases, a crown ether phase and a poly(butylene sebacate) phase. These exciting result demonstrate the mobility of the macrocycle along the polyester backbone in melt and solution states, allowing aggregation and crystallization without dethreading.
- Gibson, Harry W.,Liu, Shu,Lecavalier, Pierre,Wu, Charles,Shen, Ya Xi
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p. 852 - 872
(2007/10/02)
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- Molecular self-assembly through hydrogen bonding: Supramolecular aggregates based on the cyanuric acid-melamine lattice
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Reaction of the tris(melamine) derivatives hubM3 (C6H3-1,3,5-[CONHC6H4-3-N(CH 2C6H4-4-C(CH3)3)COC 6-H3-2-NHC3Ns
- Seto, Christopher T.,Whitesides, George M.
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p. 905 - 916
(2007/10/02)
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- 1-(3,3,3-Triarylalkyl)-4-phenyl-piperidinealkanols
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The present invention encompasses compounds of the formula STR1 and pharmaceutically acceptable acid addition salts thereof wherein the Alk is straight or branched chain alkylene containing 2-4 carbon atoms; M is alkylene having 1-4 carbon atoms; Ar and Ar' are phenyl, alkyl substituted phenyl wherein the alkyl contains from 1-4 carbon atoms or halo substituted phenyl; Ar" is phenyl, alkyl substituted phenyl wherein the alkyl contains 1-4 carbon atoms, halo substituted phenyl or pyridyl; X is hydrogen, halogen, trifluoromethyl or alkyl having from 1-4 carbon atoms; R is hydrogen alkyl having from 1-7 carbon atoms or an alkanoyl having from 2-5 carbon atoms. These compounds are potent antidiarrheal agents characterized by little, if any, central nervous system activity.
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