Oxidation of 2-Pyridyldimethylsilyl Group to Hydroxyl Group by H2O2/KF. Implication of Fluoride Ion Accelerated 2-Pyridyl−Silyl Bond Cleavage

1999 ◽  
Vol 64 (23) ◽  
pp. 8709-8714 ◽  
Author(s):  
Kenichiro Itami ◽  
Koichi Mitsudo ◽  
Jun-ichi Yoshida
Keyword(s):  
Bond Cleavage ◽  
Hydroxyl Group ◽  
Fluoride Ion

scholarly journals Genotoxic properties of fluorines (review)

2020 ◽  
Vol 99 (3) ◽  
pp. 253-258
Author(s):  
Е.Э. E. Калюжная ◽  
А.Ю. Yu. Просеков ◽  
Валентин Павлович Волобаев
Keyword(s):  
Dna Damage ◽  
In Vivo Studies ◽  
Hydroxyl Group ◽  
Fluoride Ion ◽  
Genotoxic Effects ◽  
Human Environment ◽  
Human Contact ◽  
Professional Contact

Introduction. Consistency of fluoride excess in the human environment and professional contact with fluoride is an actual and underestimated problem. Fluoride ion is able to displace the hydroxyl group in calcium hydroxyapatites, forming stable crystals of mixed form of apatites, inducing bone pathology, fluorosis. Despite the high prevalence of fluorosis, there are only a few studies discussing the ability of fluoride ion to increase the level of genotoxic effects. At the same time, such studies are in high demand in connection with a direct correlation between genetic instability and the risk of carcinogenesis. Material and methods. A literature search was conducted according the following queries: “fluoride, fluoride ion, fluorides, DNA damage, genetic damage, genotoxicity.” The search was conducted on the databases PubMed, MEDLINE, Embase and Google Scholar for various articles (all publications until June 2018). All publications were analyzed and included in this review. Results.The present review examines the results of studies aimed at investigation of the ability of fluoride to induce DNA damage, published since the 50-s of 20th century to the present. The analyse of data about genotoxic and mutagenic properties of fluorine observed in In vitro and In vivo studies is provided. It is summarized that at concentrations of sodium fluoride in drinking water of more than 1 mM, fluoride ion has the ability to induce DNA damage and increase the frequency of clastogenic effects in humans and large monkeys. At the same time, for a significant increase in genotoxic effects in rodents, large concentrations of fluorides are required. The main hypotheses about the mechanisms of the fluoride genotoxic properties are described. Conclusion. Considering results published nowadays, it can be noted that fluoride ion obviously showes a number of genotoxic features and can have mutagenic properties in case of chronic and direct contact with cellular objects. It remains questionable issue about genotoxic risk accompanied human contact with fluoride compounds.

Do Thermally-Labile 1,4-Benzodiazepines Rearrange under Electrospray and Particle Bombardment?

2001 ◽  
Vol 7 (4-5) ◽  
pp. 359-371 ◽  
Author(s):  
Sophie Bourcier ◽  
Yannik Hoppilliard ◽  
Taraneh Kargar-Grisel ◽  
Jean Marie Pechiné ◽  
Felix Perez
Keyword(s):  
Particle Bombardment ◽  
Bond Cleavage ◽  
High Energy ◽  
Hydroxyl Group ◽  
Molecular Orbital Calculations ◽  
Energy Collision ◽  
Fragmentation Mechanisms ◽  
Uv Photons ◽  
The Stability ◽  
Protonated Molecules

Nordiazepam (N), diazepam (D), lorazepam (L), oxazepam (O)and temazepam (T)are 1,4-benzodiazepines. L, O and T are substituted in position 3 of the seven-membered ring by a hydroxyl group and are known to be thermally unstable. N and D are unsubstituted in position 3 and are expected to be thermally stable. We have studied the stability of all these molecules under electrospray conditions and under particle bombardment (MeV ions and UV photons). The fragmentations induced by low energy collision-induced dissociation and high energy collision-activated dissociation of molecules protonated by electrospray were compared with the spontaneous fragmentations of these molecules ionized by particle bombardment. The fragmentation mechanisms were determined using labeled compounds and by means of ab initio calculations using 1,4-diazepine and 3-hydroxy-1,4-diazepine as models. The fragmentation is dramatically dependent upon the substitution in position 3 and upon the internal energy of protonated molecules. At low collision energies, the non-hydroxylated benzodiazepines eliminate CO by opening of the diazepine ring whereas 3-hydroxy-1,4-benzodiazepines eliminate water after ring contraction. At high collision energies, all protonated benzodiazepines eliminate a hydrogen atom by simple bond cleavage. Molecular orbital calculations give arguments in favor of an isomerization in the gas phase of the protonated 3-hydroxybenzodiazepines and of a partial thermal decomposition of 1,4-benzodiazepines occurring before protonation under particle bombardment.

scholarly journals GENOTOXIC PROPERTIES OF FLUORINES (REVIEW)

2020 ◽  
Vol 99 (3) ◽  
pp. 253-258
Author(s):  
E. E. Kalyuzhnaya ◽  
A. Yu. Prosekov ◽  
Valentin P. Volobaev
Keyword(s):  
Dna Damage ◽  
In Vivo Studies ◽  
Hydroxyl Group ◽  
Fluoride Ion ◽  
Genotoxic Effects ◽  
Human Environment ◽  
Human Contact ◽  
Professional Contact

Introduction. Consistency of fluoride excess in the human environment and professional contact with fluoride is an actual and underestimated problem. Fluoride ion is able to displace the hydroxyl group in calcium hydroxyapatites, forming stable crystals of mixed form of apatites, inducing bone pathology, fluorosis. Despite the high prevalence of fluorosis, there are only a few studies discussing the ability of fluoride ion to increase the level of genotoxic effects. At the same time, such studies are in high demand in connection with a direct correlation between genetic instability and the risk of carcinogenesis. Material and methods. A literature search was conducted according the following queries: “fluoride, fluoride ion, fluorides, DNA damage, genetic damage, genotoxicity.” The search was conducted on the databases PubMed, MEDLINE, Embase and Google Scholar for various articles (all publications until June 2018). All publications were analyzed and included in this review. Results.The present review examines the results of studies aimed at investigation of the ability of fluoride to induce DNA damage, published since the 50-s of 20th century to the present. The analyse of data about genotoxic and mutagenic properties of fluorine observed in In vitro and In vivo studies is provided. It is summarized that at concentrations of sodium fluoride in drinking water of more than 1 mM, fluoride ion has the ability to induce DNA damage and increase the frequency of clastogenic effects in humans and large monkeys. At the same time, for a significant increase in genotoxic effects in rodents, large concentrations of fluorides are required. The main hypotheses about the mechanisms of the fluoride genotoxic properties are described. Conclusion. Considering results published nowadays, it can be noted that fluoride ion obviously showes a number of genotoxic features and can have mutagenic properties in case of chronic and direct contact with cellular objects. It remains questionable issue about genotoxic risk accompanied human contact with fluoride compounds.

scholarly journals Synthesis, characterization, and anticancer properties of organometallic Schiff base platinum complexes

2015 ◽  
Vol 93 (10) ◽  
pp. 1140-1146 ◽  
Author(s):  
Stéphanie Jean ◽  
Kevin Cormier ◽  
Alyssa E. Patterson ◽  
Christopher M. Vogels ◽  
Andreas Decken ◽  
...  
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligand ◽  
Bond Cleavage ◽  
Cancer Cell Line ◽  
Platinum Complexes ◽  
Hydroxyl Group ◽  
Aliphatic Chain ◽  
X Ray Diffraction ◽  
Anticancer Properties ◽  
Chloride Ligand

A small family of organometallic platinum complexes containing a chloride, cis-cyclooctene, and a Schiff base ligand have been prepared and characterized fully. Three aliphatic amines and four aromatic amines were chosen as representative examples. All complexes were stable in air except for 7, derived from the pinacol-protected 4-aminophenylboronate ester 4-H2NC6H4Bpin (pin = 1,2-O2C2Me4), which decomposed via B–C bond cleavage. Both complexes 4 (derived from aniline) and 7 were further characterized by single-crystal X-ray diffraction studies and confirmed the square planar nature of the platinum centre whereby the chloride ligand lies trans to the deprotonated hydroxyl group of the Schiff base ligand. The imine functionality is trans to the organic cyclooctene group. Complex 3, which contained the longest aliphatic chain studied (an octyl group), was the most promising for inducing apoptosis in the malignant MB231 breast cancer cell line. Conversely, complexes 4–6, which contained aromatic groups, were the most active against renal cell carcinoma (RCC) cell lines.

Cross-linked networks that selectively and controllably disassemble on-demand via cascading bond cleavage

2018 ◽  
Vol 5 (5) ◽  
pp. 831-836 ◽  
Author(s):  
Grant C. Daniels ◽  
Eugene Camerino ◽  
James H. Wynne ◽  
Erick B. Iezzi
Keyword(s):  
Bond Cleavage ◽  
Fluoride Ion ◽  
On Demand

Silyl-containing polyurethane thermosets disassemble in multiple directions via cascading bond cleavage when exposed to a fluoride ion stimulus.

Detection method of combustion oscillation characteristics under strong noise background

2020 ◽  
Vol 21 (6) ◽  
pp. 612
Author(s):  
Yunkun Wei ◽  
Tianhong Zhang ◽  
Zhonglin Lin ◽  
Qi Xie ◽  
Yan Zhang
Keyword(s):  
Radiation Thermometry ◽  
Hydroxyl Group ◽  
Interference Signal ◽  
Engine Vibration ◽  
Combustion Technology ◽  
Lean Fuel ◽  
Combustion Oscillation ◽  
Aero Engines ◽  
Temperature Measurement System ◽  
Multispectral Radiation Thermometry

After the lean fuel premixed combustion technology is applied to aero engines, severe combustion oscillations will be cased and led to hidden safety hazards such as engine vibration, further energy waste and other problems. Therefore, it is increasingly important to actively control combustion oscillations. In this paper, a multispectral radiation thermometry (MRT) is used to analyze the hydroxyl group, which is a measurable research object in the combustion chamber of an aero engine, and to fit the functional relationship between the radiation intensity ratio and the temperature in different bands. The theoretical value of the error is <2%. At the same time, in order to solve the problem of weak detection signal and excessive interference signal, an improved frequency domain filtering method based on fast Fourier transform is designed. Besides, the FPGA platform is used to ensure the real-time performance of the temperature measurement system, and simulations and experiments are performed. An oscillating signal with an oscillation frequency of 315 Hz is obtained on the established test platform, and the error is only 1.42%.

Sign in / Sign up

Export Citation Format

Share Document