The photolytic preparation of cyclopentadienyl and phenyl nitrene from benzene derivatives

1968 ◽  
Vol 303 (1473) ◽  
pp. 139-156 ◽  
Keyword(s):  
Flash Photolysis ◽  
Phenyl Isocyanate ◽  
Benzene Derivatives ◽  
Substituted Benzenes ◽  
Fission Process ◽  
Ring Fission

The flash photolysis of phenols, anilines, nitrobenzenes and some other benzene derivatives results in a novel ring fission process and the production of cyclopentadienyl radicals. The spectra of cyclopentadienyl, and its derivatives obtained from doubly substituted benzenes, have been recorded and analysed in part. A spectrum attributed to phenyl nitrene has been observed after flash photolysis of ortho chloro aniline, ortho bromo aniline and phenyl isocyanate.

Enhanced basicity of 1,3-dialkoxy-substituted benzenes: cyclophane derivatives

1994 ◽  
Vol 72 (12) ◽  
pp. 2388-2395 ◽  
Author(s):  
Guangzhong Zhang ◽  
Yijian Shi ◽  
Renée Mosi ◽  
Thao Ho ◽  
Peter Wan
Keyword(s):  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Structural Constraints ◽  
Excited Singlet ◽  
Deuterium Incorporation ◽  
Stable Conformation ◽  
Substituted Benzenes ◽  
Singlet States ◽  
Excited Singlet States

The photoprotonation of four dialkoxy-substituted benzenes in their excited singlet states has been studied. The parent systems 4 and 5 are regioselectively photoprotonated at the 2-position, with significant quantum efficiencies for deuterium incorporation at acidities greater than pH 2. The structurally related cyclophane derivatives 6 and 7 did not show any deuterium exchange over the same acidity range but fluorescence quenching by proton (in aqueous solution) and laser flash photolysis studies (in 1,1,1,3,3,3-hexafluoro-2-propanol) indicate that photoprotonation does take place with these compounds. Due to structural constraints imposed by the most stable conformation adopted by these molecules (6 and 7), the attacking proton (deuteron) is also the proton (deuteron) that is deprotonated from the cyclohexadienyl cation (2,6-dialkoxybenzenonium ion) intermediate, resulting in the absence of incorporation of deuterium.

scholarly journals The absorption spectra of benzene derivatives in the vacuum ultra-violet. II

1947 ◽  
Vol 191 (1024) ◽  
pp. 32-38 ◽  
Keyword(s):  
Absorption Spectra ◽  
Ultra Violet ◽  
Phenyl Isocyanate ◽  
The Other ◽  
Side Chain ◽  
Benzene Derivatives ◽  
Phenyl Acetylene ◽  
Long Wave ◽  
Methyl Styrene ◽  
Vacuum Ultra Violet

The far ultra-violet spectra of styrene, α -methyl styrene, phenyl acetylene, phenyl cyanide and phenyl isocyanate are described. Many of the observed regions of absorption are cor­related with those of the benzene spectrum. The important fact emerges that, with increasing conjugation of the side chain with the ring, the benzene 1980 A absorption moves much farther to long wave-lengths than do the benzene 2600 and 1790 A absorptions. α -Methyl styrene shows a shift to the violet of certain regions of its spectrum relative to styrene. Phenyl isocyanate has a spectrum much closer to that of benzene than have the other molecules discussed.

Laser flash photolysis of a 4,4'-methylene bis(phenyl isocyanate) (MDI) based polyurethane and model carbamates

1988 ◽  
Vol 21 (9) ◽  
pp. 2727-2730 ◽  
Author(s):  
C. E. Hoyle ◽  
Y. G. No ◽  
K. G. Malone ◽  
S. F. Thames ◽  
David Creed
Keyword(s):  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Phenyl Isocyanate

Untersuchungen der kernmagnetischen Resonanz von Phosphorverbindungen, XXIX

1972 ◽  
Vol 27 (7) ◽  
pp. 764-766 ◽  
Author(s):  
Gernot Heckmann ◽  
Ekkehard Fluck
Keyword(s):  
Solvent Effects ◽  
Chemical Shifts ◽  
Van Der Waals ◽  
White Phosphorus ◽  
Van Der Waals Interactions ◽  
Benzene Derivatives ◽  
Substituted Benzenes ◽  
Halogen Free

The n.m.r. signal of white phosphorus in some substituted benzenes and halogen-free solvents was measured. In both types of solvents the chemical shifts were caused mainly by van der Waals interactions. An average anisotropy term of +2.4 ppm was obtained for phosphorus dissolved in benzene derivatives. A possible use for the large solvent effects of white phosphorus is given.

Efficient Synthesis of Tetra- and Penta-substituted Benzenes via Domino Cycloaddition Reaction of pyridinium ylide and Chalcone o-Enolate

2021 ◽  
Author(s):  
Feng-Shun Xu ◽  
Chen Yan ◽  
Jing Sun ◽  
Chaoguo Yan
Keyword(s):  
Cycloaddition Reaction ◽  
Benzene Derivatives ◽  
Efficient Synthesis ◽  
Substituted Benzenes ◽  
Pyridinium Bromide ◽  
High Efficient ◽  
Pyridinium Ylide

A very simple and high efficient synthetic protocol for tetra- and penta-substituted benzene derivatives has been provided by tetramethylguanidine (TMD) promoted reaction of 4-(N,N-dimethylamino)-1-phenacyl-pyridinium bromide with chalcone o-enolates in DMF...

Coefficients of molecular homeomorphism and crystalline isomorphism in the series of para-disubstituted benzene derivatives

1991 ◽  
Vol 88 ◽  
pp. 509-514 ◽  
Author(s):  
MA Cuevas Diarte ◽  
T Calvet ◽  
M Labrador ◽  
E Estop ◽  
HAJ Oonk ◽  
...  
Keyword(s):  
Benzene Derivatives ◽  
Disubstituted Benzene
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