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Tricyclic compounds with an imidazolinone ring fused to 1,2- and 1,4-naphtoquinones were synthesized by a reaction of 4-amino-1,2-naphthoquinone and 2-amino-1,4-naphthoquinone with electrophilic symmetric and non symmetric diazenes.

Tricyclic compounds with an imidazolinone ring fused to 1,2- and 1,4-naphtoquinones were synthesized by a reaction of 4-amino-1,2-naphthoquinone and 2-amino-1,4-naphthoquinone with electrophilic symmetric and non symmetric diazenes.

Conjugated phenylazoalkenes add anionic reagents to give 2-substituted anti phenylhydrazones, as demonstrated by 1 H NMR spectroscopy and, in some cases, by comparison with authentic samples.

Conjugated phenylazocycloalkenes sterically hindered towards the antiparallel attach react with PhMgBr via parallel attack, to givesyn-phenylhydrazones. When such a sterical hindrance is absent in the azoalkenes, the reaction occurs via antiparallel attack even when the arylmagnesium bromide bears a particularly hindering aryl group. The conformation of thesyn-phenylhydrazones obtained by the above reactions and those of the corresponding ketones are discussed with the aid of the benzylic proton NMR analysis.

The heterocyclization reaction of arylsulfonylhydrazones from alkyl substituted 1,2-cyclohexanediones is sensitive to the steric requirements of the alkyl groups. A mechanism for the cyclization in acidic medium is also reported.

Conjugated phenylazoalkenes react with aliphatic amines to give mixtures of syn - and anti -phenylhydrazones, the composition of which is solvent dependent. A mechanism for these reactions is proposed. The structures of the products were determined by spectroscopic methods.

The aromatic arylation of ortho-substituted azobenzenes with phenylmagnesium bromide has been investigated. 2,2′-Disubstituted symmetric azobenzenes do not undergo the reaction. 2-Methoxy-6-methyl- and 2-methoxy-2′-methyl-azobenzene give 2-phenyl-6-methyl- and 2-methoxy-2′-methyl-6′-phenyl-azobenzene, respectively. Comparison of the behaviour of 2-methyl-, 2-ethyl- and 2-phenyl-azobenzenes shows that the larger the substituent in the azo derivative, the lower the reactivity of the latter towards arylation. The results obtained support the mechanism previously reported.

The heterocyclization reaction of arylsulfonylhydrazones from alkyl substituted 1,2-cyclohexanediones is sensitive to the steric requirements of the alkyl groups. A mechanism for the cyclization in acidic medium is also reported.

A synthesis of the title compounds with the substituents at C-2 and C-6 trans to each other is described. 2-Aryl-cyclohexanones were converted into 1-phenylazo-6-arylcyclohexenes, which by reaction with Grignard reagents led to trans-2,6-diaryl- and trans-2-alkyl-6-aryl-cyclohexanone phenylhydrazones. These compounds by oxidative hydrolysis furnished the corresponding trans-ketones, which were readily epimerised into the more stable cis-isomers.

4-Methyl- and 4-t-butyl-1-arylazocyclohexenes react with aliphatic and aromatic Grignard reagents, to furnish, after oxidative hydrolysis of the intermediate aryihydrazones, 2-alkyl-4-methyl-, 2-aryl-4-methyl-, 2-alkyl-4-tbutyl-, and 2-aryl-4-t-butyl-cyclohexanones, with a trans-configuration. From the reactions with o-tolyl- and α-naphthyl-magnesium bromide only the cis-isomers were obtained. The structures of the products were, determined by spectroscopic methods and by epimerization of the trans-cyclohexanones into the more stable cis-isomers.