par Lambert, Hasso P.;Martin, Richard
Référence Bulletin des Sociétés chimiques belges, 61, 9-10, page (513-523)
Publication Publié, 1952
Article révisé par les pairs
Résumé : Summary9,10‐dimethyl‐1,2,3,4,5,6‐tribenzanthracene (VII) has been prepared from the corresponding quinone by the method of Sandin and Fieser. A new synthesis of 1,2,3,4,5,6‐tribenzanthraquinone (VI) involving the following steps is described: condensation of phenanthrene‐9,10‐dicarboxylic anhydride (IV) (preparation improved) with 1‐naphthyl‐magnesium bromide [9‐(α‐naphthoyl)‐10‐phenanthroic acid (V)], cyclisation with H3PO4+P2O5 [1,2,3,4,5,6‐tribenzanthraquinone; small yield]. The acetoxy‐lactone (VIII) was isolated after treatment of the crude reaction mixture with acetic anhydride. Other cyclising agents such as C6H5COCl+H2SO4, phthalic anhydride+C6H5COCl, H3BO3+H2SO4 and ClSO3H failed to give the desired quinone. Attempts to cyclise 9‐(β‐naphthoyl)‐10‐phenanthroic acid (IX), an isomere of the above keto‐acid, gave no better results. The oxydation of 1,2,3,4,5,6‐tribenzanthracene with sodium bichromate in acetic acid has been shown to give a mixture of three quinones: 1,2,3,4,5,6‐tribenzanthraquinone (m.p. 250–251°; yield: 52%), an ortho‐quinone (only detected by isolation of the corresponding phenazine) and an ortho‐para‐bisquinone (m.p. 318–320°). Copyright © 1952 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim