Photochemical Reactions of Azo Compounds. I. Spectroscopic Studies of the Conjugate Acids of cis- and trans-Azobenzene

1960 ◽  
Vol 25 (12) ◽  
pp. 2193-2195 ◽  
Author(s):  
G. E. LEWIS
Keyword(s):  
Spectroscopic Studies ◽  
Photochemical Reactions ◽  
Azo Compounds ◽  
Cis And Trans ◽  
Trans Azobenzene

Photochemical reactions of azo compounds. XII. Dark reaction of cis-azobenzene with acetyl chloride

1967 ◽  
Vol 20 (9) ◽  
pp. 1899 ◽  
Author(s):  
GE Lewis ◽  
RJ Mayfield
Keyword(s):  
Trans Isomer ◽  
Potassium Hydroxide ◽  
Acetyl Chloride ◽  
Photochemical Reactions ◽  
Azo Compounds ◽  
Dark Reaction ◽  
Purple Coloration ◽  
Dark Blue ◽  
Induced Reaction ◽  
Trans Azobenzene

cis-Azobenzene has been shown to react with acetyl chloride in the absence of light to form N,N?-diacetyl-4-chlorohydrazobenzene and N?- acetyl-4-chloro-hydrazobenzene as the principal products; 4- phenylaminoazobenzene and acetanilide are also formed in small amounts. In the course of the reaction a metastable dark blue product arises, and, although this could not be satisfactorily characterized, it was found to yield 4-phenylaminoazobenzene on decomposition in methanolic potassium hydroxide or in acetyl chloride. The intense blue-purple coloration, which occurs as soon as the reactants are mixed, enables cis-azobenzene to be readily distinguished from its trans isomer. The nature of the currently reported reaction is discussed in relation to the previously reported photo-induced reaction of trans- azobenzene with acetyl chloride, which yields N,N?-diacetyl-4- chlorohydrazobenzene practically exclusively.

Photochemical reactions of azo compounds. XV. Ortho/para substitution ratios in the photoinduced reactions of trans-azobenzene with acid chlorides

1968 ◽  
Vol 21 (4) ◽  
pp. 1053 ◽  
Author(s):  
DPG Hamon ◽  
GE Lewis ◽  
RJ Mayfield
Keyword(s):  
Acetyl Chloride ◽  
Main Product ◽  
Photochemical Reactions ◽  
Azo Compounds ◽  
Acid Chlorides ◽  
Analogous Reaction ◽  
Subsequent Hydrolysis ◽  
Photoinduced Reactions ◽  
Trans Azobenzene

Irradiation of trans-azobenzene in acetyl chloride, and subsequent hydrolysis-oxidation of the photo product, has been shown to yield a small amount of 2-chloroazo-benzene in addition to 4-chloroazobenzene (main product). Analogous reaction sequences, starting with different acid chlorides, show marked variations in ortho/para substitution ratios; and correlations indicate that the relative extents of ortho and para substitution are associated with the ionizability of the acid chlorides.

Photochemical reactions of azo compounds. IX. Further studies related to the photochemical reactions of bisazo compounds

1967 ◽  
Vol 20 (2) ◽  
pp. 321 ◽  
Author(s):  
NC Jamieson ◽  
GE Lewis
Keyword(s):  
Sulphuric Acid ◽  
Photochemical Reaction ◽  
Photochemical Reactions ◽  
Azo Compounds ◽  
Bisazo Compounds ◽  
First Time

The photochemical reactions of 4,4?-bis(phenylazo)biphenyl and 4- phenyl-azoazobenzene in 98% sulphuric acid have been examined, for comparison with the corresponding reactions in 22N acid. Photochemical cyclodehydrogenation of 4-phenylazoazobenzene to two benzo[c]cinnoline derivatives has thereby been effected for the first time. The observed course of the latter reaction has led, in turn, to studies of the benzidine rearrangement of 2-(2-phenylhydrazino)benzo[c]- cinnoline, of the photochemical cyclodehydrogenation of 3-phenylazobenzene, and of the photochemical reaction of 2-phenylazobenzo[c]cinnoline. The results of these investigations are now recorded and discussed.

ChemInform Abstract: CLATHRATION OF CIS- AND TRANS-AZOBENZENE BY THE COMPLEX NI(4-METHYLPYRIDINE)4(NCS)2

1973 ◽  
Vol 4 (41) ◽  
pp. no-no
Author(s):  
WIKTOR KEMULA ◽  
ZOFIA BORKOWSKA ◽  
DANUTA SYBILSKA
Keyword(s):  
Cis And Trans ◽  
Trans Azobenzene

ChemInform Abstract: Aliphatic Azo Compounds. Part 15. cis- and trans-Tetracyclopropyl- and Tetra-tertbutylazomethanes.

1986 ◽  
Vol 17 (40) ◽  
Author(s):  
W. BERNLOEHR ◽  
M. A. FLAMM-TER MEER ◽  
J. H. KAISER ◽  
M. SCHMITTEL ◽  
H.-D. BECKHAUS ◽  
...  
Keyword(s):  
Azo Compounds ◽  
Cis And Trans
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