The binding of analogues of coralyne and related heterocyclics to DNA triplexes

1995 ◽  
Vol 73 (1-2) ◽  
pp. 11-18 ◽  
Author(s):  
Laura J. P. Latimer ◽  
Natasha Payton ◽  
Gavin Forsyth ◽  
Jeremy S. Lee
Keyword(s):  
Thermal Denaturation ◽  
Positive Charge ◽  
Triplex Dna ◽  
Alkyl Chains ◽  
Dna Triplexes ◽  
Weak Binding ◽  
Related Alkaloid ◽  
General Preference ◽  
Nitrogen Ring ◽  
Derivatives Of

Coralyne has been shown previously to bind well to both T∙A∙T- and C∙G∙C+-containing triplexes. Derivatives of coralyne were prepared and their binding to poly(dT)∙poly(dA)∙poly(dT) and poly[d(TC)]∙poly[d(GA)]∙poly[d(C+T)] was assessed from thermal denaturation profiles. A tetraethoxy derivative showed only weak binding to both types of triplex. Analogues with extended 8-alkyl chains showed good binding to poly(dT)∙poly(dA)∙poly(dT), but the preference for triplex poly[d(TC)]∙poly[d(GA)]∙poly[d(C+T)] was decreased compared with the duplex. Sanguinarine, a related alkaloid, bound well to poly(dT)∙poly(dA)∙poly(dT) but only weakly to the protonated triplex. It is hypothesized that the position of the protonated nitrogen ring is important for binding to poly[d(TC)]∙poly[d(GA)]∙poly[d(C+T)]. A series of other chromophores was studied and only those with a positive charge bound to triplexes. All of these bound well to poly(dT)∙poly(dA)∙poly(dT) but only weakly if at all to the duplex poly(dA)∙poly(dT). In contrast, most of them did not bind well to the triplex poly[d(TC)]∙poly[d(GA)]∙poly[d(C+T)] and those that did still showed a preference for duplex poly[d(TC)]∙poly[d(GA)]. In general, preference for triplex poly(dT)∙poly(dA)∙poly(dT) compared with the duplex is a common feature of intercalating drugs. On the other hand, specificity for protonated triplexes may be very difficult to achieve.Key words: triplex DNA, DNA-binding drugs, intercalation.

scholarly journals Antimonial analogues of the acridine series. Dilhydrostibacridines

1933 ◽  
Vol 143 (848) ◽  
pp. 38-47 ◽  
Keyword(s):  
Nitro Derivative ◽  
Starting Material ◽  
Arsenic Compounds ◽  
Ring Systems ◽  
Nitrogen Ring ◽  
Derivatives Of

In pursuing our investigation out the antimony analogues of certain nitrogen ring-systems, we Lave now succeeded in obtaining derivatives of dilhydrostibacridines, of when some of the corresponding arsenic compounds have been studied recently by Gump and Stolzenburg. The starting material for the work was o -aminodiphenylmethane obtained from the corresponding nitro derivative when, in turn, was prepared from o -nitrobenzyl chloride and benzene by Taneseseu's modification of the Friedel-Crafts reaction.

scholarly journals Reversible Photodimerization of Ester Derivatives of Thymine Having Long Alkyl Chains in Solid Film

2000 ◽  
Vol 32 (6) ◽  
pp. 492-500 ◽  
Author(s):  
Eiko Mochizuki ◽  
Norimitsu Tohnai ◽  
Yuhua Wang ◽  
Takao Saito ◽  
Yoshiaki Inaki ◽  
...  
Keyword(s):  
Alkyl Chains ◽  
Solid Film ◽  
Derivatives Of

Diyne Cyclization in Camphor Derivatives - Experimental and Theoretical Investigation

1996 ◽  
Vol 51 (11) ◽  
pp. 1655-1662 ◽  
Author(s):  
Gabriele Wagner ◽  
Christian Heiß ◽  
Uwe Verfiirth ◽  
Rudolf Herrmann
Keyword(s):  
Oxygen Atom ◽  
Theoretical Investigation ◽  
Positive Charge ◽  
Membered Ring ◽  
Titanium Chloride ◽  
Nmr Studies ◽  
Methylene Carbon ◽  
Camphor Derivatives ◽  
Exocyclic Methylene ◽  
Derivatives Of

Derivatives of 3-oxo-camphorsulfonimide (1) with two phenylethynyl groups in the endo positions at the carbons C-2 and C-3 were prepared, and their reactivity towards halogenes and titanium chloride was studied. In every case, the two ethynyl groups led to the annulation of a five-membered ring to the bicyclo[2 .2 .1] system in an orientation which depends on the bulkiness of the additional substituent in position 3. NMR studies show that cationic species like 6 and 8 are the first detectable intermediates. They not only contain the fused five-membered ring but also a bond between its exocyclic methylene carbon and an oxygen atom of the sulfonyl group, thus transferring the positive charge mainly to sulfur. Semiempirical calculations (PM3) suggest two intermediates in the formation of such cations.

Catalytic Oxidation of 2-Mercaptoethanol by Cationic Water-soluble Phthalocyaninatocobalt(II) Complexes

1997 ◽  
Vol 01 (04) ◽  
pp. 309-313 ◽  
Author(s):  
MUTSUMI KIMURA ◽  
YUJI YAMAGUCHI ◽  
TOSHIKI KOYAMA ◽  
KENJI HANABUSA ◽  
HIROFUSA SHIRAI
Keyword(s):  
Catalytic Activity ◽  
Catalytic Oxidation ◽  
Absorption Spectra ◽  
Positive Charge ◽  
Alkyl Chain ◽  
Solvent Polarity ◽  
Water Soluble ◽  
Uv Absorption Spectra ◽  
Alkyl Chains ◽  
The Stability

The cationic amphiphilic cobalt(II) phthalocyanines have been prepared, and are characterized by UV-absorption spectra in water and organic solvents and in their mixtures. The monomer–dimer transformation equilibrium was affected by solvent polarity and the length of the alkyl chains in the amphiphilic parts. All complexes are efficient catalysts for the oxidation of 2-mercaptoethanol in the presence of dioxygen. The positive charge around the complex increases the acceleration of the dissociation of 2-mercaptoethanol under neutral pH. The catalytic activity is affected by the length of the alkyl chain; consequently the stability of aggregation between cobalt(II) phthalocyanines, as catalysts for the oxidation of 2-mercaptoethanol, can be changed.

scholarly journals Induction of smectic polymorphism in bent-core derivatives of the 6-oxoverdazyl by partial fluorination of alkyl chains

RSC Advances ◽  
2016 ◽  
Vol 6 (104) ◽  
pp. 102343-102347 ◽  
Author(s):  
Sylwia Ciastek ◽  
Piotr Kaszyński ◽  
Damian Pociecha ◽  
Marcin Jasiński
Keyword(s):  
Alkyl Chains ◽  
Derivatives Of

A series of bent-core mesogens 2[m,n] derived from the 6-oxoverdazyl radical and containing partially fluorinated alkyl tails was prepared and investigated by thermal, optical, XRD and EPR methods.

scholarly journals Synthesis and thermal denaturation studies of covalently linked DNA triplexes

2009 ◽  
Vol 53 (1) ◽  
pp. 165-166 ◽  
Author(s):  
I. Okamoto ◽  
S. Ito ◽  
T. Ono ◽  
A. Ono
Keyword(s):  
Thermal Denaturation ◽  
Dna Triplexes ◽  
Covalently Linked

scholarly journals New (Iso)Quinolinyl-Pyridine-2,6-dicarboxamide G-Quadruplex Ligands. A Structure-Activity Relationship Study

2021 ◽  
Author(s):  
Enrico Cadoni ◽  
Pedro R. Magalhães ◽  
Rita M. Emídio ◽  
Eduarda Mendes ◽  
Jorge B. Vítor ◽  
...  
Keyword(s):  
Small Molecules ◽  
Thermal Denaturation ◽  
Positive Charge ◽  
Quinoline Ring ◽  
Dynamic Simulations ◽  
Structure Activity ◽  
Parallel Structures ◽  
G Quadruplex ◽  
Relationship Study ◽  
Wide Potential

Quadruplex-interactive small molecules have a wide potential application, not only as drugs but also as sensors of quadruplexes structures. The purpose of this work is the synthesis of analogues of the bis-methylquinolinium-pyridine-2,6-dicarboxamide G4 ligand 360A, to identify relevant structure-activity relationships to apply to the design of other G4-interactive small molecules bearing bis-quinoline or bis-isoquinoline moieties. Thermal denaturation experiments revealed that non-methylated derivatives with a relative 1,4 position between the amide linker and the nitrogen of the quinoline ring are moderate G4 stabilizers, with a preference for the hybrid h-Telo G4. Insertion of a positive charge upon methylation of quinoline/isoquinoline nitrogen increases compounds capacity to selectively stabilize G4s compared to duplex DNA, with a preference for parallel structures. Among these, compounds having a relative 1,3-position between the charged methylquinolinium/isoquinolinium nitrogen and the amide linker are the best G4 stabilizers. More interestingly, these ligands showed different capacities to selectively block DNA polymer-ization in a PCR-stop assay and to induce G4 conformation switches of hybrid h-Telo G4. Mo-lecular dynamic simulations with the parallel k-RAS G4 structure showed that the relative spatial orientation of the two methylated quinoline/isoquinoline rings determines the ligands mode and strength of binding to G4s.

Ion binding to lysine-modified derivatives of cytochrome c

1977 ◽  
Vol 55 (2) ◽  
pp. 146-151 ◽  
Author(s):  
R. A. Morton ◽  
K. Breskvar
Keyword(s):  
Cytochrome C ◽  
Equilibrium Constant ◽  
Negative Charge ◽  
Positive Charge ◽  
Ion Binding ◽  
Ferrocytochrome C ◽  
Cacodylate Buffer ◽  
Anion Site ◽  
Derivatives Of ◽  
Apparent Equilibrium

The effect of Cl− and K+ ions on the apparent equilibrium constant of the reaction between horse ferricytochrome c and potassium ferrocyanide was studied. Unmodified cytochrome was compared with two lysine-modified derivatives. One, guanidinated, had all lysyl groups converted to homoarginine (but retained the same positive charge); the other was trinitrophenylated at one lysine (measured spectrophotometrically). Both modified derivatives had a somewhat larger equilibrium constant in the reaction of the reduced protein with ferricyanide, but, unlike trifluoroacetylated cytochrome c (which has a negative charge), the redox properties were not dramatically different. The native protein and the lysine-modified cytochromes showed differential K+ binding in Tris–cacodylate buffer at constant ionic strength (0.003–0.005 M). More K+ was bound to ferrocytochrome c. This redox-linked binding, however, was unaffected by modification of lysine. All three derivatives also showed redox-linked differential Cl− ion binding (more Cl− ion was bound to ferricytochrome); however, in this case, the binding was reduced in the lysine-modified molecules. This was interpreted as loss of a single anion site. This anion site critically depends on one or a few lysines which are more reactive with trinitrobenzene sulfonate.

scholarly journals A new class of organogelators based on triphenylmethyl derivatives of primary alcohols: hydrophobic interactions alone can mediate gelation

2017 ◽  
Vol 13 ◽  
pp. 138-149 ◽  
Author(s):  
Wangkhem P Singh ◽  
Rajkumar S Singh
Keyword(s):  
Hydrophobic Interactions ◽  
Water Soluble ◽  
Protecting Group ◽  
Primary Alcohols ◽  
Alkyl Chains ◽  
New Class ◽  
Group A ◽  
Gelation Concentration ◽  
Xrd Techniques ◽  
Derivatives Of

In the present work, we have explored the use of the triphenylmethyl group, a commonly used protecting group for primary alcohols as a gelling structural component in the design of molecular gelators. We synthesized a small library of triphenylmethyl derivatives of simple primary alcohols and studied their gelation properties in different solvents. Gelation efficiency for some of the derivatives was moderate to excellent with a minimum gelation concentration ranging between 0.5–4.0% w/v and a gel–sol transition temperature range of 31–75 °C. 1,8-Bis(trityloxy)octane, the ditrityl derivative of 1,8-octanediol was the most efficient organogelator. Detailed characterizations of the gel were carried out using scanning electron microscopy, FTIR spectroscopy, rheology and powder XRD techniques. This gel also showed a good absorption profile for a water soluble dye. Given the non-polar nature of this molecule, gel formation is likely to be mediated by hydrophobic interactions between the triphenylmethyl moieties and alkyl chains. Possible self-assembled packing arrangements in the gel state for 1,8-bis(trityloxy)octane and (hexadecyloxymethanetriyl)tribenzene are presented. Results from this study strongly indicate that triphenylmethyl group is a promising gelling structural unit which may be further exploited in the design of small molecule based gelators.

Description of Bond Pseudorotation, Bond Pseudolibration, and Ring Pseudoinversion Processes Caused by the Pseudo-Jahn–Teller Effect: Fluoro Derivatives of the Cyclopropane Radical Cation

2014 ◽  
Vol 67 (3) ◽  
pp. 435 ◽  
Author(s):  
Wenli Zou ◽  
Dieter Cremer
Keyword(s):  
Radical Cation ◽  
Positive Charge ◽  
Radical Cations ◽  
Molecular Geometry ◽  
Teller Effect ◽  
Curvilinear Coordinates ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Derivatives Of ◽  
Fluoro Derivatives

Curvilinear coordinates are used to describe the molecular geometry and the pseudo-Jahn–Teller surface of F-substituted cyclopropane radical cations using the equation-of-motion coupled cluster EOMIP-CCSD/cc-pVTZ approach. The monofluoro derivative 2 undergoes bond pseudolibration (incomplete bond pseudorotation) between two symmetry-equivalent biradicaloid forms separated by a barrier of 2.2 kcal mol–1 (1 kcal mol–1 = 4.186 kJ mol–1) at low temperature. Bond pseudorotation and ring pseudoinversion have barriers of 12.1 and 16.5 kcal mol–1 respectively. The relative energies of 2 are affected by the distribution of the positive charge in the C3 ring and the formation of a CF bond with partial π character. There is a change of the CF bond length from 1.285 to 1.338 Å along the bond pseudorotation path. The changes of the CF bond outweigh the deformation effects of the C3 ring; however, both are a result of the pseudo-Jahn–Teller effect according to an (A′ + A′′) ⊗ (a′ + a′′) interaction. For the pentafluoro derivative 3 of the cyclopropane radical cation, bond pseudorotation has a barrier of 16.3 kcal mol–1 whereas ring pseudoinversion is hindered by a barrier of 21.7 kcal mol–1. Radical cation 3 is the first example of a trimethylene radical cation.

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