ChemInform Abstract: Facile 5-endo Ring Closures to the Azo Group. A Free Radical Synthesis of Indazoles

ChemInform ◽  
1990 ◽  
Vol 21 (38) ◽  
Author(s):  
C. P. A. KUNKA ◽  
J. WARKENTIN
Keyword(s):  
Free Radical ◽  
Azo Group ◽  
Group A

Facile 5-endo ring closures to the azo group. A free radical synthesis of indazoles

1990 ◽  
Vol 68 (4) ◽  
pp. 575-580 ◽  
Author(s):  
Cheryl P. A. Kunka ◽  
John Warkentin
Keyword(s):  
Free Radical ◽  
Rate Constants ◽  
Functional Group ◽  
Radical Cyclization ◽  
Double Bonds ◽  
Aryl Radicals ◽  
Azo Group ◽  
Group A ◽  
Radical Clock

Five 1-alkyl-3-methylindazoles were prepared by treatment of 1-(2-bromophenyl)-1-methoxy-1-(2-alkylazo)ethanes with tri-n-butyl stannane and AIBN at 80 °C in benzene. Yields in the radical cyclization step ranged from 39 to 92%. 1-Phenyl-3-methylindazole was prepared by an analogous route but in very poor yield (<5%). Rate constants for the 5-endo radical closures [Formula: see text], estimated by the radical clock method, were 5.2 × 109 s−1 and 9.2 × 108 s−1 for two of the alkyl systems. Rate constants for analogous 5-endo cyclizations of aryl radicals onto C—C double bonds are much smaller than those for cyclizations to the azo functional group. Keywords: cyclization, radical; azo group, radical closure to; indazoles, radical synthesis of.

scholarly journals Szabadgyök-felszabadulás vizsgálata femtoszekundum lézerrel asszisztált capsulotomiát követően

2016 ◽  
Vol 157 (47) ◽  
pp. 1880-1883 ◽  
Author(s):  
Gábor Tóth ◽  
Gábor László Sándor ◽  
Dénes Kleiner ◽  
Nóra Szentmáry ◽  
Huba J. Kiss ◽  
...  
Keyword(s):  
Free Radical ◽  
Femtosecond Laser ◽  
Anterior Chamber ◽  
Treatment Method ◽  
Interquartile Range ◽  
Control Group ◽  
Relative Light Unit ◽  
Free Radical Production ◽  
Radical Production ◽  
Group A

Introduction: Femtosecond laser is a revolutionary, innovative treatment method used in cataract surgery. Aim: To evaluate free radical quantity in the anterior chamber of the eye, during femtosecond laser assisted capsulotomy, in a porcine eye model. Method: Seventy fresh porcine eyes were collected within 2 hours post mortem, were transported at 4 ºC and treated within 7 hours. Thirty-five eyes were used as control and 35 as femtosecond laser assisted capsulotomy group. A simple luminol-dependent chemiluminescence method was used to measure the total scavenger capacity in the aqueous humour, as an indicator of free radical production. The emitted photons were expressed in relative light unit %. Results: The relative light unit % was lower in the control group (median 1%, interquartile range [0.4–3%]) than in the femtosecond laser assisted capsulotomy group (median 4.4%, interquartile range [1.5%–21%]) (p = 0.01). Conclusions: Femtosecond laser assisted capsulotomy decreases the antioxidant defense of the anterior chamber, which refers to a significant free radical production during femtosecond laser assisted capsulotomy. Orv. Hetil., 2016, 157(47), 1880–1883.

[3+3]Cycloalkyne Dimers Linked by an Azo Group:  A Stablecis-Azo Compound Forms Polymeric Aggregates by Nonplanar π−π Interactions

2003 ◽  
Vol 125 (31) ◽  
pp. 9268-9269 ◽  
Author(s):  
Yuto Saiki ◽  
Hiroki Sugiura ◽  
Keiichi Nakamura ◽  
Masahiko Yamaguchi ◽  
Tomonori Hoshi ◽  
...  
Keyword(s):  
Azo Compound ◽  
Π Interactions ◽  
Azo Group ◽  
Group A

Plasmon induced polymerization using a TERS approach: a platform for nanostructured 2D/1D material production

2017 ◽  
Vol 205 ◽  
pp. 213-226 ◽  
Author(s):  
Zhenglong Zhang ◽  
Marie Richard-Lacroix ◽  
Volker Deckert
Keyword(s):  
High Efficiency ◽  
Polymerization Process ◽  
Polymerization Reaction ◽  
Self Assembled Monolayer ◽  
Thin Polymer ◽  
Azo Group ◽  
Group A ◽  
Tip Enhanced Raman Spectroscopy ◽  
Light Energy Conversion ◽  
Dimerization Reaction

Plasmon-induced chemical reactions have recently attracted great attention as a promising method for high efficiency light-energy conversion and proved to be useful in a wealth of different domains of chemistry and physics. One of the interesting and, so far, less explored avenues of such reactions is their potential for efficient, highly localized and controlled polymer production. Here, we present the first example of a localized, directed plasmon catalyzed polymerization process of a self-assembled monolayer on both silver and gold surfaces monitored by surface- and tip-enhanced Raman spectroscopy (SERS and TERS). As a proof-of-concept, a bi-functionalized dibenzo(1,2)dithiine-3,8-diamine (D3ATP) molecule that undergoes a well-known plasmon-induced coupling via the amino group into an azo group has been used. Initial dimerization is demonstrated using established marker bands associated with the formation of the azo group. A subsequent indicator for a polymerization reaction, the appearance of a new characteristic band, is monitored by time-dependent SERS and TERS experiments. We demonstrate that the dimerization reaction and hence, the subsequent polymerization, can be induced by a plasmonic feature, e.g. a TERS tip, at specific nanoscale locations and, at a much larger micron scale, by continuously scanning the plasmonic probe. The presented results provide the basis for designing further plasmonic catalysis experiments in general, and offer a new platform for producing ultra-thin polymer films with a defined structural dimension.

Electron microscopic radioautographic studies on the incorporation of 3H proline in the glomerular basement membrane (GBM) in antistreptococcal-cell-membrane (SCM) injected mice

1984 ◽  
Vol 42 ◽  
pp. 188-189
Author(s):  
R.P. Nayyar ◽  
C.F. Lange ◽  
J. L. Borke
Keyword(s):  
Body Weight ◽  
Cell Membrane ◽  
Basement Membrane ◽  
Glomerular Basement Membrane ◽  
Mesangial Matrix ◽  
Electron Microscopic ◽  
Group A ◽  
Injection Protocol

Streptococcal cell membrane (SCM) antiserum injected mice show a significant thickening of glomerular basement membrane (GBM) and an increase in mesangial matrix within 4 to 24 hours of antiserum administration (1,2,3). This study was undertaken to evaluate the incorporation of 3H proline into glomerular cells and GBM under normal and anti-SCM induced conditions. Mice were administered, intraperitoneally, 0.1 ml of normal or anti-SCM serum followed by a 10 µC/g body weight injection of 3H proline. Details of the preparation of anti-SCM (Group A type 12 streptococcal pyogenes) and other sera and injection protocol have been described elsewhere (2). After 15 minutes of isotope injection a chase of cold proline was given and animal sacrificed at 20 minutes, 1,2,4,8,24 and 48 hours. One of the removed kidneys was processed for immunofluorescence, light and electron microscopic radioautographic studies; second kidney was used for GBM isolation and aminoacid analysis.

An ultrastructural study of sertoli cells in two geographically isolated populations of Aphanius dispar

1992 ◽  
Vol 50 (1) ◽  
pp. 548-549
Author(s):  
Taber A. Ba-Omar ◽  
Philip F. Prentis
Keyword(s):  
Ultrastructural Level ◽  
Uranyl Acetate ◽  
Freshwater Teleost ◽  
Isolated Populations ◽  
En Bloc ◽  
The North ◽  
Group A ◽  
Ultrathin Sections ◽  
Group B ◽  
Geographically Isolated

We have recently carried out a study of spermiogenic differentiation in two geographically isolated populations of Aphanius dispar (freshwater teleost), with a view to ascertaining variation at the ultrastructural level. The sampling areas were the Jebel Al Akhdar in the north (Group A) and the Dhofar region (Group B) in the south. Specimens from each group were collected, the testes removed, fixed in Karnovsky solution, post fixed in OsO, en bloc stained with uranyl acetate and then routinely processed to Agar 100 resin, semi and ultrathin sections were prepared for study.

Potentiation of bromotrichloromethane hepatotoxicity in male rats exposed to 10 ppm dietary chlordecone: Electron Microscopic and biochemical study

1990 ◽  
Vol 48 (3) ◽  
pp. 284-285
Author(s):  
O. M. Faroon ◽  
R. W. Henry ◽  
M. G. Soni ◽  
H. M. Mehendale
Keyword(s):  
Free Radical ◽  
Biochemical Study ◽  
Prior Exposure ◽  
Male Rats ◽  
Cellular Injury ◽  
Low Doses ◽  
Mixed Function Oxidase ◽  
Electron Microscopic ◽  
Potent Inducer ◽  
Cellular Energy

Previous work has shown that mirex undergoes photolytic dechlorination to chlordecone (CD) (KeponeR) in the environment. Much work has shown that prior exposure to nontoxic levels of CD causes potentiation of hepatotoxicity and lethality of CCl4, BrCCl3 and other halomethane compounds. Potentiation of bromotrichloromethane hepatotoxicity has been associated with compounds that stimulate the activity of hepatic mixed-function oxidase (MFO). An increase in the metabolism of halomethane by the MFO to a free radical initiates peroxidative decomposition of membranal lipids ending in massive cellular injury. However, not all MFO inducers potentiate BrCCl3 hepatotoxicity. Potentiation by much larger doses of phenobarbital is minimal and th at by a more potent inducer of MFO, mirex, is negligible at low doses. We suggest that the CD and bromotrichloromethane interaction results in a depletion of cellular energy and thereby reducing the cellular ability to undergo mitosis.

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