Reaction of azulenes with derivatives of aromatic dicarboxylic acids

The reaction of azulenes with phthalic and naphthalene-1,8-dicarboxylic acid derivatives was investigated. Working with acids dichloride in the presence of Lewis acids (SnCl4 and AlCl3) the obtained products were gem-di-(azulen-l-yl)-lactones, di-(1-azulenoyl) ketones and (1-azulenoyl)-carboxylic acids. The reaction of phthalic anhydride in the same conditions occurred with low yields affording only corresponding lactone whereas the naphthalic anhydride was recovered unreacted. The Vilsmeier reaction of azulenes with both diamides failed. The reaction route starting from the dichloride was discussed.