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. 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. 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.

scholarly journals Opinion to: Design, Synthesis, Antimicrobial, and Antioxidant Activities of Novel {4,5-(substituted diphenyl)-4H-1,2,4-triazol-3-ylthio}acetyl Chloride

2019 ◽  
Vol 16 (11) ◽  
pp. 817-821
Author(s):  
Khamid U. KHODJANIYAZOV ◽  
Kohei TORIKAI
Keyword(s):  
Acid Chloride ◽  
Spectroscopic Data ◽  
Acetyl Chloride ◽  
Antimicrobial Agents ◽  
Antioxidant Activities ◽  
Acid Chlorides ◽  
Design Synthesis ◽  
Design And Synthesis ◽  
Mechanistic Insight

To discover novel triazole-based antimicrobial agents, design and synthesis of acid chlorides possessing a 1,2,4-triazole core was reported in this journal in 2018. However, we found that the reported spectroscopic data did not show any agreement with the proposed acid chloride structure. Herein, we described our opinion, which was supported by IR data, circumstantial evidences, and mechanistic insight, that the products obtained in the topical paper would be thioesters.

Photochemical reactions of azo compounds. III. Photochemical cyclodehydrogenations of substituted azobenzenes

1964 ◽  
Vol 17 (9) ◽  
pp. 1036 ◽  
Author(s):  
GM Badger ◽  
RJ Drewer ◽  
GE Lewis
Keyword(s):  
Carboxylic Acid ◽  
Sulphuric Acid ◽  
Photochemical Reactions ◽  
Azo Compounds ◽  
Methyl Substituent ◽  
Acid Lactone

2,4,6-Trimethylazobenzene has been shown to undergo photochemical cyclodehydrogenation in sulphuric acid to give 2,4-dimethylbenzo[c]cinnoline and 1,2,4-trimethylbenzo[c]cinnoline. The formation of the former involves cyclization with the loss of a methyl substituent : the formation of the latter involves cyclization with the migration of a methyl substituent. The reaction involves a photochemical disproportionation: 4-(4-aminophenyl)-2,4,6-trimethylcyclohexa-2,5-dienone was also isolated, having been formed by acid-catalysed rearrangement (and hydrolysis) from 2,4,6-trimethylhydrazobenzene. Substituted azobenzenes having a carboxy, iodo, or chloro substituent in the 4-, 3-, or 2-position have also been irradiated and the resulting benzo[c]cinnolines and benzidines isolated and characterized. Irradiation of 2-substituted azobenzenes has been found to give the parent benzo[c]cinnoline as well as the 4-substituted benzo[c]-cinnoline, showing that carboxy-, iodo-, and chloro-substituents can be ejected as well as methyl substituents. The irradiation of azobenzene-3-carboxylic acid has given 1-hydroxybenzo[c]cinnoline-10-carboxylic acid lactone in addition to benzo[c]-cinnoline-3-carboxylic acid.

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