5-Nitroimidazoles. II: Unexpected reactivity of ronidazole and dimetridazole with thiols

1993 ◽  
Vol 71 (9) ◽  
pp. 1349-1352 ◽  
Author(s):  
Michel Girard ◽  
François Clairmont ◽  
Aspi Maneckjee ◽  
Nicole Mousseau ◽  
Brian A. Dawson ◽  
...  
Keyword(s):  
Biological Systems ◽  
Product Distribution ◽  
Veterinary Drugs ◽  
Spectroscopic Techniques ◽  
Reaction Products ◽  
Nucleophilic Reaction ◽  
Alternative Path ◽  
Rate Of Reaction ◽  
Bound Residues ◽  
Aqueous Conditions

Ronidazole and dimetridazole, two important veterinary drugs, were found to react readily in the presence of cysteine, under neutral aqueous conditions, leading to the formation of 5-S-cysteinyl-1-methylimidazole-2-methanol carbamate and 5-S-cysteinyl-1,2-dimethylimidazole respectively through nitro displacement. The reaction products were identified by spectroscopic techniques. The rate of reaction was accelerated by increasing the pH of the medium and was accompanied by a slight change in the product distribution. The reaction was also observed, albeit at a slower rate than that of cysteine, with glutathione, another ubiquitous thiol substrate found in biological systems. While this type of nucleophilic reaction has previously been observed for suitably substituted nitrobenzene derivatives, to the best of our knowledge its occurrence with nitro-heteroaromatics has never been reported. The ready reaction of the parent nitro drugs under such mild aqueous conditions suggests that this may be an alternative path for the formation of nonextractable bound residues in tissues.

Oxidation of hydrocarbons in the liquid phase: n-dodecane in a borosilicate glass chamber at 200 °C

1969 ◽  
Vol 47 (22) ◽  
pp. 4175-4182 ◽  
Author(s):  
B. D. Boss ◽  
R. N. Hazlett
Keyword(s):  
Liquid Phase ◽  
Borosilicate Glass ◽  
Current Knowledge ◽  
Reaction Chamber ◽  
Cyclic Ethers ◽  
Reaction Products ◽  
Isomer Distribution ◽  
Oxidation Of Hydrocarbons ◽  
Volatile Products ◽  
Rate Of Reaction

The 5-h oxidation of n-dodecane at 200 °C by air at 1 atm is reported for experiments in a borosilicate glass reaction chamber equipped with a gas bubbler. The rate of reaction was limited by the rate of oxygen diffusion from the gas phase due to the rapid reaction of dissolved oxygen. The reaction products were analyzed in aliquots taken periodically from the reaction chamber. Chemical analyses, gas–liquid phase chromatography (g.l.p.c.), tandem g.l.p.c.-mass spectroscopy, infrared, and ultraviolet were used to identify products accounting for 98% of the oxygen reacted. The isomer distribution of the dodecenes, dodecanols, and dodecanones formed, as well as the distribution of carboxylic acids, were determined. Three classes of intramolecular reaction products, cyclic ethers, cyclic hydrocarbons, and lactones, were detected. Many volatile products were detected. A filterable precipitate obtained after 10 h of oxidation was studied using infrared attenuated total reflectance techniques. A reaction mechanism is discussed based on current knowledge of other systems, the products identified, and the stoichiometry of the reaction.

Reactions Involving HOCl or ClO2 with Fatty Acids Under Aqueous Conditions and Mutagenicity of Reaction Products

1987 ◽  
Vol 20 (1) ◽  
pp. 19-24 ◽  
Author(s):  
C.I. Wei ◽  
A.C. Sen ◽  
M.F. Fukayama ◽  
H.A. Ghanbari ◽  
W.B. Wheeler ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Reaction Products ◽  
Aqueous Conditions

Mechanism of interference with the Jaffé reaction for creatinine.

1987 ◽  
Vol 33 (7) ◽  
pp. 1129-1132 ◽  
Author(s):  
M H Kroll ◽  
N A Roach ◽  
B Poe ◽  
R J Elin
Keyword(s):  
Carbonyl Group ◽  
Equilibrium Constants ◽  
Molar Absorptivity ◽  
Reaction Products ◽  
Cyclic Ketones ◽  
Common Structure ◽  
Aliphatic Ketones ◽  
Rate Of Reaction ◽  
The Common

Abstract We investigated the mechanism of the Jaffé reaction for determination of creatinine by studying the spectrophotometric, kinetic, and equilibrium properties of the reaction of picrate with creatinine and with cyclic and aliphatic ketones. Absorbance spectra for the reaction products of picrate with all the ketones were superimposable with that of creatinine (Amax, 490 nm). Cyclic ketones not containing nitrogen had a molar absorptivity less than half that of creatinine and equilibrium constants approximately 0.01 that of creatinine. Aliphatic ketones, except for benzylacetone, had molar absorptivities similar to that of creatinine, but all of these compounds had equilibrium constants approximately a tenth or less that of creatinine. The common structure for all of the compounds reacting with picrate is the carbonyl group. The variable magnitude of interference for aliphatic and cyclic ketones is ascribable to the different rate constants, molar absorptivities, and equilibrium constants as compared with creatinine. Structures adjacent to the carbonyl group significantly affect the absorptivity and equilibrium constant, but steric hindrance is the major factor affecting the rate of reaction. We postulate that the carbonyl group is required for the Jaffé reaction, and we suggest a mechanism for the reaction.

scholarly journals THE PERIODATE-SCHIFF REACTION: SPECIFICITY, KINETICS, AND REACTION PRODUCTS WITH PURE SUBSTRATES

1965 ◽  
Vol 13 (6) ◽  
pp. 423-430 ◽  
Author(s):  
ARNE DAHLQVIST ◽  
INGE OLSSON ◽  
ÅKE NORDÉN
Keyword(s):  
Nucleic Acids ◽  
Simple Relation ◽  
Test Tube ◽  
Reaction Products ◽  
Chromatographic Mobility ◽  
Reaction Specificity ◽  
Rate Of Reaction ◽  
Pure Substances ◽  
Schiff Reaction ◽  
Aldehyde Groups

A quantitative test-tube method has been used to study the periodate-Schiff reaction of a number of pure substances. The rate of reaction, the amount of color produced, and in some cases the amount of periodate consumed, have been measured. The dye produced by different carbohydrates has been analyzed by spectrophotometry and paper chromatography. Glycogen, starch and dextran reacted slowly and produced much less color than the corresponding amount of free monosaccharides. Oligosaccharides and heteropolysaccharides were either periodate-Schiff-negative or very weakly positive. Proteins and nucleic acids were negative. There was no simple relation between the intensity of the periodate-Schiff reaction and the amount of periodate consumed or the amount of aldehyde groups formed on the oxidation by periodate. The dyes formed with different carbohydrates had essentially the same absorption curve, but differed in their chromatographic mobility.

scholarly journals Positively charged polysilsesquioxane/iodide lonic liquid as a quasi solid-state redox electrolyte for dye-sensitized photo electrochemical cells: Infrared,29SiNMR, and electrical studies

2006 ◽  
Vol 2006 ◽  
pp. 1-8 ◽  
Author(s):  
Vasko Jovanovski ◽  
Boris Orel ◽  
Robi Ješe ◽  
Gregor Mali ◽  
Elias Stathatos ◽  
...  
Keyword(s):  
Solid State ◽  
Specific Conductivity ◽  
Sol Gel ◽  
Electrochemical Cells ◽  
Spectroscopic Techniques ◽  
Reaction Products ◽  
Dye Sensitized ◽  
Redox Electrolyte ◽  
Grotthus Mechanism ◽  
Positively Charged

A new sol-gel precursor based on 1-methyl-3-[3-(trimethoxy-λ4-silyl)propyl]-1H-imidazolium iodide (MTMSPI+I−) was synthesized and investigated as a potential novel quasi solid-state ionic liquid redox electrolyte for dye-synthesized photoelectrochemical (DSPEC) cells of the Graetzel type. MTMSPI+I−was hydrolyzed with acidified water and the reaction products of the sol-gel condensation reactions assessed with the help of29SiNMR and infrared spectroscopic techniques. Results of the time-dependent spectra analyses showed the formation of positively charged polyhedral cube-like silsesquioxane species that still contained a small amount of silanol end groups, which were removed after heating at200°C. After cooling, the resulting material formed is a tough, yellowish, and transparent solid, which could be reheated again and used for assembling DSPEC cells. The addition of iodine increased the specific conductivity of the hydrolyzed and nonhydrolyzed MTMSPI+I−, which we attributed to the formation of triiodide ions contributed to the conductivity via the Grotthus mechanism. DSPEC cells based on a titania-dye system with MTMSPI+I−electrolyte containing iodine (0.1 M) reached an overall efficiency between 3.3–3.7%.

Hydrolysis and ammonolysis of EDTA in aqueous solution

1979 ◽  
Vol 57 (9) ◽  
pp. 1018-1024 ◽  
Author(s):  
Ramunas J. Motekaitis ◽  
David Hayes ◽  
Arthur E. Martell ◽  
Wayne W. Frenier
Keyword(s):  
Aqueous Solution ◽  
Iminodiacetic Acid ◽  
Order Rate Constant ◽  
Spectroscopic Techniques ◽  
Reaction Products ◽  
First Order ◽  
Molar Ratios ◽  
Ph Values ◽  
Rate Of Hydrolysis ◽  
Protonated Nitrogen Atom

The hydrolysis and ammonolysis of EDTA were studied in aqueous solution over a range of temperatures and at various pH values with the aid of nmr, gc, and gc – mass spectroscopic techniques. At high pH in the presence of ammonia, both ammonolysis and hydrolysis occur with the production of N-(2-aminoethyl)iminodiacetic acid (UEDDA), N-(2-hydroxyethyl)-iminodiacetic acid (HEIDA), and iminodiacetic acid (IDA) in molar ratios such that [IDA] = [UEDDA] + [HEIDA]. The first-order rate constant for the disappearance of EDTA at 175 °C in dilute aqueous ammonia is 8.6 × 10−5 s−1 whereas in the absence of ammonia its hydrolysis constant is 4.2 × 10−5 s−1. The value of ΔH0 for this reaction is approximately 35 kcal/mol. When methylamine replaces ammonia, the UEDDA is replaced by N-(2-methylaminoethyl)iminodiacetic acid. The rate of hydrolysis is increased by the presence of a tertiary amine but the latter does not become incorporated into the reaction products. A reaction mechanism is proposed involving bimolecular SN2 attack by base on a carbon atom of the ethylene bridge adjacent to a protonated nitrogen atom of EDTA with concomitant displacement of iminodiacetic acid.

scholarly journals Organoborierung von Alkinylstannanen, XIV Organoborierung von Bis(alkinyl)stannanen: Mechanismus und Anwendung der 119Sn–NMR-Spektroskopie/ Organoboration of Alkynylstannanes, XIV Organoboration of Bis(alkynyl)stannanes: Mechanism and Application of 119Sn NMR Spectroscopy

1984 ◽  
Vol 39 (8) ◽  
pp. 1037-1041 ◽  
Author(s):  
Susanna Kerschl ◽  
Bernd Wrackmeyer
Keyword(s):  
Quantitative Analysis ◽  
Reaction Mechanism ◽  
Nmr Spectroscopy ◽  
Product Distribution ◽  
Reaction Products ◽  
Nmr Data ◽  
119Sn Nmr ◽  
119Sn Nmr Spectroscopy

AbstractDimethylbis(phenylethynyl)stannane (1) reacts with trialkylboranes, BR3 (2), to give bis(alkenyl stannanes (5) (R = C2H5), 1-bora-4-stanna-2,5-cyclohexadienes (6 ) (R = C2H5, C3H7i), 1- stanna-2,4-cyclopentadienes (7) (R = C2H5) and l-stanna-3-cyclopentenes (8 ) (R = CH3, C2H5). 13C and 119Sn NMR data prove the structure of the reaction products (5 to 8 ). 119Sn NMR is useful (i) for following the course of the reaction (mechanism!) and (ii) for quantitative analysis of the product distribution. Deorganoboration reactions play an important role in the formation of the various heterocyclic systems.

scholarly journals Microwave-Assisted Claisen-Schmidt Condensation Reaction of Ethyl p-methoxycinnamate to Synthesize p-Methoxystyryl Ketone Derivatives and Evaluate Anti-inflammatory Activity of Synthetic Products

2021 ◽  
Vol 53 (1) ◽  
pp. 86-96
Author(s):  
Ismiarni Komala ◽  
Supandi Supandi ◽  
Nurmeilis Nurmeilis ◽  
Yardi Yardi ◽  
Ofa Suzanti Betha ◽  
...  
Keyword(s):  
Condensation Reaction ◽  
Inflammatory Activity ◽  
Spectroscopic Techniques ◽  
Reaction Products ◽  
Protein Assay ◽  
Microwave Assisted ◽  
Ethyl Methyl ◽  
Anti Inflammatory ◽  
Main Component

The rhizome of Kaempferia galanga has been known to contain ethyl p-methoxycinnamate (EPMC) (1) as a main component, which has anti-inflammatory properties. Previously we have reported the structural modification of EPMC (1) to form another ester, nitrostyrene, and cinnammamide derivatives and then studied their structure-activity relationships as anti-inflammatory agent. In continuing our research, in this paper, we report the microwave-assisted Claisen-Schmidt condensation of EPMC (1) to synthesize a series of p-methoxystyryl ketones followed by a study of their anti-inflammatory activity. The reaction begins with microwave-assisted cleavage oxidation of hydrolyzed product of EPMC, p-methoxycinnamic acid (2) with Ca(NO3)2 for the synthesis of p-methoxybenzaldehyde (3). Furthermore, 3 was reacted with acetophenone, ethyl methyl ketone and acetone via microwave-assisted Claisen-Schmidt condensation for the synthesis of (E)-1-(4-methoxyphenyl)-3-phenylprop-2-en-1-one (5a) (E)-1-(4-methoxyphenyl)pent-1-en-3-one (5b) and (E)-4-(4-methoxyphenyl)but-3-en-2-one (5c), respectively. The reaction products were characterized using spectroscopic techniques and were then tested for anti-inflammatory activity using in vitro anti-denaturation of protein assay. It was found that converting EPMC (1) to 5a and 5b reduced anti-inflammatory activity, while 5c retained anti-denaturation activity with an IC50 of 72.8 µg/ml.

Vibrational Spectroscopic Characterization and Coherent Anti-Stokes Raman Spectroscopy (CARS) Imaging of Artepillin C

2020 ◽  
Vol 74 (7) ◽  
pp. 751-757
Author(s):  
Wallance M. Pazin ◽  
Leonardo N. Furini ◽  
Vita Solovyeva ◽  
Tibebe Lemma ◽  
Rafael J. G. Rubira ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Biological Systems ◽  
Spectroscopic Characterization ◽  
Spectroscopic Techniques ◽  
Spectroscopic Characteristics ◽  
Cars Microscopy ◽  
Surface Enhanced Raman ◽  
Artepillin C ◽  
Interesting Compound ◽  
Anti Stokes

In the following work, the vibrational spectroscopic characteristics of artepillin C are reported by means of Fourier transform infrared (FT-IR) and Raman spectroscopies, surface-enhanced Raman scattering (SERS), and coherent anti-Stokes Raman scattering (CARS) microscopy. Artepillin C is an interesting compound due to its pharmacological properties, including antitumor activity. It is found as the major component of Brazilian green propolis, a resinous mixture produced by bees to protect their hives against intruders. Vibrational spectroscopic techniques have shown a strong peak at 1599 cm−1, assigned to C=C stretching vibrations from the aromatic ring of artepillin C. From these data, direct visualization of artepillin C could be assessed by means of CARS microscopy, showing differences in the film hydration obtained for its neutral and deprotonated states. Raman-based methods show potential to visualize the uptake and action of artepillin C in biological systems, triggering its interaction with biological systems that are needed to understand its mechanism of action.

The Role of Multivariant Analysis on the Interpretation of FTIR and Raman Spectra

2020 ◽  
pp. 104-129 ◽  
Author(s):  
Sefa Celik ◽  
Ali Tugrul Albayrak ◽  
Sevim Akyuz ◽  
Aysen E. Ozel
Keyword(s):  
Biological Systems ◽  
Principal Component ◽  
Biological Macromolecules ◽  
Spectroscopic Techniques ◽  
Linear Discriminant ◽  
Wide Range ◽  
Vibrational Bands ◽  
Multivariant Analysis

FTIR and Raman spectroscopy are complementary spectroscopic techniques that play an important role in the analysis of molecular structure and the determination of characteristic vibrational bands. Vibrational spectroscopy has a wide range of applications including mainly in physics and biology. Its applications have gained tremendous speed in the field of biological macromolecules and biological systems, such as tissue, blood, and cells. However, the vibrational spectra obtained from the biological systems contain a large number of data and information that make the interpretation difficult. To facilitate the analysis, multivariant analysis comprising the reduction of the dimension of spectrum data and classification of them by eliminating redundancy data, which are obtained from the spectra and does not have any role, becomes critical. In this chapter, the applications of Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA), and their combination PCA-LDA, which are widely used among multivariant techniques on biological systems will be disclosed.

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