Molecular Rearrangements. Part I. The Thermal Rearrangement of the Benzyl Naphthyl Ethers

1972 ◽  
Vol 50 (2) ◽  
pp. 259-262 ◽  
Author(s):  
M. Zarif A. Badr ◽  
H. A. H. El-Sherief
Keyword(s):  
Thermal Rearrangement ◽  
Molecular Rearrangements ◽  
Homolytic Fission

Heating benzyl-β-naphthyl ether at 260° for some days causes benzylic migration to the α-position, together with the formation of β-naphthol, toluene, dibenzyl, and 9-phenyl-1,2,7,8-dibenzoxanthene.Benzyl-α-naphthyl ether rearranges under similar conditions to give 2- and 4-benzyl-1-naphthol, toluene, dibenzyl, and 9-phenyl-3,4,5,6-dibenzoxanthene.Rearrangement of the benzyl-α-naphthyl ether in quinoline gives the normal products of the rearrangement together with 2- and 4-benzylquinolines and 2-quinolyl-1-hydroxynaphthalene. In phenol and in anisole, the rearrangement is accompanied by benzylation of the solvent.It is concluded that the thermal rearrangement of the benzyl naphthyl ethers depends on a homolytic fission of the ether to benzyl and naphthyloxy radicals.

Molecular Rearrangements. Part IV. Aryl (Alkyl) Amines (1), Thermal Rearrangement of N-Benzyl-N-Methylaniline

1974 ◽  
Vol 52 (2) ◽  
pp. 293-298 ◽  
Author(s):  
M. Zarif A. Badr ◽  
M. M. Aly
Keyword(s):  
Free Radicals ◽  
Reaction Mechanism ◽  
Tertiary Amine ◽  
Thermal Rearrangement ◽  
Molecular Rearrangements ◽  
Intermediate Products ◽  
Alkyl Amines ◽  
Rearrangement Process ◽  
Homolytic Fission

Heating N-benzyl-N-methylaniline under reflux or heating at ∼315° in sealed tubes, in the absence of any promotor for 100 h, resulted in its rearrangement, producing methylamine, diphenylmethane, and dibenzyl together with o-toluidine and 4-methylacridine. Heating N-methylaniline in a sealed tube under the same conditions, in absence of any promotor, resulted in its rearrangement, producing methylamine and o-toluidine together with unidentified neutral products.When pyrolysis of the tertiary amine was carried out with quinoline as a solvent, the normal products of rearrangement were obtained together with 2-and 4-benzylquinolines and 2,2′-biquinolyl.The reaction mechanism is discussed on the basis of the products separated, from which it is concluded that the tertiary amine undergoes homolytic fission to benzyl and N-methylphenylamino free radicals, followed by a series of homolytic fissions of initially separated intermediate products, during the rearrangement process. Throughout the whole mechanism, the C—N bonds are the only ones to suffer homolytic fission.

Molecular Rearrangements. Part VI. Aryl(alkyl)amines (II) Thermal Rearrangement of N-Benzylaniline

1975 ◽  
Vol 53 (24) ◽  
pp. 3831-3836 ◽  
Author(s):  
M. Z. A. Badr ◽  
H. A. H. El-Sherief
Keyword(s):  
Free Radicals ◽  
Secondary Amine ◽  
Thermal Rearrangement ◽  
Molecular Rearrangements ◽  
Alkyl Amines ◽  
Trans Stilbene ◽  
Homolytic Fission

Heating N-benzylaniline resulted in migration of the benzyl group to the ortho- and para-positions of the aniline nucleus. Ammonia, toluene, biphenyl, diphenylmethane, dibenzyl, trans-stilbene, aniline, together with 9-phenylacridine, and 2,3-diphenylindole, were also formed.When phenol, quinoline, or isoquinoline were used as solvents, the normal rearrangement products were accompanied by 2- and 4-benzylphenols, 3-benzylquinoline, 2- and 4-(aminophenyl)quinoline, 4-benzylisoquinoline, and 1-(aminophenyl)isoquinolines.It is concluded that the pyrolysis of the secondary amine depends on its homolytic fission to benzyl and phenylamine free radicals. Homolysis of some initially separated products was also observed.

Molecular rearrangements. III. Thermal decomposition of some selected thioesters

1982 ◽  
Vol 60 (22) ◽  
pp. 2870-2875 ◽  
Author(s):  
Aboel-Magd A. Abdel-Wahab ◽  
Ahmed M. El-Khawaga ◽  
Mohamed T. Ismail
Keyword(s):  
Thermal Decomposition ◽  
Acetic Acid ◽  
Benzoic Acid ◽  
Phenylacetic Acid ◽  
Coupling Reactions ◽  
Phenyl Acetic Acid ◽  
Molecular Rearrangements ◽  
Homolytic Fission

Four selected thioesters (1–4) were prepared and pyrolyzed in the absence of promoters either alone or in isoquinoline solvent. These esters include benzyl thiobenzoate (1), phenyl phenylthioacetate (2), benzyl phenylthioacetate (3), and phenyl thiobenzoate (4). Pyrolysis of 1 gave mainly 2,3,4,5-tetraphenylthiophene in addition to benzene, biphenyl, benzyl thiol, and benzoic acid. Thermal decomposition of 1 under nitrogen gave benzaldehyde, benzil, and only a trace of benzoic acid in addition to the former products. Compound 2 afforded essentially toluene and dibenzyl in addition to benzene, biphenyl, phenyl sulphide, thiophenol, and phenyl acetic acid. Thermolysis of 3 gave toluene and stilbene beside small quantities of benzyl thiol and phenylacetic acid. Finally, thermal decomposition of 4 in isoquinoline gave benzene, biphenyl, phenyl sulphide, thianthrene, thiophenol, benzoic acid, and 1-phenylisoquinoline. H2S and CO are also produced in all cases. In these rearrangements, the C—S bonds undergo homolytic fission either simultaneously or selectively. No isomer redistribution precedes the coupling reactions. Plausible mechanisms for the above facts are proposed.

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