Study of the mechanism of cyclisation in the preparation of dioxazines and developments of synthetical methods based upon the results

Abstract

The work was roughly divided into two sections. The first involved the preparation of known triphenodioxazine pigments and the purification and examination of their properties which had not been hitherto carried out. Much adaption of existing methods for the preparation of 1-aminopyrene and 3-aminocarbazole was required in order to prepare them pure in large quantities. 3-Amino-9-ethylcarbazole was prepared pure in large quantities, its melting point considerably elevated above that given in the literature. The arylaminoquinones and triphenodioxazines were prepared from the condensation of chloranil with the given amines: - 1-aminppyrene, 3-amino-9-ethylcarbazole, 3-aminocarbazole and 4-aminodiphenylamine; the triphenodioxazines from the latter two not-being obtained in a pure state.

The second part of the work involved making 6,13- dichlorotriphenodioxazine, 6-chlorotriphenodioxazine, and triphenodioxazine, by the adoption of existing methods and also attempting new methods of preparation. The preparation and purification of 2,5-dianilino-3,6-dichloro- 1,4-benzoquinone, 2,5-dianilino-3-chloro-1,4-benzoquinone, and 2,5-dianilino-l, 4-benzoquinone was carried out and these products were subjected to various thermal experiments. The technique of thin layer chromatography was developed and proved a valuable tool for the identification and quantitative estimation of the products formed during the various described reactions.