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. XVII Photoinduced reaction of 2,2,4,4,-tetrachloroazobenzene with acetyl chloride

1976 ◽  
Vol 29 (8) ◽  
pp. 1713 ◽  
Author(s):  
GE Lewis ◽  
RJ Mayfield
Keyword(s):  
Oxidation Product ◽  
Potassium Hydroxide ◽  
Acetyl Chloride ◽  
Main Product ◽  
Side Reaction ◽  
Photochemical Reactions ◽  
Azo Compounds ◽  
Photoinduced Reaction

The photoinduced reaction of 2,2',4,4'-tetrachloroazobenzene with acetyl chloride has been found to give an unexpected mixture of products, incorporating only a relatively poor yield of the predicted main product, N,N '-diacetyl-2,2',4,4',6-pentachlorohydrazobenzene. It has been found, moreover, that the latter compound in aqueous methanolic potassium hydroxide, in addition to yielding the expected hydrolysis/oxidation product, 2,2',4,4',6-pentachloroazobenzene, undergoes an interesting side reaction which regenerates 2,2',4,4'-tetrachloroazobenzene.

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. XVI. Reactions with acetyl chloride leading to Di-, Tri-, and Tetra-chloroazobenzenes

1968 ◽  
Vol 21 (6) ◽  
pp. 1601 ◽  
Author(s):  
GE Lewis ◽  
RJ Mayfield
Keyword(s):  
Acetyl Chloride ◽  
Photochemical Reactions ◽  
Azo Compounds

A previously reported method for converting azobenzene into 4-chloroazobenzene (via N,N'-diacetyl-4-chlorohydrazobenzene) has been extended to the preparation of di-, tri-, and tetra-chloroazobenzenes.

Photochemical reactions of azo compounds. VII. Studies of the photochemical reactions of azobenzene under various acidic conditions

1966 ◽  
Vol 19 (8) ◽  
pp. 1445 ◽  
Author(s):  
GE Lewis ◽  
RJ Mayfield
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Sulphuric Acid ◽  
Photochemical Reaction ◽  
Acetyl Chloride ◽  
Photochemical Reactions ◽  
Aluminium Chloride ◽  
Azo Compounds ◽  
High Yield ◽  
Acidic Conditions

An investigation has been made of the photochemical and dark reactions of azobenzene in acetic acid-ferric chloride and acetic acid-aluminium chloride mixtures for comparison with the corresponding reactions of azobenzene in sulphuric acid. The photochemical reactions resulted in cyclodehydrogenation of azobenzene to benzo[c]cinnoline, and small quantities of reduction products of azobenzene were also isolated. The formation of reduction products was again observed in the dark reactions, but there was no sign of cyclodehydrogenation. The significance of these observations is now discussed. Irradiation of azobenzene in acetyl chloride, or in acetic anhydride containing hydrogen chloride, resulted in a novel photochemical reaction in which NN?-diacetyl-4-chlorohydrazobenzene was formed in high yield.

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.

Photochemical reactions of azo compounds. X. Photochemical properties of azobenzene-2-carboxylic acids

1967 ◽  
Vol 20 (5) ◽  
pp. 929 ◽  
Author(s):  
CP Joshua ◽  
GE Lewis
Keyword(s):  
Hydrogen Bonding ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
Intramolecular Hydrogen Bonding ◽  
Photochemical Reactions ◽  
Azo Compounds ◽  
Neutral Compounds ◽  
Methyl Derivatives ◽  
Intramolecular Hydrogen ◽  
Derivatives Of

Two chloro and two methyl derivatives of azobenzene-2-carboxylic acid have been found to yield the corresponding derivatives of benzo[c]cinnoline-4- carboxylic acid in good yields when irradiated in 98% sulphuric acid. The question of intramolecular hydrogen bonding in relation to the properties of azobenzene-2-carboxylic acids is discussed. Infrared absorption spectra of the neutral compounds have provided confirmation of internal hydrogen bonding. Attempts to prepare the cis isomers of these azo compounds have been unsuccessful.

Oxidations with iodosobenzene diacetate. X. The Oxidation of 3 (or 6)-Substituted-2-nitroanilines

1958 ◽  
Vol 11 (4) ◽  
pp. 491 ◽  
Author(s):  
LK Dyall ◽  
KH Pausacker
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Sodium Hypochlorite ◽  
Potassium Hydroxide ◽  
Acetic Acid Solution ◽  
Azo Compounds ◽  
New Methods ◽  
Lead Tetra Acetate

The oxidation of eight 3(or 6)-substituted-2-nitroanilines with iodosobenzene diacetate, in both benzene and acetic acid solution, has been investigated. Benzo-furazan oxides and azo compounds were produced in varying yields. Certain of these amines have also been oxidized with iodosobenzene diacetate in other solvents, and with sodium hypochlorite in ethanolic potassium hydroxide. Six of these 3(or 6)- substituted-2-nitroanilines have been oxidized with lead tetra-acetate, in both benzene and acetic acid solution, and varying yields of azo compounds were obtained. Benzaldehyde was isolated from the oxidation of benzylamine with iodosobenzene diacetate, in either benzene or acetic acid solution. The mechanisms of these reactions are discussed. New methods of synthesizing 6-methoxy-2-nitroaniline and 3-methoxy-2-nitroaniline are described.

Photochemical Reactions of Primary Aromatic Amines with Chloromethanes in Solution. I. Spectrochemical Studies

1989 ◽  
Vol 44 (12) ◽  
pp. 1585-1588 ◽  
Author(s):  
Wojciech Boszczyk ◽  
Tadeusz Latowski
Keyword(s):  
Hydrogen Chloride ◽  
Stability Constants ◽  
Aromatic Amines ◽  
Photochemical Reactions ◽  
Quantum Yields ◽  
Excited Singlet ◽  
Singlet States ◽  
Primary Aromatic Amines ◽  
Excited Singlet States ◽  
Induced Reaction

Interactions were studied of aniline, 4-methoxyaniline and 4-ethoxyaniline with tetrachloromethane, chloroform and dichloromethane in their ground and first excited singlet states. Stability constants of the complexes of these amines with the chloromethanes in cyclohexane were determined as well as their quantum yields of fluorescence in this solvent. The quenching of fluorescence of aniline and its derivatives by the chloromethanes was ascertained and characterized. Quantum yields of the formation of hydrogen chloride, ψΗCl, were measured during photochemically induced reaction of the amines in tetrachloromethane, chloroform and dichloromethane.

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