- Design and synthesis of a highly sensitive off-on fluorescent chemosensor for zinc ions utilizing internal charge transfer
-
Fluorescence imaging is a powerful tool for the visualization of biological molecules in living cells, tissue slices, and whole bodies, and is important for elucidating biological phenomena. Furthermore, zinc (Zn2+) is the second most abundant heavy metal ion in the human body after iron, and detection of chelatable Zn2+ in biological studies has attracted much attention. Herein, we present a novel, highly sensitive off-on fluorescent chemosensor for Zn2+ by using the internal charge transfer (ICT) mechanism. The rationale of our approach to highly sensitive sensor molecules is as follows. If fluorescence can be completely quenched in the absence of Zn2+, chemosensors would offer a better signal-to-noise ratio. However, it is difficult to quench the fluorescence completely before Zn 2+ binding, and most sensor molecules still show very weak fluorescence in the absence of Zn2+. But even though the sensor shows a weak fluorescence in the absence of Zn2+, this fluorescence can be further suppressed by selecting an excitation wavelength that is barely absorbed by the Zn2+-free sensor molecule. Focusing on careful control of ICT within the 4-amino-1,8-naphthalimide dye platform, we designed and synthesized a new chemosensor (1) that shows a pronounced fluorescence enhancement with a blueshift in the absorption spectrum upon addition of Zn 2+. The usefulness of 1 for monitoring Zn2+ changes was confirmed in living HeLa cells. There have been several reports on 4-amino-1,8-naphthalimide-based fluorescent sensor molecules. However, 1 is the first Zn2+-sensitive off-on fluorescent sensor molecule that employs the ICT mechanism; most off-on sensor molecules for Zn2+ employ the photoinduced electron transfer (PeT) mechanism.
- Hanaoka, Kenjiro,Muramatsu, Yasuaki,Urano, Yasuteru,Terai, Takuya,Nagano, Tetsuo
-
-
Read Online
- Base-Promoted Tandem Synthesis of 2-Azaaryl Tetrahydroquinolines
-
A novel method to synthesize 2-azaaryl tetrahydroquinolines by the base-promoted tandem reaction of azaaryl methyl amines and styrene derivatives is reported (over 30 examples, yields up to 95%). Mechanistic probe experiments demonstrate that the deprotonation of the benzylic C-H bond and the addition to the styrene vinyl group proceeds via the SNAr mechanism.
- Chen, Shuguang,Yang, Langxuan,Shang, Yongjia,Mao, Jianyou,Walsh, Patrick J.
-
supporting information
p. 1594 - 1599
(2021/03/08)
-
- Amidation of unactivated ester derivatives mediated by trifluoroethanol
-
A catalytic amidation protocol mediated by 2,2,2-trifluoroethanol has been developed, facilitating the condensation of unactivated esters and amines, furnishing both secondary and tertiary amides. The complete scope and limitations of the method are described, along with modified conditions for challenging substrates such as acyclic secondary amines and chiral esters with retention of chiral integrity.
- McPherson, Christopher G.,Caldwell, Nicola,Jamieson, Craig,Simpson, Iain,Watson, Allan J. B.
-
p. 3507 - 3518
(2017/04/26)
-
- 4-Aminoquinoline Antimalarials Containing a Benzylmethylpyridylmethylamine Group Are Active against Drug Resistant Plasmodium falciparum and Exhibit Oral Activity in Mice
-
Emergence of drug resistant Plasmodium falciparum including artemisinin-tolerant parasites highlights the need for new antimalarials. We have previously shown that dibemequines, 4-amino-7-chloroquinolines with dibenzylmethylamine (dibemethin) side chains, are efficacious. In this study, analogues in which the terminal phenyl group of the dibemethin was replaced with a 2-pyridyl group and in which the 4-amino-7-chloroquinoline was either maintained or replaced with a 4-aminoquinoline-7-carbonitrile were synthesized in an effort to improve druglikeness. These compounds exhibited significantly improved solubility and decreased lipophilicity and were potent against chloroquine-sensitive (NF54) and -resistant (Dd2 and 7G8) P. falciparum strains with 5/6 having IC50 100 nM against the NF54 strain. All inhibited both β-hematin (synthetic hemozoin) formation and hemozoin formation in the parasite. Parasitemia was reduced by over 90% in P. berghei infected mice in 3/6 derivatives following oral dosing at 4 × 30 mg/kg, with microsomal metabolic stability data suggesting that this could be attributed to highly active metabolites.
- Joshi, Mukesh C.,Okombo, John,Nsumiwa, Samkele,Ndove, Jeffrey,Taylor, Dale,Wiesner, Lubbe,Hunter, Roger,Chibale, Kelly,Egan, Timothy J.
-
p. 10245 - 10256
(2018/01/10)
-
- PRODRUGS OF PHENOLIC TRPV1 AGONISTS IN COMBINATION WITH LOCAL ANESTHETICS AND VASOCONSTRICTORS FOR IMPROVED LOCAL ANESTHESIA
-
Described herein are compounds, pharmaceutical compositions and medicaments that include such compounds, and methods of using such compounds to modulate transient receptor potential vanilloid 1 receptor (TRPV1) activity.
- -
-
Paragraph 00180
(2017/12/29)
-
- An iron(iii) tetradentate monoamido complex as a nonheme iron-based peroxidase mimetic
-
A mononuclear iron(iii) complex of a noncyclic tetradentate monoamido ligand, Fe(iii)mpaq, catalyses the oxidation of Orange II, guaiacol, ABTS and Amplex Red with H2O2 in aqueous solutions at neutral pH. Under identical conditions, other structurally related nonheme iron complexes showed only negligible activities.
- Hitomi, Yutaka,Hiramatsu, Kazuaki,Arakawa, Kengo,Takeyasu, Toshiyuki,Hata, Masashi,Kodera, Masahito
-
p. 12878 - 12882
(2013/09/12)
-
- An unusually stable octanuclear σ-mesityl-bridged μ4-oxo-copper(i) complex encapsulated by a pyrazolate-based compartmental ligand scaffold
-
A new compartmental pyrazole-derived chelating ligand, four equivalents of mesitylcopper and stoichiometric amounts of dioxygen lead to the formation of a remarkably stable organometallic framework that can be described as a heteroleptic O-centered cuprate anion [(MesCuI) 4(μ4-O)]2- linked via σ-mesityl- bridges to two surrounding binuclear CuI-pyrazolate clamps. The Royal Society of Chemistry.
- Stollenz, Michael,Grosse, Christian,Meyer, Franc
-
p. 1744 - 1746
(2008/12/22)
-
- Photoresponsive Heterocyclic Azo Compound, Method for Producing the Same, and Optical Information Recording Medium
-
There are provided a novel optical information recording material or medium excellent in various holographic optical information recording properties such as sensitivity, response speed, long-term storage stability, and repeatability, and a substance therefor. A photoresponsive heterocyclic azo compound contains an oligomer or polymer having a photoresponsive moiety in at least one of the main chain and side chain, and the photoresponsive moiety is a building block represented by the following formula (1): wherein HC1 and HC2 each represent a ring structure, at least one of them being a heterocyclic structure containing 1 or more heteroatom in the ring, R1 and R2 each represent a hydrogen atom or a substituent connected to the ring structure and may be the same or different ones, s and t each represent the number thereof, and X1 and X2 each represent a terminal group or a linking group, at least one of them being a linking group connected to the main chain of the oligomer or polymer and the terminal group being a hydrogen atom or a substituent.
- -
-
-
- Novel multicyclic compounds and the use thereof
-
The present invention is directed to novel multicyclic molecules that mediate enzymatic activity. In particular, the compounds may be effective in the treatment of diseases or disease states related to the activity of PARP, VEGFR2, and MLK3 enzymes, including, for example, neurodegenerative diseases, inflammation, ischemia, and cancer.
- -
-
-
- Practical and efficient synthesis of C2 symmetrical diamines with Zn / Me3SiCl
-
C2 symmetrical diamines are efficiently obtained by reductive coupling of imines with the couple Zn/Me3SiCl. This high yielding method is very practical and cheap for large scale preparation.
- Alexakis, Alexandre,Aujard, Isabelle,Mangeney, Pierre
-
p. 873 - 874
(2007/10/03)
-
- Irreversible HIV protease inhibitors, intermediates, compositions and processes for the preparation thereof
-
The present invention provides cis-epoxide compounds represented by formula (I-1), (I-2) or (I-3) which are useful for treating or preventing diseases caused by HIV infection: STR1 wherein: A, B, D, E, R1, R10, R11, K, G, Q, r and J have the meanings as defined in the specification.
- -
-
-
- Cis-epoxide derivatives useful as irreversible HIV protease inhibitors and process and intermediates for their preparation
-
The present invention provides cis-epoxide compounds represented by formula (I-1), (I-2) or (I-3) which are useful for treating or preventing diseases caused by HIV infection: wherein:, A, B, D, E, R1, R10, R11, K, G, Q, r and J have the meanings as defined in the specification.
- -
-
-
- Symmetry-Based Inhibitors of HIV Protease. Structure-Activity Studies of Acylated 2,4-Diamino-1,5-diphenyl-3-hydroxypentane and 2,5-Diamino-1,6-diphenylhexane-3,4-diol
-
The structure-activity relationships in two series of novel, symmetry-based inhibitors of HIV protease, the enzyme responsible for maturation of the human immunodeficiency virus, are described.Beginning with lead compounds 3-6, the effect of adding polar, heterocyclic end groups to one or both ends of the symmetric or pseudosymmetric inhibitors was probed.Aqueous solubility was enhanced >1000-fold while maintaining potent inhibition of purified HIV-1 protease and anti-HIV activity in vitro.Pharmacokinetic studies in rats indicated a substantial difference in the absorption properties of mono-ol-based and diol-based inhibitors.The oral bioavailability of inhibitor 19 in rats was 19percent; however, the Cmax obtained failed to exceed the anti-HIV EC50 in vitro.Substantial plasma levels of potent inhibitors of the diol class were not obtained after oral administration in rats; however, the optimal combination of aqueous solubility and in vitro antiviral activity of several inhibitors support their potential use in intravenous therapy.
- Kempf, Dale J.,Codacovi, Lynnmarie,Wang, Xiu Chun,Kohlbrenner, William E.,Wideburg, Norman E.,et al.
-
p. 320 - 330
(2007/10/02)
-
- POTENTIAL CNS ACTIVE 1-ARYL-2-AMINO-1-ETHANOL DERIVATIVES
-
New N-(picolyl)-2-(methylamino)-1-aryl-1-ethanols (I) and their O-acyl derivatives (II) were synthesized.Their dopaminomimetic and antidepressant biological activities were examined and compared with the activities of N-(2-aminobenzyl)-2-(methylamino)-1-aryl-1-ethanols (III).It was established that in the reaction of N- methylamine (2) and styryl oxide, the two directions of the splitting of the epoxide ring give rise to two different products that were isolated and identified in the form of their O-acetyl derivatives (13 and 15, respectively).
- Zara-Kaczian, Erzsebet,Deak, Gyula,Gyoergy, Lajos
-
p. 441 - 454
(2007/10/02)
-
- Titanium Induced Coupling of Imines to Symmetrical Vicinal (R*,R*)-Diamines
-
Symmetrical vicinal (R*,R*) -d,l-diamines were prepared from the corresponding imines and low valent titanium species generated by the action of titanium tetrachloride on amalgamated magnesium.
- Mangeney, P.,Tejero, T.,Alexakis, A.,Grosjean, F.,Normant, J.
-
p. 255 - 257
(2007/10/02)
-
- Compounds with Bridgehead Nitrogen 52 -NMR Spectra and Stereochemistry of the 2-Alkylperhydroimidazolopyridines
-
In contrast to perhydro-oxazolopyridine and perhydrothiazolopyridine, which adopt equilibria in CDCl3 solution at room temperature containing ca 70percent trans-fused conformers in equilibria with O- or S-inside cis-fused conformers, 2-alkylperhydroimidazolopyridines are found to adopt equilibria containing >98percent trans-fused conformers.Comparison of NMR parameters of 2-methylperhydroimidazolopyridine with those of the two isomers of 1,2-dimethylperhydroimidazolopyridine indicates an equilibrium for the former compound between the two trans-fused conformers, with ca 83percent of that conformation containing a transarrangement of nitrogen lone pairs of electrons.These observations are explained in terms of the generalized anomeric effect.KEY WORDS Perhydroimidazolopyridine Conformational equilibria 1H and 13C NMR
- Banting, Lee,Crabb, Trevor A.
-
p. 696 - 706
(2007/10/02)
-
- Oxidations with Cerium(IV) Sulfate: Intramolecular Cyclization of N-Benzyl-&β-aminoketones Yielding 4-Benzoyl-1,2,3,4-tetrahydroisoquinolines
-
Preparation and regiospecific cerium(IV) sulfate of the substituted N-benzyl-β-aminoketones 3 are described. 4-Benzoyl-1,2,3,4-tetrahydroisoquinolines 4 so obtained are reduced by sodium borohydride.
- Holzgrabe, Ulrike
-
p. 647 - 654
(2007/10/02)
-
