scholarly journals Reaction of cis- and trans-Dichlorotetra(Dimethylsulfoxide)Ruthenium(II) With the Antiviral Drug Acyclovir

2000 ◽  
Vol 7 (6) ◽  
pp. 325-334 ◽  
Author(s):  
Aglaia Koutsodimou ◽  
Giovanni Natile
Keyword(s):  
Trans Isomer ◽  
Early Stage ◽  
Antiviral Drug ◽  
Metallic Substrate ◽  
Purine Base ◽  
Coordination Environment ◽  
Molar Ratios ◽  
Discrete Amount ◽  
Cis And Trans ◽  
Cis Isomer

NMR was used to investigate the reaction of cis- and trans-[RuCl2(DMSO)4] with the antiviral drug acyclovir, a guanine derivative containing the acyclic (2-hydroxo) ethoxymethyl pendant linked to N(9). Studies were performed in aqueous solutions at ambient temperature and at 37 °C, and at various molar ratios. Both isomers yielded two compounds, a monoadduct and a bisadduct, the relative yields being dependent upon the metal to ligand concentration ratios. The products derived from the two Ru isomers displayed identical NMR spectra, suggesting that they have the same coordination environment, however the rate of formation of the monoadduct was higher in the case of the trans isomer than in the case of the cis isomer, while the rate of conversion of the monoadduct into the bisadduct appeared to be similar in both cases. As a consequence in the case of the trans isomer there is accumulation of monoadduct in the early stage of the reaction, whose concentration afterwards decreases with the progress of the reaction. As for platinum, also for ruthenium the preferred binding site is N(7) of the purine base, however, in the case of ruthenium a discrete amount of bisadduct is formed even in the presence of an excess of metallic substrate with respect to the acyclovir ligand; under similar conditions a platinum substrate would have given, nearly exclusively, the monoadduct.

[1H,15N] N.M.R. Kinetic Studies of Reactions of cis- and trans-[PtCl2(15NH3)(c-C6H1115NH2)] with Guanosine 5'-Monophosphate

1999 ◽  
Vol 52 (3) ◽  
pp. 173 ◽  
Author(s):  
Sarah J. Barton ◽  
Kevin J. Barnham ◽  
Abraha Habtemariam ◽  
Urban Frey ◽  
Rodney E. Sue ◽  
...  
Keyword(s):  
Trans Isomer ◽  
Active Metabolite ◽  
Kinetic Studies ◽  
Trans Influence ◽  
Trans Complex ◽  
Kinetics Of Reaction ◽  
Cis And Trans ◽  
Kinetics Of ◽  
Cis Isomer ◽  
Amine Ligand

cis-[PtCl2(15NH3)(c-C6H11NH2)] is an active metabolite of the oral platinum(IV) anticancer drug cis,trans,cis-[PtCl2(CH3CO2)2(NH2)(c-C6H11NH2)]. Since it is likely that guanine bases on DNA are targets for this drug, we have analysed the kinetics of reaction of this platinum(II) metabolite with guanosine 5′-monophosphate (5′-GMP) at 310 K, pH 7, using [1H, 15N] n.m.r. methods. Reactions of the trans isomer are reported for comparison. The reactions proceed via aquated intermediates, and, for the cis isomer, the rates of aquation and substitution of H2O by 5′-GMP are 2-5 times faster trans to the amine ligand (c-C6H11NH2) compared to trans to NH3 for both the first and second steps. For the trans complex, the first aquation step is c. 3 times faster than for the cis complex, as expected from the higher trans influence of Cl¯, whereas the rate of the second aquation step (trans to N7 of 5′-GMP) is comparable to that trans to NH3. These findings have implications for the courses of reactions with DNA.

Sur la réduction de polyméthyldihydro-2,3 phénalènones-1 par l'hydrure de lithium et d'aluminium

1974 ◽  
Vol 52 (17) ◽  
pp. 3106-3112 ◽  
Author(s):  
E. Costakis ◽  
P. Canonne ◽  
R. St-Jean
Keyword(s):  
Trans Isomer ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Considerable Extent ◽  
Lithium Aluminum ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
Cis Isomer ◽  
Steric Constraints

The reduction of some polymethyl-2,3-dihydro phenalen-1-ones by lithium aluminum hydride yields a mixture of cis and trans isomers; the percentage of each isomer depends to a considerable extent on its structure. Indeed, for some, the trans isomer predominates while for others the cis isomer is obtained in up to 88% yields. Moreover, in the particular case in which the trans isomer is formed in low yields, its preferred conformation is trans diaxial.The steric constraints which render certain transition states unfavourable during the attack of the hydride are discussed with the aid of spectroscopic data on the alcohols obtained. [Journal translation]

Concertedness in the Thermolysis of Some 1-Pyrazolines

1974 ◽  
Vol 52 (17) ◽  
pp. 3134-3139 ◽  
Author(s):  
Robert J. Crawford ◽  
Masatomi Ohno
Keyword(s):  
Trans Isomer ◽  
Diphenyl Ether ◽  
Rate Determining Step ◽  
Nitrogen Bonds ◽  
Cis And Trans ◽  
Kinetics Of ◽  
Cis Isomer ◽  
Nitrogen Evolution

A mixture of cis- and trans-3,5-divinyl-1-pyrazoline was synthesized and isolated at 0° by the cycloaddition of vinyldiazomethane to butadiene. The kinetics of the thermolysis in diphenyl ether at 35–65° were studied by measuring the rate of nitrogen evolution. The cis isomer gave log (k1/s−1) = (12.28 ± 0.9 ) − (22.8 ± 0.4 )/θ where θ = 2.303RT in kcal mol−1, for the trans isomer log(k2/s−1) = (13.9 ± 0.9 ) − (25.7 ± 0.4 )/θ was obtained. These data when compared with those of 1-pyrazoline and 3-vinyl-1-pyrazoline lead to the conclusion that both carbon–nitrogen bonds are being broken in the rate determining step. Thus the alkyl-1-pyrazolines are concerted whereas the azoalkanes are not.

Photochemistry of the cis- and trans-Dichlorobisethylenediamine Chromium(III) Cations in Acidic Aqueous Solutions. Observation of a Stereochemical Change in Photoaquation

1971 ◽  
Vol 49 (9) ◽  
pp. 1524-1528 ◽  
Author(s):  
A. D. Kirk ◽  
K. C. Moss ◽  
J. G. Valentin
Keyword(s):  
Aqueous Solution ◽  
Quantum Yield ◽  
Aqueous Solutions ◽  
Trans Isomer ◽  
Ligand Field ◽  
Acidic Aqueous Solution ◽  
Ethylenediamine Complex ◽  
Cis And Trans ◽  
Cis Isomer

The photoreactions of cis- and trans-[CrCl2(en)2]+ have been investigated in acidic aqueous solution at pH 3 and 0 °C. On photolysis in the ligand field bands the cis isomer was found to undergo mainly ethylenediamine aquation, apparently to a thermally unstable monodentate protonated ethylenediamine complex, with a quantum yield of 0.13. In addition chloride aquation occurred with[Formula: see text]. In contrast, the trans isomer underwent exclusive chloride aquation with quantum yield 0.32. The results are qualitatively, but not quantitatively, in agreement with predictions of Adamson's empirical rules. It was found that for trans-[CrCl2(en)2]+ photolysis, the reaction product [CrCl(H2O)(en)2]2+ was produced at least 70% in the cis configuration.

Reactions of Alkynes with Dicarbonyl(η-cyclopentadienyl)iridium

1979 ◽  
Vol 32 (10) ◽  
pp. 2147 ◽  
Author(s):  
PA Corrigan ◽  
RS Dickson
Keyword(s):  
Trans Isomer ◽  
Spectroscopic Data ◽  
Spectroscopic Properties ◽  
Organometallic Complexes ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
Related Reaction ◽  
Cis Isomer

Six organometallic complexes have been isolated from the reaction between (η-C5H5)Ir(C0)2 and hexafluorobut-2-yne at 120-160�. Both the cis and trans isomers of the σ-bridging alkyne complex (η C5H5)2Ir2(CO)2(CF3C2CF3) were obtained; the cis isomer is slowly transformed to the trans isomer at 160�. These complexes do not react further with alkynes. Two other products were identified as an iridiocyclobutenone complex and a iridiocyclopentadiene complex, viz.(η-C5H5){IrC(CF3)=C(CF3)CO}(CO) and (η-C5H5){IrC(CF3)=C(CF3)C(CF3)}(CO)These complexes are also inert to further reaction with hexafluorobut-2-yne, and the iridiocyclopentadiene complex could not be converted into the cyclopentadienone complex (η-C5H5)Ir{C4(CF3)4-CO). The spectroscopic properties of a product of formula (η-C5H5)Ir(CF3C2CF3)2(C4HF5) indicate it incorporates a 1-(2',2'-difluoroethenyl)-1,2,3,4,5-pentakis(trifluoromethyl)cyclopenta-2,4-diene ligand. The final product was formulated as (η-C5H5)Ir2(CO)3(CF3C2CF3)2H and five alternativestructures are consistent with the spectroscopic data. The related reaction between (η-C5H5)Ir(CO)2 and but-2-yne at 180� gives a small amount of hexamethylbenzene plus the maleoyl complex(η-C5H5){IrC(O)(Me=C(Me)C(O)}(CO).

Vinyl ether hydrolysis. XXIX. 1-Methoxy-1,3-butadiene: reaction mechanism and implication for hydrolysis of the mutagen fecapentaene-12

1994 ◽  
Vol 72 (7) ◽  
pp. 1632-1636 ◽  
Author(s):  
Yvonne Chiang ◽  
Robert Eliason ◽  
Gary H.-X. Guo ◽  
A. Jerry Kresge
Keyword(s):  
Vinyl Ether ◽  
Trans Isomer ◽  
Acid Catalysis ◽  
Isotope Effects ◽  
Hydronium Ion ◽  
Rapid Formation ◽  
Methyl Vinyl Ether ◽  
Cis And Trans ◽  
Hydrolysis Of ◽  
Cis Isomer

The hydrolysis of cis- and trans-1-methoxy-1,3-butadiene in aqueous solution occurs by hydron transfer to the δ-carbon atom with little or no β-hydronation to give crotonaldehyde as essentially the sole aldehyde product. The reaction gives appreciable hydronium-ion isotope effects in the normal direction [Formula: see text] and shows general acid catalysis; five carboxylic acid catalytic coefficients for hydrolysis of the trans isomer give a good Brønsted relation with the exponent α = 0.59. This is taken as evidence that these reactions occur by the conventional mechanism for vinyl ether hydrolysis involving rate-determining hydron transfer to substrate carbon followed by rapid formation and decomposition of a hemiacetal intermediate. Comparison of the reactivity of the present dienyl ethers with that of their monoenyl analog, methyl vinyl ether, shows that introduction of the second double bond decreases reactivity considerably: the hydronium-ion catalytic coefficient is reduced by a factor of 8.3 for the trans isomer and by a factor of 160 for the cis isomer. This reduction supports a hypothesis advanced to explain the occurrence of reaction by a different mechanism recently discovered in the hydrolysis of the strongly mutagenic polyenyl ether, fecapentaene-12.

Molecular Optical Switches Based on [Ru(OAC)(2MQN)2NO](H2MQN=2-methyl-8-quinolinol)

2013 ◽  
Vol 645 ◽  
pp. 60-63 ◽  
Author(s):  
Jian Ru Wang ◽  
Xiao Wei Jin ◽  
Yan Zhao ◽  
Xiao Yan Qiao ◽  
Hong Fei Wang
Keyword(s):  
Trans Isomer ◽  
Density Functional ◽  
Density Functional Theory Calculation ◽  
Optical Switches ◽  
Functional Theory ◽  
Main Absorption Band ◽  
1H Nuclear Magnetic Resonance ◽  
Cis And Trans ◽  
Theory Calculation ◽  
Cis Isomer

Reversible photoisomerization between the cis and trans isomer of [Ru(OAc)(2mqn)2NO] (H2mqn=2-methyl-8-quinolinol) was studied quantitatively, using 1H Nuclear magnetic resonance (NMR) spectra. The kinetic study showed that the photoisomerization from trans to cis isomer was first-order and the rate constant (k) is 0.014 (min-1) at 420 nm, 0.0034 (min-1) at 550 nm, respectively. The main absorption band in UV-Vis region for cis and trans isomer was observed from 300 nm to 550 nm, the electronic structure of these compounds was performed with DFT (Density functional theory) calculation and was discussed based on HOMO–LUMO analyses. The study provide detail information to design advance optoelectronic materials based on nitrosylruthenium(II) complexes.

Structure et réactivité. V. Étude par résonance magnétique nucléaire des produits d'halogénation des tert-butyl-3 methoxycarbonyl-4 cyclohexènes

1983 ◽  
Vol 61 (2) ◽  
pp. 362-365 ◽  
Author(s):  
Jeanine Bouteiller-Prati ◽  
Jean-Claude Bouteiller ◽  
Jean-Pierre Aycard
Keyword(s):  
Carboxylic Acid ◽  
Trans Isomer ◽  
Chlorination Reaction ◽  
Stable Isomer ◽  
Tert Butyl ◽  
Twist Conformation ◽  
Résonance Magnétique ◽  
Acid Lactone ◽  
Cis And Trans ◽  
Cis Isomer

The product of the bromination (chlorination) reaction on cis and trans 3-tert-butyl 4-carbomethoxy cyclohexene is studied by nmr. The results show that the reaction of the cis isomer gives 90% of the trans 4-bromo (chloro) cis 3-hydroxy trans 2-tert-butyl cyclohexane 1-carboxylic acid lactone and the reaction of the trans isomer gives trans 1,2-dibromo (dichloro) cis 3-tert-butyl trans 4-carbomethoxy cyclohexane which adopts a twist conformation. For the dibromo compound this kinetic product gives the corresponding thermodynamically more stable isomer, trans 1,2-dibromo trans 3-tert-butyl cis 4-carbomethoxy cyclohexane, by a diotropic rearrangement. The formation of the kinetic product is explained by the reaction of the less stable diaxial conformer of the cyclohexene derivative.

Isolation of the Products Resulting from the Reaction of cis and trans Diaminedichloroplatinum [II] with DNA and Chromatin on the Dowex 50 W Column

1984 ◽  
Vol 39 (11-12) ◽  
pp. 1057-1062 ◽  
Author(s):  
Ryszard Olinski ◽  
Zofia Walter
Keyword(s):  
Nucleic Acid ◽  
Trans Isomer ◽  
Main Product ◽  
Double Helix ◽  
Major Product ◽  
Nucleic Acid Bases ◽  
Chromosomal Proteins ◽  
Cis And Trans ◽  
Derivatives Of ◽  
Cis Isomer

Abstract The production of platinated derivatives of nucleic acid bases resulting from the reaction of cis and trans DDP with DNA and chrom atin was studied. Bifunctional complex of guanine appeared to be the major product of the interaction of cis isomer with both DNA and chromatin, although other bifunctional adducts of A-Pt-G and A-Pt-A were also isolated. The main product of the interaction of trans DDP with DNA was a monofunctional adduct of guanine. Small amounts of the bifunctional complexes were also isolated. When ssDNA was incubated with trans DDP more bifunctional complexes appeared, what suggests that geometric constrains of double helix prevent formation of these complexes. Trans isomer reacts more easily with chromosomal proteins than cis DDP does. Therefore after the reaction of trans DDP with chromatin less platination occurs on DNA moieties.

scholarly journals Synthesis and electrochemistry of linear and cofacial conjugated binuclear phthalocyanines covalently linked by alkyne and alkene bridges

1991 ◽  
Vol 69 (9) ◽  
pp. 1457-1461 ◽  
Author(s):  
Steven Vigh ◽  
Herman Lam ◽  
Pavel Janda ◽  
A. B. P. Lever ◽  
Clifford C. Leznoff ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Key Words ◽  
Trans Isomer ◽  
Gel Permeation Chromatography ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Gel Permeation ◽  
Covalently Linked ◽  
Cis And Trans ◽  
Cis Isomer

Semihydrogenation of 1,2-bis(3,4-dicyanophenyl)ethyne gave cis-1,2-bis(3,4-dicyanophenyl)ethene. From these precursors, binuclear phthalocyanines were produced containing linear binuclear phthalocyanines having an ethyne bridge and a mixture of cis and trans isomers of binuclear phthalocyanines linked by an ethene bridge. The cis and trans isomers could be separated and differentiated by gel permeation chromatography as the very extended trans isomer elutes faster than the cofacial globular cis isomer. Strong coupling between the conjugated binuclear phthalocyanine was not observed when examined by cyclic voltammetry. Key words: phthalocyanines, cofacial, binuclear, cyclic voltammetry.

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