The cyclic voltammetry behavior of a series of five 1-substituted azulenes has been investigated as well as the electrochemical chlorination of these compounds. In the case of azulene compounds containing electron withdrawing groups which have higher oxidation potentials than that of the chloride ion, the electrochemical chlorination led usually to 3-chloro derivatives. The electrochemical chlorination fails for azulenes with lower oxidation potentials.

Some 3-substituted 4-(azulene-1-yl)-2,6-diphenyl-azulene are prepared from their corresponding pyranylium perchlorates or directly from 3-chloro-2,6-diphenyl-pyridine. Their physical and chemical properties are discussed

The synthesis of 4-azulene-substituted 2,6-diphenyl- and 2,6-dimethyl-pyranylium salts and 2-azulene-substituted 4,6-dimethyl-pyranylium salts by nucleophilic substitution at pyranylium moiety with various azulenes was studied. The starting materials for 2,6-diphenyl derivatives were 4 chlorinated pyranylium salts. They were obtained by the halogenation with PCl5 of corresponding pyranones and were used either in situ or after separation. For the

Pathways for the solvent-free condensation between Schiff Bases and methylenic compounds are discussed taking into account the reported mechanistic purposes and new experimental data.

Azulenic β-diketones were synthesized in the reaction of different β-diketones with 1-azulenecarboxylic acid chloride, in the presence of MgCl2 and pyridine, as a result of condensation and subsequent acyl elimination. The obtained dicarbonyl compounds were used for the generation of azulenic pyrazoles and isoxazoles. The structure and some physico-chemical properties of the obtained products were reported.

NMR spectra of azulen-1-yl diazenes, Schiff bases and corresponding ethenes are discussed in order to find the correlation between the compound structures and the chemical shifts of the protons or carbon-13. Some of the above-cited compounds were protonated and the modification in chemical shifts produced by this process was investigated.

The coupling between diazonium salts obtained from the three aminopyridine 1-oxides and azulene allowed the synthesis in good yield of the corresponding azulene-1-azopyridine 1'-oxides, which were characterised. The reduction and the methylation of the products were studied. The last two reactions allowed to synthesize azulene-1-azo-2'-pyridine and its alkylpyridinium salts, unavailable on other way. The UV-vis spectra of azulene-1-azopyridines were

A MOPAC program using the AM1 and PM3 methods was used for the calculation of the charge densities, free valences indexes and electrophilic Fukui indexes for N-substituted pyridindiazonium salts. The results enable us to anticipate their stability and their coupling capacities with aromatic amines and phenols. Our anticipations were experimentally confirmed in most cases.

The purpose of this paper is to offer a short and systematic review of the variety of nucleophilic aromatic substitution and to explain the differences between the reactivity of aromatic substrates in order to find the best conditions for these transformations. In spite of the fact that nucleophilic aromatic substitution is a transformation thermodynamically allowed, it is kinetically forbiden by the antiaromatic transition states that develop by

The investigation of azulene-1-azopyridines alkylation at pyridine nitrogen with several dihalogeno derivatives leaded to a protocol for the generation in good yields of bis-pyridinium salts with interesting structures and properties.